PUBLIC INFRASTRUCTURE
6.1 Public Infrastructure Impacted by Illahee Creek
The primary public infrastructure systems in Illahee are sewer, water, and storm water. The infrastructure systems in Illahee are impacted by Illahee Creek similarly to the transportation system as infrastructure generally follows and conforms to the roadway system. As stated in the transportation chapter, Illahee Creek essentially forces the roadway system, and thus its infrastructure system, to detour one and one-half miles around the creek. This especially impacts the sewer systems in the area as Illahee Creek also provides the general separation boundary between the City of BremertonÕs sewer basin area and the Kitsap County sewer basin area.
Because much of the buildable area has already been developed, no major capital improvement systems are currently planned for this area for sewers, water, or storm water. There are, nevertheless, some major issues with sewers, water, and storm water that need to be resolved by the community and other governmental bodies.
6.2 Sewer
Kitsap County provides the sewer infrastructure currently existing in Illahee. Sewer service is provided along the Wheaton Way corridor and east along McWilliams Road where it serves developments primarily to the north (Figure 6.1). Kitsap County notes the sewer system has been sized to accommodate future growth in the basin area.
The City of Bremerton would be the logical provider of future sewer service to the area south of Illahee State Park and south of Sylvan Way due to the formidable barrier of the canyons of Illahee Creek and the distance and cost to run the sewer connector lines. This area is covered by the City of Bremerton in the Trenton Avenue Basin, as noted in BremertonÕs 2005 Comprehensive Plan Update.
Because of the delicate ground water balance system necessary to support the base flows in Illahee Creek, the advisability of sewers for the area around Illahee Creek is being questioned. Sewers diminish the water recharge of the basin area and can thereby affect stream flow. Additionally, when sewer systems are available the zoning density increases as does the commensurate impermeable surfaces, which also diminish ground water recharge. Recent hydrological studies point to the fact that this area is a recharge sensitive area, and sewers and higher density zoning are not supportive of maintaining base flow levels in Illahee Creek.
Figure 6.1 Illahee Community Wastewater Map
6.3 Water
General
Only one water purveyor, North Perry Avenue Water District, serves the Illahee community. The Water System Plan (WSP) for the North Perry Avenue Water District has been prepared in accordance with Washington State Administrative Code 246-290-100 and the Department of Health ÒWater System Planning Handbook, April 1997.Ó The WSP is currently on file at the District office located at 2921 Perry Ave NE, Bremerton, WA 98310.
History
The North Perry Avenue Water District was formed on November 24, 1942. The original project consisted of construction of approximately 6.6 miles of water mains along North Perry Avenue from Riddell Road to Stone Way and adjacent streets. Water supply was purchased from the City of Bremerton, and a 50,000-gallon tank on a 70-foot tower was constructed for storage near the corner of Olympus Drive and Sylvan Way. Significant additions to the water system were made in the 1950s, including additional mains, new wells, a booster station, and a storage tank. The District was expanded into two pressure zones. The Illahee Water District, which operated a small system in the Illahee area, merged with North Perry in the 1960s, as well as the merger of a small, private system in the Gilberton area. Negotiations between the District and the City of Bremerton in the 1970s have resulted in an agreement on a joint service area boundary. The agreement was signed in 1976, which resulted in transferring some customers to establish the current boundary between the two systems. The present service area boundary was further defined in 1989 by agreement between the District, Silverdale Water District No. 16, and with Kitsap County PUD No. 1. The North Perry Avenue Water District service area (Figure 6.2) currently covers approximately 12 square miles and has 12 wells in service, seven storage reservoirs, and more than 82 miles of water main.
Geography
Most of the geographic service area is rolling terrain with a ridge running north and south through the approximate center of the Water District. A creek valley cuts through the Water District in an east-west direction near Brownsville. The ground elevation varies from near sea level at the eastern side of the Water District to approximately 460 feet at the highest point. Steep slopes exist in some areas, and several small streams with steep side slopes intercept the service area. The occasional occurrence of wetlands restricts building in some areas. These topographic features affect the locations of water facilities and the method of serving the Water District.
Figure 6.2 North Perry Avenue Water District Map
Description of Facilities/Components
The Water District service area contains five pressure zones, 10 source wells, two backup wells, and one drilled well not yet in service. The total sustainable capacity of the District facilities is 3,680 gpm. Because the raw water quality is so high, the District does not perform water treatment, but does add chlorine to the water for the purpose of taste and odor control. There are seven storage reservoirs with a current total capacity of 4.75 MG, with 1.898 MG of standby/fire suppression storage. There are more than 82 miles of water mains. Much of the older pipe in the District is constructed of asbestos cement, and recent installations have used ductile iron pipe with typical diameters of six or eight inches. There are three pump stations. One inter-tie exists between the District system and adjacent (Bremerton) systems and is used only for emergencies. A significant distance between the District system and other adjacent systems and the topography of the service area typically makes inter-ties infeasible.
Related Plans
Land use planning and coordination of capital facility planning on a regional basis is the responsibility of Kitsap County. Water facilities are planned to accommodate and provide for the level of zoning and density included in the following related plans:
- Kitsap County Coordinated Water System Plans
- Kitsap County Ground Water Management Plan
- Kitsap County Initial Basin Assessment (a summary of available information on ground and surface waters, rainfall, stream flows, and fisheries habitat in Kitsap County, on file at the branch libraries)
- Kitsap County Comprehensive Plan (recognizes water is a limited resource and creates a framework for identifying and conserving sufficient volumes of clean surface and ground water for human use, fish and wildlife survival, and shell fish certification to sustain a healthy economy and environment within the constraints of these natural resources)
Zoning and Land Use
The land use planning for the service area is controlled by Kitsap County. The northwest part of the District is zoned for rural medium density, which provides for relatively large lots for residential use. Regulations generally prohibit utility service for development in rural areas. Most of the remaining portion of the District is zoned for low-to-medium density residential use, with some commercial areas along State Highway 303 and other selected locations. Past water system planning has been based on serving the use as it has developed. Land use is generally consistent with zoning.
Future Service Area
As part of its Capital Improvement Program, the District plans to construct new distribution piping in portions of its service area not currently served by water mains. These service areas are undeveloped property within the current District boundaries. Water service to these areas will generally be provided through developer extension agreements.
Design and Performance Standards
Any property owner developing a new plat of commercial property not served by existing water mains is required to design and construct a water main extension in accordance with the DistrictÕs current developerÕs standards, and to transfer title of the facilities to the District upon completion of the construction as a condition of acceptance. Costs associated with the design and construction of these water main extensions are the responsibility of the developer.
Population Projections and Demand Forecasting
The Kitsap County Comprehensive Plan projects an average annual growth rate of 1.0% from 1997 to 2012 in unincorporated areas; however, the historical average annual growth rate within the District has been higher. A more conservative growth rate of 2.5% is being used for demand forecasting. A second factor affecting demand is the overall weather conditions and the weather patterns during the summer. A third condition is the success of a conservation program.
Recent Hydrologic Studies
Kitsap County has noted Category 1 and Category 2 Critical Aquifer Recharge areas next to Illahee Creek. Additionally, recent hydrologic studies in the area have noted low base flows in Illahee Creek and the discovery of a relatively porous separation layer between the shallow aquifer supplying the creek and the deeper aquifers that supply local wells. This means that the use of wells within the hydraulic drawdown vicinity of Illahee Creek can result in a decrease in the base flow of the creek.
6.4 Storm Water
Historic Conditions
The Illahee community is comprised of rolling hills and is primarily located on the east slope of a hill that reaches approximately 500 feet above Port Orchard Bay. The hillside was originally covered with forests and a variety of vegetation typically found in the Puget Sound Lowlands. The limited amount of surface water runoff generated in the forested environment was carried to small streams by many shallow swales and larger ravines. The main stream still in existence is Illahee Creek. Figure 6.3 notes the storm water systems within and surrounding the Illahee community.
Figure 6.3 Illahee Community Storm Water Map
Existing Conditions
There are some significant storm water problems in Illahee that remain unresolved. They primarily result from the natural topography of steep and unstable slopes that cannot handle either a major single event storm or a series of smaller storms in rapid succession. These have been documented since the late 1960s and early 1970s when there were no storm water mitigation requirements. As storm water flushes through the deeply incised ravines during these storm events, they create problems for the streams as well as the downstream property owners. There are no easy fixes for these problems, and, as a result, they have existed for nearly 40 years. The most recent acknowledgement of the problem with Illahee Creek occurred in the mid-1990s when a new culvert was being planned. It was noted in the report for the culvert that a basin study is required to best understand how to deal with controlling the storm water in Illahee Creek.
More recently, two significant storm water related items have surfaced. The first was a report, entitled ÒIllahee Creek, A Stream Destined for Disaster,Ó which highlighted problems with various issues, including storm water surge problems. The second was a statement of area storm water problems via a Department of Ecology grant application submitted by the Port of Illahee, which advises engineering studies are needed to determine how best to control the surges that plague Illahee Creek. The PortÕs grant scored high in the state of WashingtonÕs rating system and was funded for studies to be accomplished in the 2007-2009 time frame.
6.5 Goals and Policies
Goal 6.2-1 Provide the availability of sewer service to residents within the Illahee community boundary where sewer systems already exist and where they are outside critical aquifer recharge areas.
Policy 6.2-1 Require all new construction and major remodel projects involving an increase in sewage beyond the existing capacity of the septic system to connect to sewer if within 200 feet of an existing line.
Policy 6.2-2 Encourage property owners on shorelines or near other critical areas to maintain their septic systems in good operating condition or connect to an available sewer system.
Goal 6.2-2 Conduct additional hydrological studies of the critical aquifer recharge areas around Illahee Creek to determine the appropriate boundaries around the creek and the recommended policies and procedures necessary to ensure base flow levels in the creek are maintained.
Policy 6.2-3 Prohibit, under this Plan, the introduction of sewers into the critical aquifer recharge regions of Illahee Creek until the necessary hydrological studies are completed.
Policy 6.2-4 Require all newly installed septic systems within the critical aquifer recharge area to be capable of returning cleaner effluent to drain fields than their earlier predecessors.
Goal 6.3 Conduct hydrological studies of the well systems around Illahee Creek to determine the appropriate boundaries around the creek to ensure base flow levels in the creek are maintained.
Policy 6.3-1 Prohibit, under this Plan, the introduction of new wells in the regions of Illahee Creek until the necessary hydrological studies are completed.
Policy 6.3-2 Begin a water balance monitoring system comparing base flows in Illahee Creek with drawdown rates of local wells.
Goal 6.4-1 Support development of a comprehensive approach to storm water management
Policy 6.4-1 Review all new developments to ensure coordination with regional and watershed storm water system planning.
Policy 6.4-2 Use environmentally proven methods such as Low Impact Development (LID) applications to enhance runoff water quality and control runoff rates.
Policy 6.4-3 Involve the Illahee community in the assessment and prioritization of storm water capital facility projects.
Policy 6.4-4 Identify areas needing improved storm water infrastructure within the Illahee community.
Goal 6.4-2 Encourage storm water management systems that preserve natural drainage systems, such as streams, and construct facilities that complement these systems by taking advantage of opportunities for filtration, infiltration, and flow control where feasible and reasonable.
Policy 6.4-5 Preserve stream and natural drainage systems.
Policy 6.4-6 Identify the remaining areas of the natural drainage system in Kitsap CountyÕs Geographical Information System as critical drainage areas.
Goal 6.4-3 Limit the amount of impervious surface that can be created on individual residential lots to reduce future increases in storm water runoff.
Policy 6.4-7 Limit impervious surface for each residentially zoned lot to a maximum of 50% on lots less than 0.50 acre and 40% on lots more than 0.50 acre.
Policy 6.4-8 Encourage the use of permeable surfaces and other new technologies such as Low Impact Development (LID) applications in building construction and property development.
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