2018 WATER RESOURCES PLAN

Transcription

1 Executive Summary June, WATER RESOURCES PLAN CONTENTS Introduction... ES-1 Current Water Supplies... ES-3 Population Projections... ES-8 Demand Projections... ES-9 Conservation and Nonrevenue Water Programs... ES-10 Evaluation of Supply and Demand... ES-12 Water Supply Alternatives... ES-15 Water Quality Considerations... ES-24 Conclusions and Recommendations... ES-25 Two primary factors are driving the current emphasis and need for water resources planning in Texas. First, population and economic growth are increasing the need for water to support that growth. Second, in arid, fast-growing states like Texas, water supplies are becoming more expensive and time consuming to develop, and there is more competition for water resources. Many utilities are faced with procuring water from distant sources and/or using water resources that require significant treatment.

2 Introduction Two primary factors are driving the current emphasis and need for water resources planning in Texas. First, population and economic growth are increasing the need for water to support that growth. Second, in arid, fast-growing states like Texas, water supplies are becoming more expensive and time consuming to develop, and there is more competition for water resources. Many utilities are faced with procuring water from distant sources and/or using water resources that require significant treatment. This 2018 Water Resources Plan is a guide to how New Braunfels Utilities (NBU) will address its future water needs. It is a strategic water supply plan looking at NBU s annual water needs. The recommended water resources were selected by: 1. An evaluation of demand-management and conservation opportunities; and 2. An assessment of a broad range of water supply options and creative solutions. This is a strategic water supply plan to address NBU s future water needs. This 2018 Water Resources Plan is aligned with NBU s Vision, Mission, and Core Values. This Plan: Serves as a strategic roadmap for building a resilient water supply for the future; Furthers NBU s ability to continue providing excellent service to its customers; Enhances the quality of life in New Braunfels by providing the most essential of public services, an assured water supply; Maintains the safety of the community by providing water for sanitary and health purposes; Embodies a team effort in the development of the Plan; Stewards NBU s existing water resources through enhanced water conservation and the implementation of strategies to stretch existing water supplies; Includes an emphasis on prudent financial management and costeffectiveness, thereby assuring appropriate rates for NBU s customers; and Serves as an effective communication tool for the NBU board and staff, and NBU s constituents. New Braunfels Utilities NBU is a municipally-owned public utility responsible for water, wastewater, and electric services for residents of the City of New Braunfels, Texas. The Vision of NBU is to be recognized as a trusted community partner dedicated to excellence in service. The Mission is to enhance the quality of our community by providing innovative essential services. NBU s drinking water system serves an area of almost 90 square miles. In 2017, NBU served more than 79,000 people. The system is rated as Superior by the Texas Commission on Environmental Quality (TCEQ). NBU s Four Fundamental Core Values:» Safety» Integrity» Team» Stewardship ES-1

3 Introduction NBU has a diverse inventory of water supply sources totaling almost 30,000 acre-feet per year (AFY). These current sources include: Run-of-river (ROR) water rights for surface water from the Guadalupe River Contracts with the Guadalupe-Blanco River Authority (GBRA) for stored surface water from Canyon Reservoir Groundwater production permits for water from the Edwards Aquifer from the Edwards Aquifer Authority (EAA) Groundwater wells in the Trinity Aquifer However, the TCEQ- and EAA-related sources of supply are subject to stoppage or curtailment during periods of drought. Texas water resources planners define a reliable or firm supply of water as being available during a repeat of the drought-of-record (DOR) which generally lasted from 1947 through 1957 in central Texas. Thus, this Water Resources Plan addresses total annual water need, even during periods of drought such as a repeat of the 1950 s DOR. NBU completed a feasibility study evaluating aquifer storage and recovery (ASR) as a water management strategy in Although ASR is not a new water source, ASR does stretch existing supplies by providing a place to store water during periods of excess, so that water can be recovered during droughts and emergencies, or to meet peak demand. NBU is aggressively moving forward with an ASR demonstration project to confirm the viability of ASR in the brackish portion of the Edwards Aquifer near the New Braunfels Regional Airport. Goals Compare future demand with current supplies Address future water needs Goals ES-2

4 Current Water Supplies Current NBU Surface Water Supplies NBU is authorized to divert, treat, and distribute surface water from two sources, summarized in Table 1: 1. The Guadalupe River: ROR water from the Guadalupe River is only available to NBU when the flow of the Guadalupe River exceeds 113 cubic feet per second (cfs) through certificates of adjudication (COAs) issued by the TCEQ, and 2. The Canyon Reservoir: Water stored in the Canyon Reservoir is reliably available through a contract with GBRA. The ability of NBU to treat these surface water supplies is limited by the current capacity of the Surface Water Treatment Plant (SWTP). The existing SWTP is a conventional treatment plant with a rated capacity of eight million gallons per day (mgd). Within this Water Resources Plan, a sustainable capacity of 7.5 mgd was used to allow for backwashing of filters and regular preventive maintenance. Certain components of the raw water pump station and the treatment plant were oversized to facilitate an expansion, including the raw water pump station which is shown in Figure 1. However, other components, such as the upflow clarifiers (Figure 2) and the treated water pipelines, will require expansion to increase the capacity of the SWTP. Table 1: Surface Water Sources of Supply COA/Contract TCEQ / ROR Quantity (AFY) 3824B-403 5, A-400 1, A Subtotal 6,952 GBRA / Canyon Reservoir ,720 Total Surface Water Authorizations 16,672 Figure 1: Raw Water Intake Pumps Figure 2: Upflow Clarifiers ES-3

5 Current Water Supplies Current NBU Groundwater Supplies Currently, NBU s groundwater supplies come from the Edwards Aquifer and the Trinity Aquifer. Production of Edwards Aquifer water is subject to restrictions under EAA s Critical Period Management rules. The volume of water NBU can pump from the Edwards Aquifer (Table 2) can be reduced by as much as 44 percent during drought conditions. The 84th Texas Legislature created the Comal Trinity Groundwater Conservation District (GCD) in At the present time, the Comal Trinity GCD does not have regulations that restrict NBU s ability to pump groundwater from the Trinity Aquifer. However, the Trinity Aquifer water requires treatment by NBU prior to distribution (Figure 3). The capacity of NBU s Groundwater Treatment Plant (GWTP), which is currently under construction, exceeds 3,700 AFY. NBU uses seven of its nine Edwards Aquifer wells (Figure 4), with a total production capacity of about 19 mgd. NBU also operates four Trinity Aquifer wellfield wells, with a total capacity of about 2,600 gallons per minute [gpm] (3.75 mgd), and two existing Copper Ridge Subdivision wells, with a capacity of about 460 gpm (0.7 mgd). Assuming a 75 percent availability factor for the Trinity Aquifer wells, that source of supply can reliably provide about 3,700 AFY. Table 2: Groundwater Sources of Supply Permit Number Edwards Aquifer Quantity (AFY) P P P P , P P Subtotal 9,269 Trinity Aquifer - 3,700 Total Groundwater Authorizations 12,969 Figure 3: Trinity Aquifer Groundwater Treatment Plant Figure 4: Edwards Well No. 3 ES-4

6 AFY of Water Available % of Years Available Current Water Supplies Surface Water Availability NBU s surface water availability was estimated using the TCEQ Water Availability Model (WAM) simulations for NBU s ROR water rights. To determine the availability of ROR water, full authorization model input files for the TCEQ WAM for the Guadalupe San Antonio River Basins were used. The WAM was used to simulate diversions under NBU water rights during a 43-year period from 1947 through 1989 using a typical monthly municipal demand pattern. The surface water ROR simulations for the 43-year study period are shown in Figure 5 and were incorporated into the NBU supply model. 8,000 7,000 6,000 5,000 4,000 84% 60% 47% 100% 90% 80% 70% 60% 50% 3,000 2,000 1, ,434 5,070 6,952 Firm Yield Supply Average DOR Year Supply Average Year Supply Maximum Authorized Volume 40% 30% 20% 10% 0% Run of River Supply Available % of Years Available Figure 5: Run-of-River Supply Availability Scenarios 1 AFY is enough water to supply 4 families for a year. ES-5

7 AFY of Water Available % of Years Available Current Water Supplies Edwards Aquifer Groundwater Availability EAA s Critical Period Management (CPM) rules significantly impact the amount of groundwater that NBU can pump, especially during periods of drought. Under the CPM rules, the volume of Edwards Aquifer water that can be pumped must be reduced by 20 percent in a Stage I drought, increasing up to 44 percent in Stage V. The stage and restriction percentage are predicated on flow from the Comal Springs and other factors. Information on EAA s CPM Critical Period stages can be found at Edwards Aquifer groundwater modeling for the 43-year study period are shown in Figure 6. 10, % 100% 8,000 86% 80% 6,000 4,000 51% 60% 40% 2, % 5,439 5,732 7,172 9,269 Firm Yield Supply Average DOR Year Supply EAA Supply Available Average Year Supply % of Years Available Figure 6: Edwards Aquifer Supply Availability Scenarios Maximum Authorized Volume 20% 0% ES-6

8 AFY of Water Current Water Supplies Summary of Current NBU Water Supplies NBU has permits, contracts, and facilities to produce almost 30,000 AFY of water during years when aquifer levels and river flows are not in a drought condition. As shown in Figure 7, NBU s current water supply sources are significantly affected by regulatory restrictions during drought. 1. During the DOR, NBU has a total reliable supply (i.e., firm yield ) of about 17,500 AFY. In the worst years of the DOR, no ROR water is available, and Edwards Aquifer groundwater is reduced by up to 44 percent. In the average year during the DOR, the total reliable supply is about 17,800 AFY. 2. In the average year during the study period, NBU had a supply of about 19,300 AFY with the current capacity of the SWTP. This total volume of water is available about 46 percent of the study period. 3. When the maximum authorized volume of water is available from all of NBU s sources, but the supply of surface water is limited to the current sustainable capacity of the SWTP (7.5 mgd), NBU has a total supply of about 21,400 AFY. This total volume of water is available only about nine percent of the study period. In years when the maximum authorized volume of water is available from all of NBU s sources, the supply would be about 29,700 AFY if the sustainable capacity of the SWTP was expanded to 15.0 mgd. The full capacity of the expanded SWTP could have been utilized about 46 percent of the study period if water was available. 35,000 30,000 25,000 ROR Water Canyon Water Edwards Aquifer Water Trinity Aquifer Water Notes: 1. Surface water sources are shown with diagonal line hatching. 2. Values are based on a study period between 1947 and ,000 15,000 10,000 5,000 0 Firm Yield Supply Average DOR Year Supply Average Year Supply w/ 7.5 MGD Max Supply w/ 7.5 MGD Average Year Supply w/ 15 MGD Max Supply w/ 15 MGD Maximum Authorized Volume Figure 7: Current Surface Water Supply Availability ES-7

9 Forecasted Population Population Projections Population projections serve as a basis for estimating future water demand. New Braunfels rapid growth in recent years makes it challenging to forecast the future population. To derive reasonable estimates, the City s recent population growth was compared to historical trends seen in similar Texas communities, such as Round Rock, Georgetown, and San Marcos. If New Braunfels follows the path of other fast-growing communities along the IH 35 corridor, a growth rate of six percent can be used to forecast the next 10 years. After this 10- year period, the annual growth will likely fall to about three percent. Using these growth rates, the estimated population for the NBU service area is shown in Table 3 and Figure , ,000 3% Growth Table 3: Forecasted NBU Service Area Population Year Number of Residents , , , , , , , , ,000 6% Growth 100,000 50, Year Figure 8: Forecasted NBU Service Area Population New Braunfels is one of the fastest growing communities in the United States. ES-8

10 Annual Demand (AFY) Demand Projections After analysis, research, and discussion, Arcadis and NBU developed a model to project NBU s water needs throughout the next 25 years. The projected total annual demand was calculated using the following equation: Total Annual Demand = (Projected Population Unit Demand) + Wholesale Demand The following data and assumptions were used to forecast demand for the NBU service area (Table 4 and Figure 9): Projected Population: The projected population was calculated under the assumption that New Braunfels will experience the same growth patterns as similar cities. This population forecast includes customers within NBU s service area. Wholesale Demand: Wholesale demand was assumed to be zero as NBU does not anticipate any potential wholesale customers. Unit Demand: The average unit demand over the last seven years was 168 gallons per capita per day (gpcd) and was used as the initial demand projection. NBU has recently set an internal water conservation goal to reach a unit demand of 120 gpcd by 2043; thus, the unit demand projection was scaled down annually to reach this long-term goal. Existing Gruene Wastewater Treatment Plant (WWTP) Reuse Capacity: NBU s Gruene WWTP has an existing reuse capacity of 16.3 million gallons (MG) per year. This reuse water was considered an annual reduction in demand and is applied starting in Table 4: Forecasted NBU Service Area Demand Year Total Annual Demand (AFY) , , , , , , , , ,775 45,000 40,000 35,000 30,000 25,000 20,000 15,000 10,000 5,000 41,719 29, Year Figure 9: Conservation Resulting from Reduced Unit Demand ES-9

11 Conservation and Nonrevenue Water Programs Current Conservation and Nonrevenue Water Programs From 2009 to 2016, unit demand among NBU customers averaged 168 gpcd. After peaking at 194 gpcd during a drought year (2011), the unit demand began decreasing by an average of six percent per year. Unit demand decreased from 194 gpcd in 2011 to 146 gpcd in NBU has set an internal goal to reach a unit demand of 120 gpcd by 2043 through additional conservation and demand management measures. This enhanced conservation results in the reduction of almost 12,000 AFY of water demand in the year Leak Detection and Meter Replacement NBU has an excellent leak detection program. State-of the-art acoustic-based- technology equipment is utilized to detect and pinpoint leaks. The methods have been very successful. At the start of the program, losses were approximately 2,700 gallons per mile. Losses are currently less than 1,000 gallons per mile. Figure 10 shows NBU personnel using their leak-detection equipment. NBU is also currently in the middle of a meter changeout / replacement program. Advanced Metering Infrastructure (AMI) allows NBU to continuously monitor the entire distribution network at hourly intervals. NBU Conservation and Drought Management Ordinances The City s Conservation and Drought Management Ordinances, most recently updated in 2014, are focused on minimizing waste. NBU s Water Conservation Plan is required as part of the Drought Management Plan. Water use reduction measures are part of NBU s Drought Management Plan and are linked to both Edwards Aquifer water levels and Comal Springs discharge. Water conservation rebates are offered for: ultra-high efficient washing machines, grass removal and replacement with drought-tolerant plants (as shown in Figure 11), permeable patios, and irrigation zone removal. Figure 10: Leak Detection Equipment Figure 11: Drought Tolerant Plants ES-10

12 Conservation and Nonrevenue Water Programs Edwards Aquifer Habitat Conservation Plan NBU is a participant in the Edwards Aquifer Habitat Conservation Plan (EAHCP), which is a cooperative, regional effort to protect groundwater resources of the southern portion of the Edwards Aquifer, both for people in the region and for the endangered species that inhabit the aquifer. The EACHP includes measures to ensure adequate springflow at Comal and San Marcos springs. Maximizing springflow at the Comal Springs has a direct benefit for NBU because it reduces the time when NBU must reduce pumping from the aquifer. Potential Conservation Technologies Conservation technologies, such as those discussed below, are also being considered by NBU to enhance the existing conservation practices. No-Des Technology The Neutral Output Discharge Elimination System (No- Des) consists of a truck-mounted alternative for flushing the distribution system as shown in Figure 12. The equipment includes pumps, filters, and rechlorination / chloramination capabilities to treat hydrant flush water prior to re-entry into distribution systems. When operating, the No-Des truck is placed between two fire hydrants, creating an above-ground loop that can target flushing of more than one area with closure of different valves. E-Pulse E-Pulse is a new technology used in conjunction with pipe condition assessments. It can be used to proactively locate weakened areas that have the potential to develop leaks in metallic, asbestos-cement, and pre-stressed concrete pipelines. WaterSmart Customer Service Portal WaterSmart is behavioral water management software, which can be used to inform NBU s customers of their water use habits and to provide conservation recommendations. The WaterSmart Customer Service Portal allows customers to log in and track their water use and receive alerts about possible leaks and higher than normal water use. WaterSavr WaterSavr is a patented, National Science Foundation-approved hydrated powder that self-spreads into a thin layer that reportedly slows evaporation. Freeze Miser Outdoor Faucet Protector In many Texas communities, a significant volume of water is wasted in winter months when homeowners drip their outside faucets to prevent freezing. Figure 13 shows a Freeze Miser on an outdoor faucet. The device starts dripping the faucet only when the water temperature inside the Freeze Miser decreases to 37⁰F. When the water gets back above that temperature, the drip is shut off. Figure 12: No-Des Truck Figure 13: Freeze Miser on Outdoor Faucet ES-11

13 AFY of Water Evaluation of Supply and Demand Comparison of Supply and Demand Well-managed water utilities in arid areas like Texas predicate their planning on having a firm supply of water available, even during a repeat of the worst year(s) of the DOR. NBU s current firm supply will be exceeded by predicted demand as early as Without additional water sources, NBU s projected demand will exceed its firm yield supply by about 6,500 AFY in 2030 and by 11,000 AFY in The projections of supply and demand illustrated in Figure 14 show that NBU needs to develop new water sources. 35,000 30,000 25,000 20,000 15,000 10,000 Firm Yield Supply during Drought of Record (DOR) Annual Demand Average Year Supply Max Year Supply w/ SWTP at 7.5 MGD 5, Year 2038 Figure 14: Comparison of NBU s Current Supply and Forecasted Demand NBU needs to develop new water sources ES-12

14 Evaluation of Supply and Demand Potential Sources of New Supply NBU and Arcadis identified 14 potential new water supply alternatives. Seven of the supply alternatives were referred for assessment in later phases or in separate studies. The remaining seven options described below were selected for the preliminary screening analysis: GBRA Mid-Basin Project is a regional treated groundwater supply project using water produced from a wellfield in Gonzales County and transmitted by pipeline to a delivery point south of New Braunfels. Up to 8,000 AFY is available from this project through a contract with GBRA. San Antonio Water System (SAWS) Vista Ridge Project is a privately-developed groundwater project delivering treated water from Burleson County to the north side of San Antonio. SAWS has determined that it can sell up to 15,000 AFY by contract to other entities for a period of 60 years. Expansion of the Trinity Aquifer Wellfield Project is an NBU groundwater project that would add four additional wells and expand the membrane GWTP that is currently under construction. Up to about 3,360 AFY of water can be produced by this project. Direct Potable Reuse is a potential NBU water treatment project that would produce high-quality potable water using effluent from the Kuehler WWTPs. The yield of this option is dependent upon the volume of effluent available from the plants. GBRA Lower Basin Project is an off-channel reservoir project in the lower Guadalupe River Basin. GBRA is developing the project to provide a firm supply of water to its municipal and industrial customers in Calhoun County. If the project is implemented, approximately 3,600 AFY of Canyon Reservoir stored water could be made available to NBU. Expansion of the Existing SWTP is an NBU project to expand the existing SWTP to a capacity of approximately 15 mgd. This option will allow NBU to treat all of its Canyon Reservoir water, as well as additional ROR water when it is available. Direct Non-Potable Reuse is a potential NBU/City of New Braunfels project to deliver treated effluent from the NBU WWTPs to City parks and public areas for irrigation purposes. As currently planned, this multi-phase project could ultimately deliver up to 807 AFY. New water supplies will be secured in addition to continuing NBU s active conservation and demand management activities and ASR program. Arcadis conducted a preliminary screening assessment of these seven alternatives based on the following factors: Alternatives Identified Options Evaluated at Preliminary Screening Level quantity of water available; estimated first-year unit cost; land or site availability; potential environmental impacts; availability date; possible NBU customers perception; amount of additional water quality treatment required to integrate the supply into the NBU distribution system; supply reliability; complexity to operate and maintain any required NBU facilities; anticipated institutional issues and regulatory requirements; and ease of physical integration of the new water into the NBU system. ES-13

15 Evaluation of Supply and Demand At an Alternatives Workshop on December 5, 2017, NBU selected three of the seven alternatives to be evaluated in greater depth: the GBRA Mid-Basin Project, Expansion of Trinity Wellfield, and Expansion of Existing NBU SWTP. Table 5 summarizes the detailed evaluation of these three water sources using the same criteria as in the preliminary screening assessment. Table 5: Detailed Analysis of Supply Alternative Ranking Matrix GBRA Mid-Basin Expansion of Expansion of Criteria Weight (%) Project Raw Weighted Trinity Wellfield Raw Weighted Existing NBU SWTP Raw Weighted Score Score Score Score Score Score First Year Unit Cost 9% Life Cycle Cost 14% Land Availability 3% Environmental Impacts 6% Availability Date 17% NBU Customer Perception Amount of Additional WQ Treatment Required 6% % Supply Reliability 20% Complexity to Operate Institutional Requirements Ease of Integration into Existing System 7% % % Total Ranking City of Seguin Supply Source NBU is also discussing a contract with the city of Seguin for a long-term supply of at least 2,500 AFY of treated water. As early as 2019, blended ground and surface water from the Seguin distribution system may be available for distribution to NBU s service area. The total cost of the water has not been determined. ES-14

16 Water Supply Alternatives This section describes the three water supply alternatives selected by NBU for detailed analysis. GBRA Mid-Basin Project The GBRA Mid-Basin Water Supply Project (MBP) will deliver to NBU treated groundwater from the Carrizo Well Field in Gonzales County as shown in Figure 15. Water will be transported from a GWTP, located in Gonzales County, via a 40-mile treated water pipeline to a delivery point in the NBU service area. The volume of water available, timeline, and project costs are summarized in Table 6. GBRA is evaluating the opportunity to develop the MBP with jointly-owned facilities in cooperation with the Alliance Regional Water Authority. Additionally, the MBP has been included in the Region L Regional Water Plan and is therefore eligible for funding through the Texas Water Development Board (TWDB). Table 6: Summary of MBP Project Firm Yield of Water Available Maximum Volume of Water Available 8,000 AFY 8,000 AFY Earliest Year Available 2023 NBU Project Cost First Year Unit Cost Contract Term $15 Million $1,868 / AFY 40 years with automatic renewals in 10-year blocks Figure 15: GBRA Mid-Basin Project Conceptual Map ES-15

17 Water Supply Alternatives Project Implementation The currently-proposed delivery point for water supplied from the MBP would be on Weltner Road (Figure 16), adjacent to property that NBU has acquired for an electrical substation. NBU will provide infrastructure for connection to the GBRA pipeline and incorporation into the existing NBU system. Necessary NBU facilities include: A 30-inch water line, for delivery of water from the MBP pipeline to a new ground storage tank (GST), A 1.5 MG GST, A chlorine residual and water quality monitoring station to ensure water received from GBRA is properly conditioned prior to incorporation into the NBU system, A high service pump station, A flow metering station, and Property adjacent to the GBRA connection point for construction of the GST, high service pump station and ancillary facilities. Construction Timeframe Construction of the proposed GBRA delivery pipeline, as well as the NBU infrastructure to receive and distribute the delivered water, is planned to be completed not later than Technical Implementation Issues NBU s Draft 2016 Water Master Plan Report shows a new 20-inch water main being constructed along Highway 46 and Weltner Road for increasing capacity to the Avery Park elevated storage tank. To allow for integration of 8,000 AFY into NBU s system from the MBP and to provide for additional growth, this line will be increased to 36 inches in diameter. To NBU Dist. System Ground Storage Tank Figure 16: Layout for Weltner Road Location Environmental Considerations GBRA will be accountable for most of the environmental issues related to the MBP; however, NBU is responsible for the purchase and development of the site on which the delivery facilities will be situated. NBU will also need to secure a right-of-way (ROW) for the length of the 36- inch distribution pipeline, located along Highway 46 and Weltner Road. Prior to purchasing the site for the NBU facilities, NBU should conduct a Phase 1 Environmental Site Assessment. Permitting Considerations Pump Station GBRA Delivery Point GBRA will be responsible for all permitting of the MBP. NBU will be responsible for any permits required to acquire and develop the site and construct the NBU facilities. ES-16

18 Water Supply Alternatives Project Costs Table 7 provides an itemized breakdown of the costs for the NBU facilities to incorporate the GBRA MBP water into the existing NBU system. With the GBRA contract, NBU begins paying its proportionate share of GBRA s land lease and groundwater district permit fees in NBU s 2019 fiscal year. The total first year cost for these fees will be approximately $1.6 million. In 2023, when MBP water is available, NBU s total unit cost of water will be approximately $1,868 per AFY or $5.73 per thousand gallons. For 8,000 AFY of water, the total annual cost will be approximately $13 million. Ite m Table 7: GBRA Mid-Basin Project Costs Description Quantit y Unit Unit Price Total 1 Cost Difference Between 20" and 36" Pipe 28,000 LF $119 $3,332, " Pipeline and Connection to GST & HSPS 700 LF $232 $162, MG Ground Storage Tank 1 EA $1,875,000 $1,875,000 4 Flow Metering Station 1 EA $40,000 $40,000 5 High Service Pump Station (550 HP) 2 1 EA $2,350,000 $2,350,000 6 Pump Station Building & Control Room 1 EA $300,000 $300,000 7 Land Acquisition 0.75 ACRE $200,000 $150,000 8 Electrical and SCADA 1 LS $913,000 $913,000 9 Roadways, Fences, Site Work etc. 1 EA $300,000 $300, Architectural Elements Escalation Factor 1 LS $1,087,500 $1,087,500 SUBTOTAL $10,509,900 Contingency $2,627,475 $1,737,600 SUBTOTAL $13,137,375 Engineering, Surveying, and Permitting $1,970,606 $1,303,200 Notes and Assumptions: 1. Costs are provided in 2018 dollars. 2. HSPS size based on 7.14 mgd of flow at 300 ft TDH. TOTAL 1 $15,107,981 ES-17

19 Water Supply Alternatives Expansion of the Existing SWTP NBU s existing SWTP has a peak capacity of 8.0 mgd and a sustainable capacity of about 7.5 mgd. Expansion of the SWTP from 8.0 mgd to 16.0 mgd will give NBU the ability to treat a greater volume of surface water from its existing supply sources, and it will allow NBU to treat any additional raw surface water it might obtain in the future. The location of the SWTP within New Braunfels is shown in Figure 17. The GBRA Canyon Reservoir contract provides a firm yield of 9,720 AFY (an annual average of 8.67 mgd). The GBRA Canyon water contract is anticipated to continue indefinitely. The remaining water for treatment would come from NBU s existing ROR rights, not requiring any other entities to be involved. In the future NBU may be able to obtain more water from Canyon Reservoir under the right of first refusal provisions that are included in the MBP contract. The ROR water rights are considered to be perpetual. The volume of water available, timeline, and project costs are summarized in Table 8. Table 8: Summary of SWTP Expansion Current Firm Yield of Water Available Expanded Firm Yield of Water Available Current Maximum Supply of Water Available Expanded Maximum Supply of Water Available Earliest Year Available NBU Project Cost First Year Unit Cost Contract Term 8,400 AFY 9,720 AFY 8,400 AFY 16,800 AFY 2022 but likely deferred to 2024 $34 Million $574 / AFY indefinite Figure 17: NBU Surface Water Treatment Plant Location ES-18

20 Water Supply Alternatives Project Implementation A proposed layout for the expansion of the SWTP is shown in Figure 18. The expansion was assumed to include: A fourth pump to expand the 16 mgd raw water pump station, thereby increasing the total capacity of the pump station to 25.9 mgd (16 mgd with the largest pump out of service); A new bulk polymer storage tank and day tank, and new metering pumps for feeding both the existing and expansion portions of the SWTP; New chlorine and ammonium sulfate facilities; A new treatment unit*, with rapid mix flocculation basins, clarifiers, filters, and an associated pipe gallery, and the associated feed and discharge yard piping; A new backwash/decant basin; Four additional sludge drying beds; An additional 1.5 MG GST; Expansion of the 10,500 gpm (15.12 mgd) high service pump station; and Distribution system improvements. Construction Timeframe Construction of an expansion of NBU s SWTP could potentially be completed by If preliminary engineering is accelerated and started by August 2018, the expansion could be completed as early as Technical Implementation Issues The largest implementation issue will be constructing the necessary facilities around an active water treatment plant without causing any major plant shutdowns. The Draft 2016 Water Master Plan Report indicates that new distribution lines designated as CIP Projects 25 and 26 will need to be implemented to convey additional water from the expanded SWTP into the distribution system. Additionally, as the plant experienced significant flooding from the Guadalupe River in 1998 and to a lesser extent in 2002, the expansion of the SWTP needs to include provisions for hardening the facilities to minimize infiltration of water into structures; maintain plant operation during and immediately after a flood; and allow quick removal and relocation of critical pieces of equipment to prevent damage. Drying Beds Decant Basins Treatment Units Environmental Considerations NBU should review its files from the original construction to confirm that there is sufficient data and information to confirm that no issues were unresolved during original construction. It may be necessary to conduct a new assessment for threatened and endangered species. Permitting Considerations Existing NBU SWTP Ground Storage Tank Figure 18: Proposed Layout for Expansion of SWTP Expansion of the SWTP will activate two TCEQ permitting requirements: a stormwater general permit for construction activities (TXR150000); and a plan review for public water systems modifications (RG-346 and 30 TAC Chapter 290 Subchapter D). As the SWTP is located within New Braunfels city limits, the New Braunfels Building Division will require a building permit application to verify that the work complies with building, electrical, mechanical, and plumbing codes required by the City. * NBU may evaluate using membrane technology for the expansion. ES-19

21 Water Supply Alternatives Project Costs Table 9 provides an itemized breakdown of the costs anticipated to construct the facilities necessary for expansion of the SWTP. In 2024, NBU s total unit cost of water will be approximately $574 per AFY or $1.76/k gal. For the average annual supply available with the expansion of 6,390 AFY of water, the total annual cost will be approximately $3,668,612 in 2024 dollars. Table 9: NBU Surface Water Treatment Plant Expansion Project Costs Item Description Quantity Unit Unit Price Total 1 Raw Water Pump Feed Pump 1 EA $350,000 $350,000 2 Chemical Metering Pumps 5 EA $5,000 $25,000 3 Chemical Piping 1 LS $30,000 $30,000 4 Bulk Polymer Storage Tank 1 EA $37,500 $37,500 5 Polymer Day Tank 1 EA $15,000 $ 15,000 6 Chlorine and Ammonia Facility 2125 SF $40 $85,000 7 Chlorine Equipment 1 EA $100,000 $100,000 8 Ammonia Equipment 1 EA $60,000 $60,000 9 Filters (10) 1 EA $3,326,400 $3,326, Flocculation Tank 1 EA $321,200 $321, Clarifier Basin 1 EA $1,449,800 $1,449, Rapid Mix Basin 1 EA $308,000 $308, Waste Pump Station 1 EA $440,000 $440, Sludge Drying Beds 1 EA $160,000 $160, Decant Tank 1 EA $1,100,000 $1,100, MG Concrete Ground Storage Tank 1 EA $1,500,000 $1,500, HSPS Booster Pumps 2 EA $159,855 $319, Yard Piping 1 LS $200,000 $200, Electrical and SCADA 1 LS $1,705,522 $1,705, Roadways, Fences, Site Work etc. 1 EA $400,000 $400, Waste Pump Station Improvements 1 LS $100,000 $100, Water Line Project # LS $4,169,880 $4,169, Water Line Project # LS $5,056,830 $5,056, Storm Resiliency Factor 1 LS $500,000 $500,000 SUBTOTAL $21,759,842 Contingency 30% $6,527,953 SUBTOTAL $28,287,795 Engineering, Surveying, and Permitting 20% $5,657,559 Notes and Assumptions: 1. Costs are provided in 2018 dollars. 2. Costs for water line project 25 & 26 are from Freese and Nichols Draft Water Master Plan TOTAL 1 $33,952,354 ES-20

22 Water Supply Alternatives Expansion of the Trinity Aquifer Wellfield NBU currently has four wells drilled in the Trinity Aquifer. The wells are northwest of New Braunfels, just outside Loop 337 as shown in Figure 19. NBU s plans for expansion of the Trinity Wellfield include drilling four additional wells in the general area of the existing wells. After allowance for backwash, maintenance downtime and losses in the treatment process, the expanded Trinity Wellfield could supply a maximum volume of about 7,060 AFY (or 6.3 mgd) of treated water. The volume of water available, timeline, and project costs are summarized in Table 10. The groundwater from the existing wells requires treatment, and it is assumed that additional wells will require similar treatment. A membrane GWTP capable of treating the groundwater to surface water standards is now under construction by NBU. This plant would require expansion to accommodate the water pumped from the additional wells. Table 10: Summary of Trinity Aquifer Wellfield Expansion Current Firm Yield of Water Available Expanded Firm Yield of Water Available Current Maximum Supply of Water Available Expanded Maximum Supply of Water Available Earliest Year Available NBU Project Cost First Year Unit Cost Contract Term 3,700 AFY 7,060 AFY 3,700 AFY 7,060 AFY 2021 assuming plant expanded with ongoing construction $19 Million $600 / AFY Indefinitely, assuming the availability of the groundwater is not affected by over pumping or future regulations Figure 19: Trinity Aquifer Wellfield Expansion Project Conceptual Map ES-21

23 Water Supply Alternatives Project Implementation A proposed conceptual layout of the expanded membrane GWTP is shown in Figure 20. The expansion was assumed to include: Addition of four wells to increase the raw water production capacity by 4,200 AFY (3.74 mgd); Two feed pumps; One feed strainer; Five membrane racks; One reverse filtration tank and pump; One backwash clarifier; Addition of a second 1.5 MG ground storage tank; and A new pump station for distribution of water into the existing NBU distribution system. The current backwash recycle pumps and blowers are anticipated to have sufficient capacity. Additionally, the current pump station between the treatment plant and the ground storage tank is anticipated to have sufficient capacity. Existing Membrane Treatment Facility Expanded Membrane Treatment Ground Storage Tank Proposed Wells No. 5-8 Figure 20: Proposed Conceptual Layout of Expanded Membrane Groundwater Treatment Plant Construction Timeframe Construction of an expansion of the Trinity Aquifer Wellfield could potentially be completed by Technical Implementation Issues The membrane GWTP capable of treating the groundwater to surface water standards is under construction, as described above. Future wells drilled in the general area will likely experience similar water quality that will need treatment. Environmental Considerations Because the GWTP is being expanded within the existing plant site, there should be no environmental permitting issues with that portion of the project. NBU should consider doing a Phase 1 Environmental Site Assessment of the new well sites. Additionally, because the new wells will be drilled in the Trinity Aquifer below the Edwards Aquifer, the design and construction of the wells must comply with the rules of the EAA. Permitting Considerations While TCEQ does not require specific permitting for GWTP expansions, a Stormwater General Permit for Construction Activities must be submitted to the TCEQ. All plant operations are still subject to the same requirements for public water systems that are currently in place. Because the membrane GWTP will be located within New Braunfels city limits, the New Braunfels Building Division requires a building permit application to verify that the work complies with building, electrical, mechanical, and plumbing codes required by the City. Well drilling into the Trinity Aquifer in Comal County is now regulated by the Comal Trinity GCD. Any additional wells drilled by NBU will be subject to the District rules. Additionally, the design and construction of the wells must comply with the rules of the EAA. ES-22

24 Water Supply Alternatives Project Costs Table 11 provides the costs for expansion of the Trinity Aquifer Wellfield. It is important to note that any costs associated with the original four wells, and the ongoing construction of the GWTP are not included. The cost analysis is an independent assessment of the expansion components only. In 2024, NBU s total unit cost of water will be approximately $600 per AFY or $1.84 /k gal. For the firm yield annual supply available with the expansion of 3,360 AFY of water, the total annual cost will be approximately $2.0 million. This total cost includes NBU s debt service and operations and maintenance expenses for the expanded treatment system. Table 11: Trinity Wellfield Expansion Project Costs Item Description Quantity Unit Unit Price Total 1 Well Construction 4 EA $633,098 $2,532,395 2 Well Pumps 4 EA $119,304 $477,216 3 High Service Pump Station 1 LS $1,725,405 $1,725, MG Ground Storage Tank 1 LS $1,114,254 $1,114,254 5 Electrical and SCADA 1 LS $1,920,118 $1,920,118 6 Wellfield Piping 1 LS $1,308,967 $1,308,967 7 Membrane Treatment System 1 LS $2,183,380 $2,183,380 8 Feed Water Tank 1 LS $117,200 $117,200 9 Chemical Feed Systems 1 LS $184,990 $184, Wastewater Line 1 LS $207,500 $207, Well Blow-off 1 LS $190,420 $190, Land Acquisition Wells 1 LS $120,000 $120, Land Acquisition ROW 1 LS $219,000 $219,000 SUBTOTAL $12,300,844 Contingency (30%) $3,690,253 SUBTOTAL $15,991,097 Engineering, Surveying, and Permitting (20%) $3,198,219 Notes and Assumptions: 1. Costs are provided in 2018 dollars. 2. Cost for treatment systems based on Preliminary Engineer Report provided to NBU by Freese and Nichols. TOTAL 1 $19,189,316 ES-23

25 Water Quality Considerations Blending new water supplies into the NBU distribution system requires careful planning to prevent unintended consequences associated with potential distribution system water quality changes, such as: Pipe corrosion and/or scale release Biological growth Development of unacceptable color, taste, or odor Difficulty maintaining a disinfectant residual Nitrification Disinfection by-product (DBP) formation A limited water quality evaluation for each of the three selected alternative water supplies was conducted. A summary of water quality considerations for each alternative is provided below: Distribution system water quality is complex and influenced by multiple factors including: Source water quality and treatment, Physical factors (materials, pipe scales, sediments), and Operational practices. GBRA MBP: GBRA will provide water quality meeting all TCEQ primary and secondary drinking water quality standards prior to delivery to the NBU distribution system. However, additional treatment may be required to assure compatibility with the water and materials in NBU s distribution system and to meet NBU water quality goals. Trinity Aquifer Wellfield Expansion: Although water quality from the additional four proposed wells has not been evaluated, it is anticipated to be similar to that from the current wells. An evaluation of the water quality from the four existing wells has been conducted and summarized in a preliminary engineering report. Additional groundwater will likely require similar treatment through chemical addition and a membrane filtration process. As NBU is currently constructing and will operate the GWTP, NBU will control the treated water quality. SWTP Expansion: As NBU currently treats raw water from the Guadalupe River at the existing NBU SWTP, expansion of this facility to treat additional Guadalupe River water is anticipated to produce similar water quality. However, different or new processes or equipment could result in changes in finished water quality entering the distribution system. Also, by treating and introducing more treated surface water into the distribution system, the current blend of water sources will shift, and corresponding shifts in water quality could occur. As NBU would own and operate the expanded SWTP, NBU will control the treated water quality. Prior to introduction of any of the new treated sources into NBU s distribution system, Arcadis recommends a staged approach to analyzing potential water quality impacts, beginning with collection of additional distribution system and treated water quality data. Additional desktop analysis of expected blend ratios and treated water compatibility with NBU s distribution system based upon these data will inform whether additional testing is recommended prior to introduction of the new source water(s). Collect Additional Water Quality Data Consider Additional Testing Conduct Desktop Analysis of Blend Ratios and Compatibility ES-24

26 Conclusions and Recommendations Conclusions Current Water Sources Population Growth Enhanced Water Conservation and Demand Management Over the last 75 years, NBU has diligently developed a diverse portfolio of water supply sources with the ability to produce almost 30,000 AFY of water during years when aquifer levels and river flows are not in a drought condition. However, almost half of that inventory is interruptible during drought due to regulatory curtailments of the surface water ROR rights and the Edwards Aquifer groundwater. During the 43-year historic period from 1947 through 1989, the entire authorized ROR volume of water is available in about 50 percent of the years, but in the worst years of the DOR, little or no water is available. The fully-authorized volume of Edwards Aquifer water is available in only about nine percent of the 43 years because of the effects of the EAHCP on Comal Springs flows, and the EAA s CPM Rules. Figures 6 and 7 illustrate the differences in the reliability of the surface water and groundwater. The firm yield of the NBU water supply inventory is currently about 17,500 AFY. In average years, NBU currently has a reliable supply of about 19,300 AFY. New Braunfels is one of the fastest growing communities in the nation. This 2018 Water Resources Plan is predicated on the forecast that population growth will continue at about six percent per year until around 2026, at which time population growth will slow to about three percent per year. The forecasted population in 2040 within the NBU service area is approximately 202,900 people. NBU is committed to further enhancing its water conservation and demand management programs. To stretch its current water supply and to responsibly manage its resources, NBU has a goal of reducing per capita water demand to 120 gpcd by the year 2043 through additional conservation and demand management measures. With an estimated population of more than 200,000 people, the total annual water demand in 2040 is projected to be about 28,500 AFY. Despite enhanced conservation and demand management measures, NBU will need additional sources of water to meet future demand, especially during times of drought. To predict future water demand and determine how much and when additional water is needed, Arcadis evaluated a study period from 2018 through Table 12 summarizes the forecasted population and estimated total annual water demand for the NBU system. Figure 14 illustrates a comparison of NBU s existing water supply and forecasted demand. NBU needs to increase its water supply inventory by as early as 2020 if a severe drought were to occur or annual population growth exceeded six percent per year. Table 12: Forecasted Population and Estimated Total Water Demand for NBU System Year Population Total Annual Demand (AFY) ,600 17, ,500 21, ,000 24, ,900 28,500 NBU needs to increase its water supply inventory by as early as ES-25

27 Water Available (AFY) Conclusions and Recommendations In developing this Water Resources Plan, NBU considered 14 alternatives for increasing its water supply inventory. After an initial assessment and discussion, seven options were evaluated at a preliminary screening level, with a focus on sources of water that would be available on a firm-yield basis. NBU ultimately selected the following three options for more detailed analysis: Alternatives Identified GBRA Mid-Basin Project Expansion of the existing NBU SWTP Expansion of the NBU Trinity Aquifer Wellfield Expanding the capacity of the existing SWTP to 15 mgd significantly improves the reliability of NBU s ROR water rights because NBU can divert and treat more water earlier in the year when the Guadalupe River flow is more likely to exceed 113 cfs. With a typical municipal demand pattern, the full ROR authorization (6,952 AFY) is available in about 47 percent of the years. With a diversion rate of 15 mgd, the full authorization is available in about 84 percent of the years. Having the additional capacity will provide significantly more water for storage in the proposed ASR wellfield. By implementing these projects and purchasing water from the city of Seguin, NBU will be able to provide water to its customers on a firm-yield basis beyond the year Figures 21 and 22 illustrate how these additional water sources can meet NBU s forecasted water demand on a firm-yield basis during the worst years of a DOR and during years with more average climatic conditions. Options Evaluated at Preliminary Screening Level Options Selected for Detailed Analysis 35,000 30,000 25,000 20,000 GBRA Mid- Basin Project NBU SWTP Expansion + 1,320 AFY + 8,000 AFY Trinity Wellfield Expansion + 3,360 AFY 15, ,500 AFY 10,000 5,000 Seguin Water Supply Forecasted Supply Forecasted Demand Year Figure 21: Proposed Firm Yield Supply with New Projects vs Demand ES-26

28 Water Available (AFY) Conclusions and Recommendations 45,000 40,000 35,000 NBU SWTP Expansion + 6,390 AFY Trinity Wellfield Expansion + 3,360 AFY 30,000 25,000 GBRA Mid- Basin Project + 8,000 AFY 20, ,500 AFY 15,000 10,000 Seguin Water Supply Forecasted Supply Forecasted Demand 5, Year Figure 22: Proposed Average Yield Supply with New Projects vs Demand Implementing these projects will allow NBU to provide water to its customers on a firm-yield basis beyond the year ES-27

29 Conclusions and Recommendations Recommendations Key recommendations from this water resources planning process include: On an annual basis, review actual population and water use data and compare those data to the assumptions used in the 2018 Water Resources Plan. Initiate preliminary design for the expansion of the existing SWTP. Continue to pursue the ASR program through a process of demonstration and evaluation, followed by the first full-scale ASR well. Closely monitor the treated water quality and quantity from the GWTP currently under construction to confirm the viability of the expansion of the Trinity Aquifer Wellfield as a future water source. After confirming suitability, purchase any needed well sites for the expansion of the Trinity Aquifer Wellfield. Continue to use water conservation and demand management measures to reduce per capita unit demand to at least 120 gpcd by Monitor the status of GBRA s Lower Basin Project, and the availability of water from other GBRA projects. If GBRA implements the Lower Basin Project, NBU should take advantage of its right-of-first-refusal to contract for additional water from Canyon Reservoir. Implement the contract with GBRA for a firm-yield supply of 8,000 AFY of water from the Mid-Basin Project and contract with the city of Seguin for a supply of at least 2,500 AFY. Before new water sources are introduced into the NBU distribution system, implement staged approach to analyzing potential water quality impacts. ES-28