2017 CAPACITY REPORTS

Transcription

1 2017 CAPACITY REPORTS FLOWS & LOADINGS I&I/FLOW MONITORING

2 2017 CAPACITY REPORTS FLOWS & LOADINGS

3 2017 Flows and Loadings Report December 2017 Prepared By: Adam Klein and Hannah McLean, Brown & Caldwell Tyle Zuchowski, LOTT Clean Water Alliance

4 PREFACE The Flows and Loadings Report is one of three related documents that are part of the annual process to monitor and evaluate capacity in the entire LOTT system. The intent, under LOTT s Wastewater Resource Management Plan (also known as the Highly Managed Plan), is to assure that needed new capacity is brought on-line just in time to meet system needs. Capacity needs evaluated include wastewater treatment, Budd Inlet discharge, reclaimed water use/recharge, and conveyance capacity in the entire LOTT system. These three reports are prepared annually, and are used to help identify capital projects for inclusion in the annual Capital Improvements Plan. Flows and Loadings Report analyzes residential and employment population projections within the Urban Growth Boundary and estimates the impact on wastewater flows and loading within the LOTT wastewater system. Inflow and Infiltration Report uses dry and wet weather sewer flow monitoring results to quantify the amount of unwanted surface (inflow) and subsurface (infiltration) water entering the sewer system and to prioritize sewer line rehabilitation projects. Capacity Assessment Report uses flows and loadings data and inflow & infiltration evaluation results to analyze system components (i.e. conveyance, treatment, and discharge), determine when limitations will occur, and provide a timeline for new system components and upgrades. The capacity assessment report was not updated in Refer to the 2016 Capacity Assessment report, as it still represents the best understanding of LOTT s operational capacity. Each report is posed on LOTT s website Flows and Loadings Report i

5 Table of Contents Preface... i Table of Contents... ii Executive Summary... iii 1. Introduction Purpose Data Elements Modeling Software Changes from Previous Reports Study Area Service Area Current Sewered Area Future Sewered Area On-site Septic Systems Population and Employment Forecast Projections Equivalent Residential Units New Connections Flows and Loadings Permit Requirements Drinking Water Analysis Base Sanitary Flow Comparison with Historical Wastewater Generation Rates Flow Projections Inflow and Infiltration Projections Loading Projections Projections Analysis Summary Flows and Loadings Report ii

6 Executive Summary In accordance with the Wastewater Resource Management Plan, also known as the Highly Managed Plan, LOTT is continuously planning to ensure it maintains adequate operational capacity to meet the community s needs. The primary goal of the annual Flows and Loadings Report is to define the current and projected wastewater characteristics of the LOTT service area in terms of both wastewater flows and pollutant constituents (loads). The Thurston Regional Planning Council (TRPC) updates its population and employment projections every five years. The latest update was published in 2013, however a residential population estimate for 2040 was released in the spring of These projections were used to develop the flows and loadings included in this report. Additional data included flow monitoring data collected as part of LOTT s inflow and infiltration evaluation program, timelines for sewering of non-sewered areas provided by each of LOTT s partner jurisdictions (Lacey, Olympia, and Tumwater), and updated current sewered areas. This report also includes a drinking water evaluation using 2016 drinking water consumption data obtained from the jurisdictions. This analysis was used to recalibrate wastewater generation rate profiles for each of the jurisdictions. Generally, the projected flows and loadings are slightly reduced from the previous year. This was mainly due to the improved data quality received from the partner jurisdictions regarding the current customer base, resulting in further refinement of the per capita wastewater generation rates Flows and Loadings Report iii

7 1. Introduction 1.1 Purpose Accurate projections of future wastewater flows and loadings are essential in planning for new treatment capacity. In accordance with the Highly Managed Plan, LOTT is continuously monitoring and planning to assure that adequate new wastewater treatment, conveyance, and discharge capacity is available just in time. The primary goal of the annual Flows and Loadings Report is to define the current and projected wastewater characteristics of the LOTT service area in terms of both wastewater flows and pollutant constituents (loads). Flows and loadings projections cover the 35-year planning cycle ( ) and will be used to evaluate LOTT s existing Capital Improvements Plan and develop recommendations for the timing of capacity related projects. 1.2 Data Elements Data used for the development of this report included wastewater flow monitoring data, sewered and non-sewered population projections, existing sewer lines, estimated timelines for sewering of non-sewered areas within the overall Urban Growth Area (UGA), and 2016 drinking water consumption data. Flow data was collected at LOTT s Budd Inlet Treatment Plant and at various flow monitoring locations throughout the collection system. Population projections, updated in 2013, were obtained from the Thurston Regional Planning Council (TRPC) in the form of projected residential and employment populations per parcel. This included a new residential population estimate for the year 2040 that was released in the spring of The estimated sewering timelines, drinking water consumption data, and existing collection system piping information were obtained from each of the partner jurisdictions (Lacey, Olympia, and Tumwater). 1.3 Modeling Software To develop flows and loadings projections, the drinking water data was combined in Microsoft Excel and then uploaded to a map of the parcels in Thurston County in a geographic information system (GIS) database. The drinking water data was allocated to its specific parcel, which contained population data and projections provided by TRPC. This combined data was exported and extrapolated in Excel. 1.4 Changes from Previous Reports This year s projections were developed similarly to those developed in the 2016 Flows and Loadings Report. Drinking water data was collected from each of the partner jurisdictions, along with parcel identification numbers, rate classes, and units per parcel. This drinking water data was sorted, organized, and assigned to the respective parcels in GIS. The GIS map held other pertinent data for each parcel including its physical location, drinking water basin, sewer basin, future sewer basin, and population projection data from TRPC. The raw drinking water data from the jurisdictions, along with the population projections from TRPC, were used to project future wastewater generation and subsequent loading rates Flows and Loadings Report 1

8 2. Study Area 2.1 Service Area The LOTT Service Area includes the Urban Growth Areas (UGAs) for the cities of Lacey, Olympia, and Tumwater. The current combined UGA encompasses approximately 52,276 acres, with a current residential population of 174,771 and an employment population of 113,964. Figure 2-1. LOTT Service Area by Jurisdiction 2017 Flows and Loadings Report 2

9 2.2 Current Sewered Area Within the LOTT service area, approximately 16,516 acres are sewered, serving a residential population of 116,108 and an employment population of 89,042. The currently sewered parcels, shown in yellow on Figure 2-2, depict the parcels for which the jurisdiction provided drinking water data. It was assumed that if a parcel had drinking water consumption data that it was currently sewered and LOTT was receiving that wastewater flow. The manually sewered parcels, shown in purple on Figure 2.2, depict the parcels for which drinking water consumption data was not received, but the parcels were physically surrounded by sewered parcels. Some of these parcels may be vacant, while others may simply be gaps in the customer database. These parcels have been modeled to become active within the next five years. Figure 2-2. Currently Sewered Area 2017 Flows and Loadings Report 3

10 2.3 Future Sewered Area In order to properly project future flows and loadings, future sewered areas must be accounted for. This includes accounting for existing development served by the sewer system, future development served by the sewer system, and development that will be converting from on-site septic systems to the sewer system in the future. The service area has been divided into sewer basins to estimate the rate and timing of sewer connections and future flows and loadings. In 2014, the three cities Lacey, Olympia, and Tumwater provided information on when sewer basins in their service area are expected to begin connecting to the sewer system and when the conversions would be complete. Figure 2-3 illustrates the future sewered areas and Table 2.1 includes the expected timeline for conversion from septic to sewer. The build out state, currently projected to occur in 2050 based on a linear regression analysis, is when all parcels within the UGA will have been developed. It should be noted that the build out state does not assume that all parcels will be connected to the sewer system by It is assumed that a certain percentage of new development within the UGA will include on-site septic systems. The development density is projected by TRPC based on the current zoning and the previous development density corresponding to that zoning. For this year s analysis, four separate scenarios, or rates, of sewering were developed, including: low rate, expected rate, aggressive rate, and full sewering. Sewer connections were prioritized based on data generated by the Interjurisdictional Regional Septic Work Group. This data was obtained from the Thurston County Geodata Center in the form of a GIS parcel file, which included an inventory of septic systems and associated risk scores based on environmental and health concerns. Basins with high environmental risk were projected to be connected earlier than those with lower risk. The low rate of sewering assumes the majority of sewer basins containing undeveloped parcels with no existing septic tank would begin the connection process by 2020 and that by 2050 about 40% of these parcels would be connected to the sewer system. For the parcels that currently have a septic tank, the start date for the connection process would begin between 2025 and 2030 and only about 23% of the parcels would be connected to the sewer system by The expected rate assumes that the undeveloped parcels with no existing septic tanks that began connection to the sewer system before 2020 would be 100% converted to sewer by The expected rate also assumes that the majority of parcels with an existing septic tank would begin sewer connection in 2030 and would be about 35% converted to sewer by The aggressive projection rate assumes that all of the undeveloped parcels with no existing septic tanks, regardless of sewer basin, will be fully sewered by The parcels with an existing septic tank would be roughly 30-58% sewered by 2050 (depending on environmental risk). The full sewering rate assumes that by 2050 all parcels, those with and without septic tanks, regardless of sewer basin, will be connected to the sewer system. The latest start date for any sewer basin is End sewering dates (build out) are all 2050 for every 2017 Flows and Loadings Report 4

11 sewer basin. This reflects the assumption made in previous LOTT flows and loadings projections. The method of calculating future sewering rates assumed a front-loaded projection. This means that the rate of sewer connection is expected to occur at a faster rate in the next ten years than is expected to occur in the following twenty to thirty years. The rate of septic conversion is assumed to follow a more linear trend. The majority of the tables and projections discussed in this report assume the expected sewering rate. Other projections are occasionally shown for comparison Flows and Loadings Report 5

12 Figure 2-3. Future Sewer Basins 2017 Flows and Loadings Report 6

13 Table 2-1. Expected Future Sewering Schedule Current Sewer Coverage (0-5, 5=Full) Septic Conversion Priority (1-3, 3 = High) Parcels with no existing septic tank Parcels with existing septic tank % Parcels Connected at 2050 Start End % Existing Septics Converted at 2050 ID Name Start End Thompson 1 Place E % % 2 Hawks Prairie % % Thompson 3 Place W % % Woodland 4 Creek % % 5 Lilly Road % % 6 South Bay % % 7 Ridgeview % % 8 Tanglewilde % % 9 Meadows % % 10 Central Lacey % % 11 Lake Forest % % 12 SE Lacey % % 13 Horizon % % 14 Carpenter Road % % 15 Hwy % % 16 Trails End % % 17 S Tumwater % % 18 SW Little Rock % % 19 Black Hills % % 20 Trosper % % Central Tumwater % % Pioneer % % 23 Black Lake % % 24 N Black Lake % % 25 Mottman % % 26 Ken Lake % % 27 West Side % % 28 Green Cove % % 29 West Bay % % 30 East Bay % % 31 E Olympia % % 32 Indian Creek % % 33 W Chambers Prairie % % 34 SE Olympia % % 35 Wilderness % % 36 Chambers Prairie % % 37 Downtown Olympia % % 2017 Flows and Loadings Report 7

14 2.4 On-site Septic Systems As discussed in the previous section, future sewering considers extension of sewer to new developments, as well as conversion of existing on-site septic systems. Figure 2-4 illustrates the locations of the parcels with septic systems. The 16,851 existing septic parcels represent a base flow of approximately 2.61 mgd. The current projection assumes sewering of 35% of those (5,898) by 2050, which would add a base flow of approximately 912,031 gallons per day (gpd) to the system. Figure 2-4. Existing Parcels with Septic Systems 2017 Flows and Loadings Report 8

15 3. Population and Employment Forecast 3.1 Projections Population projections used for this analysis were obtained from TRPC in the form of a GIS parcel file, which included projected residential population for the years 2010, 2015, 2020, 2025, 2030, and Employment projections included the years 2010 and Also included was a maximum density estimate, or build out state, which was projected to occur in 2050 based on linear regression analysis. For each parcel location, the following attributes were assigned: jurisdiction, drinking water basin, sewer basin, future sewer basin, drinking water consumption, whether the parcel was sewered or septic, and whether the parcel was predominately residential or commercial. The parcel data and associated attributes were exported from the GIS file into a Microsoft Access database for grouping of the attributes. A total of 2,036 unique groups were formed: each parcel in each group was located in the same drinking water, sewer, and future sewer basin, and jurisdiction; their drinking water consumption data was summed per group, as well as all of the population prediction data. These groups were then exported from the Access database into Excel to perform the forecasting calculations. The future projections, shown in Table 3-1, were calculated through a linear extrapolation of the data provided by TRPC and the projected rate at which the sewered areas would expand. The residential and employment populations include all persons and employees within the UGA. The sewered residential population and sewered employment population include only those contained within the sewered areas. Future expansion of the sewered areas is accounted for in the projections throughout the forecast period. Figure 3-1 displays the projected population and employment forecasts for the planning period ( ) Flows and Loadings Report 9

16 Year Table 3-1. Population and Employment Projections Residential Population Employee Population Sewered Residential Population Sewered Employee Population , , ,108 89, , , ,957 91, , , ,976 93, , , ,201 96, , , ,534 98, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,528 Full Sewering 258, , , , Flows and Loadings Report 10

17 Figure 3-1. Population and Employment Projections ( ) 300, ,000 Population 200, , ,000 50, Population Employment Sewered Population Sewered Employment 3.2 Equivalent Residential Units For billing purposes, each customer connection to the sewered system is measured in terms of equivalent residential units (ERUs). One ERU is the amount of wastewater presumed to come from an average connected single-family household every month. For multi-family housing (apartments), each living unit is counted as 70% of an ERU. Commercial and industrial dischargers are billed on a volume basis using water consumption data, which is mathematically converted to ERUs. Established in 1976 as part of the original LOTT Interlocal Agreement, LOTT has defined an ERU as 900 cubic feet of wastewater volume per month (224 gallons per day). Since that time, residential wastewater generation rates have decreased as a result of water conservation efforts. LOTT is currently developing an updated ERU estimate. A recent study analyzed the LOTT partners customer accounts to better define its current service population. The three cities provided customer drinking water consumption data and information regarding how they measure ERUs. This information was compiled and ERUs were calculated for single family, mobile home, multi-family, and commercial units for each city. The study resulted in a lower number of overall ERUs (57,619) but is more precise than previous years estimations. Table 3-2. Jurisdiction ERU Summary 2017 Jurisdiction Residents/ERU Employees/ERU Lacey Olympia Tumwater Weighted Average Table 3-3 displays the annual average number of ERUs for each of the jurisdictions over the last 19 years Flows and Loadings Report 11

18 Table 3-3. ERU Totals 19-Year Comparison Year Lacey Olympia Tumwater Total ,966 21,430 6,447 38, ,363 21,860 6,845 40, ,786 22,242 6,962 40, ,356 22,398 6,625 42, ,362 23,062 6,582 42, ,493 23,142 6,667 43, ,689 23,445 6,999 44, ,206 23,552 7,161 44, ,543 23,939 7,572 46, ,326 24,575 7,808 47, ,647 24,453 8,127 50, ,497 24,522 8,441 51, ,092 24,333 8,622 52, ,463 24,220 8,819 52, ,376 24,452 9,131 53, ,372 24,324 9,464 54, ,789 25,161 10,136 56, ,000 25,100 9,600 55, ,895 26,502 10,319 58, ,497 26,316 9,806 57, ERU count reflects more accurate data reported as part of Cost of Service assessment 3.3 New Connections New connections to the system are billed a one-time connection fee, called a Capacity Development Charge (CDC). One CDC is assessed for each ERU connected to the system. Table 3-4 lists the number of CDCs collected over the last 20 years. Table 3-5 lists the projected new connections over the planning period. There was a large increase in CDCs in 2016, the largest total observed since Table 3-4. New Connections 20-Year Comparison Year Lacey Olympia Tumwater Total , , , , , , , , , , , , , , , , Flows and Loadings Report 12

19 Future ERU projections are based upon current ERU estimates. In 2016, there were a total of 57,619 ERUs in the system. Of these, 46,525 were residential, while 11,094 were commercial. This was the first time that it was possible to develop an accurate estimate of commercial ERUs, and this was accomplished through the ongoing Cost of Service study. The previous estimate of commercial ERUs was much higher (14,118). The change in the number of commercial ERUs means that the current estimate of employees per ERU has increased from 6.0 to 8.1. For the projections, this means that the projected number of employment ERUs and CDCs will decrease. CDC projections are summarized in Table 3-5. Table 3-5. New Connection Projections Through the Year 2050 Year Lacey Olympia Tumwater Total , , , , , , , , , , , , , , , , , , , , Flows and Loadings Report 13

20 4. Flows and Loadings 4.1 Permit Requirements The National Pollutant Discharge Elimination System (NPDES) permit number WA for the Budd Inlet Treatment Plant was issued by the Department of Ecology on August 26, 2011, and became effective on October 1, Permit compliance is based primarily on loadings of biological oxygen demand (BOD), total suspended solids (TSS), and total inorganic nitrogen (TIN), rather than flow. The permit was originally issued to be in effect through September 30, LOTT submitted a permit renewal application in March 2016, which is currently under consideration by the Department of Ecology. LOTT will operate under the previous permit requirements until a new permit is issued. Table 4-1 lists the loadings-based permit limitations. Table 4-1. NPDES Permit Limitations Winter Shoulder Summer (November-March) (April, May, October) (June-September) Parameter Monthly Weekly Monthly Weekly Monthly Weekly BOD (lbs/day) 5,640 8, , ,006 TSS (lbs/day) 5,265 7,898 5,265 7,898 5,265 7,898 TIN 3 mg/l, 338 lbs/day 3 mg/l, 288 lbs/day Ammonia (as N) 26 mg/l 36 mg/l 4.2 Drinking Water Analysis For this report, drinking water consumption data for 2016 was collected from each of the jurisdictions as part of the Cost of Service study. Drinking water consumption was reported monthly for each parcel. In order to determine the baseline drinking water consumption rate and minimize the effect of irrigation, only winter (November, December, January, and February) drinking water consumption data were used for sewered customers. The total consumption was divided by the total number of days to determine the gallons per day per parcel. The wastewater generation rates were then updated using the population and employment data provided by TRPC. The drinking water basins were created by consolidating sewer basins with similar consumption characteristics into larger basins. Figure 4-1 illustrates the drinking water basins included in this analysis. The wastewater generation rates are organized by drinking water basin in Table 4-2. The variance in drinking water consumption (and therefore, wastewater generation) between basins may be attributed to a number of contributing factors including the predominant type of residential units in the basin (single-family, multi-family, senior housing, etc.), the predominant era of home construction, the average age of residents, and the various commercial, industrial, or public-sector employers present in each basin Flows and Loadings Report 14

21 Figure Drinking Water Basins 2017 Flows and Loadings Report 15

22 Basin Table 4-2. Wastewater Generation Rates by Drinking Water Basin Sewered Residential Population Drinking Water Consumption 1 Sewered Employee Total gpd Residential gpd Employee gpd Adjusted Wastewater Generation Rate Residential gpcd 2 Employee gped ,018 11,626 1,051, , , , , ,171 52, ,489 4,651 1,580,018 1,366, , ,179 8, , , , ,797 8, , , , , , ,197 20, ,677 2, , , , ,025 5, , , , ,456 9,105 1,044, , , ,275 3, , , , ,001 9, , , , ,901 5, , ,883 88, ,938 2, , ,677 48, , , ,991 16, ,230 5, ,161 57, , , ,672 53, , ,440 1, ,734 97,042 12, Total 113,114 89,840 9,497,859 7,227,390 2,270, Raw data, only a portion of total parcels accounted for. Data not adjusted for sewer base flows. 2 Gallons per capita per day 3 Gallons per employee per day 4 Averages 4.3 Base Sanitary Flow In order to accurately forecast flows based on population changes within the service area, a base sanitary flow (BSF) must be established to calibrate residential and employee wastewater generation rates. The base sanitary flow is defined as the minimum average flow generated in the entire collection system registered over a 7-day period in each year, and is assumed to have little to no influence from inflow and infiltration. Base sanitary flow is measured at the influent of the Budd Inlet Treatment Plant (BITP). Reclaimed water produced by the Martin Way Reclaimed Water Plant, which is diverted to the Hawks Prairie and Woodland Creek infiltration basins, is added to the flow measured at the BITP to ensure that flows of the entire system are accounted for. The BSF data, measured in million gallons per day (mgd) from 2001 to 2016, is provided in Table 4-3 and excludes flow from the Tumwater brewery Flows and Loadings Report 16

23 Table 4-3. Base Sanitary Flow in LOTT Service Area Year Base Sanitary Flow (mgd) Equals the raw degritted sewage flow at the Budd Inlet Treatment Plant, minus brewery flow, plus flow treated at the Martin Way Reclaimed Water Plant The current NPDES permit requires that the LOTT Clean Water Alliance conduct an annual infiltration and inflow evaluation such that the entire collection system is evaluated once every seven years. LOTT currently has a total of 10 flow monitors, 5 of which are rotated on an annual basis. In the summer of 2016, LOTT rotated the 5 flow meters to new locations within the system. This, along with flows recorded during previous years, allows for a more detailed analysis of each jurisdiction s base flow. The BSF for each of the jurisdictions is provided in Table 4-4. A more detailed analysis is included in the 2017 Inflow & Infiltration and Flow Monitoring Report (December 2017). Table 4-4. Base Sanitary Flow by Jurisdiction (mgd) Year Lacey Olympia Tumwater Point Sources (TESC 1, etc.) Total The Evergreen State College (TESC), artesian wells, and Pepsi Bottling Company 2 June 2011 May 2012 Average Figure 4-2 presents the base sanitary flow projections and compares them with those published in the 2016 Flows and Loadings Report, as well as historical observations since The latest projections fall between the previous two projections Flows and Loadings Report 17

24 20.0 Figure 4-2. Base Sanitary Flow Projections Base Flow (MGD) Current Projection Report Report 2.0 Historical Comparison with Historical Wastewater Generation Rates Historically, wastewater generation rates were developed for each city based upon flow monitoring data. Beginning in 2007, drinking water consumption data has been obtained directly from each of the jurisdictions, enabling a more precise estimation of the wastewater generation rate profiles as shown in Table 4-2. These have been organized into city-specific profiles for comparison with previous estimates. Table 4-5 summarizes the historical generation rate profiles, along with the corresponding values developed in this report. Table 4-5. Wastewater Generation Rate Gallons Per Capita Per Day (gpcd) Source Lacey Olympia Tumwater Employment CIP CIP Budd Inlet Master Plan (2004) CIP Flows and Loadings Flows and Loadings Flows and Loadings Flows and Loadings Flows and Loadings Flows and Loadings Flows and Loadings Flows and Loadings Flows and Loadings Flows and Loadings Flows and Loadings These values are extrapolated from the values in Table 4-2 though they were not used in the model. They are presented for the sake of comparison to previous years profiles Flows and Loadings Report 18

25 4.5 Flow Projections Flow projections are calculated by multiplying the projected sewered populations by the wastewater generation rate. The per capita generation rates are drinking water basin specific. The projected sewered population projections are dependent on whether the parcel is currently sewered, on a septic system, or not sewered and not septic. The model assumes that these generation rates are constant throughout the simulation period ( ). Each year these wastewater generation rates will be recalibrated based on ongoing flow monitoring and population estimates. Figure 4-3 displays the projected base flow, annual average, permit compliance period (winter, summer, shoulder), and peak flows through the year Inflow and Infiltration Projections The impact of inflow and infiltration on projected flows was also modeled using the projected inflow and infiltration rates as documented in the 2017 Inflow & Infiltration (I&I) and Flow Monitoring Report. Projections were developed for the following risk-based I&I scenarios: 1) annual average; 2) 10-year peak day; 3) 10-year peak hour; 4) 10-year peak month; 5) summer (June-September); 6) shoulder (April, May, and October); and 7) winter (November-March) time period flows. Flow projections are displayed in Figure 4-3 and listed in Table Flows and Loadings Report 19

26 Figure 4-3. Flow Projections Flow, mgd Avg Annual Peak Day Peak Hour Peak Month Shoulder Summer Winter

27 Year Base Sanitary Flow Table 4-6. Flow Projections (mgd) Annual Average Peak Hour (10-year) Peak Day (10-year) Peak Month (10-year) Shoulder 1 Summer 2 Winter Full Sewering April, May, and October 2. June, July, August, and September 3. November, December, January, February, and March 21

28 4.7 Loading Projections Loading projections are updated each year based upon observed BOD and TSS loadings at the Budd Inlet Treatment Plant. In 2016, the average monthly BOD and TSS loads to the Budd Inlet Treatment Plant were 25,069 lbs/d and 25,025 lbs/d, respectively. Load removal at the Martin Way Reclaimed Water Plant is taken into account when estimating ERU generation rate profiles. In 2016 the Martin Way Plant removed approximately 1,510 lbs/d of BOD and 948 lbs/d of TSS. Projected BOD and TSS loadings for this report are based on a correlation of loadings from , with the 2007 through 2016 values corrected to account for loadings removal at the Martin Way Reclaimed Water Plant. These values are broken down into blanket residential and employment generation rates based upon the latest population and employment projections. These rates are provided in Table 4-7. Table 4-7. Wastewater Load Generation Rate Profiles (lbs per capita/employee day) Residential Employment BOD TSS BOD TSS Figure 4-4 displays the historical influent loading characteristics at the Budd Inlet Treatment Plant to include monthly averages for BOD and TSS. Loadings were observed to decrease in 2016, ending a four-year trend of increases. Figure 4-4. Historical Primary Influent Loads (Monthly Average) 2017 Flows and Loadings Report 22

29 Figure 4-5 and Table 4-8 present the projected BOD and TSS loadings in the LOTT service area through These loading rates are calculated by multiplying the projected sewer populations by the per capita loading rates detailed in Table 4-7. Figure 4-5. Projected Loadings 2017 Flows and Loadings Report 23

30 Table 4-8. Projected Flows and Loadings Year Average Day BOD (lbs/day) Average Day TSS (lbs/day) ,908 26, ,599 27, ,340 28, ,099 28, ,771 29, ,441 30, ,010 30, ,467 31, ,931 31, ,420 31, ,918 32, ,424 32, ,938 33, ,461 33, ,061 34, ,671 35, ,291 35, ,922 36, ,563 36, ,326 37, ,101 38, ,886 39, ,588 39, ,300 40, ,727 40, ,156 41, ,585 41, ,016 42, ,448 42, ,881 42, ,316 43, ,752 43, ,190 44, ,629 44,569 Full Sewering 56,867 54, Flows and Loadings Report 24

31 4.8 Projections Analysis The following plots compare the projections summarized in this report with historical trends. This annual recalibration is intended to ensure that projections remain consistent with both projected development within the service area, as well as with historical trends. The plots present the four sets of projections which were defined earlier in section 2.3. To reiterate, the aggressive rate assumes full sewering by 2050 and septic conversion by The full sewering projection assumes full sewering and septic conversion by The low rate assumes that full sewering of the cities and UGA will not be achieved until after 2150 and that most conversion of parcels with existing septic systems would not begin until The expected rate assumes 75-80% sewering within the cities and UGA, and conversion of 35% of existing septic tanks by These projections are compared against historical flows and loads observed since The expected projection from last year s report is included for comparison Figure 4-6. Comparison of Historical Base Flow and Base Flow Projected from Four Different Projection Models Full Sewering Aggressive Rate Expected Rate Low Rate Flow (MGD) Historical 2016 Report Linear (Historical) Flows and Loadings Report 25

32 Figure 4-7. Comparison of Historical BOD Loadings and BOD Projected from Four Different Projection Models 60,000 50,000 40,000 Load (lb/d) 30,000 Full Sewering 20,000 Aggressive Rate Expected Rate Low Rate 10,000 Historical 2016 Report Linear (Historical) Figure 4-8. Comparison of Historical TSS Loadings and TSS Projected from Four Different Projection Models 60,000 50,000 40,000 Load (lb/d) 30,000 Full Sewering 20,000 Aggressive Rate Expected Rate Low Rate 10,000 Historical 2016 Report Linear (Historical) Flows and Loadings Report 26

33 Figure 4-9. Comparison of Historical Average Daily Flow and Average Daily Flow Projected from Four Different Projection Models Flow (MGD) 15.0 Full Sewering 10.0 Aggressive Rate Expected Rate Low Rate 5.0 Historical 2016 Report Linear (Historical) In general, the updated projections represent a small decrease compared to those in the 2016 Flows and Loadings Report. This is related to an increase in the estimated current service population, which caused per capita wastewater generation rates to decrease slightly. The cause of this change is improved data from the LOTT partners, which includes the ability to identify vacant parcels within the currently sewered area. The decrease in loadings is linked to the reduction in observed loadings in 2016, which affected the six-year trend used as the basis of the per capita loading rate estimates. Figure 4-10 shows the difference in projected 2050 base flow in the LOTT sewer basins between the expected sewering projection and the full sewering projection. Areas with a large difference are those which are most impacted by the rate of sewering. These areas, concentrated in southeastern Lacey, are relatively far from the existing sewer network, and have a high proportion of parcels with septic tanks. More aggressive sewering and septic conversion rates would result in higher sewer flows originating in these areas, with impacts to the LOTT Martin Way sewer interceptors, the Indian Creek Interceptor, the Martin Way Pump Station, and the Martin Way Reclaimed Water Plant Flows and Loadings Report 27

34 Figure Difference in Flow (Full Sewering Expected Sewering, 2050) 2017 Flows and Loadings Report 28

35 5. Summary Generally, flows and loadings projected in 2017 are slightly reduced from the previous year. This is mainly due to the improved data quality received from the partner jurisdictions regarding the current customer base, resulting in further refinement of the per capita wastewater generation rates Flows and Loadings Report 29

36 2017 CAPACITY REPORTS I&I/FLOW MONITORING

37 2017 Inflow & Infiltration and Flow Monitoring Report (Data from August 2016-August 2017) December 2017 Prepared By: Adam Klein and Hannah McLean, Brown & Caldwell Tyle Zuchowski, LOTT Clean Water Alliance

38 PREFACE The Inflow & Infiltration and Flow Monitoring Report is one of three related documents that are part of the annual process to monitor and evaluate capacity in the entire LOTT system. The intent, under LOTT s Wastewater Resource Management Plan (also known as the Highly Managed Plan), is to assure that needed new capacity is brought on-line just-in-time to meet system needs. Capacity needs evaluated include wastewater treatment, Budd Inlet discharge, reclaimed water use/recharge, and conveyance capacity in the entire LOTT system. These three reports are prepared annually, and are used to help identify capital projects for inclusion in the annual Capital Improvements Plan. Flows and Loadings Report analyzes residential and employment population projections within the Urban Growth Boundary and estimates the impact on wastewater flows and loadings within the LOTT wastewater system. Inflow and Infiltration Report uses dry and wet weather sewer flow monitoring results to quantify the amount of unwanted surface (inflow) and subsurface (infiltration) water entering the sewer system and to prioritize sewer line rehabilitation projects. Capacity Assessment Report uses flows and loadings data and inflow & infiltration evaluation results to analyze system components (i.e. conveyance, treatment, and discharge), determine when limitations will occur, and provide a timeline for new system components and upgrades. The capacity assessment report was not updated in Refer to the 2016 Capacity Assessment report, as it still represents the best understanding of LOTT s operational capacity. Each report is posted on LOTT s website

39 Table of Contents PREFACE Introduction Overview Program History Flow Measurement Methodology Basin Summary Year 14 Flow Monitoring Site Summary Flow Monitoring Data Inflow and Infiltration Analysis Flow Data Analysis Summary of I&I Statistics for All Flow Monitoring Sites Analysis of Base Flow Analysis of Inflow and Infiltration Rotating Sites Site SV Site SV Site SV Site SV Site SV Permanent Sites Site OL Site OL Site L System-Wide Updated I&I Model I&I Benchmarks and Basin Ranking Comparison of I&I from Year 7 to Year SV SV SV SV SV Program Wrap-up Recommendations Flow Monitoring Site Installation Reports Inflow & Infiltration and Flow Monitoring Report 1

40 1. Introduction The LOTT Clean Water Alliance flow monitoring program was initiated in In accordance with National Pollutant Discharge Elimination System (NPDES) Permit WA , an inflow and infiltration (I&I) evaluation for all sub-basins within the LOTT system is required such that the entire system is evaluated once every seven years. The purpose of this program is to ensure permit compliance, characterize flows within the collection system, identify areas of concern for I&I, and aid in the prioritization of rehabilitation projects to reduce I&I. The program is also intended to fulfill requirements of the Intergovernmental Contract for Inflow and Infiltration Management and New Capacity Planning, originally dated March 27, 1995, as presented in Exhibit J to the LOTT Interlocal Cooperation Act Agreement for Wastewater Management by the LOTT Wastewater Alliance. This report includes an overview of the LOTT I&I program as well as the results and analysis of the monitoring program for the monitoring period. The monitoring program has been in place for fourteen years, and has just completed its second 7-year cycle. Brown and Caldwell provides data quality assurance and control, and assists in annual I&I analyses. LOTT has contracted with SFE Global NW to install flow monitors throughout the system (Table 1-1) and collect monitoring data. For , flow monitors include five permanent monitoring sites and five temporary sites. The five temporary sites rotate throughout the LOTT tributary system on an annual basis. As this is the seventh year of the second 7-year cycle, the five temporary sites were placed at the same locations as the seventh year of first round of monitoring ( ) in order to compare how flows at these sites have changed over the past seven years. This report covers the monitoring year The report is arranged as follows: Section 2 provides an overview of the program, including a summary of the sewer basins being studied, and an inventory and assessment of the flow monitoring sites, equipment, and technology Section 3 presents the results of the inflow and infiltration analyses Section 4 summarizes the 14-year program Section 5 discusses the implications of the data presented in this report, and provides recommendations 2017 Inflow & Infiltration and Flow Monitoring Report 2

41 2. Overview Inflow is defined as surface water entering the sewer via manholes, flooded sewer vents, illicitly connected storm drains, basement drains, and by means other than groundwater. Inflow is usually the result of rain and/or snowmelt events. Infiltration is defined as groundwater that enters the sewer, usually through leaky sewer pipe joints, manholes, and service connections. 2.1 Program History When the program was instituted in 2003, information on system-wide I&I was limited. I&I modeling was conducted on flows recorded at the Budd Inlet Treatment Plant (BITP) and then allocated across the system based upon assumptions involving the age of the pipe and a subjective assessment of flows measured at pump stations. Large sections of the service area were excluded from this allocation. Figure 2-1 shows the distribution of 10-year peak day I&I assumed in Inflow & Infiltration and Flow Monitoring Report 3

42 Figure Year Peak Day I&I Allocation in 2002 A major goal of this program was to more accurately define the spatial distribution of I&I. This would help LOTT with capacity planning for its collection system, as well as its treatment system, which includes both the BITP and the Martin Way Reclaimed Water Plant (MWRWP), and plans for other satellite treatment facilities. Another goal of this program was to assess changes in I&I over time, which would allow LOTT to highlight areas of concern, and advise the LOTT partners of areas to focus remediation efforts. In order to accomplish these goals, the program was founded upon the concept of rotating flow monitoring stations. Typically, a rotating flow monitoring station was set up for one calendar year, allowing for assessment of base flow during the summer, and I&I during the winter Inflow & Infiltration and Flow Monitoring Report 4

43 Over the past 14 years, sewage flow has been monitored at a total of 73 sites. Some of these sites were less useful than others in the sense that the data they provided were limited, either due to low flows, pump station impacts, or geometrical oddities which compromised the flow measurement. Others were monitored by LOTT partners for specific, short-term purposes. A total of 54 sites, plus the three LOTT pump stations and the Tumwater Hixon Street flow monitoring site are incorporated into LOTT s system-wide I&I model. Figure 2.2 shows all monitoring locations to date, and Figure 2.3 shows their connectivity. Table 2-1 lists the flow monitoring sites included in this program and the associated tributary sewer basins measured by each site. Monitors installed and operated by the City of Olympia in association with LOTT are also included. Figure 2-2. Location of Flow Monitoring Sites 2017 Inflow & Infiltration and Flow Monitoring Report 5

44 Figure 2-3. Connectivity of the LOTT Flow Monitoring Stations Name Cycle Year Manhole Table 2-1. Flow Monitoring Sites, with Tributary Basins Pipe Diameter Location Basins Served OL25 P MH " Private Drive off of Deschutes Parkway OL31 P MH " Indian Creek Bypass OL33 P SSMH9 24" 4th Avenue Bridge 56,59,60,61,62,63, 54,55,57,58,64,65,66,67,68,69,70,71,TE SC 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,25 L6 P MH " 8468 Martin Way E (Jack in the Box) 1,2,3,4,5,6,7,10,11,13,14,15,16,17 L7 P MH " 8503 Martin Way E (Arco Station) 8,9,12 OL26 1 MH " R.R. Grade W. of Mottman Rd 54,55,57,58,64,65,66,68,69,70,71,TESC OL27 1 MH " Access Road East of Mottman Rd 69,70,71 OL " Swimming Pool Grounds off Park Dr 68 OL29 1 MH " Cooper Pt. Road East of Capital Mall Dr 54,55,57,58,64,65,TESC OL " Off the Road at Cooper Pt. Road and Capital Mall Drive (at the Keg) 57 L1 2 VCJ01 15" Lacey Blvd and Sleater-Kinney Rd 8,9 L2 2 WGD01 12" 5223 Lacey Blvd 10, L3 2 WGF02 27" 1310 Lebanon St 6,7 L5 2 VSE01 15" th Loop SE 8 O " Henderson I-5 Exit 24,26 O " 16th Wilson Street 22,23,25 O " East Bay and State 33 T " Deschutes Parkway next to Simmons Rd 72 T " Custer Way at Capitol Blvd 76 T " Capitol Blvd at E St 73,74,75,78,79 D " 222 Capitol Way 51 D " 621 Capitol Way 44,45,46,47, Inflow & Infiltration and Flow Monitoring Report 6

45 Name Cycle Year Manhole Pipe Diameter Location Basins Served D " 505 Jefferson St 49 D " th St 43 D6 4 MH " 1109 Plum St SE D " 114 Jefferson St 50 D " 705 4th Ave 38 D9 4 MH " 809 Legion Way 32,37,39 D10 4 MH " 700 Plum St 27,41,42 D11 4 MH " Plum and Union Parking Lot 27,42 WB " Madison and Thomas 61 WB " West Bay Dr 59 WB " 200 Olympia Way (from Harrison) 62 WB " 400 Olympia Way (from SW) 63 WB " 508 E Bay Rd NE (San Francisco Line) 31 NL01 6 WB801 10" 5815 Clearbrook Dr SE 11 NL03 6 RK602 18" 1200 Galaxy Ave (LA Fitness) 2 NL04 6 RK401 24" 1200 Galaxy Ave N 1 NL05 6 MH " 5750 Martin Way E 1,2,15,16,17 NL " 2424 Hillside Dr 27 SV " 1627 East Bay 30 SV " 1102 Quince St SE 29 SV " 1705 Boundary St SE 28 SV " Indian Creek Trail east of Blvd and Wheeler 21 SV NA 4503 Capitol Blvd S 75,78,79 NL02C Off-Cycle WA401 27" Lacey Blvd and Pacific Roundabout 3,4,5,6,7,10,11 O3 Off-Cycle " Boulevard 31st Avenue 25 O5 Off-Cycle " 406 Lilly Rd partial - 19 SV07 Off-Cycle MH " Indian Creek Path east of Blvd and Wheeler SV08 Off-Cycle MH " 333 Martin Way E SV10 Off-Cycle 70B003 18" 101 Capital Mall Dr partial - 64,65 T4 Off-Cycle " Tyee Dr (Home Depot) 80,87,88 WS02 Off-Cycle " Harrison near Cooper Pt partial - 64,65 WS05 Off-Cycle " Columbia & 21st 45 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,28 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18, Flow Measurement Methodology All monitoring sites installed and monitored by SFE Global consist of SFE Custom Compound Weirs or area-velocity meters. The SFE Weir is a variant of the V-notch type weir. Permanent flow monitoring sites feature a Lexan-bodied weir, while the rotating temporary sites contain weirs constructed of ¾-inch thick plywood. Flow was calculated by measuring the depth of water flowing over the weir, and then applying a rating curve, which was developed individually for each weir during installation and calibration. SFE Global downloads the data from on-site data logging equipment a monthly basis. The flow monitor located at LOTT s Budd Inlet Treatment Plant (BITP) uses a different technology to measure flows. An Acoustic Doppler Flow Monitor (ADFM) was installed by MGD Technologies, 2017 Inflow & Infiltration and Flow Monitoring Report 7

46 Inc. in the 60-inch influent pipe in September The Martin Way Pump Station (MWPS) and Capitol Lake Pump Station (CLPS) have Doppler Ultrasonic strap-on flow meters installed on the discharge piping. The Kaiser Road Pump Station (KRPS) monitors pump run-time, which is mathematically converted to gallons per minute (gpm) and ultimately to million gallons per day (mgd) ((GPM/60)* ). These monitoring locations were integrated into the Budd Inlet Treatment Plant SCADA system in January 2005, and are now included in the I&I evaluation program. 2.3 Basin Summary The 88 LOTT sewer basins were redefined as part of the 2014 Flows and Loadings Report based on sewer maps and basin realignments provided by the cities of Olympia, Lacey, and Tumwater. Seven basins are currently unsewered. Of the remaining 81 basins, 27 are monitored with a single flow monitor located at a point downstream from all inputs into the basin, 32 are monitored by a flow monitor that gathers data from a group of several basins, and six are monitored individually with data gathered on the upstream and downstream ends of the basins, allowing for flow assessment by difference. I&I in the remaining basins is estimated through a system-wide regression model, which incorporates data from 58 flow monitors and pump stations, measured over the past seven years. The 88 sewer basins are illustrated on Figure Inflow & Infiltration and Flow Monitoring Report 8

47 Figure 2-4. Flow Monitoring Basins 2.4 Year 14 Flow Monitoring Site Summary A total of five temporary sites were monitored during the period. All of these sites were previously monitored during the period. Section assesses the change in inflow and infiltration over the 7-year period. Table 2-2 lists attributes for the area served by each site monitored within the period, including permanent flow monitors and LOTT pump stations. The equivalent residential units (ERU) values shown in Table 2-2 are based on data and the inch-diameter-mile (IDM) values are based on data Inflow & Infiltration and Flow Monitoring Report 9

48 Flow Monitor Sewered Residents Table 2-2. Flow Meter Basin Summary Sewered Employees ERU 1 IDM 2 Acres % Sewered SV01 2, ,000 85% SV04 1, % SV % SV06 1,695 1, % SV11 3,765 3,348 1, ,447 78% OL25 16,208 15,534 8, ,815 86% OL31 61,395 35,131 29,654 2,055 25,320 65% OL33 8,036 2,511 3, ,476 87% L6 43,394 16,720 25,484 1,447 19,314 60% L7 6,999 6,980 3, ,142 91% CLPS 29,402 29,347 15,747 1,242 13,851 76% KRPS 1, % WWTP 117,964 86,592 59,334 4,542 45,223 73% MWPS 42,576 16,016 19,535 1,421 18,156 60% 1. ERU: Equivalent Residential Unit (see Flow and Loadings Report for more details) 2. IDM: Inch-diameter-mile of sewer pipe (includes gravity and STEP sewers) 2.5 Flow Monitoring Data SFE Global s contracted data quality objectives were met over 90% of the time during the monitoring period. Figure 2-5 summarizes the flow monitoring reliability by showing the portion of flow data that was available and passed quality assurance checks each month. Figure 2-5. Flow Monitoring Data Quality (All SFE-monitored sites combined) Days Lost Days Lost % Passing Aug-16 Nov-16 Feb-17 May % 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% % Passing QA/QC Check 2017 Inflow & Infiltration and Flow Monitoring Report 10

49 2.6 Inflow and Infiltration Analysis To effectively evaluate the amount of I&I within each basin, a base sanitary flow (BSF) was computed for each basin based on the basin s local population and employment wastewater generation rates. The wastewater generation rates were calibrated in 2017 based on an analysis of drinking water consumption throughout the LOTT service area. The wastewater generation rates are developed in an Excel-based model using drinking water consumption rates provided by the partner jurisdictions and population projections provided by the Thurston Regional Planning Council. The rates are calibrated annually based upon flows observed at the Budd Inlet Treatment Plant, and on drinking water consumption data. The flow measured at each site in excess of the BSF was assumed to be due to I&I. An I&I analysis was performed using Capacity Assessment and Planning Environment (CAPE) modeling software, a wastewater forecasting and management tool provided by Brown and Caldwell. The record of observed flow data was plotted alongside a concurrent record of rainfall data. The model calculates flow based upon rainfall using a variety of hydrologic parameters. These parameters were calibrated until the model flows matched the observed flows over the period of record. Once calibrated, the model was applied to a long-term historical precipitation record (in this case, rainfall observed at the Olympia Regional Airport from 1955 to 2017). The long-term simulation produced risk-based estimates of the I&I flow over the full range of weather conditions contained in the historical rainfall record. An example of a CAPE calibration plot is presented on Figure 2-6. This plot depicts flow monitored at the BITP (blue), rainfall (green), and modeled flow at the BITP (red). The model has been calibrated such that the modeled and observed flows match very closely. Figure 2-6. CAPE Model Calibration for the BITP 2017 Inflow & Infiltration and Flow Monitoring Report 11

50 Figure 2-7 presents the model calibration from Figure 2-6 applied to the long-term precipitation record. Figure 2-7. Long Term I&I Projection for the BITP The data in Figure 2-5 are used to calculate risk-based I&I. LOTT uses a 10-year return period as the basis of its peak flow projections. A 10-year peak flow carries a 10% risk of being surpassed in any given year. The CAPE model was used to calculate risk-based I&I for each of the flow monitoring sites and combinations presented in Table 3-1. These data are presented and analyzed in the next section Inflow & Infiltration and Flow Monitoring Report 12

51 3. Flow Data Analysis This section describes the results of the analysis conducted using the flow data collected during the monitoring season. 3.1 Summary of I&I Statistics for All Flow Monitoring Sites A summary of the I&I results for each of the flow monitoring sites is provided in Table 3-1. Table Flow Monitoring Sites Inflow and Infiltration Summary (Total Flow, mgd) Flow Monitor Base Sanitary Flow Average Annual 10-year Peak Month 10-year Peak Day 10-year Peak Hour Summer Shoulder Winter SV SV SV SV SV L L OL OL OL CLPS KRPS Hixon MWPS WWTP Analysis of Base Flow Base sanitary flow (BSF) is wastewater which does not include I&I. There are three ways to determine BSF: 1. Direct measurement (flow monitoring), with the BSF typically calculated from the minimum 7-day average flow during the year. 2. Estimate based on winter drinking water consumption. 3. Model based on population and employment data, using the per capita wastewater generation rates. Table 3-2 lists an estimate of measured base sanitary flow versus population and employmentbased modeled BSF Inflow & Infiltration and Flow Monitoring Report 13

52 Monitoring Location Table 3-2. Comparison Between Measured Base Sanitary Flow and Modeled Base Sanitary Flow (mgd) Measured Base Sanitary Flow Modeled Base Sanitary Flow Difference Difference as % of Modeled BSF SV % SV % SV % SV % SV % L % L % OL % OL % OL % CLPS % KRPS % MWPS % BITP % Differences between monitored base flow and modeled base flow often reflect typical variability in wastewater flows and error associated with measurement of sewer flows. Differences may also reflect inaccurate sewer basin boundaries, unknown or mistaken sewer routes or connections, or impacts associated with pump stations. Drinking water consumption dissociated from wastewater (such as lawn watering or industrial uses) may also lead to differences between these values. Most critically, leaky sewers or fugitive emissions can cause the monitored base flow to vary from projected values. In general, the majority of the temporary sites measured flow from a single basin where a small difference between measured and monitored flow can result in a large percent difference. Model base flow at SV04 was 136% higher than the measured base flow. This basin contains several apartment complexes, which are often difficult to characterize. The low flow measurement in this basin suggests lower-than-modeled occupancy. This is an example where the magnitude of the difference (46,000 gpd) is relatively small. Flow at site SV11 was approximately 110,000 gpd higher than projected. This site serves several basins with a larger than average commercial component. The high proportion of commercial users can lead to inaccuracies in modeling base flow. The model flow was higher than the measured flow at the permanent sites OL25 and OL33. This could be related to an increase in the drinking water consumption rate within the City of Olympia. The water consumption rate increased from 63.9 to 70.1 gpd within the City, and this would have increased the model flow at both sites compared to the previous year. The largest discrepancy between modeled and measured base flow was at the Kaiser Road Pump Station. Flow at KRPS is difficult to assess, and the discrepancy can be attributed to the flux of students at The Evergreen State College (TESC). Figure 3-1 shows how widely the flow at KRPS varies, from 50,000 gpd in the summer to over 120,000 gpd in the winter Inflow & Infiltration and Flow Monitoring Report 14

53 Figure 3-1. KRPS Flow Pattern The modeled base flow is comprised of 130,000 gpd, which was the average winter season water consumption at TESC, and the modeled flow for Basin 54, which was approximately 140,000 gpd. The KRPS flow record from Figure 3-1 is difficult to reconcile with these figures. The data suggest that the pump station flow meter may be out of calibration. Notably, the summer base flow in 2016 was closer to 100,000, and the summer base flow in previous years ( ) was closer to 130,000 gpd. 3.3 Analysis of Inflow and Infiltration There are a number of ways to assess the quality and integrity of the sewer system. Some of the most commonly used methods involve a calculation of I&I per inch-diameter-mile (IDM) of pipe, I&I per ERU, and the ratio of the peak hour flow to the base flow. Table 3-3 summarizes these statistics for each of the flow monitors. These may be compared with benchmark values, established in the 2007 Inflow & Infiltration and Flow Monitoring Report and listed at the bottom of the table. For existing pipe, the amount of I&I will vary widely depending on the age of pipe, local maintenance standards, and most importantly, the degree of sewer separation (i.e. whether downspouts are strictly disconnected or whether any sewer to storm pipe cross-connections exist) during the original design of the collection system Inflow & Infiltration and Flow Monitoring Report 15

54 Table 3-3. Summary of I&I Statistics Annual Peak Peak Average Peak Hour Average Day Hour Annual Peak Day Peak Hour Flow/Base Flow I&I/ERU I&I/ERU I&I/ERU I&I/IDM I&I/IDM I&I/IDM Flow Benchmark Monitor (gpd) (gpd) (gpd) (gpd) (gpd) (gpd) (mgd) Ratio 1 SV ,298 1,465 2,369 11,555 13, SV ,028 1,221 2,905 13,351 15, SV , SV ,119 6,654 8, SV ,095 6, L ,358 1, L ,511 7,062 10, OL ,314 6, OL ,743 2, OL ,505 3,299 3,000 35,932 47, CLPS ,359 5, KRPS ,091 4, MWPS , WWTP ,111 10, Benchmark ,500 2, The benchmark ratio is the average value of seven ratios, corresponding to the first seven columns of the table (starting with average annual I&I/ERU and ending with the peak hour flow/base flow). The value in this table is divided by the benchmark. For example, the benchmark ratio at site OL25 is the average of the following values: {66/20; 404/150; 488/250; 867/200; 5,314/1,500; 6,425/2,400; 3.8/2.5} = I&I benchmarks established in the 2007 LOTT Inflow and Infiltration Report. The following sections discuss the flow records and I&I model results at each site. 3.4 Rotating Sites The rotating sites were spread across the collection system, and the I&I benchmarks varied considerably Site SV01 Site SV01 collects flow from Basin 30 in the area south of Priest Point Park in the East Bay area of Olympia. This basin is mainly composed of residential gravity sewers. The basin has aging infrastructure and is prone to high levels of I&I. Miller & Ann and Miller & Central Pump Stations both discharge to this basin. With a benchmark ratio of 9.5, this basin contributes high levels of I&I to the system Site SV04 Flow monitor site SV04 measures flow generated in Basin 29, which collects flow in southeast downtown Olympia near 11th Ave SE. This basin is mainly composed of residential gravity sewers, many of which are advanced in age. I&I in this basin is also high, with a benchmark ratio of Site SV05 Site SV05 measures flow generated in Basin 28, which is a residential area south of I-5 and east of Watershed Park in Olympia. This basin flows into the downstream portion of the LOTT Indian Creek Interceptor. Its benchmark ratio of 2.6 is correlated to relatively low levels of I&I in this basin Inflow & Infiltration and Flow Monitoring Report 16

55 3.4.4 Site SV06 Site SV06 measures flow generated in Basin 21 just north of Fones Road. The flow monitor is located between Fones Road and I-5. Basin 21 contains a mix of residential and commercial users and lies on the border between Olympia and Lacey. This basin has a benchmark ratio of 4.3, slightly higher than the adjacent Basin 28. In the past, the relatively high levels of I&I at this site have been linked to its proximity to Chambers Lake Site SV11 Site SV11 measures flow generated in Basins 74, 75, 78, and 79. This meter is located in Tumwater on Capitol Blvd. Flow from southern Tumwater either passes this location or enters the Hixon Siphon. These basins contain a mix of residential and commercial users and have a relatively low benchmark ratio of Permanent Sites Changes in the permanent and LOTT sites since last year include a large increase in I&I measured at sites OL31 and OL33, a smaller increase at L6, and the rest of the sites having similar profiles to the previous year Site OL33 The OL33 flow meter is located at the 4th Avenue Bridge and measures flow from northwest Olympia. In the past, this meter s ultrasonic level sensor had a maximum flow reading around 4.3 mgd. Recently, this meter was replaced with an area-velocity (AV) meter which is able to read higher flows. The resulting peak flows at this site were higher than previously assumed. Over the past year, flows exceeding 13 mgd have been noted at this location (Figure 3-2). Figure 3-2. Flow Meter OL Inflow & Infiltration and Flow Monitoring Report 17

56 Since the change in meter technology, the system-wide I&I model has gradually attempted to assign enough I&I to match meter observations. This year, the benchmark ratio increased from 11.4 to 16.1, with a projected peak hour I&I of 11.9 mgd Site OL31 Site OL31 saw a large increase in summer, shoulder, and winter I&I compared to last year (averaging 50-60% increase). Last year s model saw a large decrease in these flows compared to the 2015 report. This site is traditionally difficult to model. The metering manhole has minimal headspace and turbulent flow, which results in a higher-than-typical amount of scatter in the data. The benchmark ratio increased from 0.8 to 1.5, which reflects the generally low amount of I&I generated in Lacey Site L6 The flow monitor at site L6 measures flows generated in east Lacey. This site s benchmark ratio increased from 0.6 to 1.0, indicating a tight sewer system with low I&I System-Wide The system-wide I&I is largely a known quantity. Projections tend to vary slightly from year to year, which reflects some of the sensitivity of the model to variables such as groundwater level, which vary independently, or at least on a larger time scale, from I&I. In the big picture, system-wide I&I appears to be trending slightly upward, which is what one would expect as the service area expands and infrastructure ages. Figures 3-3 and 3-4 plot the system-wide I&I over the course of the 14-year program Inflow & Infiltration and Flow Monitoring Report 18

57 Figure 3-3. System-wide I&I Trends Figure 3-4. System-wide I&I Trends 2017 Inflow & Infiltration and Flow Monitoring Report 19

58 3.6 Updated I&I Model Inflow and infiltration estimates for each flow meter are translated to basin I&I estimates using a best-fit technique taking all of the data from all of the meters into account. In this way, basin I&I estimates may be updated on an annual basis, and compared with the previous year s estimate. As the I&I program progresses, model projections for each of the permanent stations will become more accurate. By recalibrating the full set of basin I&I profiles each year, the overall system model will increase its accuracy on a continuous basis. Note that approximately one-third of the basins have not been monitored directly. In these basins, the I&I estimates are based on the regression of data from all downstream flow monitors, as well as the system as a whole. Table 3-4 summarizes the basin I&I statistics. Basin City Location 1 L Hawks Prairie Table 3-4. Basin I&I (gpd) Average Annual Peak Month Peak Day Peak Hour Summer (6,7,8,9) Shoulder (4,5,10) Winter (Nov- Mar) 131, , , ,100 56, , ,000 2 L Meridian 23,600 73, , ,600 13,300 30,400 45,900 3 L Meadows 14,900 20,600 22,400 37,400 2,700 9,100 18,800 4 L Lacey STEP 14,900 19,100 22,400 37,400 4,300 13,700 18,800 5 L SE Corner 14,900 19,000 22,400 37,400 2,400 5,100 17,500 6 L Horizon View 3,700 35,400 98, ,100 3,400 5,000 10,000 7 L Ruddell 3,700 48,800 98, ,800 2,800 7,700 10,000 8 L S Chambers Lake 20,300 88, , ,100 5,500 14,000 37,400 9 L N Chambers Lake 34,800 76, , ,600 14,700 29,300 51, L Lacey Blvd 18,800 56, , ,000 6,600 15,700 30, L Lacey Confluence 24,900 65,400 81, ,900 10,300 22,500 38, L South Sound Center 115, , , ,700 45,400 95, , L St. Martins 14,900 20,700 22,400 37,400 5,900 13,600 18, L Chinook 13,300 17,600 20,500 31,700 6,400 10,000 13, L Britton Pkwy 16,600 52,100 85,600 99,200 8,500 19,600 32, L N Tanglewilde 16,600 35,600 85,600 92,400 5,200 9,400 32, L S Tanglewilde 16,600 37,000 85, ,200 4,600 19,100 32, O Motel 8 18,300 52,600 71, ,100 4,800 13,000 30, O Lilly Rd 18,300 52,600 71, ,100 4,800 13,000 30, O South Bay Rd 880 1,200 1,300 1, ,100 1, O Fones 84, , , ,500 29,700 71, , O Boulevard 20,700 60,100 78,400 83,800 10,800 23,600 40, O Wiggins Indian 24 O Summer 8,900 19,000 93, ,100 4,200 8,200 14, Inflow & Infiltration and Flow Monitoring Report 20

59 Average Peak Basin City Location Annual Month Day Hour (6,7,8,9) (4,5,10) Mar) South 25 O Boulevard 19,600 55,400 84, ,900 7,600 16,900 31,900 Peak Peak Summer Shoulder Winter 26 O Henderson 8,900 31,900 93, ,200 3,100 7,800 14, O North St 28,200 83, , ,200 9,900 23,500 45, O Indian Creek 8,500 26,500 68, ,900 2,900 7,100 14, O SE Downtown 101, , , ,300 30,200 72, , O Priest Point 220, , ,200 1,193,000 43, , , O San Francisco 155, ,500 1,443,200 2,035,100 51, , , O NE Downtown 8,000 39, ,800 1,919,800 2,500 3,600 14, O Bigelow 28,700 77, , ,700 11,400 25,100 44, O Puget St 6,100 17, , ,600 1,700 3,900 7,700 Bigelow 35 O Springs 6,100 17, , ,600 1,700 3,900 7, O State Ave 6,100 17, , ,800 1,800 4,000 7, O Lybarger 8,000 29, , ,200 2,000 7,700 14, O 4th Ave E 11,600 37, , ,700 3,900 9,500 19, O 5th Ave E 8,000 46, , ,600 2,600 7,100 14, O Pear 13,800 38, , ,200 4,000 8,900 17, O Plum 142, ,900 1,545,600 2,273,600 46, , ,000 I-5 42 O Interchange 7,100 24, , ,300 2,500 7,000 14, O Stevens Field 62, ,700 1,511,500 3,815,300 20,300 50, , O S Capitol 24th 14,500 41, , ,100 3,000 22,300 26, O S Capitol 22nd 8,300 57, ,400 1,236, ,800 16, O S Capitol 17th 16,900 31, , ,300 8,600 11,300 17, O State Capitol 16,000 57, , ,700 8,900 12,400 26,100 N Capitol 48 O Campus 16,100 47, , ,100 3,400 8,900 24, O State Offices 23,000 76, , ,300 7,900 19,100 38,400 Central 50 O Downtown 102, ,600 1,640,900 3,531,000 35,700 84, , O Sylvester 129, ,200 2,674,500 4,696,000 47, , , O Heritage Park 125, ,300 2,558,200 2,955,800 10,600 50, , O Port Peninsula 13,800 38, , ,200 4,000 8,900 17, O Cedrona 9,800 19,600 34,800 56,500 5,200 7,500 11, O Westwood O Old Port 80, , , ,000 29,100 69, , O Cooper Point 59, , , ,100 8,900 45,000 99,700 (Nov Inflow & Infiltration and Flow Monitoring Report 21

60 Basin City Location Average Annual Peak Month Peak Day Peak Hour Summer (6,7,8,9) Shoulder (4,5,10) Winter (Nov- Mar) 58 O Goldcrest 42, , , ,200 4,700 21,200 49, O West Bay 16,900 60, , ,200 3,000 11,900 31, O West Side 53, , , ,500 14,500 52,800 68, O Jefferson 244, ,900 2,343,400 2,948,500 94, , , O Harrison 18,200 80, , ,300 5,500 13,700 31,700 Decatur 63 O Woods 53, , , ,500 18,200 44,000 89, O Grass Lake 39,500 42, , ,400 4,900 11,800 23, O West Olympia 2,800 7,200 12,600 22,900 1,100 2,000 3, O Capital Mall 37, , , ,300 7,300 26,200 50, O Percival Creek 15,400 68, , ,800 3,700 15,000 26, O Ken Lake 109, , , ,300 39,000 89, , O Mottman 93, , , ,300 22,000 68, , T N Black Lake T Sapp 148, , , ,700 75, , , T Tumwater Hill 86, , , ,000 30,300 71, , T E Street 5,600 16,500 33,100 36,000 2,200 4,400 10, T H Street 4,500 14,700 27,300 35,200 1,900 3,500 8, T Barnes Lake 12,000 38,600 67,200 88,300 4,900 10,000 19, T NE Tumwater 22,600 62, , ,300 8,600 19,400 36,100 Tumwater 77 T Valley , T Southgate 64, , , ,900 24,200 56, , T Trosper 2,500 7,600 25,200 31,800 2,000 2,100 4, T Littlerock 5,200 15,200 34,900 62,400 2,000 4,400 8,600 Tumwater 81 T City Hall 4,800 18,000 50,900 61,100 1,400 3,600 8, T Trails End 4,800 18,000 50,900 61,100 1,400 3,600 8, T Hwy 99 4,800 18,000 50,900 61,100 1,400 3,600 8, T Airport T S Airport 4,800 18,000 50,900 61,100 1,400 3,600 8, T Kimmie 4,800 18,000 50,900 61,100 1,400 3,600 8, T Salmon Creek T Black Lake The Evergreen TESC State College 16,300 48, , ,300 3,800 8,900 22, Inflow & Infiltration and Flow Monitoring Report 22

61 3.6.1 I&I Benchmarks and Basin Ranking The intergovernmental agreement which established the LOTT I&I program includes a nondegradation clause. Based upon this clause, LOTT will annually evaluate I&I in each of its sewer basins. If the amount of I&I in a basin is found to be significantly increasing, LOTT and its partners will prioritize work in that basin to remedy the situation. In order to provide a measure which can be tracked on an annual basis, the I&I benchmarks listed in Table 3-5 have been selected. These benchmarks are drawn from a statistical analysis of the LOTT basins. They represent the top 33rd percentile of I&I measures across all of the basins when the benchmark was established in That is, two-thirds of the LOTT basins exhibited I&I parameters worse than these benchmarks at that time. Table 3-5. LOTT Sewer Basin I&I Benchmarks Average Annual I&I per ERU 20 gpd/eru Peak Month I&I per ERU 50 gpd/eru Peak Day I&I per ERU 150 gpd/eru Peak Hour I&I per ERU 250 gpd/ ERU Average Annual I&I per IDM 200 gpd/idm Peak Month I&I per IDM 500 gpd/idm Peak Day I&I per IDM 1,500 gpd/idm Peak Hour I&I per IDM 2,400 gpd/idm Peak Hour Flow to Base Flow Ratio 2.5 Each LOTT basin is compared with the benchmark in each of the nine categories. A benchmark average is then calculated, which provides a representation of how each basin compares to the benchmark. A basin in the top one-third in each of the 9 categories will have a score less than 1.0. A ranking of the 88 LOTT basins, along with some key I&I figures and the benchmark score, is provided in Table 3-6. Table 3-6. LOTT Sewer Basins Inflow and Infiltration Ranked from Highest to Lowest Severity of I&I Rank Basin City Location Average Annual I&I/ERU (gpd) Average Annual I&I/IDM (gpd) Peak Hour/BSF Benchmark Ratio 2016 Benchmark Ratio Change from Previous Year Absolute Change from Previous Year 1 52 O Heritage Park % O Lybarger % O State Capitol % O S Capitol 22nd % O Sylvester % O Central Downtown % O S Capitol 24th % O Harrison % O Pear % O Plum % O Bigelow Springs % O Stevens Field % O Puget St % O N Capitol Campus % Inflow & Infiltration and Flow Monitoring Report 23

62 Rank Basin City Location Average Annual I&I/ERU (gpd) Average Annual I&I/IDM (gpd) Peak Hour/BSF Benchmark Ratio 2016 Benchmark Ratio Change from Previous Year Absolute Change from Previous Year O S Capitol 17th % O Jefferson % O San Francisco % O Ken Lake % T Barnes Lake % O State Offices % O NE Downtown % O SE Downtown % O State Ave % O Old Port % O Priest Point % L South Sound Center % T Tumwater Hill % T Southgate % O Bigelow % O 4th Ave E % O 5th Ave E % O Motel % O West Side % O Mottman % O Decatur Woods % O Goldcrest % T Sapp % O West Bay % O Fones % L S Tanglewilde % L Britton Pkwy % O North St % O Port Peninsula % O Capital Mall % O South Boulevard % O Cooper Point % O I-5 Interchange % T E Street % L Lacey Blvd % L Lacey Confluence % T S Airport % Inflow & Infiltration and Flow Monitoring Report 24

63 Rank Basin City Location Average Annual I&I/ERU (gpd) Average Annual I&I/IDM (gpd) Peak Hour/BSF Benchmark Ratio 2016 Benchmark Ratio Change from Previous Year Absolute Change from Previous Year 52 1 L Hawks Prairie % L N Tanglewilde % T Trails End % L N Chambers Lake % L S Chambers Lake % O Indian Creek % O Grass Lake % L Meridian % L Chinook % O Percival Creek % T NE Tumwater % L St. Martins % T Hwy % L Meadows % T H Street % O Indian Summer % O Cedrona % O West Olympia % T Kimmie % O Lilly Rd % O Boulevard % O Henderson % T Littlerock % T Tumwater City Hall % L Ruddell % T Trosper % L Horizon View % L Lacey STEP % T Tumwater Valley % Inflow & Infiltration and Flow Monitoring Report 25

64 Figure 3-5. LOTT Sewer Basins, Magnitude of I&I as Expressed by Ratio of I&I Parameters to Benchmark Values Basins Labeled by Basin ID 2017 Inflow & Infiltration and Flow Monitoring Report 26

65 Figure 3-6. LOTT Sewer Basins, Ranked by I&I Severity (Basins Labeled by Rank) 2017 Inflow & Infiltration and Flow Monitoring Report 27

66 The basins with the most I&I are concentrated in the central downtown area of Olympia (low ranking). This corresponds with the location of most of the combined sewer pipes in the system. High levels of I&I were also noted in both the East Bay and West Bay areas of Olympia, corresponding to the areas with the oldest residential developments. Outside of central Olympia, the highest levels of I&I were noted in the Barnes Lake area of Tumwater and the Ken Lake area of Olympia. The lowest levels of I&I were found in south Lacey, southwest Tumwater, and the STEP areas of southeast Lacey and southeast Olympia. Overall, the system benchmark ratio was 3.54, which is slightly lower than the previous year s average (3.75). Average ratios for the LOTT partner jurisdictions were: Lacey: 1.0 Olympia: 6.0 Tumwater: 2.1 The difference in benchmark values from the 2016 I&I Report to the 2017 I&I Report is shown on Figure Inflow & Infiltration and Flow Monitoring Report 28

67 Figure 3-7. Change in Benchmark Values in LOTT Basins from 2016 to 2017 I&I Report 2017 Inflow & Infiltration and Flow Monitoring Report 29

68 The changes since 2016 do not follow a discernible pattern, but include some highlights. Major changes were observed in several of the SV basins monitored this year (Basins 21, 29, and 78). Otherwise, the West Bay area in Olympia became notably better, while Basin 62 became notably worse, likely caused by the increased I&I modeled at meter OL33. Downtown I&I shifted somewhat from the west side of Capitol Blvd to the east side, which may reflect a general evening out of I&I across the downtown basins. The basin with the highest benchmark is Basin 52 in Olympia. This is a small basin which includes Heritage Park and the 4th Avenue Bridge (Figure 3-8). There is no direct flow monitoring of this basin, and its high allocation of I&I reflects the system-wide model s efforts to allocate high flows at the BITP and the Water Street Pump Station. To some extent, the model allocates I&I to this basin when it can t allocate it anywhere else. The lack of direct flow monitoring makes this one of few downtown sewer basins which can accommodate such flows (see Figure 2-4, which highlights the basins where I&I is only calculated from the system-wide model in gray). Figure 3-8. Basin 52 Basin 52 s benchmark ratio decreased from 196 to 126. This change reflects efforts made to improve the system-wide model to reduce allocation to the unmonitored basins. As noted above, the model reapportioned I&I from several basins west of Capitol Blvd (Basins 44, 46, 47, 48, 51, and 52) over to the east side of Capitol Blvd (Basin 50 in particular). This may be related to a change in the system-wide model which deemphasized data from Olympia s Water Street Pump Station (the data being several years old and of questionable reliability). Another notable change was a reduction of I&I in Basin 85 in southern Tumwater, which may reflect more accurate monitoring of the Hixon Siphon, as well as monitoring from site SV Inflow & Infiltration and Flow Monitoring Report 30

69 As noted in the previous year s report, annual benchmark changes tend to have little to do with improving I&I conditions in the respective basins, and more to do with improvements in the sewered population map, the sewer geodatabase, and the tracking of residential and commercial ERUs in Lacey, Olympia, and Tumwater. Many of the largest changes take place in basins which are not directly monitored, and are therefore subject to annual shifts associated with changes elsewhere in the model. A better way to assess changing I&I conditions is the direct comparison of flow monitoring data, as will be discussed in the following section Comparison of I&I from Year 7 to Year 14 Five of the sites monitored for this report were previously monitored in The purpose of re-monitoring these sites is to assess the change in I&I and highlight areas for I&I reduction. The CAPE model was used to compare I&I measured in with I&I measured in Raw data are presented in Table 3-7, while benchmark data are presented in Table 3-8. Table 3-7. Comparison of I&I, 2010 versus 2017 I&I (mgd) SV01 SV04 SV05 SV06 SV11 Year Base sanitary flow Annual average year peak month year peak day year peak hour FM Site Table 3-8. Comparison of ERUs and Benchmark Ratios for 2010 versus 2017 ERU Percent Benchmark Ratio Change Difference Change Percent Difference SV % % SV % % SV % % SV % % SV % % SV01 This site s tributary basin is located in East Bay south of Priest Point Park. Site SV01 s I&I benchmark increased from 7.4 to 9.5. This basin has older infrastructure and is prone to high levels of I&I. All of this site s I&I projections increased since The City of Olympia does not list any combined sewers in this basin. Therefore, I&I is most likely related to leaking sewer pipes, leaking manholes, and connections from house gutters and downspouts into the sewer. Figures 3-9 and 3-10 compare the flow record at this site across seven years. Note how the base flows in the summer periods to the left and right of the plots are similar, but the wet season flows are far higher now than they were seven years ago. This explains the benchmark change Inflow & Infiltration and Flow Monitoring Report 31

70 Figure Minute Flow Data from Site SV01 in Figure Minute Flow Data from Site VS01 in SV04 Site SV04 monitors flow along 11th Ave SE in southeast downtown Olympia. This site saw the largest increase in benchmark since 2010 with an increase from 6.1 to 9.6 (a 37% increase). The number of ERUs in this basin has not changed significantly from 2010 and the base flow remains very low (34,000 gpd). The flow records (Figure 3-11 and 3-12) are quite different. In both cases, the base flow in the summer period was quite low. During the wet season, however, flows peaked at 0.30 to 0.40 mgd in 2017 Inflow & Infiltration and Flow Monitoring Report 32

71 , but increased to 0.45 to 0.55 mgd in Similar to SV01, this site has aging infrastructure, and the I&I increase may reflect gradually deteriorating pipe. Figure Minute Flow Data from Site SV04 in Figure Minute Flow Data from Site SV04 in Inflow & Infiltration and Flow Monitoring Report 33

72 SV05 Site SV05 monitors flow south of the Woodland Trail along 22nd Ave. This site s benchmark remained stable, changing from 1.0 to 1.1. As shown on Figure 3-13, flow at this site is very stable, with little seasonal influence. Figure Minute Flow Data from Site SV05 in SV06 I&I benchmarks decreased at site SV06 from 5.1 to 4.3. SV06 measures flow from Basin 21, which borders Chambers Lake, making the basin s low elevation prone to I&I during certain parts of the year. Figure Sewer Basin Inflow & Infiltration and Flow Monitoring Report 34

73 SV11 I&I benchmarks did not change significantly at site SV11, which is located along Capitol Blvd in Tumwater. Benchmarks increased from 2.6 to 2.7. The flow pattern shows a gradual seasonal change suggestive of groundwater-associated infiltration rather than inflow (Figure 3-15). Figure Minute Flow Data from Site SV11 in Inflow & Infiltration and Flow Monitoring Report 35

74 4. Program Wrap-up LOTT s I&I program has vastly improved the knowledge of the collection system over the last 14 years. Figures 4-1 and 4-2 compare the presumed 10-year peak day I&I distribution in 2002 and Figure 4-1. Presumed 10-year peak day I&I distribution in Inflow & Infiltration and Flow Monitoring Report 36

75 Figure 4-2. Presumed 10-year peak day I&I distribution in 2017 Figure 4-3 presents the change in peak day I&I over that same period Inflow & Infiltration and Flow Monitoring Report 37

76 Figure 4-3. Change in presumed 10-year peak day I&I from 2002 to 2017 It is important to understand that Figure 4-3 is not necessarily indicating that I&I got better or worse in those basins over the past 14 years. Instead, it is suggesting that understanding of the distribution of I&I has improved dramatically. While in 2002 most of the I&I had been allocated to the downtown Olympia combined sewer system, and to areas adjacent to large diameter LOTT interceptors (Figure 4-1), the current I&I projection has distributed that I&I over the entire collection system. This information is critical for collection system planning and management, as well as for capacity planning with respect to satellite treatment systems. A major conclusion of this 14-year study is that the inherent variability and scatter in wastewater flow data does not lend itself to short-term comparisons. Attempts to comment on basin benchmark changes from one year to the next have largely been unproductive. Over a longer term, it is 2017 Inflow & Infiltration and Flow Monitoring Report 38

77 possible to comment, for example, that I&I appears to be getting worse in the basins served by flow monitors SV01 and SV04. Yet even here the data must be viewed with some discretion. Over the intervening period, the accuracy of the service population data as well as the pipeline data has improved, and the I&I benchmarks are based on flow per ERU or flow per IDM of pipe. So changes to the population and pipeline inputs can cause changes to the benchmark, even when flow data are identical. Moving forward, the I&I program will become more static. The rotating flow monitoring sites have served their purpose, allowing for detailed allocation of I&I across the 88 sewer basins. In the future, a smaller number of permanent sites will allow for long term tracking of I&I. Periodically, temporary monitoring will be performed at certain locations which have shown marked deterioration over the course of this program, or where the permanent meters suggest that upstream assessment is warranted. 5. Recommendations 1. The flows recorded at KRPS do not match reasonable expectations of base sanitary flow. LOTT should investigate the calibration of flow monitoring equipment at this location. 2. Increased magnitude of I&I at flow monitoring sites SV01 and SV04 suggest deteriorating infrastructure within the City of Olympia at the following locations. The City should be notified of these findings: Basin 30 in northeast Olympia (Figure 5-1) Figure 5-1. Basin Inflow & Infiltration and Flow Monitoring Report 39

78 Basin 29 in southeast downtown (Figure 5-2) Figure 5-2. Basin Having completed two cycles of the flow monitoring program, the recommendation is to shift to a more static program which relies upon long-term flow monitoring at fewer sites. The past 14 years have allowed LOTT to allocate I&I across its system. The next phase in the program will involve tracking changes in I&I over time, and this is best accomplished through long-term monitoring at static locations Inflow & Infiltration and Flow Monitoring Report 40

79 Flow Monitoring Site Installation Reports Monitoring Sites SV-01 SV-04 SV-05 SV-06 SV Inflow & Infiltration and Flow Monitoring Report 41

80 Site Assessment CLIENT FLOW MONITORING #: U SFE PROJECT #: NAME: LOTT Alliance SFE SITE #: Date / Time: 7/24/2015 U SV-01 Project Specific Information Client Name: LOTT Alliance End User Name: LOTT Alliance Project Name: U Client Contact: Tyle Zuchowski Field Contact: Adrian Marshall SFE PM Contact: Paul Loving Site Equipment Install / Remove Date: 7/24/2015 Meter Make & Model: Isco 2150 AV Level Type: Pressure Velocity Type: Average Primary Device: Weir Wireless: Yes Redundancy: Yes Logging Rate: 5min Site Location Information Site Profile Client Manhole #: Address (Location): SV East Bay Road Pipe #1 Size: 8 Inches City, State: Olympia, WA Pipe #2 Size: 15 Inches GPS (North - West ): Pipe #3 Size: 15 Inches Landmarks: LA Fitness Pipe #4 Size: 8 Inches Additional Information: On Road in front of LA Fitness Constant: 91.5 Inches Map of Area Laterals / Rungs: Additional Information: Yes Yes Manhole Layout Traffic Control Requirements Provider: Third Party Date & Time: Condition Moderate Traffic Depth: Frequency: Install Velocity: Speed Limit: 30 Turbulent: # of Lanes Effected: 3 Surcharge: Lane Configuration: Roadway Silting: Additional Information: Solids: Notes Notes Site Hydraulics 09/16/16 13: Inches 1 FPS NA No No Yes Revision 3.1

81 Site Pictures CLIENT FLOW MONITORING #: U SFE PROJECT #: NAME: LOTT Alliance SFE SITE #: Date / Time: 7/24/2015 U SV-01 Picture 1 Picture 2 Picture 3 Picture 4 Picture 5 Picture 6 Notes Revision 3.1

82 CCW Installation Form CLIENT FLOW MONITORING #: U SFE PROJECT #: U NAME: LOTT Alliance SFE SITE #: SV-01 Date / Time: 7/24/2015 Technician 1: Technician 2: Adrian Marshall Assistant Meter Depth vs.. Field Depth Calibration / Verification Reading Date Time Field Meas Meter Depth Number (in.) (in) Initial 7/24/ : /24/ : /24/ : /24/ : Average Comments (Zero Meter Level before Installation) Constant Measurement (in) Rim to Weir Lip D1+ D2 = CNST D2 Pipe Diameters (in) Pipe 1 8 Pipe 2 15 Pipe 3 15 Pipe 4 8 D4=Invert to Weir Lip (D3-D1) D D Obvert to Weir Lip D4 Revision 3.1

83 Final Check-off Sheet CLIENT FLOW MONITORING #: U SFE PROJECT #: U NAME: LOTT Alliance SFE SITE #: SV-01 Date / Time: 7/24/2015 Flow Meter Information Meter Make: Meter Model: Sensor Type Meter Serial Number: Battery Volts: Isco Logging Rate: 5 Minute 2150 Flow Units: CFS AV Velocity Units: FPS 207K01064 Depth Units Inches 11 Surcharge Meter (Y/N): Yes Site Physical Information Silt Level: Slope: Uniform Flow (Y/N) Debris in Flow (Y/N): Pipe Material: 0 NA Y Y Concrete Weather: Weir Size: Depth Only(DO) or Look up Table(LT) Comments Overcast 600 mm NA LT Time Set: Depth Calibrated: Velocity Profile: Download Data: Meter Running: Pipe Size Verified: Photograph Taken: Site Cleaned: Site Secured: Yes x x x x x x x x No x Check Off List Revision 3.1

84 Site Assessment CLIENT FLOW MONITORING #: U SFE PROJECT #: NAME: LOTT Alliance SFE SITE #: Date / Time: 09/16/16 U SV-04 Project Specific Information Client Name: LOTT Alliance End User Name: LOTT Alliance Project Name: U Client Contact: Tyle Zuchowski Field Contact: Adrian Marshall SFE PM Contact: Paul Loving Site Equipment Install / Remove Date: 09/16/16 Meter Make & Model: Isco 2150 AV Level Type: Pressure Velocity Type: Average Primary Device: AV in Pipe Wireless: Yes Redundancy: No Logging Rate: 5min Site Location Information Site Profile Client Manhole #: Address (Location): U Quince Street Pipe #1 Size: 15 Inches City, State: Olympia, WA Pipe #2 Size: 15 Inches GPS (North - West ): Pipe #3 Size: NA Inches Landmarks: Pipe #4 Size: NA Inches Additional Information: Constant: Inches Map of Area Laterals / Rungs: Additional Information: No Yes Manhole Layout 2 Sensor Loc 1 Traffic Control Requirements Site Hydraulics Provider: Third Party Date & Time: 09/16/16 8:30 Condition Local Depth: 2 Inches Frequency: install Velocity: 1.5 FPS Speed Limit: 25 Turbulent: No # of Lanes Effected: 2 Surcharge: Possible Lane Configuration: Road Silting: No Additional Information: Solids: Notes Notes Revision 3.1

85 Site Pictures CLIENT FLOW MONITORING #: U SFE PROJECT #: NAME: LOTT Alliance SFE SITE #: Date / Time: 09/16/16 U SV-04 Picture 1 Picture 2 Picture 3 Picture 4 Picture 5 Picture 6 Notes Revision 3.1

86 Area Velocity Site Installation Form CLIENT FLOW MONITORING #: U SFE PROJECT #: U NAME: LOTT Alliance SFE SITE #: SV-04 Date / Time: 09/16/16 Technician 1: Technician 2: A Marshall James Scott Meter Depth vs.. Field Depth Calibration / Verification Reading Date Number Initial 9/16/ /16/ /16/2016 Time 8:45 8:49 8:51 Field Meas (in.) Meter Depth (in) Comments (Zero Meter Level before Installation) 3 9/16/2016 8: Average Manhole Depth (in) = CNST Pipe Diameters (in) Pipe 1 15 Pipe 2 15 Pipe 3 NA Pipe 4 NA CNST (in) Sensor Location Revision 3.1

87 Velocity Profile Form CLIENT FLOW MONITORING #: U SFE PROJECT #: NAME: LOTT Alliance SFE SITE #: Date / Time: 09/16/16 U SV-04 Pipe Diameter (in): 15 Weather Overcast PV Meter AV Meter: Flowmate Isco D Method Depth from Invert (in) Left Corner Left Center Right Right Corner Average all readings 0.9 Vmax Method If depth is less than 4", use Max measured velocity x 0.9 Use above 2-D method as preferred method when possible Max 1.66 Max * Velocity Profile Summary Profile Meter Meter Depth of Average Reading Coeff. Flow (in.) fps fps NA 2.5 Time 8:45 Sensor Location x 2 Meter Location and Orientation Comments: Section View Revision 3.1

88 Final Check-off Sheet CLIENT FLOW MONITORING #: U SFE PROJECT #: U NAME: LOTT Alliance SFE SITE #: SV-04 Date / Time: 09/16/16 Flow Meter Information Meter Make: Meter Model: Sensor Type Meter Serial Number: Battery Volts: Isco 2150 AV 207K Logging Rate: Flow Units: Velocity Units: Depth Units Surcharge Meter (Y/N): 5 Minute CFS FPS Inches Yes Site Physical Information Silt Level: Slope: Uniform Flow (Y/N) Debris in Flow (Y/N): Pipe Material: 0 NA Y Y Concrete Weather: Weir Size: Depth Only(DO) or Look up Table(LT) Comments Overcast NA NA NA Time Set: Depth Calibrated: Velocity Profile: Download Data: Meter Running: Pipe Size Verified: Photograph Taken: Site Cleaned: Site Secured: Yes x x x x x x x x x No Check Off List Revision 3.1

89 Site Assessment CLIENT FLOW MONITORING #: U SFE PROJECT #: NAME: LOTT Alliance SFE SITE #: Date / Time: 08/09/16 U SV-05 Project Specific Information Client Name: LOTT Alliance End User Name: LOTT Alliance Project Name: U Client Contact: Tyle Zuchowski Field Contact: Adrian Marshall SFE PM Contact: Paul Loving Site Equipment Install / Remove Date: 08/09/16 Meter Make & Model: Isco 2150 AV Level Type: Pressure Velocity Type: Average Primary Device: Weir Wireless: Yes Redundancy: Yes Logging Rate: 5min Site Location Information Site Profile Client Manhole #: Address (Location): SV Boundary Street Pipe #1 Size: 8 Inches City, State: Olympia, WA Pipe #2 Size: 8 Inches GPS (North - West ): Pipe #3 Size: NA Inches Landmarks: Pipe #4 Size: NA Inches Additional Information: Constant: Inches Map of Area Laterals / Rungs: Additional Information: Yes Yes Manhole Layout 2 1 Traffic Control Requirements Provider: SFE Date & Time: Condition None Depth: Frequency: Install Velocity: Speed Limit: 25 Turbulent: # of Lanes Effected: 1 Surcharge: Lane Configuration: Roadway Silting: Additional Information: Solids: Notes Notes Site Hydraulics 09/16/16 10:30 1 Inches 1.5 FPS NA No No Yes Revision 3.1

90 Site Pictures CLIENT FLOW MONITORING #: U SFE PROJECT #: NAME: LOTT Alliance SFE SITE #: Date / Time: 08/09/16 U SV-05 Picture 1 Picture 2 Picture 3 Picture 4 Picture 5 Picture 6 Notes Revision 3.1

91 CCW Installation Form CLIENT FLOW MONITORING #: U SFE PROJECT #: U NAME: LOTT Alliance SFE SITE #: SV-05 Date / Time: 08/09/16 Technician 1: Technician 2: Adrian Marshall Assistant Meter Depth vs.. Field Depth Calibration / Verification Reading Date Time Field Meas Meter Depth Number (in.) (in) Initial 8/9/ : /9/ : /9/ : /9/ : Average Comments (Zero Meter Level before Installation) Constant Measurement (in) Rim to Weir Lip D1+ D2 = CNST D2 Pipe Diameters (in) Pipe 1 8 Pipe 2 8 Pipe 3 NA Pipe 4 NA D4=Invert to Weir Lip (D3-D1) D D Obvert to Weir Lip 16 D4 Revision 3.1

92 Final Check-off Sheet CLIENT FLOW MONITORING #: U SFE PROJECT #: U NAME: LOTT Alliance SFE SITE #: SV-05 Date / Time: 08/09/16 Flow Meter Information Meter Make: Meter Model: Sensor Type Meter Serial Number: Battery Volts: Isco Logging Rate: 5 Minute 2150 Flow Units: CFS AV Velocity Units: FPS 207K01083 Depth Units Inches 12.6 Surcharge Meter (Y/N): Yes Site Physical Information Silt Level: Slope: Uniform Flow (Y/N) Debris in Flow (Y/N): Pipe Material: 0 NA Y Y Concrete Weather: Weir Size: Depth Only(DO) or Look up Table(LT) Comments Overcast 350 mm NA LT Time Set: Depth Calibrated: Velocity Profile: Download Data: Meter Running: Pipe Size Verified: Photograph Taken: Site Cleaned: Site Secured: Yes x x x x x x x x No x Check Off List Revision 3.1

93 Site Assessment CLIENT FLOW MONITORING #: U SFE PROJECT #: NAME: LOTT Alliance SFE SITE #: Date / Time: 08/09/16 U SV-06 Project Specific Information Client Name: LOTT Alliance End User Name: LOTT Alliance Project Name: U Client Contact: Tyle Zuchowski Field Contact: Adrian Marshall SFE PM Contact: Paul Loving Site Equipment Install / Remove Date: 08/09/16 Meter Make & Model: Isco 2150 AV Level Type: Pressure Velocity Type: Average Primary Device: Weir Wireless: Yes Redundancy: Yes Logging Rate: 5min Site Location Information Site Profile Client Manhole #: Address (Location): SV-06 Indian Creek Trail Pipe #1 Size: 18 Inches City, State: Olympia, WA Pipe #2 Size: 18 Inches GPS (North - West ): Pipe #3 Size: NA Inches Landmarks: Pipe #4 Size: NA Inches Additional Information: Constant: 88 Inches Map of Area Laterals / Rungs: Additional Information: Yes Yes Manhole Layout 2 1 Traffic Control Requirements Provider: SFE Date & Time: Condition None Depth: Frequency: Install Velocity: Speed Limit: 10 Turbulent: # of Lanes Effected: 0 Surcharge: Lane Configuration: Path Silting: Additional Information: Solids: Notes Notes Site Hydraulics 09/16/16 10:30 1 Inches 1.5 FPS NA No No Yes Revision 3.1

94 Site Pictures CLIENT FLOW MONITORING #: U SFE PROJECT #: NAME: LOTT Alliance SFE SITE #: Date / Time: 08/09/16 U SV-06 Picture 1 Picture 2 Picture 3 Picture 4 Picture 5 Picture 6 Notes Revision 3.1

95 CCW Installation Form CLIENT FLOW MONITORING #: U SFE PROJECT #: U NAME: LOTT Alliance SFE SITE #: SV-06 Date / Time: 08/09/16 Technician 1: Technician 2: Adrian Marshall Assistant Meter Depth vs.. Field Depth Calibration / Verification Reading Date Time Field Meas Meter Depth Number (in.) (in) Initial 8/9/ : /9/ : /9/ : /9/ : Average Comments (Zero Meter Level before Installation) Constant Measurement (in) Rim to Weir Lip D1+ D2 = CNST D2 Pipe Diameters (in) Pipe 1 18 Pipe 2 18 Pipe 3 NA Pipe 4 NA D4=Invert to Weir Lip (D3-D1) D D Obvert to Weir Lip D4 Revision 3.1

96 Final Check-off Sheet CLIENT FLOW MONITORING #: U SFE PROJECT #: U NAME: LOTT Alliance SFE SITE #: SV-06 Date / Time: 08/09/16 Flow Meter Information Meter Make: Meter Model: Sensor Type Meter Serial Number: Battery Volts: Isco Logging Rate: 5 Minute 2150 Flow Units: CFS AV Velocity Units: FPS 203B00914 Depth Units Inches 12 Surcharge Meter (Y/N): Yes Site Physical Information Silt Level: Slope: Uniform Flow (Y/N) Debris in Flow (Y/N): Pipe Material: 0 NA Y Y Concrete Weather: Weir Size: Depth Only(DO) or Look up Table(LT) Comments Overcast 600mm NA LT Time Set: Depth Calibrated: Velocity Profile: Download Data: Meter Running: Pipe Size Verified: Photograph Taken: Site Cleaned: Site Secured: Yes x x x x x x x x No x Check Off List Revision 3.1

97 Site Assessment CLIENT FLOW MONITORING #: U SFE PROJECT #: NAME: LOTT Alliance SFE SITE #: Date / Time: 08/09/16 U SV-11 Project Specific Information Client Name: LOTT Alliance End User Name: LOTT Alliance Project Name: U Client Contact: Tyle Zuchowski Field Contact: Adrian Marshall SFE PM Contact: Paul Loving Site Equipment Install / Remove Date: 08/09/16 Meter Make & Model: Isco 2150 AV Level Type: Pressure Velocity Type: Average Primary Device: Weir Wireless: Yes Redundancy: Yes Logging Rate: 5min Site Location Information Site Profile Client Manhole #: Address (Location): SV Capitol Blvd Pipe #1 Size: 12 Inches City, State: Olympia, WA Pipe #2 Size: 12 Inches GPS (North - West ): Pipe #3 Size: NA Inches Landmarks: Pipe #4 Size: NA Inches Additional Information: Constant: Inches Map of Area Laterals / Rungs: Additional Information: Yes Yes Manhole Layout 2 1 Traffic Control Requirements Provider: SFE Date & Time: Condition Moderate - Local Depth: Frequency: Install Velocity: Speed Limit: 35 Turbulent: # of Lanes Effected: 0 Surcharge: Lane Configuration: Roadway Bike Lane Silting: Additional Information: Solids: Notes Notes Site Hydraulics 09/16/16 10: Inches 1.5 FPS NA No No Yes Revision 3.1

98 Site Pictures CLIENT FLOW MONITORING #: U SFE PROJECT #: NAME: LOTT Alliance SFE SITE #: Date / Time: 08/09/16 U SV-11 Picture 1 Picture 2 Picture 3 Picture 4 Picture 5 Picture 6 Notes Revision 3.1

99 CCW Installation Form CLIENT FLOW MONITORING #: U SFE PROJECT #: U NAME: LOTT Alliance SFE SITE #: SV-11 Date / Time: 08/09/16 Technician 1: Technician 2: Adrian Marshall Assistant Meter Depth vs.. Field Depth Calibration / Verification Reading Date Time Field Meas Meter Depth Number (in.) (in) Initial 8/9/ : /9/ : /9/ : /9/ : Average Comments (Zero Meter Level before Installation) Constant Measurement (in) Rim to Weir Lip D1+ D2 = CNST D2 Pipe Diameters (in) Pipe 1 12 Pipe 2 12 Pipe 3 NA Pipe 4 NA D4=Invert to Weir Lip (D3-D1) D D Obvert to Weir Lip D4 Revision 3.1