APPENDIX K DRO AIRPORT WATER AND WASTEWATER MASTER PLAN

Transcription

1 APPENDIX K DRO AIRPORT WATER AND WASTEWATER MASTER PLAN

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3 Durango-La Plata County Airport Water and Wastewater Master Plan Prepared for: Jviation, Inc. 900 S. Broadway, Suite 350 Denver, CO Wright Water Engineers, Inc. November

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5 TABLE OF CONTENTS Page 1.0 EXECUTIVE SUMMARY WATER DEMANDS AND WASTEWATER FLOWS Existing Water Demands Metered Water Use Enplanements Water Demand per Enplanement Future Water Demands Aviation-Related Uses Non-Aviation Commercial Uses Total 2035 Projected Water Demand Existing Wastewater Flows Future Wastewater Demands WATER RIGHTS Potable System Water Rights Non-Potable Irrigation Water Rights NON-POTABLE WATER ALTERNATIVES Summary Raw Water for Irrigation Graywater Reuse Wastewater Reuse EXISTING TREATMENT SYSTEMS Summary Existing Water Treatment Facilities Summary of Water Treatment Distribution Infrastructure Capacities, Configurations and General Conditions i

6 5.2.3 Existing Excess Water Treatment Capacity Existing Wastewater Treatment Facilities Summary of Wastewater Treatment Infrastructure Effluent Discharge Limits Capacities, Configurations and General Conditions Existing Excess Wastewater Treatment Capacity FUTURE EXPANSION NEEDS Location of Terminal and Water/Wastewater Impacts Alternatives 1 and Alternative Future Improvements, Triggers and Timelines Water Treatment Facilities Improvements Wastewater Treatment Facilities Improvements OPINION OF PROBABLE CAPITAL COSTS Recommended Improvements to Existing Facilities Improvements to Existing Facilities/Systems to Monitor Required Improvements to Meet Future Demand POTENTIAL FUTURE REGIONAL WATER AND WASTEWATER SYSTEMS ii

7 TABLES TABLE 1 Metered Water Usage TABLE 2 Durango-La Plata County Airport Enplanements TABLE 3 Aviation-Related Water Use per Enplanement TABLE 4 TABLE 5 TABLE 6 TABLE 7 TABLE 8(a) TABLE 8(b) TABLE 9 TABLE 10 TABLE Projected Enplanements 2035 Projected Water Demands (Aviation-Related Uses) 2035 Projected Water Demands (Non-Aviation Commercial Uses) Wastewater Treatment Plant Effluent (Aviation-Related Discharge) Wastewater Treatment Plant Effluent per Enplanement (Aviation Only) Daily Airport Wastewater Effluent Flows (All Uses) 2035 Projected Water Demands and Wastewater Treatment Plant Effluent Durango-La Plata County Airport Water Rights for Potable Water Supply Durango-La Plata County Airport Water Rights for Irrigation Uses FIGURE 1 Monthly Enplanements FIGURES FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 5 FIGURE 6 Water and Wastewater Treatment Demands Over Time Existing Water and Wastewater Treatment Infrastructure Existing Facilities Treatment Process Flow Diagram La Plata Archuleta Water District Boundary La Plata Archuleta Water District - Preliminary Pipeline Routing & Distribution System APPENDICES A Durango-La Plata County Airport Water and Wastewater Raw Data B C D E Durango-La Plata County Airport Enplanement History and Projections CDPHE Alternative Filtration Acceptance Letter Wastewater Treatment Lagoon Preliminary Temperature and Nitrification Calculations Glossary of Acronyms iii

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9 DURANGO-LA PLATA COUNTY AIRPORT WATER AND WASTEWATER MASTER PLAN AMENDMENT A The growth rate for DRO s projected enplanements through 2035 has been reduced from 3.5% to 3.3%. The Durango-La Plata County Airport Water and Wastewater Master Plan was prepared using the growth rate of 3.5%. The estimates of future water and wastewater usage are based on these projected enplanements. These estimates are used to provide a target date for upgrading these systems to accommodate the increased demand. With the reduction in the projected enplanements the target timeframes for system upgrades may occur later. The actual enplanements will need to be monitored to determine the timing for the recommended upgrades based on the enplanement triggers. Date of Amendment A: October 19, 2015 iv

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11 DURANGO-LA PLATA COUNTY AIRPORT WATER AND WASTEWATER MASTER PLAN 1.0 EXECUTIVE SUMMARY Wright Water Engineers, Inc. (WWE) prepared this Water and Wastewater Master Plan for the Durango-La Plata County Airport (Airport) as a companion document to Jviation, Inc. s (Jviation) planning for the Airport s future growth and expansion through the year WWE s planning evaluated the water and wastewater treatment infrastructure and capacities. The evaluation of water distribution and wastewater collection systems infrastructure will be included in Jviation s overall site and utilities engineering planning. Future growth scenarios presented in this Master Plan include projected growth in enplanements and evaluation of the water and wastewater treatment needed to meet the expansion, replacement, or relocation of the existing terminal. WWE observed the existing treatment facilities, consulted with Airport staff, Colorado Department of Public Health and Environment (CDPHE) engineering staff and CDPHE documents and reviewed design drawings and reports related to the treatment facilities. The Airport s existing water treatment system consists of one spring, an infiltration gallery that was recently expanded, Lower Pump House and Raw Water Storage Tank, Upper Pump House (two jockey pumps), membrane filtration system, chlorine feed system, two fire pumps, and two treated water storage tanks with a total capacity of 144,000 gallons. The wastewater treatment facility consists of a three-cell aerated lagoon system. The facility is relatively new, constructed in 2006 and is well operated and is in good condition. WWE established water demands and wastewater flows treatment for existing conditions, and developed per-enplanement flow factors for future growth forecasts using projections of enplanements through These existing and future water demands and wastewater flows also include non-aviation commercial facilities that are served by the airport. WWE calculated existing excess treatment capacities and assessed the future water demand and wastewater flow forecasts for the need to expand treatment facilities Wright Water Engineers, Inc. Page 1 November 2014

12 Durango-La Plata County Airport Water and Wastewater Master Plan Based on the evaluation presented in this Master Plan, to meet 2035 potable water demands, the potable water treatment facility will either require expansion or connection to the La Plata Archuleta Water District. The existing wastewater treatment facility is adequate to meet both existing and 2035 calculated flows. The specific water demands and wastewater flows determined for the Master Plan are summarized in the following table, in gallons per day (gpd) unless otherwise noted: Wright Water Engineers, Inc. Page 2 November 2014

13 Durango-La Plata County Airport Water and Wastewater Master Plan POTABLE WATER AND WASTEWATER SUMMARY TABLE Enplanements 2013 Enplanements 192,000 Projected 2035 Enplanements, using annual 3.5% Growth Factor 411,900 Existing Potable Water Demand Existing Annual Average Day Aviation Use Existing Annual Average Day All Uses (Aviation and Non-Aviation Commercial) Existing Maximum Month, Average Day All Uses Existing Maximum Day (1.2 Peaking Factor) All Uses Existing Water Treatment Capacity Existing Excess Water Treatment Capacity 20 gal/enplanement 11,400 gpd 15,200 gpd 18,200 gpd 33,000 gpd 14,800 gpd Projected 2035 Potable Water Demand Projected Annual Average Day Aviation Use Projected Maximum Month Average Day Aviation Use Projected Annual Average Day All Uses Projected Maximum Month Average Day All Uses Projected Maximum Day (1.2 Peaking Factor) All Uses Projected Maximum Day Treatment with 20% Safety Factor All Uses 22,300 gpd 25,000 gpd 27,500 gpd 31,500 gpd 37,800 gpd 45,400 gpd Existing Wastewater Flows Existing Annual Average Day Aviation Use 10.5 gal/enplanement Existing Annual Average Day All Uses 7,000 gpd Existing Maximum Month, Average Day All Uses 9,400 gpd Existing Wastewater Treatment Hydraulic Capacity Existing Excess Hydraulic Capacity 25,000 gpd 15,600 gpd Projected 2035 Wastewater Flows Projected Annual Average Day Flows All Uses Projected Maximum Month Average Day Flows All Uses Projected Excess Capacity 15,800 gpd 18,300 gpd 6,700 gpd The engineering team considered three locations of the future terminal and the impacts to the water and wastewater treatment facility locations. Jviation assessed three terminal locations: remodel the existing terminal, build a new terminal just north of the existing terminal, or abandon the existing terminal and build a new terminal facility on the east side of the Airport Wright Water Engineers, Inc. Page 3 November 2014

14 Durango-La Plata County Airport Water and Wastewater Master Plan property. In all three cases, the engineering team recommends maintaining the locations of the existing water and wastewater treatment plants for future service. WWE identified improvements and estimated study level planning costs for these improvements. Additionally, based on the growth projections used in this Master Plan, the water treatment infrastructure will require capacity expansion to meet 2035 water demands. Conversely, the existing wastewater treatment system is adequate for both existing flows and the 2035 future discharge forecasts. The Airport appears to have adequate water rights on an instantaneous basis and on a monthly basis to meet the calculated year 2035 water needs. There has not been a call on the lower Florida River. If a call by a senior water right were to occur, the Airport does not currently have means of replacing depletions in the non-irrigation season (i.e. October through April). Therefore, in the event of a future call during the non-irrigation season, WWE recommends that the Airport develop adequate augmentation supply through construction of reservoirs or contracting with the Florida Water Conservation District for water releases. Development of augmentation supply may require future permitting or water court actions and should include evaluation of potential water service by La Plata Archuleta Water District. WWE evaluated the opportunity for non-potable water use. The Airport currently irrigates approximately 10 acres with non-potable water and we recommend that this system continue to be used in the future. While graywater and wastewater reuse are potential water sources for irrigation, these are neither necessary nor recommended for the Airport given the existing irrigation system use and water rights status. WWE recommends several improvements to the existing water treatment infrastructure to address equipment service life, improved operations and increased water efficiency, as shown in the table below. For planning purposes, implementation of these improvements should be considered within approximately one to five years Wright Water Engineers, Inc. Page 4 November 2014

15 Durango-La Plata County Airport Water and Wastewater Master Plan Improvement 10,000 to 12,000-gallon Buried Lower Pump House Water Storage Tank Telemetry improvements from the Lower Pump House to the infiltration gallery pump Estimated Cost $160,000 $20,000 Replacement micro-filtration (MF) membrane modules $7,500 Engineering study to evaluate the treatment alternatives for lowering the concentrations of Disinfection by Products (DBPs) $35,000 Option of GAC treatment process to address DBPs $110,000 WWE also recommends maintenance on the existing infiltration gallery and an option to improve the existing facilities at the infiltration gallery. The Airport should perform backwashing of the gallery, which should improve the production rate. If the water production of the infiltration gallery does not increase to acceptable levels after the recommended maintenance, an option would be to construct a surface water intake on the Florida River to convey water to the water treatment system. Option of Surface water intake from the Florida River $215,000 Additional water treatment capacity will be required to meet the 2035 forecasted water demands, operational by the year Replacement Membrane Treatment Skid with increased capacity $420,000 An alternative to additional treatment capacity to meet increasing future demands may be to participate with the La Plata Archuleta Water District, a regional municipal water service provider, which is projected to expand service to the Airport area by the year WATER DEMANDS AND WASTEWATER FLOWS WWE calculated existing water demands and wastewater flows for the Airport using data provided by Airport staff (Appendix A). WWE calibrated these existing flows to a per enplanement flow-factor basis from enplanement data provided by Jviation for the same years Wright Water Engineers, Inc. Page 5 November 2014

16 Durango-La Plata County Airport Water and Wastewater Master Plan (Appendix B). Using enplanement forecasts for the Airport expansion planning from Jviation, WWE applied the per enplanement flow-factor and estimated future flows for a twenty-year planning horizon to year WWE defined the service area for the Airport expansion to include aviation-related uses and existing non-aviation commercial space currently served by the Airport s potable water and wastewater systems. Aviation-related uses include all terminal and general aviation uses, such as car rental agencies, general aviation private hangers, existing restaurant use, and other domestic uses in the Airport. Future water demand and wastewater flow forecasts for the expanded Airport assumed proportionate use for the associated aviation-related services (i.e. the future water demands and wastewater flows are assumed to increase at a rate equal to, and consistent with, future enplanement estimates). This includes expanded restaurant service(s), car rental facilities, private hangers, and sanitary facilities. The existing non-aviation commercial water use served by the Airport currently consists of an office complex, a warehouse, and limited outdoor irrigation. WWE projected the 2035 water and wastewater service for these non-aviation facilities assuming full employee occupancy conditions for the existing buildings only. At the direction of Airport personnel, for the purposes of this master plan, WWE excluded the potential for future off-site, commercial and industrial expansion of the Airport service area. If these types of expanded uses arise in the future, they will need to be evaluated separately for water demands and wastewater flows and the availability of water and wastewater services within the constraints and capacities of the Airport s water and wastewater treatment systems. Outdoor irrigation at the Airport is currently provided from a non-potable irrigation system that is separate from the Airport s potable water supply. For the future Airport expansion scenarios, WWE assumed that this non-potable irrigation system would continue to be utilized and that the need to use potable water for outdoor irrigation would not be required (other than the limited outdoor irrigation at the existing non-aviation commercial space serviced by the Airport) Wright Water Engineers, Inc. Page 6 November 2014

17 Durango-La Plata County Airport Water and Wastewater Master Plan Fire flows for the expanded airport terminal building had not been defined at the time of this planning. When these updated fire flows (flow rate, time duration, and corresponding storage volume) are determined, the potential for additional water storage and possibly fire flow pumps will need to be assessed and incorporated in this planning. WWE assessed existing and future water demands flows to address annual demand, peak month, and peak day to account for overall source supply adequacy, storage requirements and treatment process capacity. The existing water demands are addressed in Section 2.1, with future water demands discussed in Section 2.2. Existing and future wastewater flows are addressed in Sections 2.3 and 2.4, respectively. 2.1 Existing Water Demands Building upon previous water supply work that WWE has performed for the Airport, several tables were updated and prepared for the water treatment facility with respect to existing use and future demands. These tables are provided at the end of this report, and summarized below Metered Water Use Airport personnel provided WWE with the metered water use from 2011 through The existing use was evaluated for the aviation and non-aviation existing commercial spaces on a monthly and annual basis (see Table 1). For the three-year period, the average annual water use was 4,200,000 gallons and the average water use was 11,400 gpd. The average day use for the maximum month during this period was 15,200 gpd. The water treatment plant capacity is 33,000 gpd, as discussed in further detail in Section 5. The peaking factor for maximum day is 1.2, which results in an estimated current peak day planning demand of approximately 18,200 gpd. This results in a current excess capacity of 14,800 gpd for the water treatment processes Enplanements Jviation personnel provided WWE with the number of enplanements recorded at the Airport from 2011 through 2013 (Appendix B). Over this time period, there was an increasing number of enplanements corresponding to the increase in the total metered water use. Table 2 shows the Wright Water Engineers, Inc. Page 7 November 2014

18 Durango-La Plata County Airport Water and Wastewater Master Plan enplanements for the three-year period and the proportion of enplanements by month, and illustrates the seasonal demand patterns at the Airport. The average annual increase in enplanements was 4.75%. The peak demand months are July and August, as shown by the Enplanements by Month graph (Figure 1). Specific data on the daily fluctuations of enplanement or load factors for the Airport were not available to WWE; however, WWE investigated this on the basis of existing flights per day and discussed with Airport staff on the general daily load factor variations. While flights are generally consistent on a daily basis, there is a slight load factor increase with Mondays and Fridays being the busiest load days at the Airport. This information was used to develop an estimate of a peaking factor of 1.2 for the peak day water demand (see Section for further discussion of peaking factor) Water Demand per Enplanement WWE calculated water use per enplanement for aviation-related use on a monthly basis for (Table 3). The average existing water use per enplanement was approximately 20 gallons for all Airport water use. This includes general aviation, sanitary facilities, car rentals, and the restaurant. Water use per enplanement does not include the water service to the nonaviation commercial office and warehouse facilities. The average existing monthly water use per enplanement fluctuates somewhat. This fluctuation may be attributed to such activities as exercising fire hydrants, the occasional demand imposed by fire flows, and water used for deicing purposes. Over the course of the three-year period, the water used also has increased, from approximately 18 gallons to 21.5 gallons per enplanement. This increase may be due to changes in water treatment to address water quality issues. These water quality issues are past excursions of Disinfection By-Products (DBPs) that have been successfully addressed by Airport staff via occasional flushing of stored water out of fire hydrants in the distribution system. Table 4 provides enplanements for and projected enplanements for the 20-year planning horizon to the year Using the Preferred Forecast 3.5% per annum increase, total Wright Water Engineers, Inc. Page 8 November 2014

19 Durango-La Plata County Airport Water and Wastewater Master Plan annual enplanements are forecast to approximately double from 191,980 in 2013 to 411,923 in Future Water Demands Aviation-Related Uses WWE developed the 2035 projected water demand by month for aviation-related uses based on the forecasted 2035 enplanements and average existing water use per enplanement. WWE applied the average existing water use per enplanement for each month to forecast water demands through the year The monthly water demands forecast for 2035 are shown in Table 5. The year 2035 average day water demand for aviation-related development is approximately 22,300 gpd, increasing to nearly 25,000 gpd average day during the maximum water demand month of November Non-Aviation Commercial Uses WWE calculated the existing water use at full employee occupancy for the commercial facilities currently serviced by the Airport (Table 6). This calculation assumed 250 employees in the office space and 10 employees in the warehouse space. The unit water use factor for this commercial and warehouse space was assumed to be 15 gallons per employee per day. A potable water outdoor irrigation use of a calculated 0.6 acres of turf grass was assumed these facilities. During peak month use in July (summer irrigation season), the calculated existing total demand of the non-aviation commercial facilities was 7,800 gpd Total 2035 Projected Water Demand The projected 2035 water demand for the Airport, non-aviation commercial indoor, and irrigation uses is shown on Table 9 (along with the forecasted wastewater treatment capacity required, discussed in Section 2.4). The calculated average day water demand for 2035 is 27,500 gpd and the calculated maximum month average day is 31,500 gpd. A peaking factor of 1.2 for maximum day was also applied to account for the maximum day within the peak month average day to result in a required daily treatment capacity of 37,800 gpd. WWE also recommends building a safety factor of 20% into the treatment capacity, so the calculated required treatment Wright Water Engineers, Inc. Page 9 November 2014

20 Durango-La Plata County Airport Water and Wastewater Master Plan capacity for 2035 is 45,400 gpd. The safety factor is important to provide a conservative estimate on the planning numbers and so that maximum day demands can be met without the need to run the treatment equipment at its full load capacity for a full 24-hour basis. The peak day forecast of 37,800 gpd compares to the existing treatment capacity of 33,000 gpd. Therefore, if the 3.5% annual enplanement increase is realized, the water treatment capacity will need to be expanded prior to Water treatment system future expansion needs are discussed in detail in Section 6. This growth is also shown graphically on Figure 2. Figure 2 shows trend lines for the upper projected growth in enplanements of 3.5% and a trend line for a lower boundary growth projection of 1.9%. Note that if the lower growth of 1.9% is realized, treatment expansion will not be necessary. 2.3 Existing Wastewater Flows WWE used data provided from Airport personnel to compare wastewater treatment flows to the metered potable water use and to develop flow factors per enplanement for future wastewater treatment capacity forecasting. Table 7 compares the metered water use and wastewater treatment plant effluent for aviation use from 2011 through Metered wastewater flows that occur during the low flow time periods when occupancy and use is low, such as during the overnight periods, are less accurate than daytime metered recordings. For this reason, the Airport wastewater operators have made an effort to calibrate the flow meters as accurately as possible since July The Airport wastewater operators have reported that meter readings since July 2012 should be considered more accurate than previous readings. Generally, the metered wastewater treatment effluent flows represent approximately 53% of the metered water use. The difference is typically higher during the summer time periods when outdoor irrigation is occurring and lower during the winter months. In the case of the Airport, the difference is also influenced somewhat by flushing water from hydrants to address water quality issues. It is noted that WWE did not perform a water audit as part of this Master Plan, and it is possible there could be water leaks or other unaccounted-for water loss Wright Water Engineers, Inc. Page 10 November 2014

21 Durango-La Plata County Airport Water and Wastewater Master Plan The wastewater flow data were used similarly to the water data to develop a per-enplanement, wastewater flow factor. For 2011 through 2013, the average wastewater effluent flow for aviation use was 10.5 gallons per enplanement, as shown on Table 8(a). WWE also calculated the average day wastewater flows for aviation and non-aviation commercial use on Table 8(b), and the average day-peak month, from the July 2012 through 2013 data provided by the Airport. The average day for the 18 reference months is approximately 7,000 gpd, and the average day during the peak month was 9,400 gpd, which occurred in September Therefore, using the peak month average day, there is currently 10,600-gpd capacity available in the wastewater treatment system until planning for expansion must commence. There is currently 15,600-gpd capacity in the existing treatment system until the hydraulic capacity is exceeded. 2.4 Future Wastewater Demands Future forecasted wastewater flows for 2035 as shown on Table 9 are 15,800 gpd average day and 18,300 gpd average day during the maximum month. This includes the per-enplanement calculations for aviation use and the addition of the indoor water use forecasted for the nonaviation commercial facilities serviced by the Airport. (100% wastewater return flow was used for the non-aviation commercial indoor water demands as a conservative planning value). A daily peaking factor, above and beyond the maximum month average day, is not necessary for the Airport s existing wastewater treatment lagoon system because the relatively long hydraulic residence time in the lagoon will dampen any peak day surcharge (the hydraulic residence time is approximately 21 days at the full design flow of 25,000 gpd, and approximately 30 days at the projected flow of 18,300 gpd). According to the design information provided to WWE, the existing wastewater treatment plant has a capacity of 25,000 gpd, so treatment capacity expansion will not be required for 2035 since the forecasted flow is 18,300 gpd. The existing wastewater treatment facility and the flow percentages that would trigger planning of treatment expansion are discussed in more detail in Section Wright Water Engineers, Inc. Page 11 November 2014

22 Durango-La Plata County Airport Water and Wastewater Master Plan 3.0 WATER RIGHTS The Airport has water rights available in two basins that are used to meet potable and nonpotable irrigation water uses, as described in this section. The Airport has available nine water rights decreed in the Florida River basin and a contract for Florida Project storage water allocation as well. In the Pine River basin, the Airport has available one direct flow water right and a Pine River Irrigation Project storage water allocation. The Airport s facilities are located on the edge of the Florida River watershed and use Florida River water rights to provide the water supply for the potable system, including for domestic, commercial and industrial uses. The Airport also irrigates a small amount of land in the Florida River basin with water rights that were historically used to irrigate those lands prior to acquisition for the Airport. The Airport s Florida River water rights generally have fairly junior priorities. Historically, however, there has not been a call on the Florida River in the vicinity of the Airport s water rights and, to date, the Airport water rights have not been administered, i.e., subject to curtailment for the benefit of senior downstream water rights. It is possible that there may be a future call in the Florida River in the vicinity of the Airport water rights. A call would most likely be from the Colorado Water Conservation Board s (CWCB) in-stream flow water right, which is senior to some of the Airport water rights. The CWCB holds two in-stream flow water rights; the upper reach is more likely to affect the Airport s water rights. The upper reach, which is from Lemon Dam to the confluence of Salt Creek with the Florida, was decreed in Case No. W-1763 and with an adjudication date of December 31, 1977, and has a rate of 14.0 cubic feet per second (cfs) from October 15 th through June 30 th and 7.0 cfs from July 1 st through October 14 th. Currently, there is not a stream gage to measure the flow in the lower Florida River or facilitate administration of the CWCB s in-stream flow water rights as against other water rights. The lands around the terminal and runway are within the irrigated area of the Airport s King Ditch water rights from the Pine River. The Pine River regularly has calls and water rights are administered based on their priority. The Pine River Irrigation Project stores water in Vallecito Wright Water Engineers, Inc. Page 12 November 2014

23 Durango-La Plata County Airport Water and Wastewater Master Plan Reservoir and is managed by the Pine River Irrigation District (PRID). This storage water provides supplemental water supplies to irrigators holding project allocations. The physical dry year yields and legal constraints of the subject water rights were not evaluated at this Master Planning level. 3.1 Potable System Water Rights The existing Airport potable water system is supplied from the Airport Spring and Collection Basin, the Airport Infiltration Gallery, and the Airport Pipeline. The Airport also has decreed conditional water rights for two storage reservoirs, Airport Phase I Reservoir and Airport Phase II Reservoir, however they are not currently constructed. The water rights for potable uses are summarized in Table 10. The uses for the Airport s direct diversion water rights for the potable water supply system vary by decree and generally include domestic, municipal, and commercial uses. The Airport also has a decreed Augmentation Plan (Case No. 99CW66) that includes a change of water rights that provides for 24.3 acre-feet (AF) per year of Historical Consumptive Use (HCU) credits from the Tyner East Side Ditch First Enlargement water right to be used for domestic and commercial uses as well as augmentation and exchange. The Augmentation Plan also includes the use of the Airport Phase I and Phase II Reservoirs for storage of water for domestic and commercial uses and for managing augmentation water storage and releases. As previously noted, these reservoirs have not been built. The Airport s potable direct flow water rights have a total diversion rate of cfs absolute and 1.09 cfs conditional, and a total storage amount of 39 AF per year. The direct flow rights include 24.3 AF per year of HCU credits that are senior in priority to the CWCB s Florida River instream flow rights. Without storage reservoirs, the HCU credits are only available during the irrigation season. The calculated peak daily water demand for the potable system is 45,386 GPD and the calculated peak monthly demands is 977,055 gallons per month (3.0 AF) (see Table 9). The Airport s decreed water rights for the infiltration gallery is 0.10 cfs absolute and 0.84 cfs conditional, as shown in Table 10. The 0.94 cfs water right for the infiltration gallery will produce 25, Wright Water Engineers, Inc. Page 13 November 2014

24 Durango-La Plata County Airport Water and Wastewater Master Plan gallons per hour and could meet the peak daily demand of 45,386 GPD in just under 2 hours. Thus, the decreed diversion rate for the airport infiltration gallery when in priority is adequate on an instantaneous basis to meet the calculated water demands. WWE reviewed the current and projected demands, return flows and depletions for the potable water supply system, as summarized in Table 9. As discussed in Section 2.3, WWE has not performed an audit of the water system and these numbers may change due to leaks, measuring accuracy and changes in water management. For the projected 2035 scenario, the Airport s total water depletions on an annual basis are less than the decreed 24.3 AF per year of HCU credits from Case No. 99CW66. Currently, there has not been a call or a requirement to replace depletions. If there was a future call, without storage, the more senior HCU credits are only available during the irrigation season and the Airport does not currently have means of replacing depletions in the non-irrigation season (i.e. October through April). In the event of a future call during the non-irrigation season, WWE recommends pursuing the development or acquisition of adequate facilities and augmentation supplies to meet the current and projected depletions, during the non-irrigation season. The primary alternatives for developing the supply are 1) construction of the Airport Phase I and II Reservoirs for storage of HCU credits and other water decreed to those reservoirs, 2) contracting with the Florida Water Conservancy District (FWCD) for releases of water for augmentation or direct uses by the Airport, or 3) developing a means to integrate the quantified HCU credits and use of FWCD water for the Airport. These options may require future permitting or water court actions. Another option might include obtaining water service by La Plata Archuleta Water District, which is described in more detail in Section Non-Potable Irrigation Water Rights The Airport has available four direct flow and storage water rights and two storage project allocations that can be used for irrigation, as shown on Table 10. Information on these water rights is from the Water Augmentation Plan for Future Aviation and Non-Aviation Development (Goff, 2000), La Plata County Water Master Plan (Bikis Water Consultants, 2011), the FWCD, PRID, and the Colorado Division of Water Resources (CDWR) records. The water rights for irrigation uses are summarized in Table Wright Water Engineers, Inc. Page 14 November 2014

25 Durango-La Plata County Airport Water and Wastewater Master Plan The Airport s most senior direct irrigation water right is from its 8 shares in the King Ditch, which is approximately 1.9 percent of the total water right in the ditch, or up to 2.0 cfs. The King Ditch diverts off of the Pine River, when in priority, and delivers water through an extensive ditch system. The King Consolidated Ditch Company owns and operates the ditch and manages water allocations to users based on share ownership. Diversions in the King Ditch are supplemented by storage water in the Pine River Irrigation Project. The Airport has available an allocation of 160 PRID acres in certificate no. 665, which, on average, yields 320 AF per year. Note that PRID uses the term acres to define an entities storage allocation. On average, a PRID acre yields 2 AF per year. The Airport also has available absolute water rights decreed to Gregg Reservoir, Gregg Pipeline No. 1 and Gregg Pipeline No. 2. Gregg Reservoir is on a small drainage that captures runoff and wastewater return flows from irrigation on the mesa, to the extent available. Water from Gregg Reservoir and Pipelines is pumped onto the mesa and used for irrigation. When La Plata County purchased land from the Fassbenders along the Florida River, it acquired 10 AF of Florida Project water allocation that can be used for the irrigation of 15 acres associated with lands along the Florida River served by the Tyner East Side Ditch. This land does not include areas on the mesa near the terminal or runway. Florida Project water may be used to supplement irrigation when needed and when there is adequate capacity in the Tyner East Side Ditch to deliver the Florida Project water to the Airport lands. The Florida Project is managed by FWCD. The decreed amount of the Airport s non-potable irrigation water rights and project allocations total 2.0 cfs of direct flow water rights associated with the King Ditch and 320 AF of storage allocations from the Pine River Basin. The Airport s non-potable irrigation rights from the Florida River Basin include 10 AF of storage allocation from the Florida River Project, and AF associated with the Gregg Reservoir and a combined total of 1.0 cfs for the Gregg Pipeline Nos. 1 and 2. Note that the physical yield of Gregg Reservoir and Pipeline water rights are not as firm as the direct diversion and project allocation water rights associated with the King Ditch. The irrigation water rights are subject to administration in the Pine River and Florida River basins respectively. The storage water in Project allocations helps to sustain an irrigation Wright Water Engineers, Inc. Page 15 November 2014

26 Durango-La Plata County Airport Water and Wastewater Master Plan water supply in dry years. The yield of the water rights varies based on administration, reservoir levels, and the amount of return flows available from neighboring land uses. Based on the available information, it appears that the Airport holds adequate water rights and project water allocations to sustain non-potable irrigation of lands around the terminal and runway with Pine River basin water rights and to continue non-potable irrigation on land owned adjacent to the Florida River with the Florida River basin water rights and Project water allocations. 4.0 NON-POTABLE WATER ALTERNATIVES 4.1 Summary There are three water sources which a Public Water System may consider for implementation of a non-potable water system: 1) raw or untreated water, 2) graywater sources, and 3) treated wastewater. All of these non-potable sources are subject to varying levels of regulatory oversight. The following text discusses these three non-potable sources generally, as specific to the Airport, and within the current and future regulatory framework. 4.2 Raw Water for Irrigation Water demands in arid climates in Colorado often use substantially greater volumes of treated potable water during the peak summer irrigation season where demands can increase 6-fold over the average day in the non-irrigation season. The Airport s existing water rights portfolio and water use includes the use of raw water for irrigation. The water rights were discussed above in Section 3, and a summary of water rights for non-potable irrigation uses is provided in Table 11. It is WWE s understanding that the Airport uses the Gregg Reservoir to capture irrigation wastewater and return flows from irrigation of nearby parcels. From the Gregg Reservoir, the Airport pumps water through the Gregg Pipeline No. 2 for irrigation of approximately 10 acres, according to diversion records obtained from the CDWR. Thus, the Airport already substantially benefits in that they do not need to treat potable water for this irrigation use. The CDWR administers water rights. This is separate of, and not related to, the CDPHE regulation and oversight of potable water systems Wright Water Engineers, Inc. Page 16 November 2014

27 Durango-La Plata County Airport Water and Wastewater Master Plan WWE recommends that the Airport maintain its current irrigation system for future expansion and evaluate comprehensive management of its irrigation water rights. 4.3 Graywater Reuse Colorado s regulatory framework does not currently allow graywater reuse. However, as a result of legislation enacted in 2013, the CDPHE is developing a graywater control regulation for consideration by the Colorado Water Quality Control Commission. Until the proposed control regulation is adopted, graywater is regulated as wastewater that must be delivered to, treated by, and discharged at an approved wastewater treatment plant. Graywater consists of water from bathroom and laundry room sinks, bathtubs, showers, laundry machines and other sources that may be authorized. Graywater does not include toilets, urinals, kitchen sinks, dishwashers and non-laundry utility sinks. Graywater reuse can be a source of LEED credits for new, energy efficient construction. With the recent legislation and the forthcoming control regulation, some new buildings are being designed and constructed with the necessary filtration and dual plumbing systems that allow graywater reuse, typically for outdoor irrigation or toilet flushing. A limited number of pilot systems are also operating. The regulatory framework for graywater also includes local building jurisdiction, namely the prevailing building and plumbing codes. For graywater implementation in the Airport s expanded facilities, code revision will likely be required in the local land planning regulations. The Airport may desire to consider graywater for their new construction if consistent with their energy efficiency goals. However, the benefit may be limited given the Airport s current nonpotable irrigation system. Additionally, there are benefits to water rights management from delivering wastewater return flows back to the stream. Other water conservation means are available for municipal wastewater systems. The Airport has installed low flow fixtures and non-flush urinals in their sanitary facilities and currently practices good water conservation Wright Water Engineers, Inc. Page 17 November 2014

28 Durango-La Plata County Airport Water and Wastewater Master Plan 4.4 Wastewater Reuse CDPHE s Reclaimed Water Control Regulation 84 governs wastewater reuse. This regulation provides the following definition: Reclaimed Water is domestic wastewater that has received secondary treatment by a domestic wastewater treatment works and such additional treatment as to enable the wastewater to meet the standards for approved uses. There are many approved uses of reclaimed wastewater that include industrial uses, landscape irrigation, commercial uses, and fire protection. This non-potable water source is commonly used for outdoor irrigation in the Colorado Front Range and some mountain communities, and has become an important aspect of municipal water conservation. An important aspect of wastewater reuse planning is that the water rights must be compatible with wastewater reuse. Typically, wastewater reuse is implemented by water and wastewater systems that have a consumptive water source supply. That is, a water supply that can be reused such as from trans-basin diversions or non-tributary water supplies from deep aquifer wells. Reuse of wastewater at the Airport could reduce their total water demands as well as the total return flows from the Airport. This affects the timing and amount of diversions and return flows that must be managed within the Airport s water rights portfolio. However, given that the Airport owns non-potable irrigation water rights, there may be limited opportunities for practical wastewater reuse at the Airport. While graywater and wastewater are potential water sources of reuse for irrigation, these are neither necessary nor recommended for the Airport given its existing non-potable irrigation system and water rights. 5.0 EXISTING TREATMENT SYSTEMS 5.1 Summary On August 19, 2014, WWE conducted a site visit of the Airport s water and wastewater facilities with Airport representative David Miller and members of the Jviation, Inc. engineering team. The purpose of the site visit was to gather information regarding the existing physical conditions of the potable water and wastewater treatment facilities including capacities, configuration and Wright Water Engineers, Inc. Page 18 November 2014

29 Durango-La Plata County Airport Water and Wastewater Master Plan general conditions. We also observed the Airport s non-potable irrigation system pond and pump station. Water and wastewater documents that have been prepared previously for the Airport, including basis of design and engineering reports, design drawings, and discharge permitting and water quality narratives, were made available to WWE. We also discussed the water and wastewater systems with the CDPHE field engineering staff, engineering review group supervisor, and wastewater discharge permit writer. We also contacted the technical representatives of the water system membrane treatment filtration unit. In general, the Airport s facilities were observed to be in mostly good to excellent condition, and the treatment systems were properly operated and well maintained. Only relatively minor system upgrades may be needed under existing flow and capacity conditions. Design capacities for the treatment processes are rated for 33,000 gpd for the water treatment plant and 25,000 gpd for the wastewater treatment plant. A location map of the Airport s existing water and wastewater infrastructure is provided in Figure 3, and a description of the existing infrastructure major components, condition and capacity follows, and a process flow diagram is presented in Figure Existing Water Treatment Facilities The Airport operates a Public Water System (PWS) under the purview of the CDPHE and in compliance with the Colorado Primary Drinking Water Regulations. The PWSID is CO and the system is classified as a Non-Transient Non-Community Water System, which is a water systems that serves the same 25 people, but does not have 15 service connections. The water supply is classified as groundwater under the influence of surface water, which is subject to the requirements of the Long Term 2 Enhanced Surface Water Treatment Rule and, therefore, requires filtration. CDPHE has an assigned population for the system of 780 people Summary of Water Treatment Distribution Infrastructure The Airport s existing water treatment and distribution system consists of one spring, infiltration gallery that was recently expanded, Lower Pump House (one pump and one storage tank), Upper Wright Water Engineers, Inc. Page 19 November 2014

30 Durango-La Plata County Airport Water and Wastewater Master Plan Pump House (two jockey pumps), membrane filtration system, chlorine feed system, two fire pumps, treated water storage tank with a capacity of 144,000 gallons, and a distribution system. The Airport s existing water demand is supplied from an infiltration gallery on the Florida River and from a spring located uphill of the lower pump house. Water is pumped from the infiltration gallery and gravity fed from the spring, as it is available from the spring. The infiltration gallery is capable of pumping water to the lower pump house at a maximum rate of approximately 40,000 gpd (or 30 gallons per minute (gpm) as limited by the pump). Water supplied from the infiltration gallery and spring is stored in a 12,000-gallon tank at the Lower Pump House. If the storage tank at the Lower Pump House is at capacity, the excess water from the spring and infiltration gallery overflows down the hill to the Florida River. Water supplied from the infiltration gallery and water pumped from the lower pump house is metered on a daily basis. The spring production and overflow are also metered. Once the water level at the Upper Pump House reaches a minimum level, water is pumped from the Lower Pump House water through a 4-inch water line. The lower pump is capable of pumping water at a maximum rate of 36,000 gpd (25 gpm). At the Upper Pump House, water is treated with membrane filtration and chlorination and stored in two 72,000-gallon storage tanks before it is distributed to the Airport facilities. The drinking water treatment system is capable of treating a maximum of 33,000 gpd Capacities, Configurations and General Conditions The following text provides additional details on the ages, conditions, configurations and operational challenges of the existing water treatment infrastructure. For an existing facilities treatment process flow diagram, refer to Figure Raw water intakes: spring and infiltration gallery The Airport is served by two separate, redundant water supply sources: a spring and an infiltration gallery. The spring is located approximately 650 feet west of the terminal building between the top of the mesa where the Airport is located and the Florida River Wright Water Engineers, Inc. Page 20 November 2014

31 Durango-La Plata County Airport Water and Wastewater Master Plan The infiltration gallery is located adjacent to, and below, the Florida River. Both raw water intakes are shown on Figure 3. The spring supply was constructed in 1975 as the original source of water supply. The spring collection pipeline consists of approximately 115 feet of 4-inch diameter slotted PVC pipe, and is buried approximately 7 feet deep and bedded in aggregate. This collection pipeline drains by gravity to a 12,000 gallon welded steel storage tank adjacent to the spring. Flows from the spring have been observed to range from 5 to 15 gpm, lowest during early winter and highest in mid-summer. Recently, the spring has been consistently averaging approximately 4,500 gpd and provides a reliable and functional water supply. The infiltration gallery was originally installed around 1987 and expanded in The original gallery pipeline was installed in the alluvium of the Florida River on a bench inside a river meander. This pipeline is approximately 120 feet of 6-inch diameter slotted PVC pipeline that drains to a pump vault. Prior to the 2012 expansion, production from this infiltration gallery was limited seasonally due to the high percent of fines in the soils and generally low recharge of the alluvium in this area. The expansion of the infiltration gallery was completed in 2012 and extended into the alluvium below the Florida River channel with the goal of increasing water production. The expansion consisted of two parallel, 20-foot long stainless steel slotted well screens buried three feet and bedded and backfilled in engineered fill (select sands, gravel and cobble). The expansion includes cleanouts and valves designed to allow back-flushing via air or water of accumulated sediments in the alluvium; however, this back-flushing has not yet been conducted. The infiltration gallery expansion connects to the original pump vault. Valves are installed to allow either, or both, of the galleries to drain to the pump vault. Shortly after installation, the observed production from the expansion was 40,000 gpd. This production has declined over two years to approximately 10,000 gpd due to accumulated sediments on top of the fill above the well screens. Back-flushing should improve this production Wright Water Engineers, Inc. Page 21 November 2014

32 Durango-La Plata County Airport Water and Wastewater Master Plan Raw water quality Both the spring and the alluvium provide generally good raw water quality with a turbidity influent to the membrane treatment plant below 2 Nephelometric Turbidity Units (NTU). The turbidity is improved to approximately 0.9 NTU when the raw water is allowed to settle in the Lower Pump House raw water storage tank. A treated water quality issue relates to the age of the water in the storage tanks and distribution system and the formation of DPBs. The precursor material for DBP formation is the naturally occurring organic matter in the raw water, discussed in Section There are no additionally known water quality issues for these two raw water sources Raw water delivery: pumping and storage The infiltration gallery pump is a submersible pump that is contained within a manhole pump-vault. The pump is operated on a timer on-off schedule and controlled by floats in the vault that turn off pumping when the water level in the vault drops to near the pump intake. Water is pumped at a throttled down rate of 30 gpm, although the pump is capable of up to 40 gpm. The original pump vault was not replaced during the 2012 infiltration gallery expansion. During the 2012 work it was known that there was a nominal head differential of approximately 3.5 feet between the water surface elevation in the Florida River and the pump intake level in the pump vault. The head differential causes the 30 gpm pump to cycle on and off frequently due to the low volume of water in the shallow sump. This rapid pump cycling could be addressed in the future by increasing the production from the infiltration gallery via sediment back-washing or with a replacement and deeper vault. The infiltration gallery pump is operated on a timer schedule to deliver water to the Lower Pump House raw water storage tank. Excess water at this location is then returned to the river via an overflow and drains. A more efficient means of operation of the infiltration gallery pump (i.e. reducing overflows) would be to add telemetry to signal this pump when the Lower Pump House Tank water level reached a low level set point Wright Water Engineers, Inc. Page 22 November 2014

33 Durango-La Plata County Airport Water and Wastewater Master Plan The Lower Pump House Raw Water Storage Tank located adjacent to the spring is a buried 12,000-gallon welded steel tank that was installed in The tank was originally epoxy-coated on the interior prior to installation. The tank has not had an interior inspection (Airport staff report that divers specialized in this procedure will not enter the tank for safety reasons). The tank is maintained and cleaned from above by Airport operations staff. There is also no known corrosion control system. The tank is believed to be nearing the end of its service life for buried steel without cathodic protection. The Lower Pump House building is located above the storage tank and is of wood frame construction on a concrete slab. The building is in good condition and subject to routine operations and maintenance and access is adequate; there are no concerns with its condition. A submersible pump within the Lower Pump House Raw Water Storage Tank delivers raw water to the membrane treatment plant at a flow rate of 30 gpm. The membrane treatment unit break-tank signals the pump to turn on Membrane and disinfection treatment processes The water treatment process infrastructure and distribution and fire flow pumps are contained in the Upper Pump House Treatment Facility. The Upper Pump House building is a wood frame structure on a concrete slab in good condition. Double access doors facilitate chemical deliveries, and, if necessary, the removal and replacement of equipment. The treatment process includes an Evoqua (previously known as a Memcor) 6L10V microfiltration membrane unit installed in approximately 2004 to filter the raw water. This unit was installed after the spring and groundwater sources were suspected to have possible direct hydraulic connection to surface water. The skid-unit consists of six separate membrane modules. The membrane treatment plant was originally designed to treat 30 gpm up to 33,000 gpd. Currently, it is typically operated at 20 gpm. The CDPHE reissued its acceptance letter for Evoqua membranes on May 23, 2014 (Appendix C) and the unit has been reclassified to treat a maximum flow rate of 27 gpm Wright Water Engineers, Inc. Page 23 November 2014

34 Durango-La Plata County Airport Water and Wastewater Master Plan The Airport water system operator programs a backwashing cycle of the membranes that activates for approximately 4 to 5 minutes every half hour. This results in the membranes producing filtrate approximately 85% of the run-time, and results in a corresponding daily treatment capacity of approximately 33,000 gpd. The design engineer, Goff Engineering & Surveying, Inc., selected the membrane units to provide long-term, high quality and safe water that additionally offered the benefit of minimum operator involvement to the greatest extent possible. (Summarized from the Goff Preliminary Engineering and Design Report, September 7, 2004). The membrane treatment plant has met these expectations and continues to function well and reliably. The membrane units also were selected for their capability to filter raw surface water, after storage and settling, diverted directly from the Florida River, if this was deemed necessary in the future. The membrane filtration unit operates on/off from automated controls signaled by the water surface elevation in the finished water storage tanks. The membrane unit also includes an automated clean-in-place (CIP) backwash process that keeps the membranes clean and is an efficient and cost effective process. The CIP uses a citric acid soak and then a chlorine soak. The cleaning chemical backwash wastewater is discharged to a septic tank adjacent to the Upper Pump House, where accumulated sediments can be removed and the wastewater can be neutralized prior to discharge to the collection system and the wastewater treatment lagoons. After filtration by the membrane treatment unit, the water is disinfected using liquid calcium hypochlorite and pumped to the water storage tanks adjacent to the Upper Pump House Treatment Facility. The chemical feed pumps are redundant diaphragm pumps. The pumps operate on a flow-paced basis signaled from a turbine flow meter outside the Pump House in the distribution system. Chorine is dosed at a pre-set point set to 0.4 mg/l. An ortho-polyphosphate chemical (commercially known as Sea Quest) is also added to the treated water to address hardness and corrosiveness Potable water pumping and storage Wright Water Engineers, Inc. Page 24 November 2014

35 Durango-La Plata County Airport Water and Wastewater Master Plan After the membrane water treatment, the treated water is stored in two welded steel 72,000-gallon Clear Wells located adjacent to the Upper Pump House Treatment Facility. These water storage tanks provide storage for emergency fire protection and for potable water use. The water storage tanks are both above grade. The first tank was constructed in the mid-1980s and the newer, second tank was constructed in approximately The tanks are inspected and cleaned on a five-year schedule, last performed in During the last inspection, some minor interior coating deterioration was noted, and the Airport plans to add corrosion protection to mitigate this issue. Otherwise, the tanks are well maintained and reported to be in good condition. This inspection frequency is important to maintain, as the age of the tanks are approaching 30 years and proper maintenance will be necessary to maintain an ongoing lifespan. The water storage tanks were constructed prior to the CDPHE Design Criteria for Potable Water Systems including criteria on water storage. The most recent criteria update (September 1, 2013) now includes water storage, and the next CDPHE inspection may address additional items from this criteria, although WWE is unaware of any specific items on which they may note deficiencies. During prior Sanitary Survey inspections, the CDPHE has noted minor items on the water storage and Airport staff have addressed those recommendations. The treated water is recirculated through the Upper Pump House Treatment Facility to allow booster chlorination as needed to maintain the minimum disinfection residual in the distribution system. Water is then pumped into the distribution system to provide distribution system pressure with redundant jockey pumps that operate on a lead/lag basis: first one pump is utilized, and then a solenoid switches the next pumping cycle to the second pump. The pumps operate at a flow rate of 35 gpm each, or 70 gpm combined. A return flow valve in the pump skid manifold that returns water to the water storage tanks maintains the distribution system pressure. The pump skid (including the fire pumps discussed below) was installed in 1997 and is believed to be in good condition Fire flow: volume and rate, emergency power supply Wright Water Engineers, Inc. Page 25 November 2014

36 Durango-La Plata County Airport Water and Wastewater Master Plan The Clear Wells are operated with the goal of maintaining maximum fire flow storage of 140,000 gallons. In addition to the two jockey pumps in the Upper Pump House Treatment Facility, there are two fire flow pumps each with a nameplate capacity of 500 gpm, or 1,000 gpm combined. Considering the storage volume, this calculates to approximately two hours of fire flow with both high demand pumps on. A diesel generator is located adjacent to the pump house, which provides emergency backup power supply in case of a primary power supply failure Treated water quality issues Maintaining the water storage volume necessary for fire flow compared to the daily water demands results in treated water being detained for 15 days or more. This has resulted in undesirable DBP water quality testing results. DBPs occur due to naturally occurring organic matter, the precursor material, in the source water combined with the chlorine required for disinfection. DBP concentrations can be exacerbated with time, correlating to the detention time, or age, of the treated water. Specifically, the Airport has experienced exceedances of Total Trihalomethanes (TTHMs), a regulated primary drinking water constituent (and DBP). Concentrations of TTHM are measured on a four quarter running annual average (RAA) basis. The RAA maximum contaminant limit (MCL) for TTHMs is mg/l. Concentrations of TTHMs were recorded in 2011 and 2012 in the range of mg/l to mg/l, slightly exceeding the MCL. To address this situation, Airport staff has initiated a program of flushing treated water from fire hydrants to decrease the detention time of the treated water in the system while still maintaining acceptable fire flow water storage. This has been successful in lowering the TTHMs to acceptable concentrations, but has also resulted in the Airport using and treating more source water supply than necessary to meet daily potable water demands. The Airport estimates that approximately 30,000 gallons of water is flushed every other month. This is approximately 5 % of the current treated water volume Wright Water Engineers, Inc. Page 26 November 2014

37 Durango-La Plata County Airport Water and Wastewater Master Plan Alternative methods to address this situation would be to provide treatment for DBPs. These are addressed further in Section Existing Excess Water Treatment Capacity Based on the allowable flows for the Evoqua membrane filtration unit, the existing water treatment capacity is 33,000 gpd. The current maximum month average day demand from 2011 through 2013 was in July 2013 at 15,200 gpd. (Higher water demand was realized in May 2013, but that is attributable to an off-site fire when the fire department obtained water from the Airport s storage tanks). The peaking factor for maximum day is 1.2, which results in an estimated current peak day planning demand of approximately 18,200 gpd. This results in a current excess capacity of 14,800 gpd for the water treatment processes. In addition to the water treatment processes capacity, the source water supply from the spring and the infiltration gallery has been declining due to the lower production of the infiltration gallery. WWE believes this production can be improved with Airport operations and maintenance, but these production rates should also be carefully monitored as a potential limiting capacity factor. 5.3 Existing Wastewater Treatment Facilities The Airport operates a wastewater treatment facility approved by CDPHE and authorized to discharge under the Colorado Discharge Permit System (CDPS) Permit No. CO The permit is for a Domestic, Minor Municipal (less than 1 million gallons per day (MGD)), Lagoon System discharging to surface water (the Florida River). The permit is valid for five years until renewal (or administrative extension by CDPHE) and was last issued effective date February 1, The permitted effluent discharge flow is rated for MGD (25,000 gpd) hydraulic capacity and 83 lbs BOD5/day organic capacity (both 30 day average), which were specified in the Site Approval The facility is fairly new, constructed in 2006; it is well operated and is in good condition. A key issue with lined lagoon wastewater treatment facilities is demonstrating to the CDPHE the liner integrity with proof that the liners do not leak. This was adequately demonstrated during Wright Water Engineers, Inc. Page 27 November 2014

38 Durango-La Plata County Airport Water and Wastewater Master Plan the last discharge permit renewal application by providing details of the lagoon liner materials data, specifications, and design drawing details from the relatively recent wastewater construction project Summary of Wastewater Treatment Infrastructure Two lift stations are located in the service area, at the U.S. Forest Service Station #1 and the existing commercial office facility. The treatment facility consists of an influent Palmer-Bowlus flume followed by a three cell, aerated lagoon system. Lagoons #1 and #2 are aerated. Lagoon #3 is used for settling. Effluent is also measured with a Palmer-Bowlus flume. Disinfection is achieved by chlorination. Means for de-chlorination are included in the facility operations, but this has not been necessary to achieve the chlorine residual effluent limit. The Fact Sheet issued with the most recent permit renewal noted in the summary of the Discharge Monitoring Report (DMR) data that the effluent monitoring demonstrated compliance with the permit limits with the exception of minor BOD5 limit excursions Effluent Discharge Limits The following table details the effluent discharge limitations and monitoring requirements in discharge permit CO Wright Water Engineers, Inc. Page 28 November 2014

39 Durango-La Plata County Airport Water and Wastewater Master Plan Effluent Discharge Limits Permit No. CO Effluent Parameter Effluent Limitations Maximum Concentrations 30-Day Average 7-Day Average Daily Maximum Monitoring Requirements Frequency Effluent Flow (MGD) Report Continuous ph (su) Weekly E. coli (#/100 ml) Quarterly TRC (mg/l) until June 30, 2017 Report 0.5 Monthly TRC (mg/l) beginning July 1, Monthly Total Ammonia as N (mg/l) until June 30, 2017 Report Report Monthly Total Ammonia as N (mg/l) beginning July 1, 2017 January Monthly February Monthly March Monthly April Monthly May Monthly June Monthly July Monthly August Monthly September Monthly October Monthly November Monthly December Monthly BOD5 (mg/l) Monthly BOD5 (% removal)) 85 (min) Monthly TSS (mg/l) Quarterly Oil and Grease (visual) Report Monthly Oil and Grease (mg/l) 10 Contingent TSDS (mg/l) PWS intake (mg/l) Report Report Quarterly WWTF effluent (mg/l) Report Report Quarterly Wright Water Engineers, Inc. Page 29 November 2014

40 Durango-La Plata County Airport Water and Wastewater Master Plan The Airport personnel, and the previous DMR summary by the CDPHE, report that the facility is generally capable of meeting these discharge limits. Minor excursions of BOD5 occurred prior to the last permit renewal, and more recently an algal bloom in Lagoon #3 led to excursions of total suspended solids (TSS). Airport operations staff addressed the excursions by cleaning this cell. New effluent limits for ammonia are effective July 1, Airport staff will perform preliminary data monitoring in the near future to gage the lagoon system s effectiveness in achieving the ammonia limits. WWE also performed preliminary calculation of lagoon water temperature and nitrification. This is discussed below in the section Wastewater Treatment Facilities Improvements Capacities, Configurations and General Conditions The following table provides additional details of the existing wastewater treatment facility unit processes. Unit Process Capacities Design Parameters Design Flow Average Daily Flow Peak Hour Flow Factor = 4 Average Daily Organic Loading Unit Process 25,000 gpd ( MGD) 83 lbs. BOD5/day Unit Process Features/Description Capacity Hydraulic/Organic Influent Flow Measuring 6" Palmer Bowlus Flume w/ Ultrasonic Sensor 0.19 MGD / NA Lagoon Cell #1 Volume = 135,000 gallons, Depth = 10 ft MGD Detention Time, td = 10.8 days 36 #BOD5/Day Aeration 4 each - 12" static tubes, 20 icfm (15.14 scfm) per tube FTR=0.482, Thus 1.2 #O2/unit/hr at 10 ft. depth 55.5 #O2/Day Lagoon Cell #2 Volume = 271,000 gallons, Depth = 10 ft MGD Detention Time, td = 10.8 days 47 #BOD5/Day Aeration 6 each - 12" static tubes, 17.5 icfm (13.24 scfm) per tube Wright Water Engineers, Inc. Page 30 November 2014

41 Durango-La Plata County Airport Water and Wastewater Master Plan FTR=0.482, Thus 1.2 #O2/unit/hr at 10 ft. depth 76.3 #O2/Day Blowers 2 each - 10 Hp Tuthill blowers Model L2 N/A 185 icfm 2500 rpm, 5.9 psi. Lagoon Cell #3 Volume = 115,000 gallons, Depth = 8 ft MGD Polishing Pond Detention Time, td = 4.6 days Total Lagoon Detention Time, td = 20.8 days (for all three cells) Chlorination Tablets Chlorine Contact Chamber 1725 gallons, Detention Time, td = 49.6 minutes MGD (Chamber plus Pipe Plug Flow) (Peak Flow) Effluent Flow Measuring 4" Palmer Bowlus Flume w/ Ultrasonic Sensor.07 MGD / NA Source: Goff Engineering & Surveying, Inc., January 23, Existing Excess Wastewater Treatment Capacity WWE reviewed recent effluent discharge summary data provided by the Airport. Based on this review, it is seen that hydraulic capacity, as opposed to BOD5 loading, is the limiting parameter in the Airport s discharge permit. This existing hydraulic capacity is 25,000 gpd. It should also be noted that by CDPHE regulations, planning for future construction must be commenced when flows reach 80%, which is 20,000 gpd. The data regarding average day wastewater discharges, provided by the Airport staff, from July 2012 through 2013 (when flow measurements were believed to be most accurate) averaged approximately 7,000 gpd. The peak month averaged 9,400 gpd. Therefore, using the peak month average day, there is currently 10,600-gpd capacity available in the wastewater treatment system until planning for expansion must commence. There is currently 15,600-gpd capacity in the existing treatment system until the hydraulic capacity is exceeded Wright Water Engineers, Inc. Page 31 November 2014

42 Durango-La Plata County Airport Water and Wastewater Master Plan 6.0 FUTURE EXPANSION NEEDS 6.1 Location of Terminal and Water/Wastewater Impacts The Airport expansion planning envisions approximately double the existing amount of enplanements by the year The expansion planning performed by Jviation for the Airport has considered three different alternative locations for the terminal as follows: Alternative 1 is to remodel the existing terminal located on the west portion of the Airport. Alternative 2 is to abandon the existing terminal and build a new terminal just north of the existing terminal site. Alternative 3 is to abandon the existing terminal and build a new terminal facility on the east side of the Airport property. These three alternatives for the location of the terminal were considered relative to the locations of the major components of the water and wastewater treatment facilities Alternatives 1 and 2 For Alternatives 1 and 2, the locations of the existing water and wastewater treatment facilities and distribution and collections systems would remain proximate to the existing terminal, and no relocation of major components of the facilities is necessary Alternative 3 For Alternative 3, a new terminal on the east side of the Airport property, relocation of the treatment facilities was evaluated. WWE was requested to evaluate the options of relocating the water and wastewater treatment facilities to the east side in conjunction with this relocated terminal. As part of this evaluation, WWE met with the Jviation engineering team to review the impacts to water and wastewater planning. This section addresses the challenges and benefits, if any, of relocating the existing facilities to the east side of the Airport Wright Water Engineers, Inc. Page 32 November 2014

43 Durango-La Plata County Airport Water and Wastewater Master Plan Factors that were considered for water and wastewater service and the potential for relocating the major components were: 1) Both the existing water and wastewater treatment facilities are in generally good operational condition and are relatively new construction. 2) Existing service obligations to non-aviation commercial space will remain in the future on the west side of the runway. 3) The existing source water supply for the Airport s potable water system is the infiltration gallery along the Florida River and the spring source supply, also on the west side. These source supplies will remain on the west side regardless of the possible relocation of the terminal to the east portion of the Airport. 4) The permitted, treated wastewater effluent discharge location is to the Florida River on the west side of the Airport property. There is a possibility of developing a discharge location to a receiving water on the east side, Salt Creek; however, the regulatory and construction processes would be expensive and time-consuming (discussed further below). 5) The Airport s existing water rights are consistent with the diversion and wastewater return flows from the Florida River. Relocating the wastewater discharge location to the east side of the Airport to Salt Creek would have additional water rights implications. Because the existing source water supplies lie on the west side of the airport and potable water service is required on both sides of the runway, the airport property would need to be crossed with a potable water distribution system regardless of where the water treatment plant was located. If the water treatment plant was relocated to the east side, then the Airport property would also need to be crossed with a new raw water pipeline because the source supply remains on the west side. Due to this, coupled with the relatively newer and generally good condition of the existing treatment plant, WWE recommends the water treatment plant not be relocated in conjunction with Alternative Wright Water Engineers, Inc. Page 33 November 2014

44 Durango-La Plata County Airport Water and Wastewater Master Plan Relocating the wastewater treatment plant to the east side of the Airport is a potential option under Alternative 3 if the wastewater discharge was relocated to Salt Creek, the receiving stream east of the Airport. This could have the benefit of a gravity discharge from the wastewater treatment plant, which is generally preferable to pumping, if possible. (Although it should be noted that service for the existing commercial facilities on the west side of the Airport would also require pumping to the relocated wastewater treatment plant.) The other wastewater treatment option for Alternative 3 would be installation of a lift station pumping from the new terminal to the existing wastewater treatment facility. Relocating the wastewater treatment plant to the east side of the Airport property would be a time-consuming and expensive regulatory, planning, and construction process. Multiple public comment periods would also be involved. A significant question in this relocation is the agency that would take regulatory purview. Typically, in Colorado, the CDPHE has primacy for wastewater discharge. However, the Airport lies within the exterior boundaries of the Southern Ute Indian Tribe (SUIT). Any new wastewater discharge permitting would need to be clarified as to the regulatory authority, CDPHE, SUIT, and Environmental Protection Agency. If the CDPHE has primacy, the steps are well defined and include a number of regulations and processes for obtaining approval. These steps include, generally in sequence: 1) Preliminary Effluent Limitations, which define the effluent limitations for the receiving water and allow selection of the appropriate treatment technologies for design purposes. 2) Regulation 22, Site Location and Design Approval Regulations for Domestic Wastewater Treatment Works 3) Design approval process in conformance with the Design Criteria Considered in the Review of Wastewater Treatment Facilities 4) Colorado Discharge Permit System Regulation 61 These steps are all part of the process to obtain construction approval and a facility discharge permit Wright Water Engineers, Inc. Page 34 November 2014

45 Durango-La Plata County Airport Water and Wastewater Master Plan A new wastewater discharge into Salt Creek could involve more strict effluent limitations than the current permit. In the past, CDPHE has raised issues with water quality concerns in Salt Creek. The low flow ratio of the discharge into Salt Creek compared to the ratio into the Florida River may also affect the required effluent limitations. These issues would be better defined with the PEL, and depending on the results, could require a more advanced, mechanical wastewater treatment plant to meet the new limits. It is also possible that an additional easement would be required to allow a discharge from the east side of the Airport property to Salt Creek. The Airport property boundaries would need to be compared against preferred discharge alignments and locations. The Site Application process requires CDPHE to consider the local long-range comprehensive plans for the area as they affect water quality and any approved water quality management plans for the area. Additionally, the site location application must be reviewed to ensure that the proposed treatment works is developed considering the local long-range comprehensive plans for the area as it affects water quality and the approved water quality management plans for the area. The CDPHE will rely substantially upon the water quality management plan for the area in deciding whether to grant site location application approval where the plan is current and comprehensive with respect to its analysis of population growth and distribution as it relates to wastewater treatment. In all cases, it is the intention of the CDPHE to have local water quality planning issues resolved at the local level, through a public process, prior to an applicant s submission the site application. The preliminary design report, detailed engineering design, and design approval and CDPS permit application would follow the site application process. The time to obtain the approval authorizing construction of a new treatment plant is estimated at a minimum of two years, and potentially substantially more time should be allowed if this alternative is pursued. Because the Airport s diversion and wastewater return flows are from and to the Florida River, a change in the location of the wastewater discharge would add significant water rights implications. This change in location would amount to the diversion becoming 100% consumptive in the reach between the diversion and the confluence of Salt Creek with the Wright Water Engineers, Inc. Page 35 November 2014

46 Durango-La Plata County Airport Water and Wastewater Master Plan Florida River. This depletion would be junior to the minimum instream flow in the Florida River and would require augmentation equal to the full diversion. Given the arduous effort to permit a new wastewater facility with discharge into Salt Creek, the uncertainty of what agency or agencies will take regulatory primacy, the existing, relatively new wastewater treatment plant performing well, and the expense to construct a new plant, the engineering team recommends that the Airport not relocate the treatment to the east side of the Airport. Instead, it is recommended that the existing plant continue to be used if Alternative 3 is selected and that the wastewater be pumped from the new terminal via a new lift station. 6.2 Future Improvements, Triggers and Timelines As discussed above, the existing water and wastewater treatment facilities at the Airport perform well, achieve current drinking water quality limits, and comply with wastewater effluent limits. There are improvements that could be made to the existing water treatment infrastructure to address service life of equipment, improve operational efficiency, and provide greater water conservation. Additionally, based on the growth projections used in this Master Plan, the water treatment infrastructure will require capacity expansion to meet 2035 demands. Conversely, the existing wastewater treatment system is adequate for both current demands and the 2035 future discharge forecasts. Figure 2 illustrates water and wastewater treatment demands over time. This Section 6 addresses the recommended improvements to the existing infrastructure, and Section 7 of this Master Plan includes cost estimates to implement these improvements Water Treatment Facilities Improvements Water Expansion Planning Criteria All modifications to Public Water Systems, including storage facilities, require review and approval by CDPHE for conformance with the Colorado Primary Drinking Water Regulation 11 and the CDPHE Design Criteria for Potable Water Systems. This requires a design report and design drawings prepared by a licensed professional engineer. Upon acceptance of the design and supporting documents, CDPHE will issue a letter Wright Water Engineers, Inc. Page 36 November 2014

47 Durango-La Plata County Airport Water and Wastewater Master Plan authorizing the construction. The extent of time needed for CDPHE review and approval can be from three to six months after the initial engineering submittal Recommended Improvements to Existing Facilities WWE recommends several improvements to the existing water treatment infrastructure to address equipment age, improved operations and increased water efficiency. For planning purposes, implementation of these improvements should be considered within approximately one to five years. None of these current recommendations are critical to daily operations or regulatory compliance, but are recommended for overall system improvement and to preclude emergency equipment replacement situations. Recommendation 1: The Lower Pump House Water Storage Tank may have reached its useful lifespan for a buried steel tank. A new, buried 12,000-fiberglass gallon storage tank is recommended. This new tank can also be equipped with the proper manway access hatches to allow periodic inspection, maintenance and cleaning. This replacement tank can be located adjacent to the existing tank and the pump house and piping and metering appurtenances could be reused. Recommendation 2: In conjunction with this new tank, an automated telemetry communication system to signal the infiltration gallery pump is recommended for operational efficiency and water conservation. Recommendation 3: The Evoqua MF filtration treatment skid includes six membrane cartridges that have an expected service life of 10 to 15 years. They have been in service approximately 10 years. The actual membrane service life can vary based on the treatment flow rate and daily duration of treatment and influent raw water quality. The daily flow rate and treatment use at the Airport has been lower than the maximum rate; the system has been operated at an approximately 20 gpm flow rate as compared to the maximum rating of 27 gpm. Additionally, the raw water quality delivered to the membranes from the spring and infiltration gallery has been better than often experienced in a surface water system. An Evoqua technical representative should evaluate these units to provide the recommended replacement timeframe. It is important to note that the Wright Water Engineers, Inc. Page 37 November 2014

48 Durango-La Plata County Airport Water and Wastewater Master Plan replacement of these membranes is an operations and maintenance item; this replacement-in-kind does not require CDPHE design review and prior approval for construction. Depending on the findings and recommendations of the Evoqua representative, this 10 to 15 year replacement schedule may also need to be repeated within the time frame of this 20-year planning evaluation. Recommendation 4: The Airport s treated potable water detention time has resulted in occasional exceedances of TTHMs. This has been successfully addressed by the Airport operations staff within the constraints of the existing treatment processes through the practice of flushing water to lower the detention time of the water in the storage tanks and the corresponding formation of TTHMs. Although effective in achieving the required water quality limitations, this is not the most efficient means to address this water quality issue. It is estimated that the Airport may be flushing up to 5% of the annual amount of water treated. WWE recommends that the Airport have performed an engineering study to evaluate the treatment alternatives to lowering the concentrations of TTHMs. The proposed study should address a) using a different disinfectant, b) the addition of a coagulation agent, or c) an additional treatment process such as Granular Activated Carbon (GAC) contactors. a) A change in the disinfectant used could be the least expensive option and may result in acceptable water quality. b) The addition of a coagulant agent operates to remove some of the DBP precursor material from the influent water prior to disinfection. This precursor material is naturally occurring organic matter (organic carbon) found in the raw water. The coagulant can allow the organic matter to form flocs that can settle via gravity in a settling basin. c) The addition of GAC contactors has proven to be an effective means to remove the organic carbon precursor material. The GAC acts to absorb the carbon in the influent water Wright Water Engineers, Inc. Page 38 November 2014

49 Durango-La Plata County Airport Water and Wastewater Master Plan Maintenance and an Option to Improve Existing Facilities/Systems The source water supplies for the Airport s potable water system consist of the spring and the infiltration gallery. The spring provides a consistent and reliable water production rate. Conversely, the infiltration gallery has experienced declining production rates. The infiltration gallery expansion included the appurtenances and means to allow backwashing the gallery piping to remove accumulated sediments in the alluvium. This backwashing should improve the production rate. Thus far, this maintenance has not been performed, and there is no explicit operational procedure developed to perform this work. The Airport should develop a standard operating procedure to address this situation and perform this backwashing activity on a periodic basis. If the water production of the infiltration gallery does not increase to acceptable levels after the recommended operations and maintenance, an option would be to implement an additional intake to the water treatment system. This was contemplated with the original design and construction of the membrane water treatment plant, and equipment was selected to treat a direct-surface water diversion from the Florida River. The Evoqua MF filtration unit would be compatible with surface water treatment, given proper treatment of the precursor material. A pretreatment step would be needed, such as a small sedimentation basin to allow the fine sediments in the river surface source to settle by gravity. This option would include a diversion structure in the river, and piping and pumping to the sedimentation basin and pumping to the Lower Pump House Water Storage Tank. The Infiltration Gallery Pump Vault could be modified for this pumping station Required Improvements to Meet Future Demand Additional filtration capacity will be required to meet the 2035 forecasted water demands. Based on the existing water uses of approximately 16,350 gpd peak day in 2013, and the projected 2035 demands of approximately 37,800 gpd peak day (Table 9), additional filtration capacity would need to be operational by the year 2031 (Figure 2). Because this recommendation is based on numerous assumptions inherent to master Wright Water Engineers, Inc. Page 39 November 2014

50 Durango-La Plata County Airport Water and Wastewater Master Plan planning, the Airport staff should continue to monitor water use to refine the year that additional capacity will be needed. An alternative to the Airport adding additional treatment capacity to meet increasing future demands may be an opportunity to participate with regional municipal water service providers that may expand to the Airport service area in the future. This opportunity should be further assessed for current conditions when the Airport s future planning in undertaken. The potential for additional regional service is addressed in Section 8. The planning and engineering for this increased filtration capacity should be initiated approximately two years prior to anticipated construction. Therefore, approximately 2029 based on the planning assumptions, or when the peak daily flows reach approximately 30,000 gpd. Based on current, approved technology and the current regulatory framework, WWE recommends that the Airport install a new, additional skid using the same Evoqua MF technology. This new skid would be installed in the Upper Pump House adjacent to the existing membrane unit. Fire flows for the expanded airport terminal building had not been defined at the time of this planning. When these updated fire flows (flow rate, time duration, and corresponding storage volume) are determined, the potential for additional water storage and possibly fire flow pumps will need to be assessed and incorporated in this planning Wastewater Treatment Facilities Improvements Based on the planning assumptions, the existing wastewater treatment capacity of 25,000 gpd is adequate to meet future forecasted flows in 2035 of 18,300 gpd. This conclusion is based on a number of key assumptions discussed below, including: Wright Water Engineers, Inc. Page 40 November 2014

51 Durango-La Plata County Airport Water and Wastewater Master Plan The existing wastewater lagoon treatment technology remains appropriate for the imposed effluent limitations that are anticipated in future 5-year discharge permit renewal cycles. The ability to meet the current permit compliance schedule items, primarily for ammonia discharge limitations. The accuracy of the discharge measurement data used for this planning. WWE reviewed the discharge permit and discussed with the CDPHE discharge permit writer the current regulatory framework governing the discharge. There are no known anticipated regulatory changes that would result in obsolescence of the current lagoon technology. The CDPHE permit writer and Airport operations staff believe also that the existing facilities will be able to meet new ammonia standards. Specifically, effluent limitation concentrations for Total Ammonia have been added to the discharge permit that was issued in 2012 that take effect in These new limitations will be carefully evaluated and monitored by Airport operations in the next two years. WWE also prepared preliminary calculations for the existing treatment facility attaining these new ammonia standards (Appendix D). Based on these preliminary calculations, it appears the existing facility should be able to meet these new limits. The Airport staff have been attempting to improve the accuracy of measuring low flows in the lagoon. If new flow measurement calibration and results indicate effluent discharges are higher than currently recorded, the potential for facility expansion may need to be revisited. The triggers for expansion of wastewater treatment facilities are included in the Airport s discharge permit. These triggers are provided below in italics Wastewater Expansion Planning Criteria Pursuant to Colorado Law, C.R.S (5 d & e), the permittee is required to initiate engineering and financial planning for expansion of the domestic wastewater treatment works whenever throughput reaches eighty (80) percent of the treatment capacity. Such planning may be deemed necessary upon a showing that the area served Wright Water Engineers, Inc. Page 41 November 2014

52 Durango-La Plata County Airport Water and Wastewater Master Plan by the domestic wastewater treatment works has a stable or declining population; but this provision shall not be construed as preventing periodic review by the Division should it be felt that growth is occurring or will occur in the area. The permittee shall commence construction of such domestic wastewater treatment works expansion whenever throughput reaches ninety-five (95) percent of the treatment capacity or, in the case of a municipality, either commence construction or cease issuance of building permits within such municipality until such construction is commenced; except that building permits may continue to be issued for any construction which would not have the effect of increasing the input of wastewater to sewage treatment works of the municipality involved. Where unusual circumstances result in throughput exceeding 80% of treatment capacity, the permittee may, in lieu of initiating planning for expansion, submit a report to the Division that demonstrates that it is unlikely that the event will reoccur, or even if it were to reoccur, that 95% of the treatment capacity would not be exceeded. Where unusual circumstances result in throughput exceeding 95% of the treatment capacity, the permittee may, in lieu of initiating planning for expansion, submit a report to the Division that demonstrates that the domestic wastewater treatment works was in compliance at all times during the events and that it is extremely unlikely that the event will reoccur. Where the permittee submits a report pursuant to unusual circumstances, and the Division, upon review of such report, determines in writing to the permittee that the report does not support the required findings, the permittee shall initiate planning and/or construction of the domestic wastewater treatment works as appropriate. Therefore, based on the current discharge limitation of 25,000 gpd, engineering and financial planning for expansion must occur when discharges reach 20,000 gpd, the 80% threshold. When discharges reach the 95% level, or 23,750 gpd, construction of improvements must be commenced Wright Water Engineers, Inc. Page 42 November 2014

53 Durango-La Plata County Airport Water and Wastewater Master Plan 7.0 OPINION OF PROBABLE CAPITAL COSTS WWE developed opinions of probable capital costs (also referred to herein as cost estimates) for the recommended improvements in Section 6. The items identified for improvement and expansion of treatment facilities in this Master Plan are all related to the water treatment facilities; no necessary improvements were identified for the wastewater treatment facilities. These cost estimates are provided for the recommended improvements to the existing facilities, potential improvements to the existing facilities, and the required improvements to meet future water demands. Cost estimates for new water distribution piping, valves, meters, etc. are not included. This is also the case for wastewater collection piping, lift stations, manholes, etc. The cost estimates provided below are developed at the study estimate level (the least accurate level), and should not be relied upon to establish firm budgets until more detailed planning is performed and detailed scopes of work are developed. The following cost estimates include provision for engineering planning, permitting and design (where appropriate) and equipment procurement and installation. Dollar values are presented in 2014 costs. 7.1 Recommended Improvements to Existing Facilities The following improvements should be considered for implementation from approximately 2015 to 2020 for improvements to daily treatment operations and to address expected equipment service life. 1) 10,000 to 12,000-gallon Buried Lower Pump House Water Storage Tank CDPHE and USACE Section 404 Permitting $25,000 Equipment and installation $80,000 30% contingency $30,000 20% engineering design allowance $25,000 Total $160,000 Nationwide 404 permit assumed Wright Water Engineers, Inc. Page 43 November 2014

54 Durango-La Plata County Airport Water and Wastewater Master Plan 2) Telemetry improvements from the Lower Pump House to the infiltration gallery pump. Telemetry design, controls and installation $20,000 Assume controls and design and installation by qualified controls vendor. No permitting tasks anticipated. 3) Replacement Evoqua MF filtration membrane modules. New membrane modules $7,500 Assumes as operations and maintenance (O&M) replacement, no engineering or permitting anticipated for this in-kind replacement. 4) Engineering study to evaluate the treatment alternatives for lowering the concentrations of DBPs Engineering study $35,000 If GAC (the most expensive anticipated alternative) is found to be the preferred alternative: CDPHE Permitting $20,000 Equipment and installation $50,000 30% contingency $20,000 20% engineering design allowance $20,000 Total $110,000 Assumed space is available to house in existing Upper Pump House building, to be verified during engineering study. 7.2 Improvements to Existing Facilities/Systems to Monitor The monitoring of the production of the spring and infiltration gallery source water supplies needs to be continued. If production rates are not improved with O&M, a new surface water intake from the Florida River may be required Wright Water Engineers, Inc. Page 44 November 2014

55 Durango-La Plata County Airport Water and Wastewater Master Plan Surface water intake from the Florida River. CDPHE and USACE Section 404 Permitting $25,000 Concrete intake structure with pump and vault $50,000 Sedimentation basin and site work $45,000 Power $20,000 30% contingency $40,000 20% engineering design allowance $35,000 Total $215,000 Nationwide 404 permit assumed. 7.3 Required Improvements to Meet Future Demand To meet future project demands, a new Evoqua 9-module MF treatment skid with increased capacity will be required in approximately The current recommended technology cost estimate is: CDPHE Permitting $20,000 MF treatment skid, installation and startup $250,000 30% contingency $80,000 20% engineering design allowance $70,000 Total $420, POTENTIAL FUTURE REGIONAL WATER AND WASTEWATER SYSTEMS The Airport is located within the La Plata Archuleta Water District (District) (Figure 5). Based on a review of the 2013 Water Management and Conservation Plan, the District was formed in 2008 as a new municipal water supplier to serve the southeast portion of La Plata County. The District currently leases water from Vallecito Reservoir and is currently negotiating with the Colorado Water Conservation Board for potable water supply from of the Animas-La Plata Project, which includes Lake Nighthorse. In cooperation with the Town of Bayfield, the District is receiving and distributing treated potable water from the Bayfield Water Treatment Plant. The District is working on establishing Wright Water Engineers, Inc. Page 45 November 2014

56 Durango-La Plata County Airport Water and Wastewater Master Plan a treatment facility on the western end of the District boundary near the Animas-La Plata Pumping Plant. The planning horizon provided in the 2013 Water Management and Conservation Plan is to year The Plan envisions a majority of the water treatment and distribution system to be completed by the year 2030 (Figure 6). The plan did not provide a more specific time frame for projecting infrastructure completion to the Airport. WWE contacted Steve Harris, P.E., District Engineer, and discussed the development plan. Mr. Harris estimated service to the airport area by the year 2020 and potentially sooner if the Airport was willing to cost-share on infrastructure. The authors are unaware of any current regional wastewater collection and treatment facilities for future connection to the airport. There have been discussions on local coordinated wastewater treatment and collection efforts between developments parcels adjacent or near the airport property. The Durango Commercial Development is a proposed industrial development near the Airport Property that may at some point have mutual benefit from consolidating wastewater treatment systems. P:\ Jviation\000\Master Plan Document\Airport Water and WW Master Plan_FINAL.docx Wright Water Engineers, Inc. Page 46 November 2014

57 Tables

58

59 Table 1 Durango-La Plata County Airport 2011 Through 2013 Metered Total Water Use Aviation Use and Existing Non-Aviation Commercial Use (all values in gallons unless otherwise noted) Month Three Year Totals: Aviation Non-Aviation Commercial Total Use Aviation Non-Aviation Commercial Total Use Aviation Non-Aviation Commercial Total Use Average Maximum Minimum (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) January 198,563 24, , ,906 25, , ,108 28, , , , ,563 February 252,118 25, , ,987 29, , ,359 33, , , , ,118 March 280,490 33, , ,177 42, , ,268 22, , , , ,768 April 276,194 41, , ,801 42, , ,517 43, , , , ,194 May 254,265 53, , ,895 56, , ,339 79, , , , ,265 June 259,354 59, , ,705 46, , ,332 89, , , , ,705 July 298,024 43, , ,908 28, , ,622 82, , , , ,908 August 229,302 41, , ,502 38, , ,531 80, , , , ,802 September 240,736 68, , ,353 43, , ,180 44, , , , ,036 October 294,766 45, , ,458 24, , ,420 51, , , , ,333 November 306,765 28, , ,112 56, , ,068 21, , , , ,898 December 305,314 48, , ,183 21, , ,660 20, , , , ,183 Annual Total 3,195, ,500 3,707,391 3,610, ,700 4,063,687 4,117, ,500 4,713,904 4,161,661 4,713,904 3,707,391 Average GPD 8,756 1,401 10,157 9,893 1,240 11,133 11,281 1,634 12,915 11,402 12,915 10,157 Max Month Average GPD* 9,896 2,203 11,413 10,757 1,823 11,839 12,568 2,887 15,214 12,822 15,214 11,413 Column Notes: (1) Column 3 minus Column 2 (2) From data provided by David Miller, Durango-La Plata County Airport: "Water-Sewer 2011." Used Commercial with Sewer table, "Total Used" column, sum of BP Operations Center and BP Warehouse. (3) From data provided by David Miller, Durango-La Plata County Airport: "Water-Sewer 2011." Used Water Production data (at bottom of table), Total RAW (4) Ibid Column (1) note (5) From data provided by David Miller, Durango-La Plata County Airport: "Water-Sewer 2012." Used Commercial with Sewer table, "Total Used" column, sum of BP Operations Center and BP Warehouse. (6) From data provided by David Miller, Durango-La Plata County Airport: "Water-Sewer 2012." Used Water Production data (at bottom of table), Total RAW (7) Ibid Column (1) note (8) From data provided by David Miller, Durango-La Plata County Airport: "Water-Sewer 2013." Used Commercial with Sewer table, "Total Used" column, sum of BP Operations Center and BP Warehouse. (9) From data provided by David Miller, Durango-La Plata County Airport: "DEC Usage 2013" and "Water-Sewer 2013." Used Water Production data (at bottom of table), Total RAW (10) Average value of the Total Usage for 2011, 2012, and 2013 (11) Maximum value of the Total Usage for 2011, 2012, and 2013 (12) Minimum value of the Total Usage for 2011, 2012, and 2013 Additional Note: * 2013 Max Month usage occurred in May due to an off-site fire. Fire suppression efforts used airport water storage; thus, the month of July has been used here as more representative of actual airport use. P:\ Jviation\000\Data\ Water&WW demand tables xls Wright Water Engineers, Inc. October 2014 Des By: BMN Rev By: SKB/DWF Ckd By: PRF/RKH/DWF

60 Table 2 Durango- La Plata County Airport Enplanements Proportional Enplanements 2012 Proportional Enplanements 2013 Proportional Enplanements Three Year Average Proportional Enplanements Month (1) (2) (3) (4) (5) (6) (7) January 11,887 11,993 15, % 6.43% 7.81% 7.01% February 11,001 12,255 14, % 6.57% 7.49% 6.78% March 12,836 13,381 14, % 7.17% 7.76% 7.42% April 12,306 12,388 14, % 6.64% 7.50% 7.06% May 14,776 14,031 15, % 7.52% 8.32% 8.10% June 16,345 17,323 18, % 9.29% 9.42% 9.35% July 18,127 18,714 19, % 10.03% 10.26% 10.22% August 17,653 19,535 18, % 10.47% 9.68% 10.08% September 16,670 18,347 17, % 9.84% 9.04% 9.47% October 15,386 17,412 16, % 9.33% 8.81% 8.98% November 13,641 15,552 12, % 8.34% 6.71% 7.61% December 14,391 15,596 13, % 8.36% 7.21% 7.93% Annual 175, , , Percent change from prior year 6.58% 2.92% Column Notes: (1) data provided by Jviation, "Durango-La Plata County Airport - Revenue Passenger Enplanements " 2014 data incomplete so was not used. (2) Ibid. (3) Ibid. (4) Number of enplanements for the month divided by total enplanements for the year. (5) Ibid. (6) Ibid. (7) Average of columns (4), (5), and (6) P:\ Jviation\000\Data\ Water&WW demand tables xls Wright Water Engineers, Inc. October 2014 Des By: BMN Rev By: SKB/DWF Ckd By: PRF/RKH/DWF

61 Table 3 Durango-La Plata County Airport Airport Water Use per Enplanement, (Aviation Water Use Only) Month Metered Water Usage 2011 Enplanements Water Use per Enplanement Metered Water Usage Enplanements Water Use per Enplanement Metered Water Usage Enplanements Water Use per Enplanement Average Monthly Water Use per Enplanement (gallons) (people) (gallons/person) (gallons) (people) (gallons/person) (gallons) (people) (gallons/person) (gallons/person/month) (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) January 198,563 11, ,906 11, ,108 15, February 252,118 11, ,987 12, ,359 14, March 280,490 12, ,177 13, ,268 14, April 276,194 12, ,801 12, ,517 14, May 254,265 14, ,895 14, ,339 15, June 259,354 16, ,705 17, ,332 18, July 298,024 18, ,908 18, ,622 19, August 229,302 17, ,502 19, ,531 18, September 240,736 16, ,353 18, ,180 17, October 294,766 15, ,458 17, ,420 16, November 306,765 13, ,112 15, ,068 12, December 305,314 14, ,183 15, ,660 13, Annual 3,195, , ,610, , ,117, , Column Notes: (1) From Table 1, Column 1 (2) From Table 2, Column (1) (3) Column (1) / Column (2) (4) From Table 1, Column 4 (5) From Table 2, Column (2) (6) Column (4) / Column (5) (7) From Table 1, Column 7 (5) From Table 2, Column (3) (9) Column (7) / Column (8) (10) Average of Columns (3), (6) and (9) P:\ Jviation\000\Data\ Water&WW demand tables xls Wright Water Engineers, Inc. October 2014 Des By: BMN Rev By: SKB/DWF Ckd By: PRF/RKH/DWF

62 Table 4 Durango-La Plata County Airport Projected Enplanements Year Enplanements , , , , , , , , , , , , , , , , , , , , , , , , ,923 Notes: enplanement data provided by Jviation, "Durango-La Plata County Airport - Revenue Passenger Enplanements " See Table Year 2015, 2020, 2025, 2030 and 2035 projections provided by Jviation. 3. Interim year projections based on 3.5% Preferred Forecast average annual growth rate provided by Jviation. P:\ Jviation\000\Data\ Water&WW demand tables xls Wright Water Engineers, Inc. October 2014 Des By: BMN Rev By:SKB/DWF Ckd By: PRF/RKH/DWF

63 Table 5 Durango-La Plata County Airport (Aviation Water Use Only) 2035 Projected Airport Water Demands Based on Water Consumption per Enplanement Projected 2035 Enplanements Average Water Use per Enplanement Total Water Demand Average Daily Water Demand Month (enplanements) (gallons per enplanement) (gallons) (gallons/day) (1) (2) (3) (4) January 28, ,110 19,520 February 27, ,845 22,994 March 30, ,678 20,732 April 29, ,252 23,308 May 33, ,587 22,761 June 38, ,881 20,696 July 42, ,450 23,692 August 41, ,278 20,815 September 38, ,312 21,077 October 36, ,207 24,039 November 31, ,854 24,795 December 32, ,267 23,105 Annual Total 411, ,134,721 Average Gallons per Day (GPD) (5) 22,287 Max Month Average Day GPD (6) (November) 24,795 Column Notes: 1) 2035 projected number of enplanements (411,923) from Table 4, based on Year 2015, 2020, 2025, 2030 and 2035 projections and 3.5% Preferred Forecast average annual growth rate provided by Jviation. Proportional allocation of enplanements per month from monthly % in Table 2 Column (7), based on enplanement data provided by Jviation: "Durango-La Plata County Airport - Revenue Passenger Enplanements " 2) From Table 3 Column (10). 3) Column (1) x Column (2) 4) Column (3) / number of days in the month 5) Total 2035 Annual Projected Demand (E22) divided by 365 days/year 6) Maximum value of Column (4) P:\ Jviation\000\Data\ Water&WW demand tables xls Wright Water Engineers, Inc. October 2014 Des By: BMN Rev By:SKB/DWF Ckd By: PRF/RKH/DWF

64 Table 6 Durango-La Plata County Airport Existing Non-Aviation Commercial Service Full Occupancy Demands Month Indoor Office Warehouse Total Indoor Irrigation Total (gallons) (gallons) (gallons) (gallons) (gallons) (1) (2) (3) (4) (5) January 116,250 4, , ,900 February 105,000 4, , ,200 March 116,250 4, , ,900 April 112,500 4, ,000 4, ,643 May 116,250 4, ,900 76, ,905 June 112,500 4, , , ,017 July 116,250 4, , , ,605 August 116,250 4, ,900 95, ,700 September 112,500 4, ,000 65, ,007 October 116,250 4, ,900 11, ,142 November 112,500 4, , ,000 December 116,250 4, , ,900 Annual 1,368,750 54,750 1,423, ,420 1,916,920 Average Gallons per Day 3, ,900 1,352 5,252 Max Month Average Day GPD (July) 7,826 Notes: 1) Based on 250 employees at 15 gallons per employee per day. 15 gallons/employee/day is per CDPHE regulations. 2) Based on 10 employees at 15 gallons per employee per day. 3) Column (1) + Column (2). 4) Based on Irrigation Water Requirement of 2.02 ft/acre for 0.6 acres of Kentucky Bluegrass, Ignacio Climate Station data, and 80% irrigation efficiency. 5) Column (3) + Column (4). P:\ Jviation\000\Data\ Water&WW demand tables xls Wright Water Engineers, Inc. October 2014 Des By: BMN Rev By:SKB/DWF Ckd By: PRF/RKH/DWF

65 Table 7 Durango-La Plata County Airport Historical Wastewater Treatment Plant Effluent (Aviation Use Only) Metered Water Usage (gallons) Wastewater WWTP Return Treatment Plant Flow as Effluent Percentage of (gallons) Total Water Use Metered Water Usage (gallons) Wastewater WWTP Return Treatment Plant Flow as Effluent Percentage of (gallons) Total Water Use Metered Water Usage (gallons) Wastewater WWTP Return Treatment Plant Flow as Effluent Percentage of (gallons) Total Water Use Three Year Average (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) January 198, ,219 64% 315, ,060 35% 297, ,092 67% 55% February 252, ,885 55% 301, ,486 36% 310, ,126 42% 44% March 280, ,197 51% 295, ,564 42% 285, ,254 40% 44% April 276, ,599 53% 298, ,760 41% 368, ,566 34% 42% May 254, ,945 56% 273, ,322 43% 427, ,958 33% 44% June 259, ,835 55% 266, ,376 65% 309, ,608 48% 56% July 298, ,793 47% 301, ,486 59% 389, ,646 64% 57% August 229, ,179 61% 328, ,276 54% 312, ,784 78% 64% September 240, ,113 52% 295, ,362 72% 314, ,866 82% 69% October 294, ,199 43% 333, ,296 65% 374, ,174 49% 52% November 306, ,875 39% 287, ,842 75% 389, ,530 53% 55% December 305, ,515 52% 312, ,972 79% 339, ,862 42% 58% Annual 3,707,391 1,646,358 4,063,687 2,001,802 4,713,904 2,146,466 Annual Average 266, ,197 52% 300, ,817 55% 343, ,872 53% 53% Column Notes: (1) From Table 1, Column (1) (2) Total for the month, less Non-Aviation Commercial Effluent Discharge (100% of Non-Aviation Commercial average winter water consumption (water use November-March); data from Durango-La Plata County Airport spreadsheet: "2011, 2012, 2013" (3) Column 2 divided by Column 1 (4) From Table 1, Column (4) (5) Ibid Column note (2) (6) Ibid Column note (3) (7) From Table 1, Column (9) (8) Total for the month, less Non-Aviation Commercial Effluent Discharge (100% of Non-Aviation Commercial average winter water consumption (water use November-March); data from Durango-La Plata County Airport spreadsheets: "2011, 2012, 2013" through May 2013; June through December data from individual month spreadsheets. (9) Ibid Column note (3) (10) Average value of the WWTP Return Flow as Percentage of Total Water Use for 2011, 2012, and 2013 Additional Notes: May 2013 Metered water usage included water from storage provided to fire district for residential fire near airport. P:\ Jviation\000\Data\ Water&WW demand tables xls Wright Water Engineers, Inc. October 2014 Des By: SKB Ckd By: PRF/RKH/DWF

66 Table 8(a) Durango-La Plata County Airport Airport Wastewater Effluent per Enplanement Month WWTP Effluent Enplanements WW Effluent per Enplanement WWTP Effluent Enplanements WW Effluent per Enplanement WWTP Effluent Enplanements WW Discharge per Enplanement Average Monthly Waste Water Discharge per Enplanement using monthly totals (gallons) (people) (gallons/person) (gallons) (people) (gallons/person) (gallons) (people) (gallons/person) (gallons/person/month) (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) January 126,219 11, ,060 11, ,092 15, February 137,885 11, ,486 12, ,126 14, March 142,197 12, ,564 13, ,254 14, April 146,599 12, ,760 12, ,566 14, May 141,945 14, ,322 14, ,958 15, June 143,835 16, ,376 17, ,608 18, July 140,793 18, ,486 18, ,646 19, August 140,179 17, ,276 19, ,784 18, September 124,113 16, ,362 18, ,866 17, October 126,199 15, ,296 17, ,174 16, November 118,875 13, ,842 15, ,530 12, December 157,515 14, ,972 15, ,862 13, Annual 1,646, , ,001, , ,146, , Column Notes: (1) From Table 7, Column (2) (2) From Table 2, Column (1) (3) Column (1) / Column (2). (4) From Table 7, Column (5) (5) From Table 2, Column (2) (6) Column (4) / Column (5) (7) From Table 7, Column (8) (8) From Table 2, Column (3) (9) Column (7) / Column (8) (10) Average of Columns (3), (6) and (9) P:\ Jviation\000\Data\ Water&WW demand tables xls Wright Water Engineers, Inc. October 2014 Des By: SKB Ckd By: PRF/RKH/DWF

67 Table 8(b) Durango-La Plata County Airport Daily Airport Wastewater Effluent Flows 2012* Month Average Average Daily WWTP Effluent (gallons) Average Daily WWTP Effluent (gallons) Average Daily WWTP Effluent (gallons) January 9,000 9,000 February 5,600 5,600 March 5,700 5,700 April 4,960 4,960 May 4,510 4,510 June 5,790 5,790 July 5,100 9,200 7,150 August 6,200 9,000 7,600 September 8,200 9,400 8,800 October 8,000 6,800 7,400 November 8,100 7,700 7,900 December 6,500 5,000 5,750 Annual 7,017 6,888 6,931 Source: Data provided by David Miller, Durango-La Plata County Airport: "DMR Summary " Note: *Airport staff implemented flow meters with higher accuracy in July 2012; thus, no data prior to July 2012 was used in these calculations. P:\ Jviation\000\Data\ Water&WW demand tables xls Wright Water Engineers, Inc. October 2014 Des By: SKB Ckd By: PRF/RKH/DWF

68 Table 9 Durango-La Plata County Airport Projected 2035 Total Monthly Water Demands and WWTP Discharge (all values in gallons unless otherwise noted) (1) (2) (3) (4) (5) (6) Projected 2035 Water Demand Month Airport Non-Aviation Commercial - Indoor Non-Aviation Commercial Irrigation Total Water Demand WWTP Discharge Calculated Depletions (AF) January 605, , , , February 643, , , , March 642, , , , April 699, ,000 4, , , May 705, ,900 76, , , June 620, , , , , July 734, , , , , August 645, ,900 95, , , September 632, ,000 65, , , October 745, ,900 11, , , November 743, , , , December 716, , , , Annual Total 8,134,721 1,423, ,420 10,051,641 5,765, Average Gallons per Day (a) Max Month Average GPD (b) (July Water; September Wastewater) Max Day GPD (Peaking Factor = 1.2) (c) Max Day GPD (Peaking Factor = 1.2) with 20% safety factor Existing Treatment Capacity Gallons per Day (d) 27,539 15,797 31,518 18,340 37,821 N/A 45,386 N/A 33,000 25,000 Column Notes: (1) Based on an estimate of 411,923 total enplanements in the year 2035, historical monthly percentages of total enplanements, and historical ( ) average daily water demands for each month. See Table 5, Column (3). (2) Based on 15 gallons per employee per day (planning value from Colorado Department of Health, Water Quality Control Division), and an estimated 250 Office employees and 10 Warehouse employees at full occupancy. (3) Based on Irrigation Water Requirement for 0.6 acres of Kentucky Bluegrass, Ignacio Climate Station data, and 80% irrigation efficiency. (4) Sum of Columns (1), (2) and (3). Includes irrigation. (5) [Column (1)*Monthly average % return flow from Table 7 - average monthly return flow over the three year period (Table 7)] plus Column (2). Excludes irrigation demands. (6) [Column (4) - Column (5)] / 325,851. Footnotes: (a) Annual Total divided by 365 days/year. b) Maximum monthly values, July water, September wastewater, divided by 31 and 30 days respectively. c) Maximum day peaking factor to allow for max weekly day aviation load factor daily water treatment. No daily peaking factor for wastewater due to long hydraulic residence time dampening peak day flows in the teatment plant. (d) Water treatment capacity from Goff Engineering Preliminary Engineering Report, Wastewater treatment capacity from CDPS Fact Sheet Permit No. CO , (e) These numbers subject to change due to leaks, measuring accuracy and changes in water management. P:\ Jviation\000\Data\ Water&WW demand tables xls Wright Water Engineers, Inc. October 2014 Des By: BMN Rev By:SKB/DWF Ckd By: PRF/RKH/DWF

69 Table 10 Durango-La Plata County Airport Airport Water Rights for Potable Water Supply Water Right Name Case No. Adjudication Date Appropriation Date Administration No. Decreed Rate/Volume Absolute Conditional Type of Water Right Source Decreed Uses Notes Airport Spring and Collection Basin W /31/1974 1/29/ cfs Spring in the Florida River watershed Domestic and commercial for airport Airport Infiltration Gallery 90CW20 12/31/1990 6/30/ cfs 0.84 cfs Groundwater Municipal and commercial at airport Airport Pipeline 99CW66 12/31/ /28/ cfs 24.3 AF/yr of HCU credits 0.25 cfs Surface Florida River Domestic, commercial (including but not limited to uses for retail stores, restaurants, car and airplane washing, airplane de-icing, and passenger enplanements), light industrial, light manufacturing, fire protection, storage, augmentation and exchange 90CW20 is for non-irrigation season supply Well Permit No. Total diversions at original POD and APOD limited to use during the irrigation season (May- Sept), up to 257 AF/yr. POD at or near Airport Infiltration Gallery, APOD at Tyner East Side Ditch First Enlargement Airport Phase I Reservoir 99CW66 12/31/ /28/ AF Storage Florida River Airport Phase II Reservoir 99CW66 12/31/ /28/ AF Storage Florida River Total CFS cfs 1.09 cfs Augmentation purposes and for the Airport uses described above for the Airport Pipeline water right Total AF 39 AF of storage and 24.3 AF absolute of HCU credits, other direct diversion amounts not quantified in acre-feet Source: Decrees Note: Ownership of water rights subject to review of legal counsel. P:\ Jviation\000\Data\water rights\ Airport Water Rights.xlsx Wright Water Engineers, Inc. 11/4/2014 Des By: BMN Ckd By: PRF

70 Table 11 Durango-La Plata County Airport Airport Water Rights for Non-Potable Irrigation Uses Water Right Name Case No. Adjudication Date Appropriation Date Administration No. Airport's Decreed Water Rights and Storage Allocations Type of Water Right Source Decreed Uses Notes King Ditch various various various various 2.00 cfs Surface Pine River Irrigation The King Consolidated Ditch Company owns and operates the ditch, which has a water right of cfs from several decrees. The County owns eight shares in the King Ditch for Airport property use which is 1.92% of total ditch water right, 2.0 cfs of the total decreed amount (Goff, 2000). Master Plan (BWC, 2011) estimates rights provide between 1.6 cfs and 2.0 cfs. Pine River Project various various various various 320 AF Storage of surface water Pine River Irrigation Certificate No. 665 for 160 acres is owned by the County in association with lands on the Airport Mesa, served by the King Ditch, according to PRID. 1 acre of PRID water yields approximately 2 AF, depending on the water year. Florida Project CA 1751-B and others various various various 10.0 AF Storage of surface water Florida River Irrigation of 15 acres A project allocation was transferred to County with purchase of parcel from Fassbender, information from recorded document. Project allocations are managed by the FWCD. Gregg Pipeline No. 1 CA1751-B 5/3/1968 3/15/ cfs Surface Florida River Gregg Pipeline No. 2 W169, W279 12/31/1970 8/30/ cfs Surface Florida River Irrigation, domestic Irrigation, domestic W169 for irrigation of 12 acres, W279 added 0.1 cfs. Gregg Reservoir W170 12/31/1970 8/30/ AF Storage of surface water Florida River Irrigation, domestic Filled by runoff and wastewater from irrigation. Water from the reservoir decreed to supply Gregg Pipeline Nos. 1 and 2. Sources La Plata County Water Master Plan, Bikis Water Consultants, May Water Augmentation Plan for Future Aviation and Non-Aviation Development, Goff Engineering, January 2000 Application and Order for Reallocation or Transfer of Florida Project Water Allotment (Reception No ), verified as final by FWCD. Pine River Irrigation District (phone conversation 10/27/14). Notes Decreed amounts are the rates (cfs) except Gregg Reservoir and Florida Project Allocation, which are in volume (acre-feet). Water Rights are sorted by seniority. Ownership of water rights subject to review of legal counsel. P:\ Jviation\000\Data\water rights\ Airport Water Rights.xlsx T11 Irrigation Water Rights WWE October 2014 des: RKH ckd: PRF

71 Figures

72

73 Figure 1 Durango-La Plata County Airport Percent Enplanements each Month % 10.50% 9.50% 8.50% 7.50% 6.50% 5.50% 2011 Proportional Enplanements 2012 Proportional Enplanements 2013 Proportional Enplanements Source: Jviation, "Durango-La Plata County Airport - Revenue Passenger Enplanements "

74 Figure 2 Durango-La Plata County Airport Treated Water Demand over Time 40,000 35,000 Gallons 30,000 25,000 Peak Water Demand at 3.5% growth (gallons/day) Peak Water Demand at 1.9% growth (gallons/day) Existing Treatment Capacity (gallons per day) 20,000 15,000 Year

75 Legend "/ Water Infrastructure Features Original Infiltration Gallery 1 inch = 500 Feet Feet Florida River "/ Airport Terminal Infiltration Gallery Expansion "/ "/ Infiltration Gallery Pump Vault Lower Pump House "/ "/ "/ "/ Spring Water Storage Tanks Upper Pump House Florida River "/ Wastewater Effluent Discharge "/ Wastewater Treatment Lagoons Document Path: P:\ Jviation\000\Mapping\Figure 3 Existing Water Infrastructure.mxd Wright Water Engineers, Inc N. Main Ave., Ste.C Durango, CO (970) ph fx DURANGO LA PLATA COUNTY AIRPORT Source: Esri, DigitalGlobe, GeoEye, i-cubed, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN, IGP, swisstopo, and the GIS User Community LA PLATA COUNTY, CO EXISTING WATER AND WASTEWATER TREATMENT INFRASTRUCTURE PROJECT NO FIGURE 3

76

77 Legend FIGURE 5-DURANGO LA PLATA AIRPORT - WATER AND WASTEWATER MASTER PLAN Archuleta Potential Service Area Bayfield Potential District El Rancho Florida Metro District Potential Ignacio Area Not In District Initial District North Potential Service Area 160A SW Archuleta Potential Service Area South Animas Potential Service Area VanDenburg Metro District Potential Twn_Rng Durango Cities Durango Bayfield 550A 172A Ignacio 151A For: LAPLAWD WMCP FIGURE 1 Date: February 2014 Harris Water Engineering, Inc. File: Z:\Projects\LAPLAWD\ServiceAreas.mxd

78 CR 321 CR 208 CR 207 CR 211 CR 141 CR 212 As preliminary pipeline is completed in certain areas, then secondary routing will be constructed. ÍÎ$ Legend "! Pumps ³ PRVs C Alternate Water Sources 3Q TP - General Vacinity UT Tanks - General Vacinity Distribution & Main Lines Twn_Rng Cities BIA BLM COLORADO USFS For: LAPLAWD Master Plan FIGURE NINE Date: October 2009 Harris Water Engineering, Inc. File: Z:\Projects\LAPLAWD\exclusions.mxd FIGURE 6-DURANGO LA PLATA AIRPORT - WATER AND WASTEWATER MASTER PLAN CR 206 UT "! 3Q C CR 213 La Plata Archuleta Water District Preliminary Pipeline Routing & Distribution System ÍÎ$ CR 215 CR 204 Animas River r CR 216 ³ C CR 219 ÍÎ$ ³ CR 214 CR 217 CR 251 CR 238 Durango./ 550A./ 550A CR 302 CR 220 CR 301 CR 301 CR 300 CR 240 CR 235 CR 233 CR 304 CR 303 CR 310 CR 234 CR 307 ÍÎ$ Florida River CR 310 CR 305 CR 229 ³ CR 225 CR 230 CR 221 CR 222 CR 308 CR 228 CR 225 ÍÎ$ ÍÎ$ CR 309a ³ ³ CR 309 Airport CR 310 "! CR 224 CR 223 ÍÎ$ CR 338 CR 311 UT "! UT ÍÎ$ ³ ÍÎ$ ³ ÍÎ$ ³ ÍÎ$ ³ CR 513 ÍÎ$ CR 512 CR 313 ³ CR 503 CR 510 CR 515 CR 314 CR 318 CR 511 CR 315 ³ CR 514 CR 319 CR 504 ÍÎ$ CR 508 CR 316 ³ Bayfield CR 509a CR 314 Ignacio CR 509 CR 505 C CR 517 CR 502 C ÍÎ$ CR 516 CR 521 CR 322 ST 172A CR 501 "! 3Q ³ CR 519 Pine River CR 323 UT C CR 518 ST 151A CR 526 CR 336 CR 324 ÍÎ$ ÍÎ$ CR 523 CR 524 CR 522 ³ ³ CR 523 CR 334 CR 333 CR 327 "! CR 528 ÍÎ$ CR 326 CR 328 ³ CR 527 CR 525./ 160A UT CR 330 CR 329 CR 332 CR 335 CR 331 CR 329

79 Appendices

80

81 Appendix A Water and Wastewater Data Durango-La Plata County Airport

82

83 Water Use Data

84

85 READ DATE: January 2011 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $10.92 AvFlight Cave AvFlight Hangar Enterprise $7.02 Budget $5.07 National $12.48 Avis $1.17 Hertz $2.34 Forest Service $7.80 Forest Service $7.80 Care Flight $24.18 BP Warehouse BP Operation Center $4, AMPT $5.07 PVT Hangar with Sewer W-1 Starbase $7.41 W-2 D&P $7.41 W-3 Rocky Mtn. Aero $7.80 W-4 N2U $1.95 W-5 0 -$7.80 W-6 0 -$7.80 W-7 ARER $7.80 W-10 Face Canyon $7.41 E-1 MSSR $7.80 E-2 GRS $7.41 E-3 SWE No Water Service 0 -$7.80 E-4 0 -$7.80 E-5 0 -$7.80 E-6 0 -$7.80 E-7 0 -$7.80 E-8 - Gemperline $7.80 T-6-A LPHP $7.80 T-6-B LPHP $7.80 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Service with no meter 0 -$7.80 A-2 No Water Service 0 -$7.80 A-3 Water Service with no meter 0 -$7.80 D-A-1 All D Hangars ond-a-2 0 -$7.80 D-A $7.80 D-A-3 0 -$7.80 D-A-4 0 -$7.80 D-A-5 Water Service with no meter 0 -$7.80 D-A-6 0 -$7.80 Sabo (1554) $7.41 McCann (1490) $0.39 May (1452) $7.80 D & J Hangar (1448) $6.63 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ Start End Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL AIRPORT TOTAL TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE 26400

86 READ DATE: February 2011 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $18.33 AvFlight Cave AvFlight Hangar Enterprise $0.78 Budget $9.75 National $12.48 Avis $3.12 Hertz $4.68 Forest Service $7.80 Forest Service $7.80 Care Flight $22.23 BP Warehouse BP Operation Center $4, McCann PVT Hangar with Sewer W-1 Starbase $0.78 W-2 D&P $7.80 W-3 Rocky Mtn. Aero $7.41 W-4 N2U $7.80 W-5 0 -$7.80 W-6 0 -$7.80 W-7 ARER $7.80 W-10 Face Canyon $7.80 E-1 MSSR $7.41 E-2 GRS $7.80 E-3 SWE No Water Svc 0 -$7.80 E-4 0 -$7.80 E-5 0 -$7.80 E-6 0 -$7.80 E-7 0 -$7.80 E-8 - Gemperline $7.80 T-6-A LPHP $7.80 T-6-B LPHP $7.80 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Svc-no meter 0 -$7.80 A-2 No Water Service 0 -$7.80 A-3 Water Svc-no meter 0 -$7.80 D-A-1 All D on D-A-2 0 -$7.80 D-A $7.80 D-A-3 0 -$7.80 D-A-4 0 -$7.80 D-A-5 Water Svc-no meter 0 -$7.80 D-A-6 0 -$7.80 Sabo (1554) $7.80 McCann (1490) $7.80 May (1452) $7.41 D & J Hangar (1448) $5.46 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ Start End Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL AIRPORT TOTAL TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE 9200

87 READ DATE: March 2011 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $9.75 AvFlight Cave AvFlight Hangar Enterprise $8.19 Budget $1.95 National $4.68 Avis $4.29 Hertz $26.52 Forest Service $58.50 Forest Service $7.80 Care Flight $26.91 BP Warehouse BP Operation Center $3, McCann PVT Hangar with Sewer W-1 Starbase $6.63 W-2 D&P $7.41 W-3 Rocky Mtn. Aero $7.41 W-4 N2U $7.80 W-5 0 -$7.80 W-6 0 -$7.80 W-7 ARER $7.80 W-10 Face Canyon $7.80 E-1 MSSR $7.80 E-2 GRS $7.80 E-3 SWE No Water Service 0 -$7.80 E-4 0 -$7.80 E-5 0 -$7.80 E-6 0 -$7.80 E-7 0 -$7.80 E-8 - Gemperline $6.24 T-6-A LPHP $7.41 T-6-B LPHP $7.80 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.41 A-1 Water Service with no meter 0 -$7.80 A-2 No Water Service 0 -$7.80 A-3 Water Service with no meter 0 -$7.80 D-A-1 All D Hangars ond-a-2 0 -$7.80 D-A $7.41 D-A-3 0 -$7.80 D-A-4 0 -$7.80 D-A-5 Water Service with no meter 0 -$7.80 D-A-6 0 -$7.80 Sabo (1554) $7.80 McCann (1490) $7.80 May (1452) $7.41 D & J Hangar (1448) $5.85 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ Start End Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL 50 AIRPORT TOTAL TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

88 READ DATE: 5/4/2011 April 2011 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $17.55 AvFlight Cave AvFlight Hangar Enterprise $5.85 Budget $0.39 National $4.68 Avis $31.20 Hertz $12.09 Forest Service $11.70 Forest Service $7.80 Care Flight $31.20 BP Warehouse BP Operation Center $3, McCann PVT Hangar with Sewer W-1 Starbase $7.41 W-2 D&P $7.80 W-3 Rocky Mtn. Aero $7.80 W-4 N2U $7.41 W $7.80 W $7.80 W-7 ARER $7.80 W-10 Face Canyon $6.63 E-1 MSSR $7.80 E-2 GRS $7.41 E-3 SWE No Water Servi 0 0 -$7.80 E $7.80 E $7.80 E $7.80 E $7.80 E-8 - Gemperline $7.41 T-6-A LPHP $7.41 T-6-B LPHP $7.41 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Service w 0 0 -$7.80 A-2 No Water Servi 0 0 -$7.80 A-3 Water Service w 0 0 -$7.80 D-A-1 All D Hangars o 0 0 -$7.80 D-A $7.80 D-A $7.80 D-A $7.80 D-A-5 Water Service w 0 0 -$7.80 D-A $7.80 Sabo (1554) $7.41 McCann (1490) $7.80 May (1452) $7.02 D & J Hangar (1448) $7.80 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ Start End Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL AIRPORT TOTAL TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

89 READ DATE: May 2011 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Over Max Building Meter # Start End Total Used Usage Charge AvFlight Durango $16.77 AvFlight Cave AvFlight Hangar Enterprise $3.12 Budget $9.36 National $5.07 Avis $1.17 Hertz $7.80 Forest Service $11.70 Forest Service $ Care Flight $28.86 BP Warehouse BP Operation Center $2, McCann PVT Hangar with Sewer W-1 Starbase $7.41 W-2 D&P $7.80 W-3 Rocky Mtn. Aero $7.41 W-4 N2U $7.80 W $7.80 W $7.80 W-7 ARER $7.80 W-10 Face Canyon $7.80 E-1 MSSR $7.41 E-2 GRS $7.80 E-3 SWE No Water Service 0 -$7.80 E-4 0 -$7.80 E-5 0 -$7.80 E-6 0 -$7.80 E-7 0 -$7.80 E-8 - Gemperline $7.41 T-6-A LPHP $7.80 T-6-B LPHP $7.41 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Service with no meter 0 -$7.80 A-2 No Water Service 0 -$7.80 A-3 Water Service with no meter 0 -$7.80 D-A-1 All D Hangars ond-a-2 0 -$7.80 D-A $9.36 D-A-3 0 -$7.80 D-A-4 0 -$7.80 D-A-5 Water Service with no meter 0 -$7.80 D-A-6 0 -$7.80 Sabo (1554) $7.80 McCann (1490) $7.41 May (1452) $7.02 D & J Hangar (1448) $3.51 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ (over max) Start End Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL AIRPORT TOTAL TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE 0 INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

90 READ DATE: June 2011 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $33.93 AvFlight Cave AvFlight Hangar Enterprise $0.78 Budget $4.68 National $5.46 Avis $13.26 Hertz $8.19 Forest Service $11.70 Forest Service $7.80 Care Flight $30.03 BP Warehouse BP Operation Center $2, McCann PVT Hangar with Sewer W-1 Starbase $7.41 W-2 D&P $7.80 W-3 Rocky Mtn. Aero $7.41 W-4 N2U $7.80 W-5 0 -$7.80 W-6 0 -$7.80 W-7 ARER $6.63 W-10 Face Canyon $7.80 E-1 MSSR $7.80 E-2 GRS $7.80 E-3 SWE No Water Service 0 -$7.80 E-4 0 -$7.80 E-5 0 -$7.80 E-6 0 -$7.80 E-7 0 -$7.80 E-8 - Gemperline $6.63 T-6-A LPHP $7.41 T-6-B LPHP $7.80 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Service with no meter 0 -$7.80 A-2 No Water Service 0 -$7.80 A-3 Water Service with no meter 0 -$7.80 D-A-1 All D Hangars ond-a-2 0 -$7.80 D-A $6.24 D-A-3 0 -$7.80 D-A-4 0 -$7.80 D-A-5 Water Service with no meter 0 -$7.80 D-A-6 0 -$7.80 Sabo (1554) $7.80 McCann (1490) $7.41 May (1452) $7.41 D & J Hangar (1448) $5.46 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ Start End Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL -39 AIRPORT TOTAL 8311 TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

91 READ DATE: July 2011 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $45.24 AvFlight Cave AvFlight Hangar Enterprise $4.68 Budget $6.63 National $12.87 Avis $16.38 Hertz $9.75 Forest Service $58.50 Forest Service $7.80 Care Flight $37.05 BP Warehouse BP Operation Center $3, McCann PVT Hangar with Sewer W-1 Starbase $7.80 W-2 D&P $7.80 W-3 Rocky Mtn. Aero $7.41 W-4 N2U $7.80 W-5 0 -$7.80 W-6 0 -$7.80 W-7 ARER $7.41 W-10 Face Canyon $7.80 E-1 MSSR $7.80 E-2 GRS $7.80 E-3 SWE No Water Service 0 -$7.80 E-4 0 -$7.80 E-5 0 -$7.80 E-6 0 -$7.80 E-7 0 -$7.80 E-8 - Gemperline $7.02 T-6-A LPHP $7.02 T-6-B LPHP $7.80 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Service with no meter 0 -$7.80 A-2 No Water Service 0 -$7.80 A-3 Water Service with no meter 0 -$7.80 D-A-1 All D Hangars ond-a-2 0 -$7.80 D-A $7.80 D-A-3 0 -$7.80 D-A-4 0 -$7.80 D-A-5 Water Service with no meter 0 -$7.80 D-A-6 0 -$7.80 Sabo (1554) $7.41 McCann (1490) $7.41 May (1452) $7.41 D & J Hangar (1448) $7.41 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ Start End Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL 79 AIRPORT TOTAL TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

92 READ DATE: August 2011 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $58.50 AvFlight Cave AvFlight Hangar Enterprise $8.58 Budget $7.41 National $5.07 Avis $19.11 Hertz $8.97 Forest Service $19.50 Forest Service $7.80 Care Flight $34.71 BP Warehouse BP Operation Center $3, McCann PVT Hangar with Sewer W-1 Starbase $7.41 W-2 D&P $7.80 W-3 Rocky Mtn. Aero $7.02 W-4 N2U $7.41 W-5 0 -$7.80 W-6 0 -$7.80 W-7 ARER $7.02 W-10 Face Canyon $7.02 E-1 MSSR $7.41 E-2 GRS $7.80 E-3 SWE No Water Service 0 -$7.80 E-4 0 -$7.80 E-5 0 -$7.80 E-6 0 -$7.80 E-7 0 -$7.80 E-8 - Gemperline $7.02 T-6-A LPHP $7.41 T-6-B LPHP $7.41 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Service with no meter 0 -$7.80 A-2 No Water Service 0 -$7.80 A-3 Water Service with no meter 0 -$7.80 D-A-1 All D Hangars ond-a-2 0 -$7.80 D-A $7.80 D-A-3 0 -$7.80 D-A-4 0 -$7.80 D-A-5 Water Service with no meter 0 -$7.80 D-A-6 0 -$7.80 Sabo (1554) $7.02 McCann (1490) $5.46 May (1452) $6.63 D & J Hangar (1448) $7.41 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ Start End Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL 69 AIRPORT TOTAL TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

93 READ DATE: September 2011 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $27.30 AvFlight Cave AvFlight Hangar Enterprise $21.84 Budget $1.95 National $2.34 Avis $18.33 Hertz $8.58 Forest Service $0.00 Forest Service $7.80 Care Flight $31.98 BP Warehouse BP Operation Center $2, McCann/AMPT PVT Hangar with Sewer W-1 Starbase $7.41 W-2 D&P $7.41 W-3 Rocky Mtn. Aero $7.02 W-4 N2U $7.80 W-5 0 -$7.80 W-6 0 -$7.80 W-7 ARER $7.02 W-10 Face Canyon $7.80 E-1 MSSR $7.80 E-2 GRS $7.80 E-3 SWE No Water Service 0 -$7.80 E-4 0 -$7.80 E-5 0 -$7.80 E-6 0 -$7.80 E-7 0 -$7.80 E-8 - Gemperline $7.02 T-6-A LPHP $7.41 T-6-B LPHP $7.80 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Service with no meter 0 -$7.80 A-2 No Water Service 0 -$7.80 A-3 Water Service with no meter 0 -$7.80 D-A-1 All D Hangars ond-a-2 0 -$7.80 D-A $7.80 D-A-3 0 -$7.80 D-A-4 0 -$7.80 D-A-5 Water Service with no meter 0 -$7.80 D-A-6 0 -$7.80 Sabo (1554) $7.80 McCann (1490) $7.80 May (1452) $7.80 D & J Hangar (1448) $7.41 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ Start End Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL 68 AIRPORT TOTAL 6003 TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION 0 PREDICTED WASTE 0 ACTUAL WASTE

94 READ DATE: October 2011 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $44.07 AvFlight Cave AvFlight Hangar Enterprise $14.04 Budget $0.39 National $1.95 Avis $15.21 Hertz $4.29 Forest Service $3.90 Forest Service $7.80 Care Flight $28.86 BP Warehouse BP Operation Center $5, McCann (AMPT) PVT Hangar with Sewer W-1 Starbase $7.41 W-2 D&P $7.80 W-3 Rocky Mtn. Aero $7.80 W-4 N2U $7.80 W-5 0 -$7.80 W-6 0 -$7.80 W-7 ARER $7.80 W-10 Face Canyon $7.41 E-1 MSSR $5.85 E-2 GRS $7.41 E-3 SWE No Water Service 0 -$7.80 E-4 0 -$7.80 E-5 0 -$7.80 E-6 0 -$7.80 E-7 0 -$7.80 E-8 - Gemperline $7.41 T-6-A LPHP $7.80 T-6-B LPHP $7.80 PVT Hangar without Sewer Gundersen $7.41 Gilmer $7.80 Patton $7.80 A-1 Water Service with no meter 0 -$7.80 A-2 No Water Service 0 -$7.80 A-3 Water Service with no meter 0 -$7.80 D-A-1 All D Hangars ond-a-2 0 -$7.80 D-A $7.41 D-A-3 0 -$7.80 D-A-4 0 -$7.80 D-A-5 Water Service with no meter 0 -$7.80 D-A-6 0 -$7.80 Sabo (1554) $7.80 McCann (1490) $0.00 May (1452) $7.41 D & J Hangar (1448) $7.41 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ Start End Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL 57 AIRPORT TOTAL TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

95 READ DATE: November 2011 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $62.40 AvFlight Cave AvFlight Hangar Enterprise $12.48 Budget $0.00 National $2.34 Avis $17.55 Hertz $5.46 Forest Service $3.90 Forest Service $7.80 Care Flight $30.81 BP Warehouse BP Operation Center $5, McCann - 317(AMPT) PVT Hangar with Sewer W-1 Starbase $7.41 W-2 D&P $7.80 W-3 Rocky Mtn. Aero $7.41 W-4 N2U $7.41 W-5 0 -$7.80 W-6 0 -$7.80 W-7 ARER $7.02 W-10 Face Canyon $7.41 E-1 MSSR $7.41 E-2 GRS $7.80 E-3 SWE No Water Service 0 -$7.80 E-4 0 -$7.80 E-5 0 -$7.80 E-6 0 -$7.80 E-7 0 -$7.80 E-8 - Gemperline $7.41 T-6-A LPHP $7.41 T-6-B LPHP $7.80 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Service with no meter 0 -$7.80 A-2 No Water Service 0 -$7.80 A-3 Water Service with no meter 0 -$7.80 D-A-1 All D Hangars ond-a-2 0 -$7.80 D-A $7.80 D-A-3 0 -$7.80 D-A-4 0 -$7.80 D-A-5 Water Service with no meter 0 -$7.80 D-A-6 0 -$7.80 Sabo (1554) $7.41 McCann (1490) $7.80 May (1452) $7.41 D & J Hangar (1448) $7.80 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ Start End Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL 52 AIRPORT TOTAL 6252 TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

96 READ DATE: December 2011 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # End End Total Used Usage Charge AvFlight Durango $22.62 AvFlight Cave AvFlight Hangar Enterprise $12.48 Budget $4.29 National $0.39 Avis $15.99 Hertz $6.63 Forest Service $3.90 Forest Service $7.80 Care Flight $30.42 BP Warehouse BP Operation Center $3, McCann - 317(AMPT) PVT Hangar with Sewer W-1 Starbase $7.41 W-2 D&P $7.80 W-3 Rocky Mtn. Aero $7.80 W-4 N2U $7.80 W-5 0 -$7.80 W-6 0 -$7.80 W-7 ARER $7.41 W-10 Face Canyon $7.80 E-1 MSSR $7.41 E-2 GRS $7.80 E-3 SWE No Water Service 0 -$7.80 E-4 0 -$7.80 E-5 0 -$7.80 E-6 0 -$7.80 E-7 0 -$7.80 E-8 - Gemperline $7.41 T-6-A LPHP $7.80 T-6-B LPHP $7.80 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Service with no meter 0 -$7.80 A-2 No Water Service 0 -$7.80 A-3 Water Service with no meter 0 -$7.80 D-A-1 All D Hangars ond-a-2 0 -$7.80 D-A $7.80 D-A-3 0 -$7.80 D-A-4 0 -$7.80 D-A-5 Water Service with no meter 0 -$7.80 D-A-6 0 -$7.80 Sabo (1554) $7.80 McCann (1490) $7.80 May (1452) $7.80 D & J Hangar (1448) $6.63 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ End End Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL 58 AIRPORT TOTAL 5512 TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

97 READ DATE: January 2012 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $24.57 AvFlight Cave AvFlight Hangar Enterprise $12.09 Budget $1.56 National $1.56 Avis $10.14 Hertz $4.68 Forest Service $3.90 Forest Service $7.80 Care Flight $45.63 BP Warehouse BP Operation Center $4, AMPT $6.24 PVT Hangar with Sewer W-1 Starbase $7.02 W-2 D&P $7.41 W-3 Rocky Mtn. Aero $7.41 W-4 N2U $7.80 W-5 0 -$7.80 W-6 0 -$7.80 W-7 ARER $7.80 W-10 Face Canyon $7.80 E-1 MSSR $14.82 E-2 GRS $7.80 E-3 SWE No Water Service 0 -$7.80 E-4 0 -$7.80 E-5 0 -$7.80 E-6 0 -$7.80 E-7 0 -$7.80 E-8 - Gemperline $7.02 T-6-A LPHP $7.41 T-6-B LPHP $7.80 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Service with no meter 0 -$7.80 A-2 No Water Service 0 -$7.80 A-3 Water Service with no meter 0 -$7.80 D-A-1 All D Hangars ond-a-2 0 -$7.80 D-A $7.80 D-A-3 0 -$7.80 D-A-4 0 -$7.80 D-A-5 Water Service with no meter 0 -$7.80 D-A-6 0 -$7.80 Sabo (1554) $7.80 McCann (1490) $7.80 May (1452) $7.80 D & J Hangar (1448) $7.41 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ Start End Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL AIRPORT TOTAL TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

98 READ DATE: February 2012 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $17.55 AvFlight Cave AvFlight Hangar Enterprise $16.38 Budget $1.56 National $0.78 Avis $10.92 Hertz $5.07 Forest Service $3.90 Forest Service $7.80 Care Flight $15.99 BP Warehouse BP Operation Center $3, AMPT PVT Hangar with Sewer W-1 Starbase $7.02 W-2 D&P $7.80 W-3 Rocky Mtn. Aero $7.02 W-4 N2U $7.80 W-5 0 -$7.80 W-6 0 -$7.80 W-7 ARER $6.63 W-10 Face Canyon $7.80 E-1 MSSR $0.39 E-2 GRS $7.80 E-3 SWE No Water Svc 0 -$7.80 E-4 0 -$7.80 E-5 0 -$7.80 E-6 0 -$7.80 E-7 0 -$7.80 E-8 - Gemperline $7.80 T-6-A LPHP $7.80 T-6-B LPHP $7.80 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Svc-no meter 0 -$7.80 A-2 No Water Service 0 -$7.80 A-3 Water Svc-no meter 0 -$7.80 D-A-1 All D on D-A $7.80 D-A $7.80 D-A-3 0 -$7.80 D-A-4 0 -$7.80 D-A-5 Water Svc-no meter 0 -$7.80 D-A-6 0 -$7.80 Sabo (1554) $7.41 McCann (1490) $7.80 May (1452) $7.41 D & J Hangar (1448) $7.41 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ End End Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL AIRPORT TOTAL TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

99 READ DATE: March 2012 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $26.91 AvFlight Cave AvFlight Hangar Enterprise $8.19 Budget $12.48 National $6.63 Avis $12.48 Hertz $10.53 Forest Service $15.60 Forest Service $7.80 Care Flight $38.61 BP Warehouse BP Operation Center $3, AMPT PVT Hangar with Sewer W-1 Starbase $6.63 W-2 D&P $7.80 W-3 Rocky Mtn. Aero $7.02 W-4 N2U $7.80 W-5 0 -$7.80 W-6 0 -$7.80 W-7 ARER $7.02 W-10 Face Canyon $7.80 E-1 MSSR $1.95 E-2 GRS $7.80 E-3 SWE No Water Service 0 -$7.80 E-4 0 -$7.80 E-5 0 -$7.80 E-6 0 -$7.80 E-7 0 -$7.80 E-8 - Gemperline $7.02 T-6-A LPHP $4.68 T-6-B LPHP $7.41 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Service with no meter 0 -$7.80 A-2 No Water Service 0 -$7.80 A-3 Water Service with no meter 0 -$7.80 D-A-1 All D Hangars ond-a-2 0 -$7.80 D-A $7.80 D-A-3 0 -$7.80 D-A-4 0 -$7.80 D-A-5 Water Service with no meter 0 -$7.80 D-A-6 0 -$7.80 Sabo (1554) $7.41 McCann (1490) $7.80 May (1452) $7.41 D & J Hangar (1448) $6.63 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ End End Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL AIRPORT TOTAL TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

100 READ DATE: 5/4/2011 April 2012 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $31.59 AvFlight Cave AvFlight Hangar Enterprise $9.36 Budget $1.56 National $3.12 Avis $7.80 Hertz $5.46 Forest Service $11.70 Forest Service $7.80 Care Flight $31.20 BP Warehouse BP Operation Center $3, AMPT PVT Hangar with Sewer W-1 Starbase $7.41 W-2 D&P $7.80 W-3 Rocky Mtn. Aero $7.80 W-4 N2U $7.80 W-5 0 -$7.80 W-6 0 -$7.80 W-7 ARER $6.24 W-10 Face Canyon $7.41 E-1 MSSR $7.80 E-2 GRS $7.80 E-3 SWE No Water Service 0 -$7.80 E-4 0 -$7.80 E-5 0 -$7.80 E-6 0 -$7.80 E-7 0 -$7.80 E-8 - Gemperline $7.02 T-6-A LPHP $7.02 T-6-B LPHP $7.80 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Service with no meter 0 -$7.80 A-2 No Water Service 0 -$7.80 A-3 Water Service with no meter 0 -$7.80 D-A-1 All D Hangars o $7.80 D-A $7.80 D-A-3 0 -$7.80 D-A-4 0 -$7.80 D-A-5 Water Service with no meter 0 -$7.80 D-A-6 0 -$7.80 Sabo (1554) $7.80 McCann (1490) $7.41 May (1452) $7.80 D & J Hangar (1448) $7.41 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ Start End Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL 1337 AIRPORT TOTAL TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

101 READ DATE: May 2012 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Over Max Building Meter # Start End Total Used Usage Charge AvFlight Durango $25.35 AvFlight Cave AvFlight Hangar Enterprise $19.89 Budget $2.73 National $1.56 Avis $12.87 Hertz $7.80 Forest Service $27.30 Forest Service $7.80 Care Flight $31.98 BP Warehouse BP Operation Center $2, AMPT PVT Hangar with Sewer W-1 Starbase $6.24 W-2 D&P $7.80 W-3 Rocky Mtn. Aero $7.02 W-4 N2U $7.41 W-5 0 -$7.80 W-6 0 -$7.80 W-7 ARER $7.02 W-10 Face Canyon $7.80 E-1 MSSR $7.80 E-2 GRS $7.41 E-3 SWE No Water Service 0 -$7.80 E-4 0 -$7.80 E-5 0 -$7.80 E-6 0 -$7.80 E-7 0 -$7.80 E-8 - Gemperline $7.02 T-6-A LPHP $7.80 T-6-B LPHP $7.41 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Service with no meter 0 -$7.80 A-2 No Water Service 0 -$7.80 A-3 Water Service with no meter 0 -$7.80 D-A-1 All D Hangars o $7.80 D-A $7.80 D-A-3 0 -$7.80 D-A-4 0 -$7.80 D-A-5 Water Service with no meter 0 -$7.80 D-A-6 0 -$7.80 Sabo (1554) $7.80 McCann (1490) $7.80 May (1452) $7.02 D & J Hangar (1448) $5.46 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ (over max) Start End Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL 61 AIRPORT TOTAL 6461 TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

102 READ DATE: June 2012 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $51.09 AvFlight Cave AvFlight Hangar Enterprise $13.65 Budget $15.21 National $0.00 Avis $14.43 Hertz $10.53 Forest Service $50.70 Forest Service $7.80 Care Flight $30.03 BP Warehouse BP Operation Center $3, AMPT PVT Hangar with Sewer W-1 Starbase $7.41 W-2 D&P $7.41 W-3 Rocky Mtn. Aero $7.41 W-4 N2U $7.80 W-5 0 -$7.80 W-6 0 -$7.80 W-7 ARER $6.24 W-10 Face Canyon $7.02 E-1 MSSR $7.80 E-2 GRS $7.80 E-3 SWE No Water Service 0 -$7.80 E-4 0 -$7.80 E-5 0 -$7.80 E-6 0 -$7.80 E-7 0 -$7.80 E-8 - Gemperline $6.63 T-6-A LPHP $7.02 T-6-B LPHP $7.80 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Service with no meter 0 -$7.80 A-2 No Water Service 0 -$7.80 A-3 Water Service with no meter 0 -$7.80 D-A-1 All D Hangars o $7.80 D-A $7.80 D-A-3 0 -$7.80 D-A-4 0 -$7.80 D-A-5 Water Service with no meter 0 -$7.80 D-A-6 0 -$7.80 Sabo (1554) $7.80 McCann (1490) $7.41 May (1452) $7.41 D & J Hangar (1448) $15.60 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ Start End Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL 87 AIRPORT TOTAL 4592 TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

103 READ DATE: July 2012 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $98.67 AvFlight Cave AvFlight Hangar Enterprise $4.68 Budget $2.34 National $10.92 Avis $23.79 Hertz $8.19 Forest Service $27.30 Forest Service $7.80 Care Flight $31.20 BP Warehouse BP Operation Center $4, AMPT PVT Hangar with Sewer W-1 Starbase $7.41 W-2 D&P $7.41 W-3 Rocky Mtn. Aero $7.41 W-4 N2U $7.80 W-5 0 -$7.80 W-6 0 -$7.80 W-7 ARER $7.41 W-10 Face Canyon $7.41 E-1 MSSR $7.41 E-2 GRS $7.41 E-3 SWE No Water Service 0 -$7.80 E-4 0 -$7.80 E-5 0 -$7.80 E-6 0 -$7.80 E-7 0 -$7.80 E-8 - Gemperline $7.41 T-6-A LPHP $6.63 T-6-B LPHP $7.41 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Service with no meter 0 -$7.80 A-2 No Water Service 0 -$7.80 A-3 Water Service with no meter 0 -$7.80 D-A-1 All D Hangars o $7.80 D-A $7.80 D-A-3 0 -$7.80 D-A-4 0 -$7.80 D-A-5 Water Service with no meter 0 -$7.80 D-A-6 0 -$7.80 Sabo (1554) $7.80 McCann (1490) $7.80 May (1452) $7.80 D & J Hangar (1448) $6.63 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ Start End Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL 81 AIRPORT TOTAL 6076 TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

104 READ DATE: August 2012 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $38.61 AvFlight Cave AvFlight Hangar Enterprise $6.24 Budget $1.56 National $14.43 Avis $30.03 Hertz $8.19 Forest Service $31.20 Forest Service $7.80 Care Flight $37.83 BP Warehouse BP Operation Center $3, AMPT PVT Hangar with Sewer W-1 Starbase $7.41 W-2 D&P $7.41 W-3 Rocky Mtn. Aero $7.80 W-4 N2U $7.80 W-5 0 -$7.80 W-6 0 -$7.80 W-7 ARER $7.80 W-10 Face Canyon $7.41 E-1 MSSR $7.80 E-2 GRS $7.80 E-3 SWE No Water Service 0 -$7.80 E-4 0 -$7.80 E-5 0 -$7.80 E-6 0 -$7.80 E-7 0 -$7.80 E-8 - Gemperline $7.02 T-6-A LPHP $29.25 T-6-B LPHP $7.80 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.41 A-1 Water Service with no meter 0 -$7.80 A-2 No Water Service 0 -$7.80 A-3 Water Service with no meter 0 -$7.80 D-A-1 All D Hangars o $7.80 D-A $7.80 D-A-3 0 -$7.80 D-A-4 0 -$7.80 D-A-5 Water Service with no meter 0 -$7.80 D-A-6 0 -$7.80 Sabo (1554) $7.02 McCann (1490) $7.80 May (1452) $7.41 D & J Hangar (1448) $7.02 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ Start End Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL -16 AIRPORT TOTAL 8184 TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

105 READ DATE: September 2012 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $30.03 AvFlight Cave AvFlight Hangar Enterprise $5.85 Budget $0.39 National $7.02 Avis $28.47 Hertz $8.19 Forest Service $3.90 Forest Service $7.80 Care Flight $33.54 BP Warehouse BP Operation Center $3, AMPT PVT Hangar with Sewer W-1 Starbase $6.63 W-2 D&P $7.80 W-3 Rocky Mtn. Aero $7.41 W-4 N2U $7.80 W-5 0 -$7.80 W-6 0 -$7.80 W-7 ARER $7.41 W-10 Face Canyon $7.41 E-1 MSSR $7.80 E-2 GRS $7.80 E-3 SWE No Water Service 0 -$7.80 E-4 0 -$7.80 E-5 0 -$7.80 E-6 0 -$7.80 E-7 0 -$7.80 E-8 - Gemperline $7.41 T-6-A LPHP $7.02 T-6-B LPHP $7.80 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Service with no meter 0 -$7.80 A-2 No Water Service 0 -$7.80 A-3 Water Service with no meter 0 -$7.80 D-A-1 All D Hangars o 0 0 -$7.80 D-A $7.80 D-A-3 0 -$7.80 D-A-4 0 -$7.80 D-A-5 Water Service with no meter 0 -$7.80 D-A-6 0 -$7.80 Sabo (1554) $7.41 McCann (1490) $7.80 May (1452) $7.80 D & J Hangar (1448) $7.41 Mosley (1414) $19.50 TOTAL USAGE CHARGES $ End End Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL 198 AIRPORT TOTAL 3098 TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

106 READ DATE: October 2012 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # End End Total Used Usage Charge AvFlight Durango $21.84 AvFlight Cave AvFlight Hangar Enterprise $3.90 Budget $3.12 National $5.07 Avis $15.60 Hertz $5.07 Forest Service $23.40 Forest Service $7.80 Care Flight $29.25 BP Warehouse BP Operation Center $3, AMPT PVT Hangar with Sewer W-1 Starbase $7.02 W-2 D&P $7.80 W-3 Rocky Mtn. Aero $7.80 W-4 N2U $7.41 W-5 0 -$7.80 W-6 0 -$7.80 W-7 ARER $7.80 W-10 Face Canyon $7.80 E-1 MSSR $7.80 E-2 GRS $7.80 E-3 SWE No Water Service 0 -$7.80 E-4 0 -$7.80 E-5 0 -$7.80 E-6 0 -$7.80 E-7 0 -$7.80 E-8 - Gemperline $7.02 T-6-A LPHP $7.41 T-6-B LPHP $7.41 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Service with no meter 0 -$7.80 A-2 No Water Service 0 -$7.80 A-3 Water Service with no meter 0 -$7.80 D-A-1 All D Hangars ond-a-2 0 -$7.80 D-A $7.80 D-A-3 0 -$7.80 D-A-4 0 -$7.80 D-A-5 Water Service with no meter 0 -$7.80 D-A-6 0 -$7.80 Sabo (1554) $7.80 McCann (1490) $7.02 May (1452) $7.41 D & J Hangar (1448) $7.80 Mosley (1414) $3.90 TOTAL USAGE CHARGES $ End End Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL 55 AIRPORT TOTAL 2955 TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

107 READ DATE: November 2012 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $25.35 AvFlight Cave AvFlight Hangar Enterprise $1.56 Budget $0.78 National $3.90 Avis $16.38 Hertz $1.56 Forest Service $3.90 Forest Service $7.80 Care Flight $31.98 BP Warehouse BP Operation Center $2, AMPT PVT Hangar with Sewer W-1 Starbase $7.02 W-2 D&P $7.80 W-3 Rocky Mtn. Aero $7.80 W-4 N2U $7.41 W-5 0 -$7.80 W-6 0 -$7.80 W-7 ARER $7.80 W-10 Face Canyon $7.80 E-1 MSSR $7.80 E-2 GRS $7.80 E-3 SWE No Water Service 0 -$7.80 E-4 0 -$7.80 E-5 0 -$7.80 E-6 0 -$7.80 E-7 0 -$7.80 E-8 - Gemperline $7.41 T-6-A LPHP $7.41 T-6-B LPHP $7.80 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Service with no meter 0 -$7.80 A-2 No Water Service 0 -$7.80 A-3 Water Service with no meter 0 -$7.80 D-A-1 All D Hangars ond-a-2 0 -$7.80 D-A $7.80 D-A-3 0 -$7.80 D-A-4 0 -$7.80 D-A-5 Water Service with no meter 0 -$7.80 D-A-6 0 -$7.80 Sabo (1554) $7.41 McCann (1490) $7.80 May (1452) $7.41 D & J Hangar (1448) $7.41 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ End End Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL 70 AIRPORT TOTAL 6270 TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

108 READ DATE: January 2013 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $38.61 AvFlight Cave AvFlight Hangar Enterprise $5.85 Budget $1.56 National $8.19 Avis $8.19 Hertz $0.78 Forest Service $3.90 Forest Service $7.80 Care Flight $46.02 BP Warehouse BP Operation Center $5, AMPT PVT Hangar with Sewer W-1 Starbase $7.41 W-2 D&P $7.80 W-3 Rocky Mtn. Aero $7.41 W-4 N2U $1.95 W $7.80 W-6 0 -$7.80 W-7 ARER $7.80 W-10 Face Canyon $7.41 E-1 MSSR $7.80 E-2 GRS $7.80 E-3 SWE No Water Service 0 -$7.80 E-4 0 -$7.80 E-5 0 -$7.80 E-6 0 -$7.80 E-7 0 -$7.80 E-8 - Gemperline $7.80 T-6-A LPHP $7.41 T-6-B LPHP $7.80 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Service with no meter 0 -$7.80 A-2 No Water Service 0 -$7.80 A-3 Water Service with no meter 0 -$7.80 D-A-1 All D Hangars ond-a-2 0 -$7.80 D-A $7.80 D-A-3 0 -$7.80 D-A-4 0 -$7.80 D-A-5 Water Service with no meter 0 -$7.80 D-A-6 0 -$7.80 Sabo (1554) $6.63 McCann (1490) $7.41 May (1452) $7.80 D & J Hangar (1448) $7.41 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ End Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL 64 AIRPORT TOTAL 4464

109 READ DATE: February 2013 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $40.56 AvFlight Cave AvFlight Hangar Enterprise $11.31 Budget $2.34 National $10.92 Avis $34.71 Hertz $7.80 Forest Service $0.00 Forest Service $7.80 Care Flight $31.59 BP Warehouse BP Operation Center $5, AMPT PVT Hangar with Sewer W-1 Starbase $6.63 W-2 D&P $7.41 W-3 Rocky Mtn. Aero $7.80 W-4 N2U $6.24 W $7.41 W $7.80 W-7 ARER $7.80 W-10 Face Canyon $7.80 E-1 MSSR $7.80 E-2 GRS $7.80 E-3 SWE No Water Servi 0 0 -$7.80 E $7.80 E $7.80 E $7.80 E $7.80 E-8 - Gemperline $3.12 T-6-A LPHP $7.80 T-6-B LPHP $7.80 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Service w 0 0 -$7.80 A-2 No Water Servi 0 0 -$7.80 A-3 Water Service w 0 0 -$7.80 D-A-1 All D Hangars o 0 0 -$7.80 D-A $7.80 D-A $7.80 D-A $7.80 D-A-5 Water Service w 0 0 -$7.80 D-A $7.80 Sabo (1554) $5.85 McCann (1490) $7.80 May (1452) $7.41 D & J Hangar (1448) $7.80 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL 62 AIRPORT TOTAL 2662 TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

110 READ DATE: March 2013 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $23.01 AvFlight Cave AvFlight Hangar Enterprise $8.97 Budget $0.39 National $1.56 Avis $23.01 Hertz $2.73 Forest Service $3.90 Forest Service $7.80 Care Flight $20.28 BP Warehouse BP Operation Center $5, AMPT PVT Hangar with Sewer W-1 Starbase $6.63 W-2 D&P $7.80 W-3 Rocky Mtn. Aero $7.41 W-4 N2U $7.41 W $7.41 W $7.80 W-7 ARER $7.80 W-10 Face Canyon $7.80 E-1 MSSR $7.80 E-2 GRS $7.80 E-3 SWE No Water Servi 0 0 -$7.80 E $7.80 E $7.80 E $7.80 E $7.80 E-8 - Gemperline $6.63 T-6-A LPHP $7.41 T-6-B LPHP $7.80 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.41 A-1 Water Service w 0 0 -$7.80 A-2 No Water Servi 0 0 -$7.80 A-3 Water Service w 0 0 -$7.80 D-A-1 All D Hangars o 0 0 -$7.80 D-A $7.80 D-A $7.80 D-A $7.80 D-A-5 Water Service w 0 0 -$7.80 D-A $7.80 Sabo (1554) $7.80 McCann (1490) $7.80 May (1452) $7.80 D & J Hangar (1448) $6.63 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL 53 AIRPORT TOTAL 6753 TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

111 READ DATE: April 2013 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $77.61 AvFlight Cave AvFlight Hangar Enterprise $9.75 Budget $1.17 National $0.39 Avis $24.18 Hertz $4.29 Forest Service $3.90 Forest Service $7.80 Care Flight $29.25 BP Warehouse BP Operation Center $5, AMPT PVT Hangar with Sewer W-1 Starbase $6.63 W-2 D&P $7.80 W-3 Rocky Mtn. Aero $7.80 W-4 N2U $7.80 W $7.80 W $7.80 W-7 ARER $7.80 W-10 Face Canyon $7.80 E-1 MSSR $7.80 E-2 GRS $7.80 E-3 SWE No Water Servi 0 0 -$7.80 E $7.80 E $7.80 E $7.80 E $7.80 E-8 - Gemperline $7.41 T-6-A LPHP $7.41 T-6-B LPHP $7.80 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Service w 0 0 -$7.80 A-2 No Water Servi 0 0 -$7.80 A-3 Water Service w 0 0 -$7.80 D-A-1 All D Hangars o 0 0 -$7.80 D-A $7.80 D-A $7.80 D-A $7.80 D-A-5 Water Service w 0 0 -$7.80 D-A $7.80 Sabo (1554) $7.80 McCann (1490) $6.63 May (1452) $7.41 D & J Hangar (1448) $7.41 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL 57 AIRPORT TOTAL 8657 TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW 0 0 OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

112 May 2013 Commercial with Sewer 6/3/2013 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Building Meter # Start End Total Used Usage Charge AvFlight Durango $62.40 AvFlight Cave AvFlight Hangar Enterprise $4.68 Budget $0.78 National $7.41 Avis $40.95 Hertz $7.41 Forest Service $58.50 Forest Service $7.80 Care Flight $33.54 BP Warehouse BP Operation Center $5, AMPT PVT Hangar with Sewer W-1 Starbase $6.24 W-2 D&P $7.80 W-3 Rocky Mtn. Aero $7.80 W-4 N2U $7.80 W $7.80 W $7.80 W-7 ARER $7.41 W-10 Face Canyon $7.80 E-1 MSSR $7.41 E-2 GRS $7.80 E-3 SWE No Water Servi 0 0 -$7.80 E $7.80 E $7.80 E $7.80 E $7.80 E-8 - Gemperline $7.41 T-6-A LPHP $7.02 T-6-B LPHP $7.80 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Service w 0 0 -$7.80 A-2 No Water Servi 0 0 -$7.80 A-3 Water Service w 0 0 -$7.80 D-A-1 All D Hangars o 0 0 -$7.80 D-A $7.80 D-A $7.80 D-A $7.80 D-A-5 Water Service w 0 0 -$7.80 D-A $7.80 Sabo (1554) $7.80 McCann (1490) $7.80 May (1452) $7.41 D & J Hangar (1448) $7.41 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL 75 AIRPORT TOTAL 7975 TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW 0 0 OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

113 READ DATE: June 2013 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $96.33 AvFlight Cave AvFlight Hangar Enterprise $10.92 Budget $2.34 National $3.12 Avis $82.68 Hertz $5.46 Forest Service $39.00 Forest Service $7.80 Care Flight $32.76 BP Warehouse BP Operation Center $4, AMPT PVT Hangar with Sewer W-1 Starbase $7.02 W-2 D&P $7.80 W-3 Rocky Mtn. Aero $7.41 W-4 N2U $7.80 W $10.53 W $4.68 W-7 ARER $7.41 W-10 Face Canyon $7.80 E-1 MSSR $7.80 E-2 GRS $7.80 E-3 SWE No Water Servi 0 0 -$7.80 E $7.80 E $7.80 E $7.80 E $7.80 E-8 - Gemperline $7.02 T-6-A LPHP $7.80 T-6-B LPHP $7.41 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.41 A-1 Water Service w 0 0 -$7.80 A-2 No Water Servi 0 0 -$7.80 A-3 Water Service w 0 0 -$7.80 D-A-1 All D Hangars o 0 0 -$7.80 D-A $7.80 D-A $7.80 D-A $7.80 D-A-5 Water Service w 0 0 -$7.80 D-A $7.80 Sabo (1554) $7.41 McCann (1490) $7.41 May (1452) $7.80 D & J Hangar (1448) $6.24 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL 73 AIRPORT TOTAL 6573 TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW 0 0 OUTFLOW 0 0 ACT PACK HOURS OF OPERATION 0 0 PREDICTED WASTE 0 ACTUAL WASTE

114 READ DATE: July 2013 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $ AvFlight Cave AvFlight Hangar Enterprise $17.16 Budget $7.80 National $2.34 Avis $83.46 Hertz $13.26 Forest Service $39.00 Forest Service $7.80 Care Flight $33.15 BP Warehouse BP Operation Center $4, AMPT PVT Hangar with Sewer W-1 Starbase $7.80 W-2 D&P $7.80 W-3 Rocky Mtn. Aero $7.80 W-4 N2U $7.02 W $7.80 W $10.92 W-7 ARER $7.80 W-10 Face Canyon $7.41 E-1 MSSR $7.80 E-2 GRS $7.80 E-3 SWE No Water Servi 0 0 -$7.80 E $7.80 E $7.80 E $7.80 E $7.80 E-8 - Gemperline $7.02 T-6-A LPHP $7.41 T-6-B LPHP $7.80 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.41 A-1 Water Service w 0 0 -$7.80 A-2 No Water Servi 0 0 -$7.80 A-3 Water Service w 0 0 -$7.80 D-A-1 All D Hangars o 0 0 -$7.80 D-A $7.80 D-A $7.80 D-A $7.80 D-A-5 Water Service w 0 0 -$7.80 D-A $7.80 Sabo (1554) $5.85 McCann (1490) $7.80 May (1452) $7.41 D & J Hangar (1448) $7.02 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL 89 AIRPORT TOTAL 8389 TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION 0 0 PREDICTED WASTE 0 ACTUAL WASTE

115 READ DATE: August 2013 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $69.81 AvFlight Cave AvFlight Hangar Enterprise $12.48 Budget $4.68 National $0.00 Avis $78.00 Hertz $10.14 Forest Service $7.80 Forest Service $7.80 Care Flight $27.69 BP Warehouse BP Operation Center $4, AMPT PVT Hangar with Sewer W-1 Starbase $7.02 W-2 D&P $7.80 W-3 Rocky Mtn. Aero $7.80 W-4 N2U $7.80 W $7.80 W $4.68 W-7 ARER $7.02 W-10 Face Canyon $7.80 E-1 Billy Morgan $7.80 E-2 GRS $7.80 E-3 SWE No Water Service 0 0 -$7.80 E $7.80 E $7.80 E $7.80 E $7.80 E-8 - Gemperline $7.02 T-6-A LPHP $7.41 T-6-B LPHP $7.80 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Service with no meter 0 0 -$7.80 A-2 No Water Service 0 0 -$7.80 A-3 Water Service with no meter 0 0 -$7.80 D-A-1 All D Hangars ond-a $7.80 D-A $7.80 D-A $7.80 D-A $7.80 D-A-5 Water Service with no meter 0 0 -$7.80 D-A $7.80 Sabo (1554) $7.02 McCann (1490) $4.29 May (1452) $7.41 D & J Hangar (1448) $6.63 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL 76 AIRPORT TOTAL 7176 TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

116 READ DATE: September 2013 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $57.33 AvFlight Cave AvFlight Hangar Enterprise $13.65 Budget $0.78 National $1.95 Avis $85.41 Hertz $13.65 Forest Service $3.90 Forest Service $7.80 Care Flight $33.54 BP Warehouse BP Operation Center $5, AMPT PVT Hangar with Sewer W-1 Starbase $7.80 W-2 D&P $7.41 W-3 Rocky Mtn. Aero $7.41 W-4 N2U $5.07 W $7.80 W $7.80 W-7 ARER $7.41 W-10 Face Canyon $7.80 E-1 MSSR $7.80 E-2 GRS $7.41 E-3 SWE No Water Servi 0 0 -$7.80 E $7.80 E $7.80 E $7.80 E $7.80 E-8 - Gemperline $7.41 T-6-A LPHP $7.80 T-6-B LPHP $7.80 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Service w 0 0 -$7.80 A-2 No Water Servi 0 0 -$7.80 A-3 Water Service w 0 0 -$7.80 D-A-1 All D Hangars o 0 0 -$7.80 D-A $7.80 D-A $7.80 D-A $7.80 D-A-5 Water Service w 0 0 -$7.80 D-A $7.80 Sabo (1554) $7.80 McCann (1490) $ May (1452) $7.80 D & J Hangar (1448) $7.41 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL -771 AIRPORT TOTAL TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

117 READ DATE: October 2013 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $39.39 AvFlight Cave AvFlight Hangar Enterprise $12.09 Budget $0.78 National $2.73 Avis $86.58 Hertz $17.94 Forest Service $3.90 Forest Service $7.80 Care Flight $34.71 BP Warehouse BP Operation Center $5, AMPT PVT Hangar with Sewer W-1 Starbase $7.80 W-2 D&P $7.80 W-3 Rocky Mtn. Aero $7.41 W-4 N2U $7.80 W $7.80 W $7.80 W-7 ARER $7.41 W-10 Face Canyon $7.80 E-1 MSSR $7.80 E-2 GRS $7.80 E-3 SWE No Water Servi 0 0 -$7.80 E $7.80 E $7.80 E $7.80 E $7.80 E-8 - Gemperline $7.41 T-6-A LPHP $6.24 T-6-B LPHP $7.41 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.41 A-1 Water Service w 0 0 -$7.80 A-2 No Water Servi 0 0 -$7.80 A-3 Water Service w 0 0 -$7.80 D-A-1 All D Hangars o 0 0 -$7.80 D-A $7.80 D-A $7.80 D-A $7.80 D-A-5 Water Service w 0 0 -$7.80 D-A $7.80 Sabo (1554) $7.80 McCann (1490) $ Zraidnik (1452) $7.02 D & J Hangar (1448) $7.41 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL 918 AIRPORT TOTAL TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

118 READ DATE: November 2013 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $3, AvFlight Cave AvFlight Hangar Enterprise $1, Budget $ National $ Avis $1, Hertz $1, Forest Service $6, Forest Service $ Care Flight $3, BP Warehouse BP Operation Center $29, AMPT PVT Hangar with Sewer W-1 Starbase $46.80 W-2 D&P $18.33 W-3 Rocky Mtn. Aero $33.93 W-4 N2U $32.37 W $7.80 W $10.92 W-7 ARER $45.24 W-10 Face Canyon $43.29 E-1 MSSR $21.84 E-2 GRS $21.84 E-3 SWE No Water Servi 0 0 -$7.80 E $7.80 E $7.80 E $7.80 E $7.80 E-8 - Gemperline $ T-6-A LPHP $ T-6-B LPHP $15.99 PVT Hangar without Sewer Gundersen $8.97 Gilmer $7.80 Patton $11.31 A-1 Water Service w 0 0 -$7.80 A-2 No Water Servi 0 0 -$7.80 A-3 Water Service w 0 0 -$7.80 D-A-1 All D Hangars o 0 0 -$7.80 D-A $10.14 D-A $7.80 D-A $7.80 D-A-5 Water Service w 0 0 -$7.80 D-A $7.80 Sabo (1554) $25.74 McCann (1490) $31.20 May (1452) $31.98 D & J Hangar (1448) $ Mosley (1414) $19.50 TOTAL USAGE CHARGES $ - 0 Total Used TERMINAL TERMINAL TERMINAL SRE TERMINAL TOTAL AIRPORT TOTAL TOTAL USAGE ALL METERS WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE INFLOW OUTFLOW ACT PACK HOURS OF OPERATION PREDICTED WASTE ACTUAL WASTE

119 READ DATE: December 2013 DURANGO-LA PLATA COUNTY AIRPORT WATER USAGE Commercial with Sewer Building Meter # Start End Total Used Usage Charge AvFlight Durango $7.80 AvFlight Cave AvFlight Hangar Enterprise $7.80 Budget $7.80 National $7.80 Avis $7.80 Hertz $7.80 Forest Service $7.80 Forest Service $7.80 Care Flight $7.80 BP Warehouse BP Operation Center $5, AMPT PVT Hangar with Sewer W-1 Starbase $7.80 W-2 D&P $7.80 W-3 Rocky Mtn. Aero $7.80 W-4 N2U $7.80 W $7.80 W $7.80 W-7 ARER $7.80 W-10 Face Canyon $7.80 E-1 MSSR $7.80 E-2 GRS $7.80 E-3 SWE No Water Servi 0 0 -$7.80 E $7.80 E $7.80 E $7.80 E $7.80 E-8 - Gemperline $7.80 T-6-A LPHP $7.80 T-6-B LPHP $7.80 PVT Hangar without Sewer Gundersen $7.80 Gilmer $7.80 Patton $7.80 A-1 Water Service w 0 0 -$7.80 A-2 No Water Servi 0 0 -$7.80 A-3 Water Service w 0 0 -$7.80 D-A-1 All D Hangars o 0 0 -$7.80 D-A $7.80 D-A $7.80 D-A $7.80 D-A-5 Water Service w 0 0 -$7.80 D-A $7.80 Sabo (1554) $7.80 McCann (1490) $7.80 May (1452) $7.80 D & J Hangar (1448) $7.80 Mosley (1414) $7.80 TOTAL USAGE CHARGES $ - 0 Total Used TERMINAL TERMINAL TERMINAL SRE 0 0 TERMINAL TOTAL 0 AIRPORT TOTAL 0 TOTAL USAGE ALL METERS 0 WATER PRODUCTION GALLERY SPRING TOTAL RAW LOWER PUMP HOUSE 0 0 INFLOW 0 0 OUTFLOW 0 0 ACT PACK 0 0 HOURS OF OPERATION 0 0 PREDICTED WASTE 0 ACTUAL WASTE 0

120

121 Wastewater Effluent Data

122

123 Durango La Plata County Airport Water and Waste Water Flow Summary 2013 Infiltration Gal. Spring Water Filter Water Filter Waste Water Waste Water Inf. Eff. Inf. Eff. Jan Feb March April May June July Aug Sept Oct Nov. Dec. Infiltration Gal. Spring Water Filter Water Filter Waste Water Waste Water Inf. Eff. Inf. Eff. Jan Feb March April May June July Aug Sept Oct Nov Dec Infiltration Gal. Spring Water Filter Water Filter Waste Water Waste Water Inf. Eff; Inf. Eff. Jan Feb March April May June July Aug Sept Oct Nov Dec

124 Durango La Plata County Airport DMR Summary 2011 Parameter Month Effluent Jan. Feb. March April May June July Aug. Sept. Oct. Nov. Dec. BOD PH TSS NH E-Coli <1 <1 < <1 <1 <1 Flow 30Da no dis Flow Da MX no dis CL BOD 5 % re Oil / Grease TDS Effluent Public Water Influent BOD BOD lb 30Da TSS Flow 30Da Flow Da MX Effluent BOD 5, TSS and ph by Month Concentration in mg/l ph in S.U Jan. Feb. March April May June BOD 5July TSSAug. phsept. Oct. Nov. Dec. 7.4 Concentration in mg/l Influent BOD 5 and TSS by Month Month BOD 5 TSS

125 Durango La Plata County Airport DMR Summary 2012 Parameter Month Effluent Jan. Feb. March April May June July Aug. Sept. Oct. Nov. Dec. BOD PH TSS NH E-Coli <1 <1 <1 <1 <1 1 1 < <1 <1 <1 Flow 30Da Flow Da MX CL BOD 5 % re Oil / Grease TDS Effluent Public Water Influent BOD BOD lb 30Da TSS Flow 30Da Flow Da MX Effluent BOD 5, TSS and ph by Month 70 9 Concentration in mg/l ph in S.U Month BOD 5 TSS ph Influent BOD 5 and TSS by Month Concentration in mg/l Month BOD 5 TSS Concentration in mg/l Eflluent BOD 5 and Influent Flow by Month MonthBOD 5 Flow Day Average Flow in MGD

126 Durango La Plata County Airport DMR Summary 2013 Parameter Month Effluent Jan. Feb. March April May June July Aug. Sept. Oct. Nov. Dec. BOD PH TSS NH E-Coli <1 < Flow 30Da Flow Da MX CL BOD 5 % re Oil / Grease TDS Effluent Public Water Influent BOD BOD lb 30Da TSS Flow 30Da Flow Da MX Plant Capacity % Flow Organic Effluent BOD 5, TSS and ph by Month Concentration in mg/l Month BOD 5 TSS ph ph in S.U Influent BOD 5 and TSS by Month 1200 Concentration in mg/l Month BOD 5 TSS Effluent BOD 5 and Influent Flow by Month Concentration in mg/l MonthBOD 5 Flow Day Average Flow in MGD

127 Durango La Plata County Airport Wastewater Flow Summary (MGD) 2011 Jan. Feb. March April May June July Aug. Sept/ Oct. Nov. Dec. Influent 30 Day Av Daily Max Effluent 30 Day Av Daily Max Jan. Feb. March April May June July Aug. Sept/ Oct. Nov. Dec. Influent 30 Day Av Daily Max Effluent 30 Day Av Daily Max Jan. Feb. March April May June July Aug. Sept/ Oct. Nov. Dec. Influent 30 Day Av Daily Max Effluent 30 Day Av Daily Max

128 Month Durango La Plata County Airport Daily Lagoon Flow June Year 2013 INFLUENT EFFLUENT Day Start Stop Total x2 Day Start Stop Total x Totals Totals Average 9766 Average 5790 MGD MGD Daily Max Daily Max 8586 MGD MGD

129 Month Durango La Plata County Airport Daily Lagoon Flow JULY Year 2013 INFLUENT EFFLUENT Day Start Stop Total x2 Day Start Stop Total x Totals Totals Average Average MGD MGD Daily Max Daily Max MGD MGD

130 Month Durango La Plata County Airport Daily Lagoon Flow August Year 2013 INFLUENT EFFLUENT Day Start Stop Total x2 Day Start Stop Total x Totals Totals Average Average MGD MGD Daily Max Daily Max MGD MGD

131 Month Durango La Plata County Airport Daily Lagoon Flow SEPTEMBER Year 2013 INFLUENT EFFLUENT Day Start Stop Total x2 Day Start Stop Total x Totals Totals Average Average 9432 MGD MGD Daily Max Daily Max MGD MGD

132 Month Durango La Plata County Airport Daily Lagoon Flow Oct. Year 2013 INFLUENT EFFLUENT Day Start Stop Total x2 Day Start Stop Total x Totals Totals Average 9739 Average 6783 MGD MGD Daily Max Daily Max MGD MGD

133 Month Durango La Plata County Airport Daily Lagoon Flow November Year 2013 INFLUENT EFFLUENT Day Start Stop Total x2 Day Start Stop Total x Totals Totals Average Average 7688 MGD MGD Daily Max Daily Max MGD MGD

134 Month Durango La Plata County Airport Daily Lagoon Flow December Year 2013 INFLUENT EFFLUENT Day Start Stop Total x2 Day Start Stop Total x Totals Totals Average 8559 Average 5450 MGD MGD Daily Max Daily Max 7892 MGD MGD

135 Appendix B Enplanement Data Durango-La Plata County Airport

136

137 DURANGO-LA PLATA COUNTY AIRPORT - REVENUE PASSENGER ENPLANEMENTS Carrier Jan-14 Feb-14 Mar-14 Apr-14 May-14 Jun-14 Jul-14 Aug-14 Sep-14 Oct-14 Nov-14 Dec-14 Total American (Envoy) Frontier Airlines US Airways (SkyWest) US Airways (Mesa) United Express (Republic) United Express (Expressjet) United Express (Skywest) American (Express Jet) Total % Change monthly from % -11.1% 0.9% -10.7% -3.3% 1.5% % Change YTD from % -12.2% -7.8% -8.5% -7.4% -5.7% Carrier Jan-13 Feb-13 Mar-13 Apr-13 May-13 Jun-13 Jul-13 Aug-13 Sep-13 Oct-13 Nov-13 Dec-13 Total American Eagle Frontier Airlines US Airways (SkyWest) United Express (Republic) United Express (Expressjet) United Express (Skywest) American Eagle (Express Jet) Total % Change monthly from % 17.3% 11.3% 16.2% 13.9% 4.4% 5.2% -4.9% -5.5% -2.9% -17.2% -11.3% % Change YTD from % 21.1% 17.6% 17.3% 16.5% 13.9% 12.3% 9.5% 7.5% 6.4% 4.2% 2.9% Carrier Jan-12 Feb-12 Mar-12 Apr-12 May-12 Jun-12 Jul-12 Aug-12 Sep-12 Oct-12 Nov-12 Dec-12 Total American Eagle Frontier Airlines US Airways (Mesa) US Airways (SkyWest) United Express (Republic) United Express (Expressjet) United Express (Skywest) Total % Change monthly from % 11.4% 4.2% 0.7% -5.0% 6.0% 5.0% 10.1% 10.1% 13.2% 14.0% 8.4% % Change YTD from % 5.9% 5.3% 4.1% 2.0% 2.8% 3.2% 4.3% 5.0% 5.9% 6.6% 6.7% Carrier Jan-11 Feb-11 Mar-11 Apr-11 May-11 Jun-11 Jul-11 Aug-11 Sep-11 Oct-11 Nov-11 Dec-11 Total American Eagle Frontier Airlines U.S. Airways (Mesa) U.S. Airways (SkyWest) United Express (Expressjet) United Express (Skywest) Total % Change monthly from 2010 % Change YTD from 2010 Source: Data provided by Jviation, Inc.: "Durango-La Plata County Airport - Revenue Passenger Enplanements "

138

139 Appendix C CDPHE Alternative Filtration Acceptance Letter

140

141 May 23, 2014 Russ Swerdfeger Product Manager Evoqua Water Technologies LLC 725 Wooten Road Colorado Springs, CO, Subject: Acceptance of the Evoqua Water Technologies Model L10V/L10N/L20V/L20N as an Alternative Filtration Technology to meet the Colorado Primary Drinking Water Regulations requirements for Giardia lamblia and Cryptosporidium Removal Dear Mr. Swerdfeger; The Colorado Department of Public Health and Environment s Water Quality Control Division ( the Department ) has received and reviewed the information for the Evoqua (formerly Siemens) Water Technologies filtration systems utilizing the L10V, L10N, L20V, and L20N modules in accordance with Section 11.8(2)(b)(ii) and 11.10(5)(j) of the Colorado Primary Drinking Water Regulations (Regulation 11), 5 CCR The SWT L10V, L10N, L20V, and L20N modules meet or exceed the requirements of the State of Colorado Design Criteria for Potable Water Systems (DCPWS) Sections 1.11, and the requirements of Regulation 11. The technology is conditionally accepted for use as an Alternative Filtration Technology and granted the removal credit in Table 4.1, Section of the DCPWS. The technical specifications and conditions of acceptance for the Evoqua filtration skids and modules are outlined in Tables 1, 2, and 3 as well as Section of the DCPWS. This acceptance supersedes the previous acceptance of the L10V and L20V modules and associated filtration skids dated September 30, 2011, and the previous acceptance of the L10N and L20N modules dated January 3, This acceptance addresses the following items: Evoqua (formerly Siemens) Water Technologies L10V, L20V, L10N, and L20N ultrafiltration elements Evoqua XP and CP filtration skids XPE Economy skids This acceptance applies only to the L10V, L10N, L20V, and L20N modules and does not constitute construction approval for installation at any public water system. Each individual submittal to the Department must demonstrate conformance with Section of the DCPWS for each installation of the filters and filtration skids. Review and approval for the design of any public water system proposing to use this technology will be handled on a case-by-case basis by the Department as required by Section 11.4 of Regulation 11.

142 Russ Swerdfeger Evoqua Water Technologies May 23, 2014 Page 2 As part of this review, the Department has evaluated the following documents: Environmental Technology Verification Report Siemens Corporation Memcor L20V Ultrafiltration Module, September 2009 Environmental Technology Verification Report Siemens Corporation Memcor L10V Ultrafiltration Module, September 2009 Membrane filtration review document (August 2010) MS Excel spreadsheet completed by Russ Swerdfeger o Supplemental information to the review documents (Exhibits A-D) including process schematics for the CP and XP modules Siemens Water Technologies Economy Membrane Treatment Solutions Packet presented by Jeff Rhodes and Russ Swerdfeger November, 2010 NSF Certification for Public Drinking Water Equipment Performance Final Report for L10N and L20N Modules (August 2012) Siemens materials certification for membrane components Any addenda that will modify the modules must be submitted to the Department for review and acceptance prior to use in Colorado by a regulated public water system. This requirement includes any changes made to the L10V, L10N, L20V, and L20N materials of construction and associated interfaces with process piping. The Department will review any additional third party verification reports and issue a revised acceptance letter if appropriate. Table 1: L10V, L20V, L10N, L20N Technical Specifications and Conditions of Acceptance Filter Manufacturer Evoqua Water Technologies Filter Model L10V L20V L10N L20N Maximum Flux (gfd -gallons per sq. ft. per 20 C Maximum Flux 1 C Max Transmembrane Pressure lbs per square inch differential (psid) 22 Alarm Transmembrane Pressure (psid) 18 Maximum Inlet Pressure lbs per square inch gauge (psig) 50 psig Minimum direct integrity test pressure (starting pressure) 10.5 psig 11.8 psig 10.5 psig 11.8 psig Direct integrity testing failure criteria >1.5 psig per minute decay per Siemens approved protocol Prefiltration micron pre-screening is required. Additional Operations and Maintenance Criteria 1. If a filter fails an integrity test, the filter must be removed from service immediately and replaced with a functional filter or repaired prior to being returned to operation. 2. The public water system must keep records of the following operational parameters (available for

143 Russ Swerdfeger Evoqua Water Technologies May 23, 2014 Page 3 Department review): a. Integrity test date, results (pass or fail), and initials of person performing the test b. Clean in place (CIP) dates with clean water permeability and integrity test result. c. Filter maintenance and fiber repair results d. Filter replacement date and reason for replacement. 3. Public water systems must maintain an operation and maintenance manual for the micro/ultratfiltration system. All integrity tests and CIP procedures must follow manufacturer prescribed procedures. Table 2: Pre-Accepted Skids Conditions of Acceptance: Skid Type Skid Model Number Maximum Daily Production (gallons) Based on max temperature See Table 1 Cross connection control (DCPWS (b)(vii)) Individual Skid Effluent Turbidity (DCPWS (a)and (d)) Flow Control (DCPWS (c) and (e)) XP 3-24L10V or L10N XP 18-42L20V or L20N Evoqua CP L20V or L20N CP L20V or L20N 25, , ,000 6,000,000 Not verified. Block and bleed for filtrate shown as optional on skids P&ID. Must be demonstrated on each submittal per DCPWS (b)(vii) Verified on P&ID. Verfied on P&ID. Table 3: Pre-Accepted XPE Skids Conditions of Acceptance: Skid Type XPE Skid Model Number 2L10V or 3L10V or 4L10V or 6L10V or 9L10V or 12L10V L10N L10N L10N L10N L10N or L10N Approved flux (gfd) Maximum production capacity (gallons per minute gpm) Cross connection control (DCPWS (b)(vii)) Individual Skid Effluent Turbidity (DCPWS (a)and (d)) Flow Control (DCPWS (c) and (e)) Not verified. Standard protocols will be kept onsite which specifies that the operator will maintain an air gap during chemical clean in place (CIP) between the membranes and the finished water. Must be demonstrated on each submittal per DCPWS (b)(vii) Not verfied. Not verified. Please be aware that any point source discharges of water from treatment facilities are potentially subject to a discharge permit under Colorado s State Discharge Permit System. Any point source discharges to state waters without a permit are subject to civil or criminal enforcement action.

144 Russ Swerdfeger Evoqua Water Technologies May 23, 2014 Page 4 Please direct any further correspondence regarding this acceptance to: Tyson Ingels, P.E. Colorado Department of Public Health and Environment Water Quality Control Division 4300 Cherry Creek Drive South Denver, CO If you have any questions or comments, please call Tyson Ingels at Sincerely, Tyson Ingels, P.E. Lead Drinking Water Engineer Engineering Section Water Quality Control Division Colorado Department of Public Health and Environment

145 Appendix D Wastewater Treatment Lagoons Temperature and Nitrification Preliminary Calculations

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147 Wright Water Engineers Date: 10/30/14 Sheet: 1 / West 26th Ave., Suite 100-A Project No.: Denver, Colorado Project Name: DRO Master Plan Tel. (303) Des. by: JJN Ckd. By: WFL Subject: Water Temperature Rev. by: DWF Ckd. By: WFL I. Purpose: To establish the temperature of the water in the lagoons II. References: 1. L.G. Rich, High Performance Aerated Lagoon Systems, Metcalf & Eddy, Wastewater Treatment and Reuse, 4th Edition, NOAA Vallecito Dam Temperature Data 4 III. Assumptions: 1. Average Air Temperature - February (Ta) -2 deg C ref #3 2. Raw Wastewater Temperature (Ti) 10 deg C ref #2 3. Depth of Lagoons (D) 3.66 m 4. Aeration Cell No. 1 Volume 135,000 gal 5. Aeration Cell No. 2 Volume 271,000 gal 6. Aeration Cell No. 3 Volume 155,000 gal 7. Proportionality Factor (f) 0.75 ref #1 8. Design Flow (Q) 25,000 gpd IV. Calculations: 1. Aeration Cell No. 1 Detention Time (N1) = 5.4 d 2. Aeration Cell No. 2 Detention Time (N2) = 10.8 d 3. Aeration Cell No. 3 Detention Time (N3) = 6.2 d 4. Total Detention Time = 22.4 d 5. Tw = [(N/D) x f x Ta] + Ti ref #1 [(N/D) x f] Aeration Cell No. 1 Temperature = 3.7 deg C 7. Aeration Cell No. 2 Temperature = 0.0 deg C 8. Aeration Cell No. 3 Temperature = 0.0 deg C 9. Average Temperature = 1.2 deg C 10/30/14

148 Wright Water Engineers Date: 10/30/14 Sheet: 2 / West 26th Ave., Suite 100-A Project No.: Denver, Colorado Project Name: DRO Master Plan Tel. (303) Des. by: JJN Ckd. By: WFL Subject: Nitrification Kinetics Rev. by: DWF Ckd. By: WFL I. Purpose: To establish the Preliminary rate of nitrification in the lagoon system. II. References: 1. L.G. Rich, High Performance Aerated Lagoon Systems, Metcalf & Eddy, Wastewater Treatment and Reuse, 4th Edition, 2002 III. Assumptions: 1. Concentration of Ammonia (N) 70.0 mg/l ref #2 2. Concentration of Dissolved Oxygen (DO) 2.0 mg/l 3. Half-saturation Constant for DO (K O2 ) 1.2 mg/l ref #1 4. ph 8.0 ref #2 5. Cell No. 1 Temperature 3.7 deg C IV. Calculations: 1. Maximum Specific Growth Rate, m m m m = 10 ( x T) = /d ref #1 2. Half-saturation Constant for Ammonia N K N = 10 (0.051 x T) = 0.11 mg/l ref #1 3. Specific Growth Rate, m ref #1 m = m m x [N/(K N + N)] x [DO/(K O2 + DO)] x [ x (7.2 - ph)] = /d 4. Percent Removal in Cell No. 1 = 91% 5. Remaining Ammonia Concentration = 6.5 mg/l 10/30/14

149 Wright Water Engineers Date: 10/30/14 Sheet: 3 / West 26th Ave., Suite 100-A Project No.: Denver, Colorado Project Name: DRO Master Plan Tel. (303) Des. by: JJN Ckd. By: WFL Subject: Nitrification Kinetics Rev. by: DWF Ckd. By: WFL I. Purpose: To establish the Preliminary rate of nitrification in the lagoon system. II. References: 1. L.G. Rich, High Performance Aerated Lagoon Systems, Metcalf & Eddy, Wastewater Treatment and Reuse, 4th Edition, 2002 III. Assumptions: 1. Concentration of Ammonia (N) 6.5 mg/l ref #2 2. Concentration of Dissolved Oxygen (DO) 1.0 mg/l 3. Half-saturation Constant for DO (K O2 ) 1.2 mg/l ref #1 4. ph 7.5 ref #2 5. Cell No. 2 Temperature -0.2 deg C IV. Calculations: 1. Maximum Specific Growth Rate, m m m m = 10 ( x T) = /d ref #1 2. Half-saturation Constant for Ammonia N K N = 10 (0.051 x T) = 0.07 mg/l ref #1 3. Specific Growth Rate, m ref #1 m = m m x [N/(K N + N)] x [DO/(K O2 + DO)] x [ x (7.2 - ph)] = /d 4. Percent Removal in Cell No. 2 = 68% 5. Remaining Ammonia Concentration = 2.1 mg/l 10/30/14

150 Wright Water Engineers Date: 10/30/14 Sheet: 4 / West 26th Ave., Suite 100-A Project No.: Denver, Colorado Project Name: DRO Master Plan Tel. (303) Des. by: JJN Ckd. By: WFL Subject: Nitrification Kinetics Rev. by: DWF Ckd. By: WFL I. Purpose: To establish the Preliminary rate of nitrification in the lagoon system. II. References: 1. L.G. Rich, High Performance Aerated Lagoon Systems, Metcalf & Eddy, Wastewater Treatment and Reuse, 4th Edition, 2002 III. Assumptions: 1. Concentration of Ammonia (N) 2.1 mg/l ref #2 2. Concentration of Dissolved Oxygen (DO) 1.0 mg/l 3. Half-saturation Constant for DO (K O2 ) 1.2 mg/l ref #1 4. ph 7.5 ref #2 5. Average Lagoon Water Temperature -1.2 deg C IV. Calculations: 1. Maximum Specific Growth Rate, m m m m = 10 ( x T) = /d ref #1 2. Half-saturation Constant for Ammonia N K N = 10 (0.051 x T) = 0.06 mg/l ref #1 3. Specific Growth Rate, m ref #1 m = m m x [N/(K N + N)] x [DO/(K O2 + DO)] x [ x (7.2 - ph)] = /d 4. Percent Removal in Cell No. 3 = 61% 5. Remaining Ammonia Concentration = 0.8 mg/l 10/30/14

151 Appendix E Glossary of Acronyms

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153 Appendix E Table of Acronyms Durango-La Plata County Airport Water and Wastewater Master Plan Acronym AF BOD CDPHE CDPS CDWR cfs CIP CWCB DBP DMR DWCD FWCD GAC gpd gpm HCU LEED MCL MF MGD NTU O&M PRID RAA SUIT TSS TTHM USACE WWE Term Acre-Feet Biochemical Oxygen Demand Colorado Department pf Public Health and Environment Colorado Discharge Permit System Colorado Division of Water Resources cubic feet per second Clean-In-Place Colorado Water Conservation Board Disinfection By-Product Discharge Monitoring Report Dolores Water Conservancy District Florida Water Conservancy District Granular Activated Carbon gallons per day gallons per minute Historical Consumptive Use Leadership in Energy and Environmental Design Maximum Contaminant Limit Micro-Filtration Million Gallons per Day Nephelometric Turbidity Units Operations and Maintenance Pine River Irrigation District Running Annual Average Southern Ute Indian Tribe Total Suspended Solids Total Trihalomethane United States Army Corps of Engineers Wright Water Engineers, Inc. P:\ Jviation\000\Master Plan Document\Appendices\ Glossary of Acronyms.xlsx Wright Water Engineers, Inc. November 2014

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155 DENVER 2490 W. 26 th Avenue Suite 100A Denver, Colorado Phone: Fax: GLENWOOD SPRINGS 818 Colorado Avenue P.O.Box 219 Glenwood Springs, Colorado Phone: Fax: DURANGO 1666 N. Main Avenue Suite C Durango, Colorado Phone: Fax: Wright Water Engineers, Inc.