Table of Contents. 3.1 Source Capacity Analysis

Transcription

1 Table of Contents 3.1 Source Capacity Analysis Design Criteria Source Capacity Evaluation Plateau Zone Cascade View Zone Storage Capacity Analysis Design Criteria Operating and Dead Storage Volumes Equalizing Volume Fire Flow Volume Standby Volume Storage Capacity Evaluation Plateau Zone Summary Cascade View Zone System-wide Summary Distribution System Analysis Analysis Methodology System Components Water Demand Allocation Calibration Modeling Scenarios Peak Hour Analysis Results Plateau Zone Cascade View Zone Fire Flow Analysis Results Plateau Zone Cascade View Zone Tables Table 3-1. Evaluation of Source Adequacy for Plateau Zone (Summer Months, Peak Season) Table 3-1a. Evaluation of Source Adequacy for Plateau Zone Zone Groups (Summer Months, Peak Season) Table 3-2. Evaluation of Source Adequacy for Cascade View Zone Table 3-3. Summary of Plateau Zone Storage Capacity Analysis (in MG) Table 3-4. Evaluation of Storage Adequacy for 297 Zone Table 3-5. Evaluation of Storage Adequacy for 650 Zone Table 3-6. Evaluation of Storage Adequacy for 700 Zone Sammamish Plateau Water and Sewer District 3-i

2 Table 3-7. Summary of Cascade View Zone Storage Capacity Analysis (in MG) Table 3-8. Calibration Table Table 3-9. Modeling Scenarios Table Areas of Low (1) in Plateau Zone (Near or Less Than 30 psi During Peak Hour Demand in 2009) See Figure Table Areas of Low in Cascade View Zone (Near or Less Than 30 psi During Peak Hour Demand in 2009) - See Figure Table Fire Flow Deficiencies - Plateau Zone (See Figure 3-4 for area locations) Table Fire Flow Availability for Larger Fire Flow Requirement Sites - Plateau Zone (See Figure 3-4 for area locations) Table Fire Flow Deficiencies - Cascade View Zone (See Figure 3-5 for area locations) Figures Figure 3-1. Storage Components Figure 3-2. Plateau Zone Peak Hour Demand Analyses Figure 3-3. Cascade View Zone Peak Hour Demand Analyses Figure 3-4. Plateau Zone Fire Flow Deficiency Map Figure 3-5. Cascade View Zone Fire Flow Deficiency Map Sammamish Plateau Water and Sewer District 3-ii

3 3. System Analysis This chapter provides an evaluation of the water system s ability to meet current and projected water supply needs. Source and storage capacity analyses are presented, followed by an evaluation of the distribution system piping network. System deficiencies are noted in this chapter, while planned system improvements are discussed in detail in Chapter 8 (Capital Improvement Program). 3.1 Source Capacity Analysis Design Criteria According to DOH planning requirements, sources of supply must be sufficient to meet maximum day demands (MDD). The source capacity analysis presented below examines the ability of the District s existing sources of supply to meet this requirement. The analysis is conducted by comparing the District s water demand forecast, presented in Chapter 2, with current source capacities. All evaluations assume that all normally-operating sources are capable of functioning 24-hours per day, consistent with DOH requirements Source Capacity Evaluation Plateau Zone Table 3-1 summarizes the comparison of the Plateau Zone s total available source capacity, based on current operating conditions during summer months, with current and future systemwide demands. Current District well capacities, in conjunction with additional supply as needed from the South Regional Connection and/or the additional supply potentially available from Well 15 (ASR recovery well), provide adequate supply through Specific groups of pressure zones within the Plateau Zone receive water from common sources (meaning, although source water may initially enter one zone, it is then transferred either through pumping or PRVs to additional zones). Table 3-1a summarizes the source capacity analysis for three such pressure zone groups (denoted here as the 297, 650, and 700 Zone groups). Additional detail regarding which pressure zones are located within each group is provided in Section 3.2.2, which summarizes the more detailed and complex storage capacity analyses for the zone groups. The available source capacities in each pressure zone group are sufficient to meet current and projected 20-year demands. The same holds true for each of the District s individual booster pump stations. No supply deficiencies are identified at these stations, with the potential exception of the 297 Booster Pump Station, which may need to be upsized to meet long-term growth needs in the 650 Zone. As noted in CIP Project BP-1, an upgrade to this facility will be re-evaluated in subsequent planning efforts. Sammamish Plateau Water and Sewer District 3-1

4 Table 3-1. Evaluation of Source Adequacy for Plateau Zone (Summer Months, Peak Season) Year Projected ERUs and Demand (1) Equivalent Residential Units (ERUs) 21,963 25,122 30,184 Average Day Demand (mgd) Maximum Day Demand (mgd) Evaluation of Existing Sources Available Existing District Sources (mgd) (2) 1R R Total Available Source (mgd) District Source Surplus/(Deficiency) (mgd) (0.76) (2.48) (5.22) Additional Available Sources South Regional Connection (Cascade) (mgd) (3) Well 15 (potentially available) (4) Total Available Source (with additional sources, mgd) Total Source Surplus/(Deficiency) (mgd) Projected demands as presented in Chapter 2. ERUs calculated as Average Day Demand / ERU water use factor (224 gpd/eru). 2. Only those sources that are normally operated during summer months (when MDD conditions exist) are considered in this analysis mgd is available through the South Regional Connection, while maintaining a pressure of 100 psi at the point of delivery. 4. ASR Recovery well, which is considered a potentially available source of supply during summer months. Sammamish Plateau Water and Sewer District 3-2

5 Table 3-1a. Evaluation of Source Adequacy for Plateau Zone Zone Groups (Summer Months, Peak Season) Year Zone Group Projected ERUs and Demand (1) Equivalent Residential Units (ERUs) 1,382 1,880 2,887 Average Day Demand (mgd) Maximum Day Demand (mgd) Available Source (mgd) (2) Total Available Source (mgd) Zone Group Source Surplus/(Deficiency) (mgd) Zone Group Projected ERUs and Demand (1) Equivalent Residential Units (ERUs) 16,969 18,983 22,142 Average Day Demand (mgd) Maximum Day Demand (mgd) Available Source (mgd) (2) 1R R RD_150HP RD_250HP _150HP _450HP Total Available Source (mgd) Zone Group Source Surplus/(Deficiency) (mgd) Zone Group Projected ERUs and Demand (1) Equivalent Residential Units (ERUs) 3,641 4,293 5,195 Average Day Demand (mgd) Maximum Day Demand (mgd) Available Source (mgd) (2) 4R Total Available Source (mgd) Zone Group Source Surplus/(Deficiency) (mgd) Projected demands as presented in Chapter 2. ERUs calculated as Average Day Demand / ERU water use factor (224 gpd/eru). 2. Only those sources that are normally operated during summer months (when MDD conditions exist) are considered in this analysis. Sammamish Plateau Water and Sewer District 3-3

6 Cascade View Zone The Cascade View Zone has two primary source wells rated at 200 gpm each. In addition, the connection to Cascade s regional supply at NE 80 th Street and Redmond Ridge Drive NE is capable of providing 400 gpm during summer months (currently only used for emergencies during the summer months). The source adequacy evaluation, summarized in Table 3-2, indicates that this capacity is sufficient in meeting current and future needs. The District s Well 14 is also available to provide additional supply during the summer if needed. It is used on a limited basis due to aesthetic taste and odor issues. Table 3-2. Evaluation of Source Adequacy for Cascade View Zone Year Projected ERUs and Demand (1) Equivalent Residential Units (ERUs) ,003 Average Day Demand (mgd) Maximum Day Demand (mgd) Evaluation of Existing Sources Available Existing District Sources (mgd) (2) 12R R Total Available Source (mgd) District Source Surplus/(Deficiency) (mgd) Additional Available Sources North Regional Connection (Cascade) (3) Total Source Surplus/(Deficiency) (mgd) Projected demands as presented in Chapter 2. ERUs calculated as Average Day Demand / ERU water use factor (224 gpd/eru). 2. Only those sources that are normally operated during summer months (when MDD conditions exist) are considered in this analysis. 3. Capacity based upon a flow rate of 400 gpm. 3.2 Storage Capacity Analysis Design Criteria According to DOH requirements, water system storage volume is comprised of five separate components: Operating volume Equalizing volume Fire flow volume Standby volume Dead volume These required volume components are illustrated in Figure 3-1. All storage components are described in more detail below. Sammamish Plateau Water and Sewer District 3-4

7 Figure 3-1. Storage Components Operating and Dead Storage Volumes Operating volume is the water that lies between low and high water storage elevations set by District operations staff to control system pumps and flow control valves. Dead volume is the volume at the bottom of the tank that cannot be used because it is physically too low to provide sufficient pressures. Operational and dead volumes are subtracted from total storage to determine the effective storage available for equalizing, standby, and fire flow Equalizing Volume Equalizing volume is the total volume needed to moderate daily fluctuations in diurnal demands during periods when the demand exceeds the capacity of the supply system. Equalizing volume requirements are greatest on the day of peak demand. Operation of a properly balanced system results in replenishment of storage facilities during times of day when the demand curve is below the capacity of the supply system, and depletion of storage facilities when the demand exceeds the supply capacity. The equalizing volume of a storage tank must be located at an elevation that provides a minimum pressure of 30 pounds per square inch (psi) to all customers served by the tank Fire Flow Volume The required fire flow volume for a given pressure zone is calculated as the required fire flow multiplied by the required duration, as established by the local fire authority. The maximum fire flow volume considered in this analysis for the Plateau Zone is two simultaneous fires with a demand of 4,500 gpm each for three hours. The maximum fire flow volume in the Cascade View Zone is 1,500 gpm for two hours. The fire flow volume of a storage tank must be located at an elevation that provides a minimum pressure of 20 psi to all customers served by the tank. DOH allows for the nesting of standby and fire flow storage, with the larger used for the storage volume. However, as some fire Sammamish Plateau Water and Sewer District 3-5

8 authorities within the District s service area do not allow for nesting, the District provides the total of calculated standby and fire flow volumes Standby Volume Standby volume is required to supply reasonable system demands during a foreseeable system emergency or outage. A key concept is that establishing standby volume involves planning for reasonable system outages those that can be expected to occur under normal operating conditions, such as a pipeline failure, power outage or valve failure. Major system emergencies, such as those created by an earthquake, are intended to be covered by emergency system operations planning, since construction of sufficient reserve volume to accommodate sustained system demands under emergency conditions is not economically feasible. DOH has established guidelines for determining minimum required standby volume. This component is calculated as the greater of: two times the average day demand, less multisource credit; or 200 gallons times the number of ERUs served by the storage facility. The multi-source credit is applicable only for pressure zones that have multiple sources of supply, and allows the required standby storage volume in such instances to be reduced. The credit assumes the largest source of supply is out of service; thus, it is calculated as the total source available to a particular pressure zone, or zone combination, less the capacity of the largest source. No credit is allowed for zones having only one source of supply Storage Capacity Evaluation The storage capacity evaluation is based upon two primary calculations: 1. Comparison of available versus required storage located at an elevation that provides at least 30 psi to the highest customer in the zone. This evaluates the ability of existing storage facilities to provide required operational and equalizing storage volumes under current and future conditions. 2. Comparison of available versus required storage located at an elevation that provides at least 20 psi to the highest customer in the zone. This evaluates the ability of existing storage facilities to provide required operational, equalizing, standby, and fire flow storage volumes under current and future conditions. These two calculations are conducted for the Plateau Zone and Cascade View Zone independently. In addition, there is a further subdivision within the Plateau Zone of analysis on select pressure zones, or combinations of pressure zones, served by the system s reservoirs. Based upon the locations of the District s reservoirs, and the interconnectedness of the various pressure zones via pressure reducing valves (PRVs), the following pressure zones and pressure zone groupings were evaluated in terms of storage capacity: Plateau Zone (All Tanks and All Zones). This analysis considers all reservoir storage available throughout the Plateau Zone, and evaluates its ability to meet needs throughout all pressure zones within the Plateau Zone. Plateau Zone (297 Zone Storage). The 297 tank provides the primary storage for the 297 Zone. There are PRVs that supply water from the 650 Zone, but the purpose of this scenario is to consider the situation where all the required storage is provided by the 297 Tank. Sammamish Plateau Water and Sewer District 3-6

9 Plateau Zone (650 Zone Storage). The 7 million gallon (MG) tank, 2 MG tank, and the two Section 36 tanks 1 serve the 650 Zone. Through PRVs and booster pumps, the 310, 375, 390, 450, 466, 475, 499, 510, 566, 400 WAV, 450 WAK, 475 PH, 550 ALD, and 700 BC pressure zones are hydraulically connected to the 650 Zone. Plateau Zone (700 Zone Storage). The 3 MG tank serves this pressure zone and the Northeast Sammamish Sewer and Water District. The storage is split between the water districts and in the storage analysis, only 1.5 MG is considered available for use in the Plateau Zone. Through PRVs, the 540, 550, 590, 400 BROD, 475 SAMSUN, and 700 SH pressure zones are hydraulically connected to the 700 Zone and are served by the 3 MG tank. The Section 36 tanks are in the 550 Zone, and directly connect to the 550 Zone. However, for theses analyses, they are considered part of the 650 Zone storage. Cascade View Zone (All Tanks and All Zones). The Well 12 and Well 13 tanks serve the 730 Zone, which in turn provides water via PRVs to the 650 CV, 642, 590 CV, and 550 CV pressure zones. The results of the storage capacity analysis are presented below Plateau Zone Summary Table 3-3 provides a summary of the storage capacity analysis for the Plateau Zone. From a system-wide perspective, there is sufficient storage in the Plateau Zone to meet current and future projected needs. The total surplus by the 20-year planning horizon is approximately 7.78 MG that provides at least 30 psi to all customers, and approximately 5.09 MG in storage that provides at least 20 psi to all customers. 1 Storage volume from the Section 36 tanks (which are located in the 550 Zone) is only available to the 650 Zone via the Section 36 Booster Pump Station. Sammamish Plateau Water and Sewer District 3-7

10 Table 3-3. Summary of Plateau Zone Storage Capacity Analysis (in MG) Year Projected ERUs and Demand (1) Equivalent Residential Units (ERUs) (2) 21,963 25,122 30,184 Average Day Demand (mgd) Maximum Day Demand (mgd) Available Source (mgd) 1R R Total Available Source (mgd) Multi-Source Credit (mgd) (3) Required Storage Calculations Operational Storage (mg) (4) Equalizing Storage (mg) (5) Standby Storage (mg) (6) Fire Flow Storage (mg) (7) Required Storage Greater than 30 psi at highest meter (mg) (8) Greater than 20 psi at highest meter (mg) (9) Existing Storage Greater Than 30 psi (mg) 7-MG Tank MG Tank Section 36-E Section 36-W Tank MG Tank Total Existing Storage at 30 psi (mg) Storage Surplus/(Deficiency) at 30 psi (mg) Existing Storage Greater Than 20 psi (mg) MG Tank MG Tank Section 36-E Section 36-W Tank MG Tank Total Existing Storage at 20 psi (mg) Storage Surplus/(Deficiency) at 20 psi (mg) Projected demands as presented in Chapter Number of ERUs are based on Average Day Demand divided by 224 gpd per ERU. 3. Multi-source credit assumes largest source is out of service (in this case, Well 8 with 3,500 gpm). 4. Required Operational Storage is based on typical operational drawdown levels (7- MG Tank - 6.7', 2-MG Tank - 8.0',Section 36 Tanks - 2.8', 297 Tank - 4.6', 3-MG Tank ') 5. Required equalization storage is calculated as [(PHD - Total Available Source) * 150 minutes], with a minimum value of 0. PHD : (Maximum Day Demand per ERU / 1440) * [(C) * (N) + F] + 18 (C & F values obtained from Table 5-1 in DOH Dec 2009 WSDM) 6. Required standby storage for existing source = greater of (2*ADD - Multi source credit) or 200 gallons per ERU. 7. Required fire flow storage = 4,500 gpm x 3 hours x 2. (assumes two simultaneous 4500 gpm fire flow) 8. Total required storage greater than 30 psi is equal to the total of operational and equalizing storage. 9. Total required storage greater than 20 psi is equal to the total of operational, equalizing, and the greater of standby or fire flow storage. Sammamish Plateau Water and Sewer District 3-8

11 Table 3-4 provides the results of the storage capacity analysis for the 297 Zone. The 297 tank has sufficient capacity to fully meet the needs of this pressure zone beyond Key findings illustrated in the table include: The 30 psi storage surplus is 1.07 MG in This is predicated on the highest customer elevation of approximately 205 feet. There are a few nodes in the hydraulic model located at higher elevations than this; however, few customers are served at these high elevations in the 297 Zone. The 20 psi storage surplus is 0.67 MG in This surplus storage is available to meet storage needs in other pressure zones through the District s 297 Booster Pump Station and the SE 43 rd Booster Pump Station. Table 3-5 shows the results of the storage capacity analysis for the reservoirs in the 650 Zone which provide storage for the following zones: 310, 375, 390, 450, 466, 475, 499, 510, 566, 650, 400 WAV, 450 WAK, 475 PH, 550 ALD, and 700 BC. The 650 Zone is the largest pressure zone in the system and has numerous other zones connected hydraulically via PRVs or pump stations. The storage in the 2 MG, 7 MG, and Section 36 Tanks are sufficient to meet current and future projected demands. Key findings illustrated in the table include: The 30 psi storage surplus is 0.88 MG in This is based on a highest customer elevation of 565 feet. The 20 psi storage surplus is 7.35 MG in This surplus storage is available to meet storage needs in other pressure zones. Table 3-6 shows the results of the storage capacity analysis for the 3 MG tank 2 in the 700 Zone. The following zones are also provided with storage in the tank via PRVs: 540, 550, 590, 700, 400 BROD, 475 SAMSUN, and 700 SH. There is a slight future deficiency shown in this zone for storage above 20 psi. Additional storage can be provided from the 650 Zone to cover the deficiency. Key findings illustrated in the table include: The 30 psi storage surplus is 0.15 MG in This is based on a highest customer elevation of 610 feet. The 20 psi storage deficiency in 2029 is 0.28 MG. This deficiency can be supplemented with surplus storage from the 650 Zone, which includes the Section 36 tanks in the 550 Zone. Water stored in the Section 36 tanks is isolated from other water entering the 650 Zone, and contains no fluoride and minimal chlorine. It is available, via pumping, to the 550 Zone or to the 700 Zone (without the introduction of fluoridated water). The 550 Zone includes approximately 50% of the demand included in the 700 Zone storage area. In addition to the ability of storage in the Section 36 tanks to support 700 Zone storage needs, it is noted that CIP Project M-8, which is a study evaluating the conversion of the 550 Zone to the blended (i.e., fluoridated) part of the system, may result in improvements removing the 550 Zone from being served by the 3 MG tank (and thereby eliminating this slight deficiency). 2 By an agreement with Northwest Sammamish Sewer and Water District, the 3 MG tank is shared between the two utilities. In this analysis, the entire tank volume is considered available because the operational storage drawdown is based on a joint operational level established by both utilities, and because the entire tank volume is fully available to either utility for emergency purposes, such as for fire suppression or standby storage. Sammamish Plateau Water and Sewer District 3-9

12 Table 3-4. Evaluation of Storage Adequacy for 297 Zone Year Projected ERUs and Demand (1) Equivalent Residential Units (ERUs) (2) 1,382 1,880 2,887 Average Day Demand (mgd) Maximum Day Demand (mgd) Available Source (mgd) Total Available Source (mgd) Multi-Source Credit (mgd) (3) Required Storage Calculations Operational Storage (mg) (4) Equalizing Storage (mg) (5) Standby Storage (mg) (6) Fire Flow Storage (mg) (7) Required Storage Greater than 30 psi at highest meter (mg) (8) Greater than 20 psi at highest meter (mg) (9) Existing Storage Greater Than 30 psi (mg) 297 Tank Total Existing Storage at 30 psi (mg) Storage Surplus/(Deficiency) at 30 psi (mg) Existing Storage Greater Than 20 psi (mg) 297 Tank Total Existing Storage at 20 psi (mg) Storage Surplus/(Deficiency) at 20 psi (mg) Projected demands as presented in Chapter Number of ERUs are based on Average Day Demand divided by 224 gpd per ERU. 3. Multi-source credit assumes largest source is out of service (in this case, Well 8 with 3500 gpm). 4. Required Operational Storage is based on typical operational drawdown levels (297 Tank - 4.6') 5. Required equalization storage is calculated as [(PHD - Total Available Source) * 150 minutes], with a minimum value of 0. PHD : (Maximum Day Demand per ERU / 1440) * [(C) * (N) + F] + 18 (C & F values obtained from Table 5-1 in DOH Dec 2009 WSDM) 6. Required standby storage for existing source = greater of (2*ADD - Multi source credit) or 200 gallons per ERU. 7. Required fire flow storage = 4,500 gpm x 3 hours. 8. Total required storage greater than 30 psi is equal to the total of operational and equalizing storage. 9. Total required storage greater than 20 psi is equal to the total of operational, equalizing, and the greater of standby or fire flow storage. Sammamish Plateau Water and Sewer District 3-10

13 Table 3-5. Evaluation of Storage Adequacy for 650 Zone Year Projected ERUs and Demand (1) Equivalent Residential Units (ERUs) (2) 16,969 18,983 22,142 Average Day Demand (mgd) Maximum Day Demand (mgd) Available Source (mgd) 1R R RD_150HP RD_250HP _150HP _450HP Total Available Source (mg) Multi-Source Credit (mgd) (3) Required Storage Calculations Operational Storage (mg) (4) Equalizing Storage (mg) (5) Standby Storage (mg) (6) Fire Flow Storage (mg) (7) Required Storage Greater than 30 psi at highest meter (mg) (8) Greater than 20 psi at highest meter (mg) (9) Existing Storage Greater Than 30 psi (mg) 7 - MG Tank MG Tank Section Section Total Existing Storage at 30 psi (mg) Storage Surplus/(Deficiency) at 30 psi (mg) Existing Storage Greater Than 20 psi (mg) 7 - MG Tank MG Tank Section Section Total Existing Storage at 20 psi (mg) Storage Surplus/(Deficiency) at 20 psi (mg) Projected demands as presented in Chapter Number of ERUs are based on Average Day Demand divided by 224 gpd per ERU. 3. Multi-source credit assumes largest source is out of service (in this case, Well 8 with 3,500 gpm). 4. Required Operational Storage is based on typical operational drawdown levels (7-MG Tank - 6.7', 2-MG Tank - 8.0') 5. Required equalization storage is calculated as [(PHD - Total Available Source) * 150 minutes], with a minimum value of 0. PHD : (Maximum Day Demand per ERU / 1440) * [(C) * (N) + F] + 18 (C & F values obtained from Table 5-1 in DOH Dec 2009 WSDM) 6. Required standby storage for existing source = greater of (2*ADD - Multi source credit) or 200 gallons per ERU. 7. Required fire flow storage = 4,500 gpm x 3 hours x 2. (assumes two simultaneous 4,500 gpm fire flow) 8. Total required storage greater than 30 psi is equal to the total of operational and equalizing storage. 9. Total required storage greater than 20 psi is equal to the total of operational, equalizing, and the greater of standby or fire flow storage. Sammamish Plateau Water and Sewer District 3-11

14 Table 3-6. Evaluation of Storage Adequacy for 700 Zone Year Projected ERUs and Demand (1) Equivalent Residential Units (ERUs) (2) 3,641 4,293 5,195 Average Day Demand (mgd) Maximum Day Demand (mgd) Available Source (mgd) 4R Total Available Source (mgd) Multi-Source Credit (mgd) (3) Required Storage Calculations Operational Storage (mg) (4) Equalizing Storage (mg) (5) Standby Storage (mg) (6) Fire Flow Storage (mg) (7) Required Storage Greater than 30 psi at highest meter (mg) (8) Greater than 20 psi at highest meter (mg) (9) Existing Storage Greater Than 30 psi (mg) 3-MG Tank Total Existing Storage at 30 psi (mg) Storage Surplus/(Deficiency) at 30 psi (mg) Existing Storage Greater Than 20 psi (mg) 3-MG Tank Total Existing Storage at 20 psi (mg) Storage Surplus/(Deficiency) at 20 psi (mg) 0.12 (0.01) (0.28) 1. Projected demands as presented in Chapter Number of ERUs are based on Average Day Demand divided by 224 gpd per ERU. 3. Multi-source credit assumes largest source is out of service (in this case, Well 8 with 3500 gpm). 4. Required Operational Storage is based on typical operational drawdown levels (3-MG Tank ') 5. Required equalization storage is calculated as [(PHD - Total Available Source) * 150 minutes], with a minimum value of 0. PHD : (Maximum Day Demand per ERU / 1440) * [(C) * (N) + F] + 18 (C & F values obtained from Table 5-1 in DOH Dec 2009 WSDM) 6. Required standby storage for existing source = greater of (2*ADD - Multi source credit) or 200 gallons per ERU. 7. Required fire flow storage = 4,000 gpm x 2 hours. 8. Total required storage greater than 30 psi is equal to the total of operational and equalizing storage. 9. Total required storage greater than 20 psi is equal to the total of operational, equalizing, and the greater of standby or fire flow storage Cascade View Zone System-wide Summary Table 3-7 provides a summary of the storage capacity analysis for the Cascade View Zone. There is sufficient storage capacity to meet current and future projected needs. The total surplus by the 20-year planning horizon is approximately 0.41 MG that provides at least 30 psi to all customers, and approximately 0.30 MG in storage that provides at least 20 psi to all customers. Sammamish Plateau Water and Sewer District 3-12

15 Table 3-7. Summary of Cascade View Zone Storage Capacity Analysis (in MG) Year Projected ERUs and Demand (1) Equivalent Residential Units (ERUs) (2) ,003 Average Day Demand (mgd) Maximum Day Demand (mgd) Available Source (mgd) Well 12R Well 13R North Regional Connection (Cascade) Total Available Source (mgd) Multi-Source Credit (mgd) (3) Required Storage Calculations Operational Storage (mg) (4) Equalizing Storage (mg) (5) Standby Storage (mg) (6) Fire Flow Storage (mg) (7) Required Storage Greater than 30 psi at highest meter (gal) (8) Greater than 20 psi at highest meter (gal) (9) Existing Storage Greater Than 30 psi (mg) Well 13 Tank Well 12 Tank Total Existing Storage at 30 psi (mg) Storage Surplus/(Deficiency) at 30 psi (mg) Existing Storage Greater Than 20 psi (mg) Well 13 Tank Well 12 Tank Total Existing Storage at 20 psi (mg) Storage Surplus/(Deficiency) at 20 psi (mg) Projected demands as presented in Chapter Number of ERUs are based on Average Day Demand divided by 224 gpd per ERU. 3. Multi-source credit assumes largest source is out of service (in this case, one well decreasing capacity to 750 gpm) 4. Required Operational Storage is based on typical operating levels (Well 13 Tank - 7.1', Well 12 Tank - 2.7') 5. Required equalization storage is calculated as [(PHD - Total Available Source) * 150 minutes], with a minimum value of 0. PHD : (Maximum Day Demand per ERU / 1440) * [(C) * (N) + F] + 18 (C & F values obtained from Table 5-1 in DOH Dec 2009 WSDM) 6. Required standby storage for existing source = greater of (2*ADD - Multi source credit) or 200 gallons per ERU. 7. Required fire flow storage = 1,000 gpm x 2 hours. 8. Total required storage greater than 30 psi is equal to the total of operational and equalizing storage. 9. Total required storage greater than 20 psi is equal to the total of operational, equalizing, and the greater of standby or fire flow storage. Sammamish Plateau Water and Sewer District 3-13

16 3.3 Distribution System Analysis Analysis Methodology The District s water system was analyzed and deficiencies were identified for the following two conditions: peak hour demands, and maximum day demands plus fire flow. All modeling calculations were performed within the H2OMap Water software produced by MWHSoft, Inc System Components The H2OMap Water software allows all pipes and junction nodes in the District s distribution system to be entered into one complete model, which consists of approximately 3,100 pipes and 2,600 junction nodes, along with pressure reducing stations, reservoirs, wells, and pump stations. As part of this Water Comprehensive Plan update, the District s existing model was updated with piping improvements that were installed in the system. Facilities in the model were verified with record drawings and system information. The pump operation and controls were checked with the District s current practices for all the pump stations according to staff input Water Demand Allocation Chapter 2 presents information on water demands for the District s water system for the existing system and provides an estimate of projected water demands for the six-year and 20-year planning horizons. For the hydraulic model, the demand forecast numbers were used to determine the total demand for customers within the District s service area. Demand allocation (i.e., spatial distribution of demand within the system) was accomplished by the following methodology. In the demand forecast, the demand by parcel was calculated. This was distributed to parcels throughout the system and then attributed to the closest node in the model. Each node in the model represents the total demand of all the nearest parcels for the current, six-year, and 20-year planning horizons. Nodes located on a transmission line or near a storage reservoir, pump station or PRV station were not included as demand nodes within the hydraulic model. All of the demands assigned to a particular node were summed up and a total average day demand was associated to demand nodes within the model. A peaking factor developed in the demand forecast from historical billing records was applied to develop the MDD. After the demand allocation process was conducted, the total historical system demand was adjusted with multipliers for each pressure zone to match the demand forecast numbers presented in Chapter 2. Demands were developed for average day, maximum day and peak hour conditions. Model demands included a global adjustment for non-revenue water. Demand allocation was assumed to be the same for the existing system, six-year and 20-year planning horizons. Sammamish Plateau Water and Sewer District 3-14

17 3.3.4 Calibration A critical step in the development of a hydraulic model, prior to using it as a predictive tool, is that of calibration. Calibration typically consists of measuring pressure and flows in the field and comparing them with model-generated pressures and flows. A key to successful calibration is ensuring that all system parameters or boundary conditions are collected at the time of testing. These boundary conditions typically consist of the demand for the day of testing, along with reservoir levels and pump station and well flows. For the District a total of 45 pressure and flow tests were collected during several days. The testing included 37 tests in the Plateau Zone and 8 tests in Cascade View, as listed in Table 3-8. The intent was to ensure that at least one pressure and flow test was completed in each pressure zone, with several tests in each of the larger zones. During the testing, a pressure gage was placed on the residual hydrant and pressure was measured under normal operating conditions (no hydrant flow). Once the pressure was recorded, a second hydrant was opened and the flow at the second hydrant was measured. While the hydrant was being flowed, the pressure was monitored at the residual hydrant. Once the flow and pressure came to equilibrium, the residual pressure was recorded. Typically a minimum of a 10 psi drop in pressure at the residual hydrant was desired in order to adequately stress the system. The testing procedure typically included one flow hydrant, however in some locations two flow hydrants were needed in order to obtain an adequate pressure drop. During the pressure and flow testing, boundary conditions were being recorded using SCADA at District headquarters for all reservoirs, booster stations and wells. Flow from hydrants was measured using one of two methods; a flow totalizer or a pitot gage. The flow totalizer measured a total volume from the hydrant over a period of time. The volume was then divided by the time period to derive a flow rate. The pitot gage was placed directly in the hydrant flow discharge and a resulting flow pressure was then converted to a flow rate depending on the size of the port flowed and the resulting pressure. One Cascade View test (number 41) was removed from the results due to the pressure being collected upstream of a PRV station that was active during the testing. The static pressure tests provide a comparison of pressures between the field and the model under normal demand conditions. The calibration was performed in May and June of At that time of year, demands were just beginning to increase with seasonal irrigation use and were near typical average day demand. The static calibration provides the user with a good overall sense of the accuracy of the model node elevations, tank elevations and PRV settings. The first thing that was noticed is that 31 out of the 44 valid tests measured a higher model static than field static, with an average overestimation of 6 psi. This suggests that the gages that were used during the calibration may have been reading inaccurately. Using the data as collected, the model static results averaged a six percent difference from the field measurements. If a correction factor of 3 psi (average of difference with outliers removed) is subtracted from the model results the overall difference is less than five percent. There are several locations that should be retested in the future to verify if in fact inaccurate gage readings were the cause of the discrepancies: test sites 44, 23, 26, 27, 5, 11 and 18. Flow tests were evaluated once the static calibration had been completed. The fire flow tests allow for a rigorous evaluation of whether the model piping is connected correctly and whether the proper diameters and friction factors have been used. Closed or partially closed valves are also commonly found during the flow calibration, where the field pressure drops are much larger Sammamish Plateau Water and Sewer District 3-15

18 than those identified with the model. During the flow calibration the pressure drop from the static to the residual is compared, this allows for the focus to be on the frictional losses versus the actual pressure readings. For example, during test number 38, a field static of 58 psi and a flow residual pressure of 45 psi was measured for a pressure drop of 13 psi. This was compared with a model static of 56 psi and a residual of 42 psi, for a drop of 14 psi. The comparison is between the field drop of 13 psi and model drop of 14 psi, with a resulting difference of 1 psi, which is considered a good match. The threshold that was used to determine where there was good agreement between the field and model flow tests was 5 psi. Those tests that had differences of less than or equal to 5 psi were considered well calibrated. Those tests that were more than 5 psi different and in some cases more than 10 psi different were not considered to be well calibrated. Of the 44 tests, 9 tests had differences greater than 5 psi and of those four had differences greater than 10 psi. No specific trends were observed between the locations where differences were greater than 5 psi. Six locations had the field predicting higher losses and three locations where the model predicted higher losses. No geographic concentration was noted for areas with differences greater than 5 psi. In general the calibration results were good from an overall perspective. Of the 9 tests that had greater than a 5 psi difference between field and model results, one was in the Cascade View Zone. All other eight tests in this service area showed acceptable differences. In the Plateau Zone, five of the remaining eight tests with differences greater than 5 psi were conducted in small pressure zones, with a single feed. Hydraulic models do not provide an exact representation of the operation of a PRV in the field. These issues typically center around the utility not knowing exactly what the setting of the larger PRV (the one that conveys fire flow) is, the exact elevation of the PRV, and the amount of loss that occurs in the PRV and associated valve box piping. These issues can be exacerbated in small zones with limited piping. Because of these issues, the District typically conducts additional field testing prior to constructing improvements in such areas, so as to confirm and adjust model parameters as necessary. There were a number of locations that showed discrepancies between the field and model as discussed previously, however for the purposes of using the model for planning level assessments the model was acceptably calibrated. No modifications to friction factors were made during the calibration effort. Ninety-eight percent of the District s piping is Ductile or Asbestos Cement (based on the model data) with a calculated C Factor of 140. No comprehensive age information is available, although the majority of the District s pipes are less than 20 years old. The District has not found any evidence of C-factor reducing tuberculation in the system. No other data based reason to modify particular pipe s C-factors could be identified that would have improved the calibration. It should be noted that model calibration is a process that requires regular updating, since the system continues to change. The model should be compared to field or SCADA data on a yearly basis. The District will continue to collect hydrant flow data and use it to further refine the model in the future. Sammamish Plateau Water and Sewer District 3-16

19 Field Static (psi) Model Static (psi) Table 3-8. Static Difference (psi) Hydrant Flow (gpm) Calibration Table Field Residual (psi) Model Residual (psi) Residual Difference (psi) Field Drop Model Drop Difference in Field and Model Drops Hydrant Test No. Zone Cascade View 44 CV CV CV CV CV CV NA NA NA NA NA NA NA NA 42 CV CV Plateau Zone BROD SH Sammamish Plateau Water and Sewer District 3-17

20 Hydrant Test No. Field Static (psi) Model Static (psi) Static Difference (psi) Hydrant Flow (gpm) Field Residual (psi) Model Residual (psi) Residual Difference (psi) Field Drop Model Drop Difference in Field and Model Drops Zone NA NA NA NA NA NA NA WAK ALD WAV SAMSUN Sammamish Plateau Water and Sewer District 3-18

21 3.3.5 Modeling Scenarios The District has an extensive distribution system with more than 250 miles of transmission and distribution pipe. Aging infrastructure, inadequately sized pipes and increasing demands all contribute to areas of low pressure during peak hour demands and substandard fire flows at locations or areas where the existing system cannot provide adequate service during existing and future maximum day demand conditions. The model was used to identify improvements that would increase the distribution system capacity to meet the required level of service for static pressures and fire flows. In accordance with WAC , a minimum pressure of 30 psi must be maintained at all customer connections under peak hour demand (PHD) conditions with equalizing storage depleted in the reservoirs. A minimum of 20 psi must be maintained for fire flows under MDD conditions with equalizing and fire flow storage depleted. If these criteria could not be met, improvements were identified and through an iterative trial-and-error process, implemented in the model until pressure criteria could be satisfied with a minimum of total pipe and facility additions. A number of steady state hydraulic analyses were completed for each pressure zone for existing (2009), six-year (2015), and 20-year (2029) demand conditions. These considered peak hour demand and fire flow demand (MDD plus fire flow) conditions. Table 3-9 describes the modeling scenarios conducted, and the sequence within which they were performed. The results of the peak hour and fire flow analyses are described in greater detail below. Table 3-9. Modeling Scenarios Description Demand Purpose Existing Year Peak Hour 2009 Peak Hour Demand Evaluate system Existing Year Fire Flow 2009 Maximum Day Demand plus fire flow Evaluate system Plan Six-Year Peak Hour Plan Year 6 Peak Hour Demand Evaluate system performance and develop CIP for Plan Year 6 peak hour conditions Plan Year Six Fire Flow Plan Year 6 Maximum Day Demand plus fire flow Evaluate system performance and develop CIP for Plan Year 6 fire flow conditions Plan Year 20 Peak Hour Plan Year 20 Peak Hour Demand Evaluate system performance and develop CIP for Plan Year 20 peak hour conditions Plan Year 20 Fire Flow Plan Year 20 Maximum Day Demand plus fire flow Evaluate system performance and develop CIP for Plan Year 20 fire flow conditions Peak Hour Analysis Results Peak hour analyses were run for each of the modeling scenarios shown in Table 3-9. Initial tank levels for all reservoirs and tanks were set at a level such that the equalizing and operating portions of storage were depleted. Sammamish Plateau Water and Sewer District 3-19

22 Plateau Zone For the Plateau Zone, under peak hour conditions, small pockets of low pressure and large areas of high pressure were observed in the system. Low pressures are mostly confined to areas around pumps, wells, and reservoirs with no services adjoined. There are three areas of low pressure with service connections within them: two areas in the 700 zone and one in the 297 zone. The areas of low pressure are due to the elevation of the services and the relative hydraulic grade line from the reservoirs in each zone. Table 3-10 and Figure 3-2 provide detail on the areas of low pressure. Particular areas are assigned a label. For locations A, B, and D there are existing services affected by low pressure. Planned improvements in the vicinity of D will eliminate deficiencies in that area. There is currently no improvement to address the deficiency at locations A and B. At location F, the services, as shown in the current pressure zone configuration, would be in the 297 Zone and have low pressures. However, these lots are currently provided service from Overdale. If provided service from the District the pressure zone configuration could be changed to provide service from the 650 pressure zone, eliminating the deficiency. Locations C and E listed in the following table do not have any services and can be disregarded since they are areas of low pressure adjacent to supply/storage facilities that do not impact existing or future customers. The areas of high pressure are defined by a pressure greater than 100 psi with some locations having a pressure above 120 psi. It is currently the practice to install individual PRVs in these areas to limit the incoming pressure entering the house or other type of facility. The topography of the Plateau Zone varies significantly resulting in the large areas of high pressure. Location G listed in the following table is the 700 SH Zone comprised of the Sammamish Highlands Shopping Center located east of 228 th between NE 4 th and NE 8 th, and the Pine Lake Plaza located west of 228 th Avenue NE and south of Inglewood Hill Road. This area is surrounded by the lower 550 and 590 pressure zones, and improvements to provide service from these lower pressure zones could eliminate these high pressure services. Descriptions of specific distribution system improvements identified for implementation throughout the 20-year planning period are provided in Chapter Cascade View Zone In the Cascade View Zone, under peak hour conditions, there is one area near Well 13 that has low pressure. The elevation of the system at that location limits the available pressure to less than 30 psi. All other areas receive pressure greater than 30 psi. Table 3-11 and Figure 3-3 provide detail on the areas of low pressure. Also, there are additional locations in the hydraulic model where pressures drop below 30 psi, but these locations are at model nodes that are not along distribution piping and do not represent service connections (e.g., nodes that are necessary for model construction near reservoirs or directly upstream of booster pumps). Sammamish Plateau Water and Sewer District 3-20

23 Table Areas of Low (1) in Plateau Zone (Near or Less Than 30 psi During Peak Hour Demand in 2009) See Figure 3-2 Area ID Description Notes A High elevation area in the 475 Zone. s of psi at end of line. Two existing services at end of lines. Deficiency resolved by CIP Project D-4a, including modification of the pressure zone boundary in this area. Due to the difficulty of a system remedy and the limited number of services with low pressure, in the interim the District provides individual booster pumps, with a one-year warranty (after B High elevation area in the 700 Zone. s of psi. C High elevation area near the Section 36 tanks and pumps in the 550 Zone. s of psi. D High elevation area in the 297 Zone. of 17 psi. E High elevation area near Boulder Creek Booster Pump Station in the 650 Zone. s of psi. F High elevation area near 297 Tank and Booster Pump Station in the 297 Zone. s of psi at high elevation nodes. G Low elevation area along the 700 Zone transmission main. Results in high pressure area. which they are the responsibility of the individual property owner). Three existing services at end of lines. No improvements planned. Due to the difficulty of a system remedy and the limited number of services with low pressure, the District provides individual booster pumps, with a one-year warranty (after which they are the responsibility of the individual property owner). No services in this location. No additional planned services. This is a transmission main with no improvements planned. One existing service at this location. Deficiency will be addressed by CIP D-17 SE 17 th PRV and Water main Extension. No services in this location. No additional planned services. No improvements planned. Under the current pressure zone configuration, there are lots with low pressure in the 297 zone. These lots are served by Overdale and can be changed to the 650 zone to eliminate the pressure deficiency. Under the current configuration, the shopping centers between NE 4 th and NE 8 th have high pressure due to service from the 700 SH Zone. Piping changes may be possible to join the shopping center east of 228 th to the 550 Zone, and the center west of the 228 th to the 590 Zone. Addressed by CIP M-9, SH 700 Zone Study. (1) All areas noted represent low (i.e., less than 30 psi) pressure, except for G which represents a specific area of high pressure. Table Areas of Low in Cascade View Zone (Near or Less Than 30 psi During Peak Hour Demand in 2009) - See Figure 3-3 Area ID Description Notes A No services in this location. One additional planned service by High elevation area near No improvements planned. Due to the difficulty of a system remedy and Well 13 in the 730 the limited number of services with low pressure, the District provides Zone. s around 28 individual booster pumps, with a one-year warranty (after which they are psi at high elevation nodes the responsibility of the individual property owner). Sammamish Plateau Water and Sewer District 3-21

24 [ % 7 V qu ie al m 208th Ave NE no NE Am F all City Rd Rd d King County UGA Boundary NE Pl l Va on 20 NE Redmo n d ts dm Re ay h 4t Hill Rd es NE W W NE U nion tl ak 236th Ave NE n Hi ll e Rd 650 CV Rd am NE mm Sa n at io arn E as City of Redmond [ % 7 V Un io ke C e s La NE ish Pk N wy E [ % Current Water Service District Boundary 244th Ave NE 228th Ave NE NE 8th St 475 [ % [ % G E Ma i 212th Ave SE V 7 V7 C SE SE 8th St D r 244th Ave La k Ea st SE 4th St 218th Ave SE es am [ % nd SE 8th St 7 V tb ea ve a rl ke D r SE 550 ALD SE We s SE 20th St SH SR 2 0 l Rd 375 d Rd P kw ys H il m am i sh 540 R Redmond Fa ll City oo d E l ew ll 550 i In g N E B 7 V Rd lt H To 390 A Retail/Future Water Service District Boundary NE 475 SAMSUN 700 Cascade View Zone s NE Ame La k e 216th Ave NE W ay SE 24th St ssa qu [ %[ % ah B eav er vd Bl Lak e Rd 2 87 t h a Kl an la h ie Av es 2 E SE 40th St E D 43 y K yr d Wa rs E SE E rd S E Issaqua R City d h F a ll th Ave S E La k er SE I [ % BC 7 V E e ak tl SE W ay S a m NW ma Ne mish wp P or kwy tw ay SE F NW Sammamish Rd 7 V en [ % [ % NW Juniper St E Rd BROD 400 WAV WAK PH 475 SAMSUN ALD SH 700 BC y ah qu Hobart Rd Re nto A Area Referred on Table 3-10 sa Is R ah SW ts a qu City of Issaquah d lv SW ts on Fr n I ss E ds woo d B E Sunset Way ah Fa ll C it y Wa oint igh P SE H W il d W ay e SE Blv d SW po rt ds 2nd Av P ark NW Mo un tai n N W a y ew N y Wa n Su s et MAJOR ROADS WATERBODIES STREAMS CURRENT DISTRICT BOUNDARY FUTURE DISTRICT BOUNDARY KING COUNTY UGA 30 psi 60 psi 80 psi 90 psi 100 psi [ % Front St N t or wp Ne W FREEWAYS 9th Ave NE N 12th Ave NW ay SE 64th Pl Dr r W LEGEND 7 VTank 450 WAK n po 17th Av ew tw Active Well Seasonal Well [ % [ % W N 475 PH it Hig hla W Ne wp or t es SE C al l [ % -F ah qu a Iss Is sa qu S S SR 308th Ave SE SE 32nd St SE y Wa e 2nd ha SE % Rd thie Hill Du ni th Ave SE e Plateau [Zone 400 WAV 510 Be av NE 24th St 400 BROD 0 2,500 5,000 7,500 Feet I Peak Hour Map Plateau Zone FIGURE 3-2 Sammamish Plateau Water and Sewer District Water Comprehensive Plan

25 West Snoqualmie Val Rd NE Carnation Duvall Rd NE Fay Rd NE Redmond R idge Dr NE Retail/Future Water Service District Boundary Cascade View Zone NE Union Hill R d 238th Av e NE V7 A 236th Ave NE NE Union Hill Rd V7 Current Water Service District Boundary King County UGA Boundary 650 CV Sahalee Way NE 400 BROD NE Ames La ke Rd Tolt Hill Rd V th Ave NE 700 SH 228th Ave SE SE 8th St NE 8th St 244th Ave SE 244th Ave NE E Main Dr NE Redmond Fall City Rd V7V7 550 ALD N E Tolt Hill Rd Active Well SR 202 LEGEND Seasonal Well V7 Tank Current District Boundary Future District Boundary King County UGA Freeways Major Roads Waterbodies Streams 30 psi 60 psi 80 psi 90 psi 100 psi A 0 2,000 4,000 6, CV 590 CV CV 730 Area Referred on Table 3-11 Feet Main St I V7 Peak Hour Map Cascade View Zone FIGURE 3-3 Sammamish Plateau Water and Sewer District Water Comprehensive Plan

26 3.3.7 Fire Flow Analysis Results Fire flow analyses were conducted in both the Plateau and Cascade View Zones. Fire flow demands were assigned based on zoning within each zone according to the following designations: 1,000 gpm for Single-Family Residential, 2,500 gpm for Medium Density Multi- Family Residential, and 3,000 gpm for High Density Multi-Family Residential, Business, or Commercial. Additional specific sites were identified by District staff as having a fire flow requirement above 3,000 gpm Plateau Zone Table 3-12 and Figure 3-4 detail the nature and location of each fire flow deficiency found in the system. Eight areas were identified with deficiencies. The deficiencies are due primarily to small diameter piping and dead end mains in the localized areas of the deficiencies. Improvements have been noted that improve or eliminate these deficiencies in the future. There are specific projects identified for six of the areas. At location A, there is an available hydrant within permissible distance and the fire flow rate is just below the required flow rate. The deficiency can be resolved through adjustment of the settings at the nearest pressure reducing station, PRV 33 located on Inglewood Hill Rd at 205th Ave NE. As modeled, most of the fire flow is being fed through PRV 33 s 2-inch bypass PRV. Adjusting PRV 33 s settings to allow PRV 33 s 6-inch main PRV to open earlier, at a higher downstream pressure, would provide additional fire flow. CIP Project D-2 improves the deficiencies at locations C and D, except for one node 5541 (zone 475). Node 5541 is located at the end of an 8-inch pipe on 211 th Avenue NE, but the high elevation (417 ft) relative to the pressure zone (475 ft) limits the fire flow availability at the end of the main. There is a hydrant located 400 feet south and at a lower elevation from this node, with sufficient pressure to provide fire flow. Connection of the water main in the upper end of 211th Ave NE (between approximately NE 13th and NE 15th) to the 700 Zone would remove the deficiency. CIP Project D-4a would include connection to the 700 Zone with an extension from either NE 15th or 211th Place NE. CIP Projects D-9 and D-19b improve the deficiencies found at location E. The model originally indicated a deficiency at location F, but closer inspection of the model results indicates there is no deficiency. Location F, Hydraulic Model Node 6222, represents demands at the end of a long cul-de-sac, and is coded as a 2-inch main. In reality, the initial section of the road has an 8-inch diameter main with a fire hydrant located prior to the decrease to a 2-inch main. The fire hydrant fire flow at the hydrant meets flow and pressure requirements. Specific sites with large fire flow requirements were analyzed in the hydraulic model. These sites are located on Figure 3-4, and the results of the analysis are summarized in Table All sites have available fire flow in excess of the requirement Cascade View Zone Table 3-14 and Figure 3-5 depict the results of the fire flow analysis for the Cascade View Zone. Deficiencies are caused by small diameter piping and dead mains in the system. The planned improvements D-51 and D-52 address the deficiency at locations A, B, D, F, and H. At location C the deficiency is on a looped 8 main in a high elevation area of the system with limited pressure. There is no planned improvement in this area. The deficiency at location G is resolved by project D-17. The remainder of the deficiencies will be eliminated by upsizing the existing pipe diameter as part of the AC Pipe Replacement Program. Sammamish Plateau Water and Sewer District 3-24

27 Map ID Hydraulic Model Node No. Table Fire Flow Deficiencies - Plateau Zone (See Figure 3-4 for area locations) Fire Flow Required (gpm) Available Flow (gpm) Available Flow (gpm) Available Flow (gpm) Zone Notes A Available hydrant is 220 feet from furthest lot and on an 8 diameter main. The deficiency is resolved by the adjacent hydrant. B >1000 >1000 Fire flow deficiency resolved by CIP Project D >1000 >1000 Fire flow deficiency resolved by CIP Project D-4. C >1000 >1000 Fire flow deficiency resolved by CIP Project D Fire flow deficiency improved by CIP Project D >1000 >1000 Fire flow deficiency resolved by CIP Project D >1000 Fire flow deficiency due to high elevation resolved by CIP Project D-4a. D >1000 >1000 Fire flow deficiency resolved by CIP Project D >1000 >1000 Fire flow deficiency resolved by CIP Project D >1000 >1000 Fire flow deficiency resolved by CIP Project D >1000 >1000 Fire flow deficiency resolved by CIP Project D-2. E > Fire flow deficiency improved by CIP Project D-9 and D-19a > Fire flow deficiency improved by CIP Project D-9 and D-19a Fire flow deficiency improved by CIP Project D-9 and D-19a. F No deficiency; model indicated 2" line, instead of 8 main until hydrant, and then 2 line. Available hydrant on 8 main provides >1,000 gpm fire flow. G >1000 >1000 Fire flow deficiency resolved by CIP Project D >1000 >1000 Fire flow deficiency resolved by CIP Project D-17. H >1000 >1000 Fire flow deficiency resolved by CIP Project D >1000 >1000 Fire flow deficiency resolved by CIP Project D >1000 >1000 Fire flow deficiency resolved by CIP Project D-24. Sammamish Plateau Water and Sewer District 3-25

28 Table Fire Flow Availability for Larger Fire Flow Requirement Sites - Plateau Zone (See Figure 3-4 for area locations) Available Flow (gpm) Available Flow (gpm) Available Flow (gpm) Map ID Hydraulic Model Node No. Zone Description Fire Flow Required (gpm) SH Commercial Business 3500 >5000 >5000 > SH Commercial Business 4000 >5000 >5000 > SH Commercial Business 3500 >5000 >5000 > SH Commercial Business 3500 >5000 >5000 > Commercial Business 3500 >5000 >5000 > School 3500 >5000 >5000 > School 3500 >5000 >5000 > Professional Office 3500 >5000 >5000 > Professional Office 4000 >5000 >5000 > Commercial Business s 3500 >5000 >5000 > Commercial Business 4500 >5000 >5000 > Intensive Commercial 3200 >5000 >5000 > Professional Office 3200 >5000 >5000 >5000 Sammamish Plateau Water and Sewer District 3-26

29 Map ID Table Fire Flow Deficiencies - Cascade View Zone (See Figure 3-5 for area locations) Hydraulic Model Node No. Fire Flow Required (gpm) Available Flow (gpm) Available Flow (gpm) Available Flow (gpm) Zone Notes A CV >1000 >1000 Fire flow deficiency resolved by CIP Project D-51. B CV >1000 >1000 Fire flow deficiency resolved by CIP Project D-51. C CV Fire flow Deficiency on 8" lines. No planned improvement. D CV End of 6" line. Deficiency to be resolved as part of AC Replacement Program. CV >1000 >1000 Intersection of three 6" lines. Fire flow deficiency resolved by CIP Project D-51. CV End of 6" line. Deficiency to be resolved as part of AC Replacement Program. E CV >1000 Fire flow deficiency resolved by AC main replacement program. CV >1000 Fire flow deficiency resolved by AC main replacement program. F CV >1000 >1000 Intersection of three 6" lines. Fire flow deficiency resolved by CIP Project D-51. G CV End of 6" line. Deficiency to be resolved as part of AC Replacement Program. H CV CV >1000 >1000 Fire flow deficiency resolved by CIP Project D-52. Sammamish Plateau Water and Sewer District 3-27

30 NE Carnation Farm Rd NE 76th St 208th Ave NE NE Union Hill Rd West Snoqualmie Val Rd NE NE 80th St NE Redmond Way City of Redmond NE 24th St East Lake Sammamish Pkwy NE 204th Pl NE NE Redmond Fall City Rd Current Water Service District Boundary King County UGA Boundary 236th Ave NE 400 BROD Cascade View Zone V7 V7 NE Ames Lake Rd NE Union Hill Rd 650 CV Ames Lake Carnation Rd NE Retail/Future Water Service District Boundary 466 G 400 WAV West Lake Sammamish Pkwy SE SE Newport Way NW Newport Way A East Lake Sammamish Pkwy SE H SAMSUN B 390 Newport Way N W Renton Issaquah Rd SE 17th Ave NW th Ave NW D 212th Ave SE C E 216th Ave NE NE Inglewood Hill Rd SE 8th St NW Sammamish Rd City of Issaquah 218th Ave SE 540 V7 475 SE 20th St SE 43rd Way SE 4th St NW Juniper St Newport Way NW W Suns et Way Mountain Park Blvd SW Wildwood B V7 475 PH Front St N V7 F 700 SH 228th Ave SE SE 64th Pl 228th Ave NE Newport Way SW lvd SW WAK V7 700 BC E Sunset Way 2nd Ave SE Front St S SE 8th St NE 8th St SE 24th St 650 9th Ave NE Highlands Dr NE 244th Ave SE 244th Ave NE Plateau Zone SE 32nd Way SE 32nd St SE Klahanie Blvd 550 E Main Dr Klahanie Dr SE SE Issaquah-Fall City Rd V7V7 West Beaver Lake Dr SE Beaver Lake Way SE SE Issaquah Beaver Lake Rd SE Duthie Hill Rd SE Issaquah Fall City Rd NE Tolt Hill Rd Redmond Fall City Rd 550 ALD SR th Ave SE LEGEND 2009 Fire Flow Deficiency (gpm) >= <500 Active Well Seasonal Well V7 Tank FREEWAYS A 1 MAJOR ROADS CURRENT DISTRICT BOUNDARY FUTURE DISTRICT BOUNDARY KING COUNTY UGA Area Referred on Table 3-12 Site with Fire Flow Requirement >3,000 gpm SR ,500 5,000 7,500 SE 40th St SE High Point Way Fireflow Deficiency and Sites with Large Fire Flow Requirements Map Plateau Zone View Feet Sammamish Plateau Water and Sewer District Water Comprehensive Plan 308th Ave SE BROD 400 WAV WAK PH 475 SAMSUN ALD SH 700 BC I FIGURE 3-4

31 Carnation Duvall Rd NE Fa y Rd N E Redmond Ridge Dr NE A B Retail/Future Water Service District Boundary Cascade View Zone NE Union Hill Rd 238th Ave NE V7 West Snoqualmie Val Rd NE C 236th Ave NE NE Union Hill Rd D V7 Current Water Service District Boundary King County UGA Boundary E G F 650 CV H V SH th Ave NE 228th Ave SE NE 8th St 400 BROD 244th Ave NE 550 E Main Dr NE Redmond Fall City Rd 650 V7V7 NE A mes Lake Rd 550 ALD LEGEND 2009 Fireflow Deficiency (gpm) >= <500 A Area Referred on Table 3-13 V7 Tank Active Well Seasonal Well Current District Boundary Future District Boundary King County UGA Freeways N E Tolt Hill Rd SR 202 Major Roads Waterbodies Streams Tolt Hi ll Rd 0 2,000 4,000 6,000 Feet 550 CV 590 CV CV 730 I Main St Fireflow Deficiency Map Cascade View Zone FIGURE 3-5 Sammamish Plateau Water and Sewer District Water Comprehensive Plan