Volume 2: Draft Gorst Planned Action Environmental Impact Statement

GORST PLANNED ACTION EIS | AFFECTED ENVIRONMENT, SIGNIFICANT IMPACTS, AND MITIGATION MEASURESconveyed as sheet flow over impervious surfaces that discharge to ditches and eventually to fish-bearing streamsand estuarine wetlands in Sinclair Inlet.Stormwater infrastructure deficiencies identified in the UGA include the lack of flow control measures forattenuating peak flows and low capacity for stormwater conveyance, as well as several undersized and crushedculverts which impound stormwater and accumulate sediment that results in flooding of areas in the UGA(Parametrix 2011, City of Bremerton 2013)The Watershed Characterization Report and model identified the Gorst UGA as an area of relatively highimportance to water flow processes but is highly degraded (City of Bremerton 2012). Given that this area is alreadydeveloped with urban uses, Creeks in the UGA are channelized with a reduced riparian cover that has impactedwater flow and increased stormwater runoff and degraded stream corridor discharge processes (City of Bremerton2012).The Gorst Creek Watershed Existing Drainage Deficiencies Technical Memorandum (City of Bremerton 2013)documents the existing drainage infrastructure deficiencies within the Gorst Creek Watershed and has beenprepared as part of the Watershed Characterization Plan. Drainage system problems and untreated stormwaterrunoff currently impact areas in the UGA. Drainage system problems were identified and categorized by type aschemical, biological and physical. Some of the problems identified include erosion, pollution loading, flooding, andfish passage barriers within the watershed. To identify system deficiencies, the City of Bremerton and K drainagecomplaint records were reviewed; discussions were held with the K Surface and Stormwater Management Division;and the Kitsap County Public Health District; and discussions were held with business and home owners nearidentified problem areas on the day after a food rainfall event of 4.09 inches within 24 hours on November 19th,2012. Drainage infrastructure deficiencies are identified at 16 sites (see Figure 3.2-3 Gorst Creek IdentifiedInfrastructure Existing Drainage Deficiencies).As previously described in Section 3.2, Water Resources, stormwater related problems included Elite Exterior andBetos Tires, development along W. Belfair Valley Road, and Peninsula Subaru. Elite Exterior has frequent floodingwhen high tides coincide with storm events. Businesses and residences along W. Belfair Valley Road haveexperienced increased flooding from high groundwater in combination with hill slope seepage and insufficientstormwater conveyance from degraded roadside ditches. Peninsula Subaru has drainage issues associated withundersized stormwater drain pipes and culverts with sink holes and slumps occurring on the property.Other stormwater runoff and drainage deficiencies during storm events included lanes of SR 3 closed down forseveral hours from when high tides coincide with storm events. Drainage ditches near Washington Cedar lumberyard and the Walidbilig properties are insufficient for conveyance of stormwater and sandbagging are required toprotect homes from overflowing banks. A drainage complaint was received by the K where the two residencesflood due to installation of private driveway culvert upstream along Sam Christopherson Road. The Countyinspected the site and noted that the culvert and driveway was on private property. The Kitsap County PublicHealth District cited an owner claimed a residence loss from streambank erosion in Gorst Creek three to four yearsago. Properties southeast of Old Belfair Valley Road and Sam Christopherson Avenue W. and west of Navy CityMetal reported past flooding. Many homes in the area are now abandoned.ImpactsThis utilities analysis is based on guidance provided by WAC 197-11-960 (SEPA environmental checklist) regardingidentification, characterization, and mitigation of impacts. The analysis of environmental consequences of theproject alternatives on utilities within the study area includes a description of the methods and summary ofimpacts.The City of Bremerton is compiling watershed data for several models that would identify and prioritize mitigationmeasures that would restore, enhance, and protect water resources and optimize investment in infrastructuresuch as water quality facilities.Draft | June 2013 3-225