CHAPTER 5 EXISTING FACILITIES

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1 CHAPTER 5 EXISTING FACILITIES INTRODUCTION The District s original wastewater collection system was constructed and brought on-line in 1970 and Additional sewer facilities have been constructed within the District over the past 40 years. The District has agreements with Everett and AWWD that provide for the treatment and disposal of all wastewater generated within the District. The majority of the wastewater collected in the District flows to the City of Everett s Wastewater Pollution Control Facility (WPCF), located approximately six miles to the north of the District boundary. The District s remaining wastewater flows through the Alderwood Water and Wastewater District s (AWWD) sewer system before continuing on to the King County Department of Natural Resources (KCDNR) for treatment. The District also has an agreement with Snohomish County and Everett for the conveyance of leachate from the Cathcart Landfill to Everett for treatment. Copies of these agreements are located in Appendix B. EXISTING WASTEWATER COLLECTION SYSTEM The District s wastewater collection system consists of 22 sewage lift stations, approximately 13.1 miles of force main, and 155 miles of gravity sewer line. A schematic representation of the District s lift stations and force mains is shown in Figure 5-1. SEWAGE LIFT STATIONS An inventory of the District s sewage lift stations is presented in Table 5-1. The three lift stations with the highest capacity are Lift Station No. 2, Pioneer Trails, and Lift Station No. 3. The drainage basin areas for each lift station, as well as the areas that drain to Everett or AWWD by gravity, are shown in Figure 5-2. FORCE MAINS An inventory of the District s force mains, sorted by pipe diameter, is presented in Table 5-2. A summary of the force main for each sewage lift station is presented in Table 5-3. Silver Lake Water & Sewer District 5-1 Wastewater Comprehensive Plan April 2011

2 TABLE 5-1 Inventory of Sewage Lift Stations Year Station Station Serial Pump No. of Capacity (2) TDH (3) Motor Impeller Surge Relief Auxiliary No. Lift Station (1) On-Line Type No. Model Pumps (gpm) (ft) Power (hp) Size (inch) Valve Power (4) th Street 2003 Vacuum Lift V 6D3B 2 1, No 60 kw th Street 2007 Vacuum Lift N 6D3B No 75 kw 3 Creekside 2001 Vacuum Lift F 4C3B No 80 kw 4 Glacier Peak 2011 Submersible TBD No None 5 Highlands East 2001 Vacuum Lift W 4D4B No 100 kw 6 Highlands I 1997 Vacuum Lift C3B No 65 kw 7 Highlands II 1999 Vacuum Lift C3B No 60 kw 8 Lift Station No Wet Pit/Dry Pit V 8D4C 3 3, (5) Yes 300 kw 9 Lift Station No Wet Pit/Dry Pit D4C 3 2, (5) No 175 kw 10 Lift Station No Vacuum Lift B4A No 40 kw 11 Lowell Larimer No Vacuum Lift K 4D4B Yes 215 kw Lowell Larimer No Vacuum Lift V 4C3B No 47 kw 13 Pioneer Trails 1987 Wet Pit/Dry Pit D4D 2 2, (5).625 No 175 kw 14 Silver Firs 1994 Wet Pit/Dry Pit D No 60 kw 15 Sector Wet Pit/Dry Pit D5 3 1, (5) Yes 450 kw 16 The Point 2011 Vacuum Lift TBD 4D4B No 80 kw 17 Thomas Lake 2000 Vacuum Lift C3B 3 1, No 80 kw 18 Valmont 2011 Vacuum Lift W 4C3B No 60 kw 19 Waldenwood 1999 Wet Pit/Dry Pit D5 2 1, (5) Yes 300 kw 20 Windsong Terrace 1988 Vacuum Lift B2D No 30 kw 21 Woodlands East 2005 Vacuum Lift V 4C2B No 35 kw 22 Woodlands North 1979 Wet Pit/Dry Pit C 4D No 60 kw (1) The location of each sewage lift station is shown in Figure 5-3. (2) Capacity is based on testing performed at startup. (3) Total Dynamic Head. (4) Size. (5) Variable Frequency Drive (VFD). 5-2 Silver Lake Water & Sewer District April 2011 Wastewater Comprehensive Plan

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4 23 ³ SCALE 1 = 3,000' LEGEND: SILVER LAKE WATER DISTRICT BOUNDARY STUDY AREA 180TH STREET 164TH STREET CREEKSIDE GLACIER PEAK HIGHLANDS EAST HIGHLANDS HIGHLANDS II LIFT STATION NO. 2 LIFT STATION NO. 3 LIFT STATION NO. 4 LOWELL LARIMER NO. 1 LOWELL LARIMER NO. 2 PIONEER TRAILS SILVER FIRS NEW SECTOR 7 THE POINT THOMAS LAKE VALMONT WALDEN WOOD WINDSONG TERRACE WOODLANDS EAST WOODLANDS NORTH EVERETT GRAVITY ALDERWOOD GRAVITY LITTLE BEAR CREEK GRAVITY SILVER LAKE WATER & SEWER DISTRICT WASTEWATER COMPREHENSIVE PLAN FIGURE 5-2 DRAINAGE BASINS

5 TABLE 5-2 Inventory of Force Mains (1) Pipe Diameter Length (LF) Length (Miles) , , , , , , Total (LF) 69, (1) District-owned force mains are Ductile Iron, Cast Iron, or HDPE. The length and capacity of each force main is provided in Table 5-3, with the capacity as calculated for a maximum velocity of 8 feet per second. The location of each force main is shown in Figure 5-3. TABLE 5-3 Inventory of Lift Station Force Mains (1) Lift Station (Force Main Source) Diameter (inches) Length (LF) Capacity (2) (gpm) 164 th Street 10 PVC 5,933 1, th Street 8 D.I. 8 O.D. DR11 HDPE 74 2,465 1, Creekside 6 D.I. 3, Glacier Peak 4 O.D. HDPE Highlands East 8 D.I. 5,550 1,253 Highlands I 6 D.I. 2, Highlands II 6 D.I. 2, Lift Station No. 2 Lift Station No. 3 (5) 18 O.D. HDPE 16 (3) D.I. 10 (4) C.I ,600 1,196 4,136 5,013 1, D.I. D.I. 10 D.I. 2,250 4,000 3,700 5,013 2,820 1,958 Lift Station No. 4 8 D.I ,253 Lowell Larimer No. 1 8 D.I. 8 O.D HDPE 1, , Silver Lake Water & Sewer District 5-3 Wastewater Comprehensive Plan April 2011

6 TABLE 5-3 (continued) Inventory of Lift Station Force Mains (1) Lift Station (Force Main Source) Diameter (inches) Length (LF) Capacity (2) (gpm) Lowell Larimer No. 2 8 D.I ,253 Pioneer Trails 10 D.I. (6) 1,058 1,958 The Point 6 C.I. 2, New Sector 7 D.I./ O.D. HDPE 5,200 2,075 Silver Firs 8 D.I. 1,0 1,253 Thomas Lake D.I. (6) 10 O.D. HDPE 4,760 1,850 2,820 1,475 Valmont 6 D.I. 1, Waldenwood East 10 D.I. 8 D.I. 3,414 3,970 1,958 1,253 Windsong Terrace 6 D.I. 2, Woodlands East 6 C.I Woodlands North 4 C.I. 1, (1) Through May, (2) Capacity based on maximum velocity of eight feet per second (8 fps). (3) 16-inch FM from Lift Station No. 2 and 10-inch FM from Waldenwood Lift Station run parallel for 3,414 LF and can be shared. (4) This section of 10-inch FM coming from Lift Station No. 2 is normally closed. (5) Two force mains (10-inch and -inch) flow from Lift Station No. 3. The 10-inch FM can be opened to convey flows to Lift Station No. 2. The -inch increases in size to a 16-inch and conveys flows to Pioneer Trails Lift Station. (6) -inch FM from Thomas Lake and 10-inch FM from Pioneer Trails run parallel for 958 lf and can be shared. GRAVITY MAINS An inventory of the District s gravity sewer lines, sorted by pipe diameter and pipe material, is presented in Table 5-4. All concrete sewer lines were installed prior to 1980, while all PVC and D.I. sewer line has been installed from 1980 to the present. The 8-inch gravity sewers collect sewage flows within residential areas. Gravity sewers larger than 8-inch collect sewage flows from smaller pipes and convey the flow to lift stations or larger trunk lines. The data in Table 5-4 was taken from the District GIS Database/Map. The database indicates 61,386 lineal feet of pipe of unknown diameter and/or material. The City of Everett South End Interceptor (30- and 36-inch pipes) are owned and maintained by Everett, and therefore these are not counted in the District s inventory. 5-4 Silver Lake Water & Sewer District April 2011 Wastewater System Comprehensive Plan

7 RE EN SCALE 1 = 3,000' LOWEL L 9 LAR IME R 15 4 '' CATHCART LANDFILL NO. LIFT STATION TH STREET 180TH STREET CREEKSIDE GLACIER PEAK HIGHLANDS EAST HIGHLANDS HIGHLANDS II LIFT STATION NO. 2 LIFT STATION NO. 3 LIFT STATION NO. 4 LOWELL LARIMER NO. 1 LOWELL LARIMER NO. 2 PIONEER TRAILS SILVER FIRS NEW SECTOR NO. 7 THE POINT THOMAS LAKE VALMONT WALDENWOOD WINDSONG TERRACE WOODLANDS EAST WOODLANDS NORTH LEGEND FORCE MAIN STUDY AREA GRAVITYSEWER SILVER LAKE WATER & SEWER DISTRICT CATHCART LANDFILL SR REE K 10 LIFT STATION EVERETT SOUTH END INTERCEPTOR MIL LC 164TH 15 '' '' SR SE AT T ND 10 6 '' 15 I-5 8TH 13 BOTHELL EVERETT LE I-5 6 MARSH IL L H 6 36 LL MA 19TH EV ER G T RET EVE ³ SECOND PARCELS 110 SILVER LAKE WATER & SEWER DISTRICT WASTEWATER COMPREHENSIVE PLAN FIGURE 5-3 EXISTING FORCE MAINS AND MAJOR GRAVITY LINES 2 180TH

8 TABLE 5-4 Inventory of Gravity Mains (1) Pipe Diameter Pipe Material (2) Length (LF) Length (Miles) 24 D.I D.I D.I. 3, D.I D.I D.I. 4, D.I. 14, D.I. 50, D.I. Subtotal 75, PVC 7, PVC PVC 6, PVC 20, PVC, PVC 519, PVC Subtotal 567, CONC CONC 7, CONC 1, CONC 3, CONC 96, Concrete Subtotal 108, Unknown Unknown 64,207.2 Total 816, (1) Data based on District GIS Database/Map. (2) D.I. = Ductile Iron; PVC Poly Vinyl Chloride; CONC = Concrete. DISTRICT SEWER AGREEMENTS All wastewater collected within the District is transported for treatment to either Everett or KCDNR via the Alderwood Water & Wastewater District (AWWD). Interlocal sewer service agreements have been established with Everett and AWWD for disposal of wastewater collected within the District. The District also maintains an interlocal agreement with Cross Valley Water District to provide sewer service within areas along Lowell Larimer Road. The District has an agreement with Snohomish County and Everett for the conveyance of leachate from the Cathcart Landfill, located in the eastern portion of the District s service area. Figure 5-4 illustrates the regional sewer system relative to the District. Figure 5-5 illustrates the service agreement areas. Silver Lake Water & Sewer District 5-5 Wastewater Comprehensive Plan April 2011

9 CITY OF EVERETT AGREEMENT In 1982, the District entered into the existing sewer agreement with Everett. The 1982 agreement rescinded the two prior agreements of 1970 and 1974, which established a cost sharing arrangement based on the number and type of connections within the District. The cost sharing arrangement is now based upon the District s required capacity within components of Everett s sewer system, including interceptor lines and Water Pollution Control Facility (WPCF). The agreement was amended in 1991, as the District purchased additional capacity within Everett s wastewater facilities. Under the agreement the District shares in the capital cost of facilities based on the percentage of the facility capacity required to service the District s wastewater flow. These improvement contributions cease when the WPCF reaches a capacity of 40.4 mgd, maximum winter month flow. A summary of the District s purchased capacity in Everett s wastewater system covered in the agreement, including the share of construction costs incurred by the District, is presented in Table 5-5. The District s purchased capacities are for Peak Wet Weather Flow for conveyance and headworks; and Maximum Month Flow for the WPCF. Flow definitions are presented in Chapter 4. The agreement with Everett does not specify wastewater characterization requirements for the wastewater delivered by the District. Therefore, the District is not required to conduct any sampling for wastewater characterization parameters within its collection system. As part of the agreement with Everett, the District pays a wastewater disposal operation and maintenance charge. This charge is based on the number of connections within the District that ultimately discharge to the Everett system. A copy of the 1982 agreement, as well as the 1991 amendment, between the District and Everett is included in Appendix B. The purchased capacities in Everett facilities were based on the populations and land use zonings in the District s 1988 Sewerage System General Comprehensive Plan Update. 5-6 Silver Lake Water & Sewer District April 2011 Wastewater System Comprehensive Plan

10 24 TRUNK C LAKE STEVENS ³ 17TH ST. INTERCEPTOR (TRUNK D) TRUNK A SOUTHEND INTERCEPTOR SWPCF S WWTP POSSESSION SOUND MUKILTEO BEACH INTERCEPTOR 30 SOUTHWEST INTERCEPTOR MEMORIAL STADIUM INTERCEPTOR 24 SUMMIT AVE. INTERCEPTOR 36 2 CENTRAL INTERCEPTOR 5 30 SNOHOMISH RIVER SWWTP UV SILVER LAKE SOUTHEND INTERCEPTOR S WWTP S S WWTP - WASTEWATER TREATMENT PLANT WPCF - WATER POLUTION CONTROL FACILITY LEGEND: INTERCEPTORS WATER LAKE STEVENS SEWER DISTRICT MUKILTEO WATER & WASTEWATER DISTRICT SILVER LAKE WATER & SEWER DISTRICT S WWTP UV 525 CITY LIMITS OF EVERETT CITY LIMITS OF SNOHOMISH ALDERWOOD WATER AND WASTEWATER DISTRICT CROSS VALLEY WATER DISTRICT SILVER LAKE WATER & SEWER DISTRICT S WWTP UV 99 UV 9 UV 522 REGIONAL SEWERS FIGURE M:\SLWD\08564 WW COMP PLAN\Figures\FIGURE 5-4.mxd

11 ³ SR 99 35TH AVENUE SE 100TH STREET SE LO W EL L LA RI M ER RO AD SCALE 1 = 3,000' 8TH SR TH STREET SE LL HI AD SR 9 132ND STREET SE E TL T A SE RO LEGEND H IL L R O AD I-5 slwd-bndry-2011.dwg Polyline STUDY AREA AWWD AGREEMENT AREA CATHCART AGREEMENT AREA CVWD AGREEMENT AREA EVERETT AGREEMENT AREA EVERETT & ALDERWOOD AGREEMENT AREAS SE AT T LE NOTE: EVERETT AGREEMENT AREA ALSO INCLUDES ALL AREAS WITHIN THE SILVER LAKE WATER & SEWER DISTRICT BOUNDARY AND CROSS VALLEY WATER DISTRICT AGREEMENT AREA. 35TH AVENUE SE 164TH STREET SE SILVER LAKE WATER & SEWER DISTRICT WASTEWATER COMPREHENSIVE PLAN FIGURE 5-5 SEWER AGREEMENT AREAS 180TH STREET SE M:\SLWD\08564 WW Comp Plan\GIS\FIGURES\FIGURE

12 TABLE 5-5 District Purchased Capacity in Everett Sewer Facilities District Purchased Capacity Total Facility Capacity District Portion of Cost (3) Everett Facility South End Interceptor (1) South End Extension 11,500 gpm 16,000 gpm 72% To Southwest Interceptor 11,500 gpm 32,000 gpm 36% Northern Segment 11,500 gpm 45,000 gpm 26% Everett Treatment Facilities Headworks (1) 11,500 gpm 80,000 gpm 14% WPCF (2) 6.6 mgd 40.4 mgd 16% (1) Capacity for Peak Hour Flow. (2) Capacity for Maximum Month Flow. (3) District portion of cost is the percentage of the total facility capacity purchased by the District. ALDERWOOD WATER AND WASTEWATER DISTRICT AGREEMENT In 1978, the District entered into an agreement with the AWWD. Subsequent agreements and amendments were superseded by an agreement signed in July of 2006 and updated in Connections in the southwest and southern portion of the District have been designated to discharge through the AWWD sewer system to the King County wastewater treatment facilities. The area covered in the agreement is shown in Figure 5-5. The agreement specifies that the District constructs and maintains sewer system facilities within the area in accordance with all King County regulations and conditions of the agreement between AWWD and the County. For the area designated in the agreement, the District pays AWWD a sewage disposal charge based upon the number of connections, and a sewer connection charge for any new developments. Individual connections are responsible to King County for their treatment impacts at the time service is provided. According to the agreement, the wastewater discharged by the District may be limited by the capacity of the AWWD system. The District is not allowed to surcharge any component of AWWD s wastewater collection facilities. As part of the agreement AWWD is to provide sufficient capacity in downstream facilities to handle the peak flow from the District area designated in the agreement and shown in Figure 5-5. A copy of the agreement between AWWD and the District is included in Appendix B. Provisions of the agreement allow for AWWD sewer flows to enter District facilities prior being discharged back to AWWD for transmission to KCDNR. These areas are shown in Figure 5-5, and include areas that drain to the District s 180 th Street Lift Station Silver Lake Water & Sewer District 5-7 Wastewater Comprehensive Plan April 2011

13 and the District s North Creek Sewer Interceptor, which is aligned in Main Street in Mill Creek. CROSS VALLEY WATER DISTRICT AGREEMENT In 1994 the District entered into an interlocal agreement with the Cross Valley Water District (CVWD) to provide sewer service to an undeveloped area along Lowell-Larimer Road. This agreement was subsequently updated in 2001, 2007, and again in The area covered in the agreement is shown in Figure 5-5. A copy of the agreement between CVWD and the District is included in Appendix B. This area is located outside of the District boundary. However, it is anticipated that the District will provide sewer service in this area for the foreseeable future. Although outside of the District boundary, future flows from this CVWD Agreement Area are projected through build-out. For the District to provide sewer service within the study area directly east of the existing agreement area, an amended agreement would need to be negotiated between the District and CVWD. SNOHOMISH COUNTY CATHCART LANDFILL AGREEMENT In 1989, the District entered into an agreement with Snohomish County and the City of Everett for the disposal of leachate from the 587-acre Cathcart Landfill site. The Cathcart Landfill (now closed) is located in the southeast portion of the study area and pumps wastewater to a manhole which drains to the District s Lift Station No. 3. This agreement was amended in April The landfill location is shown on Figure 5-5. Leachate from the landfill undergoes a pre-treatment process in a lagoon prior to discharging to the District s sewer system. The agreement allows a maximum of 100 gallons per minute (144,000 gallons per day) to be pumped into the District, with a maximum off-peak rate of 400 gpm allowed. The volume of leachate pumped from Cathcart is monitored by Snohomish County, and shall at no time exceed 144,000 gallons per day. A copy of the agreement between the District, Snohomish County and the City of Everett is also included in Appendix B. Snohomish County has surplussed much of the approximately 330 acres of the area adjacent to the Carthcart Landfill for schools, parks, and future private development. The area in question is within the District s current service area boundary. If residential housing is constructed consistent with the densities allowed in that region of Snohomish County, the impact could be as many as 803 additional dwelling units, plus commercial development. The Plan will address the impacts of the land use changes for the undeveloped portion of Snohomish County land adjacent to the Cathcart Landfill. As part of the agreement with Snohomish County, wastewater from the landfill must meet the wastewater characterization requirements as specified in the Industrial Waste 5-8 Silver Lake Water & Sewer District April 2011 Wastewater System Comprehensive Plan

14 Discharge Permit (IWDP) for the Cathcart Landfill. Snohomish County monitors the parameters of BOD, TSS, ph, oils and grease, total organic carbon, and total metals. The Maximum Contaminant Levels (MCLs) are specified in the IWDP. A copy of the IWDP for the Cathcart Landfill is included in Appendix E. Silver Lake Water & Sewer District 5-9 Wastewater Comprehensive Plan April 2011