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HomeMy WebLinkAbout821093003 Stormwater Mgmt EXHIBIT 6 Draft Environmental Impact Statement PORT LUDLOW WASTEWATER TREATMENT SYSTEM EXPANSION ~'. Co-lead Agencies: Washington Department of Ecology and Jefferson County July 16-, 1986 Booth Gardner Andrea Beatty Riniker Governor Director SUMMARY Objective~ Purpose~ and Need Objective Ludlow Utilities Company, a subsidiary of Pope Resources is the project proponent.. The objective of the project is to adequately deal with the need for wastewater collection and treatment for the Port Ludlow area (see Figure 1) in the manner meeting the highest reasonable stan- dards of environmental protection, long-range planning, engineering excellence, social acceptability, and cost-effectiveness. Purpose The existing wastewater collection and treatment system at Port Ludlow serves a total of 422 residential and commercial units. The plant provides secondary treatment, disinfection using a chlorination process, and discharges treated effluent through an outfall into Port Ludlow Bay, adjacent to the site. The plant had been violating effluent limitations established in the National Pollutant Discharge Elimination System (NPDES) permit until improvements were made in 1984. The improvements have enabled the plant to consistently meet effluent limits for BOD (organic matter), TSS (solids) and fecal coliform (bacteria). There also appears to be capacity in the improved plant for up to 70 additional units, making the total projected capacity of the plant 492 units. Need Based on existing commitments, Ludlow Utilities Company is obligated to provide treatment for a total of 1,206 connections. In addition, completion of a new development in the South Bay area would result in a total of 1,868 connections that would require service by the Port Ludlow Wastewater Treatment Plant (WWTP). Based on existing commitments and the future development for the Port Ludlow area, it is necessary to increase the capacity of, or to develop an alternative to, the wastewater treat- ment facility to continue meeting secondary treatment standards. This project is needed to allow for planned development while protecting the water quality of Ludlow Bay. Proposed Action The proposed action is for an expansion of the existing wastewater collection and treatment facility and extension of the plant outfall. The proposed action is divided into two phases involving both treatment plant expansion and improvements to the conveyance system. If disinfection were inadequate, colifo'rm levels could exceed Class AA criteria within portions of the bay. Adequate disinfection by increased chlorination could cause recommended chlorine residual levels in the vicinity of the outfall to be exceeded. No substantial decreases in dissolved oxygen, or increases in turbidity, would be expected within the bay. -1 The proposed treatment method is contact stabilization. This method of secondary treatment can be constructed on the existing treatment plant site; it is in widespread use and would provide the flexibility needed to handle the seasonally fluctuating wastewat~r flows. The lift stations connecting the South Bay community with the treatment plant would be upgraded to handle increased flows. Lift stations #3 and #4 would be rebuilt at their existing locations. A new lift station #1 would be located north of the marina and would pump wastewater through a force main that parallels Port Ludlow Road to the treatment plant. The plant and all lift stations would meet the Department's criteria for reliability. The plant outfall would also be extended 3000 feet to the north as a part of the proposed action. Alternatives A variety of possible solutions to fulfill the need for additional wastewater treatment capability in Port Ludlow Bay were examined. Four different types of alternatives were considered: 1) facility size, 2) location, 3) treatment process, and 4) outfall location. Based on available information and the proponent's objectives, the possible alter- natives were evaluated using engineering, economic and environmental considerations. Facility Size Evaluation of alternative facility sizes to meet the demand for wastewater treatment in the Port Ludlow area indicates that both the no action alternative and a smaller facility would not provide sufficient secondary treatment for the planned development. Both the regional facility and the smaller facility would not provide a significant reduc- tion in water quality impacts, but would result in a greater user cost. The increased costs would either be borne by residential property owners along Ludlow Bay Road and/or in the Swansonville/Mats Mats area, or it would be borne by state and federal taxpayers. The no action and the smaller facility also would not fulfill the proponent's objective. Location Evaluation of alternative facility location involved a comparison of a single facility at the existing site, a single facility at a new site and a split facility. Construction of a new facility at a new location would result in greater environmental impacts due to upland construction but would not result in any reduction of water quality impacts. Construc- tion and land acquisition costs would be substantially greater. A split facility using the existing WWTP would involve both upgrading the existing facility and constructing a 'new facility. Similar to only constructing an all new facility, this alternative would have greater construction impacts in upland areas not now developed and greater construction costs. A split facility at two new sites would involve the construction of two entirely new wastewater treatment facilities and reconstruction of the '..~' -~ .... ; ~:.,.co~leGtion~,and.~ conveyance facilities,~-. The,~ construction~.and..,land~. ...... ~ acq~isition'~osts associated with this alternative would be 'exCeSsive. -4- Treatment Processes Several different secondary treatment options have been evaluated, including: complete mix activated sludge treatment, contact stabiliza- tion treatment, oxidation ditch treatment, and land treatment. Opera- tional options considered include;timing effluent discharges with favorable tides, ultraviolet disinfection in lieu of chlorination and anaerobic sludge digestion in lieu of aerobic digestion. · The complete mix activated sludge treatment is the most versatile and widely used biological process in wastewater treatment, and typically removes 85-95% of organics (Biological Oxygen Demand or BOD) and sus- pended solids. New construction would be required for all unit processes except sludge digestion and thickening. · The contact stabilization treatment method (proposed action) is a modification of the complete mix activated sludge treatment method. This method would reduce organics (BOD) and suspended solids by as much as 90% to 95%. The contact stabilization method also requires new construction for all unit processes except sludge digestion and thickening. The treatment process can handle widely fluctuating loading better than a complete mix activated sludge system but requires additional operator attention. · The oxidation ditch treatment operates in an extended aeration mode and does not require primary treatment. New construction would be required for all unit processes except the primary clarifier, sludge digestion and thickening. The facility is larger than the previous two discussed and would require the acquisition of adjacent lands. One of the advantages of the oxidation ditch treatment method is the ease of operation relative to the complete mix and contact stabilization treat- ment methods. · Land treatment of wastewater involves the use of plants, the soil . surface, and the soil matrix for wastewater treatment After a number of candidate sites were assessed, the Hood Canal tree farm was selected for detailed evaluation. Wastewater would be collected in the existing system and conveyed southwest along existing roads to the tree farm site. A large storage lagoon would be used for storage of wastewater during periods when wastewater flows exceed the hydraulic loading rate of the soils. Although land treatment would have greater terrestrial impacts, it would reduce the water quality impacts to the bay. · Anaerobic digestion is one of several methods available for stabilization (decomposition of organic matter and solids reduction) of solids removed in the wastewater treatment process. Anaerobic digestion was eliminated from consideration at Port Ludlow due to the high cost and site constraints. · Rather than continuously discharging into Port Ludlow Bay, effluent could be stored during slack water and flood tidal conditions. This alternative would require construction of a 200,000 to 300,000 gallon reservoir offsite and associated pump and pipeline facilities. ~...~t~ ~Wh~thia~i% ~rojected %o~ result, in a five-fold increase in dilution, increasing dilution is to modify the outfall. -5-- · Ultraviolet (lA?) light disinfection has been reported to be an effective method of disinfection having no apparent toxicity to aquatic animals· The reliability of this process is questionable, however, especiallv at a small facility. Given the need to provide very reliable disinfection, chlorination was selected over UV disinfection. The chlor- ination system and outfall will be designed to mitigate potential adverse environmental impacts to sensitive aquatic species from chlorination. · Tertiary treatment of wastewater involves treatment beyond secon- dary levels aimed at removal of nitrogen, phosphorus, or suspended solids. Based on the results of the water quality investigation of Port Ludlow Bay~ the need for tertiary treatment could not be demonstrated. Receiving water quality benefits of tertiary treatment were considered minimal compared to the high cost and tertiary treatment of wastewater was eliminated from further consideration. Outfall Location Three outfall options were considered' extending the existing outfall 400 feet east further into Port Ludlow Bay, extending the existing outfall 3,000 feet north to the edge of Port Ludlow Bay, and extending the outfall beyond Tala Point into Admiralty Inlet. Impacts associated with the outfall options are primarily related to water quality in Admiralty Inlet and Port Ludlow Bay. Careful evaluation of the discharge sites was required to determine any effects of the dis- charge on clam beds at ColVos Rock and the general water quality in Ludlow Bay, Admiralty Inlet and Hood Canal. An analysis of currents and circulation in Port Ludlow Bay indicates that flushing at a site 400 feet east of the existing outfall would provide suitable dilution for effluent from an expanded treatment plant. Extending the outfalt 3,000 feet to the north would not provide a major improvement in water quality within the bay However, several minor water quality improvements are asso- ciated with this northern outfall and it has been identified as the proposed action. A preliminary assessment suggests that a portion of the effluent from any discharge in the vicinity of Tala Point would tend to be carried into Port Ludlow Bay; the remainder would be dispersed direct- ly into Admiralty Inlet or Hood Canal. Placement of the outfall at Tala Point would be expected to result in a reduction in effluent concentra- tion within Port Ludlow Bay compared with the existing outfa]l site. In all alternatives, however, the predicted effluent concentrations ~'~thin Port Ludlow Bay are very ±O~ . Impacts Both construction (short-term) and operation (long-term) impacts associated with the proposed action are summarized ,below. Impacts are presented by elements of the natural and built environments. Natural Environment Earth. Short-term: The proposed action calls for site expansion and-.~~ve~ents"to .%he exi'stin~dTP"tha~woutd+~eq~ire excavation-for~i,- ~ . -6- new treatment components and trenching for new sewer lines. Construction activities would result in an increased potential for erosion and sedimentation from storm runoff. The outfall would also involve some nearshore, intertidal, and subtidal sediment disturbance. Long-term: Allow for this area to continue to be developed in accordance with the Comprehensive Plan Air. Short-term: While under construction, the WWTP improvements would r--~sult in a temporary deterioration of the ambient air quality. Vehicular traffic resulting from ingress and egress of construction vehicles would increase ambient levels of carbon monoxide, hydrocarbons, and photochemical oxidants (sulphur and nitrogen oxides). Long-term: Sludge hauling would increase from an average of one trip per week to five trips per week at full usage of the plant (about 2030). There would be a corresponding increase in vehicle emissions. Increased operational capacity may increase obtrusive odors emanating frOm the plant. Water. Short-term: Construction of the outfall pipe would increase turbidity in the immediate area. Long-term: The allowable discharge of pollutants would increase as follows' Discharge at Present Capacity (Estimate) Flow 100,000 gallons/day 380,000 gallons/day BOD 19 lbs/day 95 lbs/day SS 15 lbs/day 95 lbs/day Fecal Coliform 50 per 100 ml <200 per 100 ml Chlorine 1.5 lbs/day 3.2 lbs/day Nitrogen 21 lbs/day 79 lbs/day Total daily loads of individual effluent constituents and effluent volumes as a whole would increase over current plant loads. However, more reliable treatment and better initial dilution are expected to improve water quality conditions in the vicinity of the outfall compared to 1984 conditions. Better mixing with larger bay volumes and less likelihood of inner bay transport of diluted effluent by north wind episodes are also expected. Effluent is not expected to cause any Class AA violations within the bay. Projected increases in BODs and ammonia would not significantly affect DO levels within the bay. Fecal coliform levels are expected to be more consistently at a level having no significant impact on water column and shellfish concentrations. Nitrogen load contributions of the treatment plant into the inner bay during the summer could be increased from 0.3% to 1.6% on average, and from 3.0% to 13.5% during an extreme condition. A proportional increase in algae productivity could be stimulated by this increase in nitrogen. ..... However, 1984 field study data suggest that algae densities are low in --7-- the inner bay because of short residence times. No noticeable decreases in water column transparency are expected from the estimated increases in algae productivity. Typical and worst-case turbidity conditions in the dilution zone of-the outfall would improve by being consistently low. Chlorine residuals would be decreased in the effluent and reduce the chance of toxic conditions for aquatic life in the vicinity of the outfall. Ammonia levels would slightly increase in the mixing zone, but are expected to be below levels considered toxic to aquatic life. Construction activities would temporarily cause Class AA turbidity violations. Plants and Animals. Short-term: During construction the presence of equipment, human activity, and noise could cause birds and mammals to avoid the area. Since the existing treatment plant is within an already disturbed site, its expansion would not result in the direct loss of additional habitat. Extension of the new outfall pipeline to the north discharge point would disrupt the subtidal soft-bottom habitat over an area 15 feet wide and 3,000 feet long. The biological community in the immediate area of the construction would be eliminated, including some geoducks. Minor impacts to marine birds and mammals could occur from habitat loss due to elimination or disturbance of subtidal areas during outfall construction; these habitat losses should be offset by recolonization along the outfall pipeline. Long-term- The expanded wastewater treatment capacity would allow for maximum residential buildout as presently planned for the Port Ludlow area. Such a buildout is likely to result in loss of habitat and increased recreational boating. If boating wastewater is not properly disposed of it could increase fecal coliform bacteria levels in Port Ludlow Bay shellfish. Treatment process upsets could result in potential impacts to marine organisms. Built Environment ~oise. Short-term- Construction noise generated from backhoes, graders, air compressors, and trucks would occur over the 12-month construction period. ' Long-term: Operational activities of the WYTP and lift stations would increase noise levels slightly in their immediate areas. Operational noise sources include blowers, pumps, mechanical operatiOns and service trucks. , Risk of Upset. Power failure, equipment failure, or flooding events could result in e~cessive water volumes in the WWTP and piping system. Under such events, wastewater would be given primary treatment and disinfected before being discharged into the bay. . -8- Water. Short-term: Short-term water quality impacts'may be caL~sed by treatment plant, outfall, and conveyance facilities construction, and impacts would be limited to turbidity caused by soil erosion and sedimen- tation in the immediate vicinity of construction activities. Mitigating measures to reduce these construction impacts are present under the earth element. Impacts related to outfall construction would be short-term increases in turbidity. Timely and efficient in-water construction, as well as use of construction techniques that minimize disturbance of the substrate, would reduce impacts. Plants and Animals. Short-term: None. Long-term: Disturbance around the existing treatment plant would be landscaped and hydroseeded. Subtidal soft-bottom habitats would be replaced with a hard surface pipeline and ballast. These hard surfaces would allow marine organisms to become established. Minimal hard surface habitat is presently available in the bay; therefore, the proposed outfall expansion could result in a net increase of organisms available for marine birds and mammals. Other mitigating measures for the outfall include limiting construction to May and June to avoid out-migrant juvenile salmonids. Built Environment Noise. Short-term: None. Long-term: Noise levels would be reduced and would not exceed 50 dBA at the property line of the facilities by using quiet electric motor pumps and designing equipment housing structures to muffle and reduce noise levels. Pumps would be housed underground. Risk of Upset. Short-term' Wastewater will continue to be treated to secondary levels during construction. No plant bypassing or reduction in treatment will occur while the new plant is being built. Long-term: Emergency power generation, with automatic switchover equipment, would be installed. In accordance with Ecology's reliability standards, multiple treatment units would be provided to minimize the loss of treatment efficiency should one of the process components f~il. Backup pumps would be installed and available for immediate use should primary pumps fail. Handling, storage, and use of chlorine gas would be in accordance with state and federal requirements; alarms, sensors, and emergency equipment would be provided. Electronic telemetry is provided for all lift stations. Land Use. Short-term: Should construction of the treatment plant require removal of existing screening vegetation, a vegetative buffer would be replanted. Long-term: Perimeter landscaping and plantings would visually screen the W~P from adjacent residences. Recreation. Short-term' None. Long-term' Efforts to continue to encourage boaters to use the wastewater pump-out facilities provided by the marina will be made in order to minimize flushing of tanks directly into the bay. . Public Services and Utilities. Short-term: None. · Long-term: The water service for the community is supplied by an existing, privately-owned facility and is designed to serve the expanding needs of the Port Ludlow community. The Port Ludlow community is a recreational/residential development with a lower-than-usual number of full-time occupants. Therefore, the service requirements are less than for a conventional residential development. The needs for additional public services and utilities also are substantially reduced for this reason. Unavoidable Adverse Impacts Short-term: Site expansion would require excavation, trenching, and backfill. Construction activities would result in temporary erosion, sedimentation, and increased water turbidity. During construction, temporary increases of suspended particulate levels would also occur. Increased vehicular traffic under operational conditions would increase ambient levels of carbon monoxide, hydrocarbons, and photochemical oxidants. A small amount of terrestrial wildlife would be affected. Construction of the outfall pipeline could have a short-term effect on marine bird and mammal use in the area. Long-term~ The increased discharge of pollutants will have an adverse impact though it will not be measurable. The mitigating measures of increased treatment plant reliability and relocation of the outfall should more than offset the increase in pollutant loading. A long term receiving water monitoring program will be incorporated into Port Ludlow's NPDES permit to provide assurance the plant is not impacting water quality. Section IV AFFECTED ENVIRONMENT, SIGNIFICANT IMPACTS, MITIGATING ~fEASURES Section IV of this EIS presents the scoping, affected environment, significant impacts, mitigating measures, and unavoidable adverse impacts for each element of the environment identified during the scoping process. The elements of the environment are divided into two groups: the natural environment and built environment. The affected environment is described as existing conditions of the project site and vicinity. Significant impacts that would or could occur are described with sufficient detail to allow assessment of their severity. Mitigating measures are described that would reduce or eliminate environmental impacts; all unavoidable adverse impacts, those without mitigation, are identified. SCOPING "Scoping" is the term used to determine the appropriate topics to be addressed in an Environmental Impact Statement. Washington administrative laws require lead agencies (in this case, Jefferson County and the Department. of Ecology) to narrow the focus of every EIS to the "probable significant adverse impacts and reasonable alternatives, including mitigation measures" (WAC 197-11-408). To ensure that every EIS is concise, yet addresses the significant environmental issues, the lead agencies must execute a scoping process with the following objectives in mind: The promotion of interagency cooperation and public participation by inviting various governmental agencies, affected tribes, and the general citizenry to suggest appropriate contents of the EIS; · Identification of reasonable alternatives to the proposed project and probable significant adverse environmental impacts; · · Elimination from detailed study those impacts that are not significant; and · Coordination with other agencies to identify and integrate, where feasible, environmental studies required for other governmental approvals. With those objectives in mind, on January 23, 1985, the Department of Ecology issued a formal "Determination of Significance and Request for Comments on Scope of the EIS." The Scoping Notice described the main features of the proposed project; the cooperative environmental review arrangement between the State, County and applicant; the apparent governmental permits and licenses required; and that the lead agencies had identified water quality as the main issue of concern. The notice -39- also invited agencies, affected tribes, and members of the public to comment on the scope of the EIS, alternatives, mitigation measures, probable significant adverse impacts, and licenses or approvals that may be required. The deadline for comments was set for February 15, ]985. As announced in the Scoping Notice, as well as in local newspapers, a Public Scoping Meeting was held at 7:30 p.m., February 7, 1985, in the Conference Center at Port Ludlow. The meeting was conducted by the Department of Ecology. Oral testimony was recorded and additional written remarks were invited prior to the February 15th deadline. Some fifteen letters were received subsequent to the Public Scoping Meeting. On February 27, 1985, the Department of Ecology, Jefferson County, the applicant, and the applicant's consultant met to determine in what manner each of the elements of the EIS would be addressed. On February 28, 1985, Department of ECology distributed a memorandum identifying the range of ElS topics as a result of the Public Scoping Meeting, written comments, and additions from Department of Ecology and Jefferson County staffs. Elements of the environment and the associated issues are summarized as follows. Element of the Environment Associated Issues I. NATURAL ENVIRONMENT A. Earth ·'physical land disturbance · cut and fill requirements · erosion and sedimentation during construction B. Air · construction dust · increased traffic · obtrusive odors C. Water · physical oceanographic (currents and circulation) conditions of bay · biological conditions (nutrients, algal blooms, chlorine, turbidity) · normal and worst-case scenario · effects of construction · effects on shellfish D. Plants and Animals · effects to marine birds and mammals · effects to marine invertebrates and fisheries E. Energy and Natural · not applicable Resources II. BUILT ENVIRON~IENT A. Environmental Health · increased noise levels ._ · risk of upset · public health effects -40- ~Elevations range from about 360 to 480 feet above sea level located on a broad north/south ridge separating the lowland on the east from Thorndyke Creek Canyon on the west. Access is limited to Highway 104 that runs east/west through the north half of the area and a logging road near the center of the area. Geology/Soils __ The geology of the. Port Ludlow area includes basaltic bedrock of the Crescent Formation and surface deposits of glacial and alluvial sediments. The soils that have formed on these deposits include the Alderwood-Sinclair association and the Olete-Hoodsport association (McCreary, 1975). The Alderwood-Sinclair associations are moderately well drained, strongly sloping to steep, gravelly soils underlain by compact glacial till. The Olete-Hoodsport associations consist of well drained and moderately well drained, strongly sloping to steep, very gravelly soils underlain by basalt or compact glacial till. The North Bay service area consists primarily of Alderwood soils. These soils have an impermeable substratum (glacial till) at a depth of 20 to 40 inches that restricts groundwater movement. A perched groundwater condition typically occurs in these soils during the winter months. The South Bay service area includes moderately well drained soils of the Olete series. These soils are underlain by basalt bedrock at a depth of 20 to 30 inches. At the treatment facility, dense to very dense glacial till was observed in the cut slopes made to construct the existing upper and lower benches at the treatment facility (Converse Consultants, Inc., 1985). Till is a homogeneous mixture of clay, silt, sand and gravel with occasional boulders. The till was consolidated by the weight of glacial ice and is commonly referred to as "hardpan." Occasional lenses of fine to medium grained sand occur within the till. The soils occurring in the area considered for the land treatment alternative have formed in glacial till and glacial outwash material (see Figure 10). The upland area (Site 2) consists of Dabob and Sinclair soils that formed in glacial till. These are moderately well drained soils with a very slowly permeable cemented horizon within 20 to 40 inches of the surface. Runoff is slow to medium on moderate slopes (less than 15%) and medium to rapid on steep slopes (15-30%), and the hazard of erosion is slight to moderate. A perched water table is often found on top of the cemented till layer during the rainy season. Soils of the lowland area (Site 1) have formed in the coarse grained glacial outwash material and have been identified as Everett, Carlsborg, and Indianola soils. These are somewhat excessively drained soils with rapid permeability. Runoff is slow and the hazard of erosion is slight to moderate. Based on this evaluation, these lowland soils have a greater capacity for hydraulic assimilation, due to their more rapid drainage capabilities. -45- IMPACTS Proposed Action Site expansion and improvements for the existing WWTP would require excavation for the aeration basins, cl. arifiers, and outfall and diffuser pipe. Estimates for the treatment plant excavations are 12,000 cubic yards. Most of the excavated material would require off-site disposal. New material for backfill and drainage control, and concrete aggregate would need to be obtained from a quarry. Site construction activities would result in an increased potential for erosion and sedimentation from storm runoff. Control measures could reduce the impact of off-site~ erosion and sedimentation. If earthwork construction is not conducted 'during the dryer summer months, the glacial till soil on the site would be easily disturbed and impossible to properly compact. When wet, disturbed soils are highly susceptible to erosion. Conveyance facility improvements would involve new force main pipelines. This would require trenching and backfilling and would result in some sedimentation to off-site areas. Off-site hauling and disposal of some excavated material could be required. Treated sludge would be applied to a remote Pope Resources tree farm site approximately five miles south of the WWTP. The stabilized sludge will be used to enhance tree growth and will be applied at rates consistent with specific soil types, vegetation cover and ground slope. A similar site nearby has recently been approved by the Jefferson County Health Department for the City of Winslow. Its soil characteristics and suitability for sludge application have been evaluated by Brown and Caldwell (1985). Under the proposed action, installation of 3,000 feet of outfall discharge pipe would require excavation of about 1,500 cubic yards of nearshore and intertidal beach sediment. Short-term turbidity increases would occur during excavation and backfill for the outfall pipe. No long-term impacts would be expected to occur. Al'ternatives Treatment Facility 'Size: Retain Existin$ Facility (No Action) The "no action" alternative would not result in clearing and grading activities associated with treatment plant improvements. New sewer service area expansion may not occur and new sewer lines would not be installed. New developments, however, may be served by individual on-site or community systems, provided that the site conditions are suitable. In this case, construction impacts associated with clearing and grading activities would occur on an individual and isolated basis. Due to steep slopes, slow permeability and shallow perched'water table, most soils in the Port Ludlow area have severe limitations for septic drainfields and would likely not meet health department requirements. -47- Treatment Facility Location' Split Facilitv~ Existing and New Site Construction of a new wastewater treatment facility would have impacts from site grading and clearing activities, and soil erosion potential similar to construction of the proposed action. The actual impacts could be greater or less, depending on the characteristics of the site selected on the south shore and the overall area affected. Often construction on an undeveloped site results in more extensive clearing and grading activities. In the south shore area, the potential to affect the beach and nearshore area exists. A new site also would require a greater overall extent of new force mains and conveyance lines from the service areas to the new facility. Construction of a second outfall pipeline would likely result in more extensive impacts to the aquatic environment as an estimated 9,000 feet of pipe would be required to reach an acceptable outfall location. Treatment Process: Land Treatment The land treatment alternative would require trenching for approximately 3.5 miles of pipeline, excavation for several lift stations, and extensive site clearing, grading, and excavation for the primary treatment lagoon systems. In addition, shallow excavations would be required for the effluent application pipelines. The influent transmission pipeline would require some ripping or blasting of basalt bedrock for trench excavations. The total area required for a land application site is based on the nitrogen uptake of native vegetation. Nitrogen uptake was calculated using the known uptake of Douglas fir (refer to the Engineering Report, Appendix A, Seton, Johnson &Odell, 1986) and the percolation rate through the root zone, assuming a reduction of nitrogen concentration from 60 mg/1 to 5 mg/1. The upland area (Site 2) soils appear to have greater limitations related to lower hydraulic assimilative capacity than the lowland (Site I) soils. Because of soil characteristics and requirements for large land areas, effluent irrigation may not be practical on these upland soils. The lowland area soils appear to have the most favorable characteristics for year-round effluent irrigation; however, their rapidly drained nature could result in inefficient effluent purificatien resulting in groundwater contamination. Conservative assumptions have been used in estimating land area re- quirements for effluent irrigation on these soils. The general conclusion is that the gravelly outwash soils of the lowland site are limited by nitrogen loading rates; approximately 200 acres of land would be needed in these soils to fulfill treatment requirements. In the upland glacial till soils, hydraulic limitations dictate a need for 600-700 acres for treatment. Due to its potential health hazard, nitrogen contribution to the groundwater is of concern. The nitrate concentration in treated effluent averages 60 mg/1 (14 mg/1 as nitrogen). State standards for nitrates in w -- water sources is 10 mg/1. The nitrates fro~ wastewater are very -48- soluble and are readily leached through the soil, thereby potentially contaminating groundwater sources. Phosphorus is considered the major nutrient and the limiting factor in contributing to the eutrophication of surface water bodies (Welch, 1978). Phosphorus absorption onto the soil particles is the major mechanism for phosphorus removal. Variations in phosphorus retention are dependent on loading rates, permeability, depth to water table, and groundwater movement characteristics. The lowland §ravelly outwash soils would have low phosphorus absorption capacity. Nitro§eh and phosphorus present in septic tank drainfields are con- verted by microbial activity in the presence of oxy§eh from anaerobic to aerobic conditions. Nitro§eh in the form of nitrates is soluble and readily carried into the groundwater, where dilution is the only effective means of reducing its concentration. Phosphorus, on the other hand, is absorbed onto the soil particles and is precipitated with soil sediments such as iron, aluminum and calcium. With extended use phosphorus absorption capacity in soils can be reduced and it may subsequently enter the groundwater. The nutrient characteristics of land irrigated with wastewater would be similar to nutrient characteristics from drainfields. Due to the estimated lower land area requirement, preliminary calculations support the conclusion that the lowland outwash soils are suitable for effluent land application. For design purposes, a more detailed field investigation of actual soil characteristics would be needed to verify U.S. Soil Conservaticun SerVice mapping and to develop a detailed delineation of individual soil series. Refinement of land area requirements could then be made along with recommendations and specifications for wastewater irrigation system siting. In order to assure that the soils remain suitable to receive appli- cation and meet requirements of the disposal permit, a monitoring program would be established. Monitoring information would be provided to the Washington State Department of Ecology and Jefferson County Health Department. It is also important to note that use of the land treatment alternative would eliminate the need for an effluent outfall and those aquatic environmental impacts associated with the proposed action would not occur. Treatment Process' U!travioie% (UV) Disinfection Disinfection through use of b~ light would have no impact on earth or soils. Outfall Location: Expand Existins to South Discharge Point The effluent outfall pipe would require excavation of about 150 cubic yards of nearshore and intertidal beach sediment to bury the pipeline. Short-term turbidity increases would occur during excavation and backfilling for the outfall pipe. No long-term impacts would occur. MITIGATING MEASURES Proposed Action Site development for expansion of the existing WWTP would include interim drainage measures to control erosion and sedimentation during construction. Measures could consist of vegetative controls, structural controls, and best management practices. Vegetative controls could consist of preservation of existing vege- tation, temporary seeding, and planting of permanent landscape vegetation strips in graded and cleared areas. Vegetative controls are the first line of defense in preventing erosion by protecting the soil surface from raindrop impact and overland flow of storm runoff. Vegetative buffers reduce runoff velocities and act as a filter in trapping sediment. Structural controls could consist of sedimentation ponds and sediment barriers. These controls are not as effective as vegetative controls, but provide an additional measure to capture sediment before it leaves the construction site. Good construction management and planning are key elements in controlling erosion from the construction site. Management decisions that could be employed during site development include the following: Immediately upon completion of the grading operation in an area, seed it with an appropriate vegetative mix to limit erosion. · Avoid exposing soils during periods when the highest potential for erosive rainfall could occur. · Develop and carry out a regular maintenance schedule for structural controls. Appropriate engineering design and safeguards for foundation excava- tions, and sewer line placement should be conducted with the supervision of a soils engineer. Subsurface explorations and recommendations for shoring, drainage, water control, and clearing and grading design measures should be provided by a qualified soils engineer prior to issuance of construction permits. Building siting should be in uniform sei!s. Retaining walls and shorings should be used for cuts exceeding four feet to prevent sloughing or sliding. Adequate subdrains should be provided. To further protect against shoreline erosion, approximately 500 cubic yards of riprap would be placed along the high-tide line in front of the WWTP. Secondary treatment and discharge would result in an estimated sludge production of 1,000 gpd at 4% solids. Sludge would be used as a fertilizer for the commercial tree farm operated by Pope Resources. -50- Alternatives Treatment Facility Size: Retain Existing Facility (No Action) and Treatment Facilitv Location: Split Facility~ Existing and New Site Mitigating measures similar to those for the proposed action are proposed for these two alternatives. It is important to note that any individual drainfields constructed under the no action alternative would not require a grading permit. Thus, any mitigating measures to reduce erosion due to construction would only occur under an individual and voluntary effort. Outfall Location: Expand Existing to South Discharge Point No mitigating measures are proposed. Treatment Process: Land Treatment Along with operational experience and an accurate determination of effluent constituent concentrations, a detailed site monitoring program would serve as an important mitigating measure for the land treatment alternative. It would provide a basis for evaluating the need for corrective measures (e.g., increased land area or adjustments in irrigation scheduling) prior to creating potentially adverse impacts on groundwater. Emphasis of this program would be on the unsaturated soil zone and nitrite-nitrogen leaching losses. With its internal drainage and absence of groundwater development, the lowland area appears well suited for land application of treated effluent. The lowland area, however, is possibly a recharge area for a more regional groundwater system (Seton, Johnson & Odell, 1986). There- fore, delineation of groundwater flow conditions and careful monitoring would be necessary. Drainage and runoff conditions in the upland area (Site 2) may constitute a potential threat to surface water, e.g., Thorndyke Creek. Application area setbacks to minimize potential surface water impacts would substantially reduce the available application area by as much as 70%. ~ile application rates and techniques can be used to mitigate impacts, the sensitivity of receiving waters (Port Ludlow Bay and Thorndvke ~av) relegates the u~!and are~ to least favorable status. UNAVOIDABLE AD\~RSE iMPACTS Proposed Action Site expansion would require excavation for the new facility and trenching of new sewer lines; excavation estimates are 12,000 cubic yards. Excavated materials would be disposed off-site. New backfill, drainage control, and concrete aggregate would be obtained from a quarry. During the construction period, temporary erosion and sedimentation would occur. The outfal] discharge pipe would require excavation of about 300 cubic yards of nearshore and intertidal beach sediment. Short-term, temporary turbidity increases would result from this activity. Alternatives Treatment Facility Size: Retain Existing Facility (No Action) Excavation for individual septic systems would result in temporary erosion and sedimentation. These earth impacts would be isolated, small in size, and occur at various times and locations. Treatment Facility Location: Split Facility, Existing and New Site Expanding the existing facility and developing a new facility at a new site would result in unavoidable adverse impacts to the earth environment similar to the proposed action. The extent of impact, however, would differ at the two locations. Excavation impacts at the existing site would be less as the extent of expansion is less than the proposed action. Impacts at a new site location would be greater than the proposed action as excavation of an undeveloped site would likely be extensive. New force main pipelines would require trenching and backfilling that could result in temporary erosion and sedimentation. Treatment Process: Land Treatment Excavation for 3.5 miles of pipeline, lift stations, and the primary treatment lagoon, including some riprapping and blasting, would result in temporary erosion and sedimentation. Adverse impacts could result from accumulation of phosphorus in the soil and nitrogen in the groundwater, although the extent, if any, of this occurrence would not be known until a monitoring system was est@blished. As previously mentioned, the use of this alternative would not require outfall construction. Treatment Process: lKz Disinfection No unavoidable adverse impacts are anticipated. Outfall Location: Extend Existin~ to $¢,~th Discharge Point The outfall discharge pipe would require excavation of about 150 cubic yards of nearshore and intertidal beach sediment. Short-term, temporary turbidity increases would result from this activity. -52- AiR QUALITY AFFECTED ENVIRONMENT Air pollution control and enforcement in the Port Ludlow area, and all of Jefferson, Clallam, Grays Harbor, Mason, Pacific and Thurston Counties, is the responsibility of the Olympic Air Pollution Control Authority. This Authority was formed in 1968 and maintains a number of monitoring stations throughout the control area. Major pollutants monitored by the Authority are carbon monoxide, nitrogen oxides, ozone, sulfur dioxide, suspended particulates, lead, and arsenic. Not all of these pollutants are monitored at every station. No monitoring station is located in the immediate project vicinity. The only monitoring station located in Jefferson County is located 15 miles north of Port Ludlow at Port Townsend. In 1983, the annual geometric mean value for suspended particulates (the only pollutant monitored at this station) was 29 ~g/ms, well below the federal standard of 75 ~g/ms and the state standard of 60 ~g/ms. There are no identified particulate emissions from point sources in the project vicinity. Particulate emissions from nonpoint sources are primarily attributed to dust from construction activities and smOke from the use of fireplaces and wood stoves. Other pollutants, such as hydrocarbons, nitrogen oxides, and photo- chemical oxidants from vehicle and boat emissions likely exist in relatively minor amounts throughout the Port Ludlow area. Relatively high ozone concentrations occur throughout the Puget Sound area and are considered a regional problem. Other major sources of pollutants throughout the control area include mills, veneer dryers, and sand and gravel companies. Operation of the existing WICFP may generate obtrusive odors. Hydrogen sulfide and ammonia are basic elements of sewage and are generated as a by-product under anaerobic conditions that occur within 20 minutes if sewage is left unoxygenated. Anaerobic conditions may occur at lift stations during abnormal pumping conditions and at the treatment plant during unregulated aerobic treatment. Hydrogen sulfide and ammonia odors generally dissipate within a few hundred feet of the source. IMPACTS Proposed Action Air quality impacts associated with this project would result principally from three activities' construction, vehicles, and operation. While under construction, the treatment plant improvements would result in a temporary deterioration of the ambient air quality. The use of heavy equipment (backhoe, dump truck, etc.) would likely increase suspended particulate levels (dust). Vehicular traffic resulting from ingress and egress of construction vehicles and sludge hauling transport trucks, as well as probable increases in population as -53- vacant lots are developed, would increase ambient levels of carbon monoxide, hydrocarbons, and photochemical oxidants (sulphur and nitrogen oxides). As the W%~P reaches ultimate design capacity, obtrusive odors may increase. Hydrogen sulfide and ammonia odor sources include: bar screen, aerated grit chamber, sludge, and aeration basin. Odors could be associated with the transportation of the sludge by truck along its route and at the sludge utilization site. Alternatives Treatment Facility Size: Retain Existing Facility (No Action) Under this alternative, the existing conditions would continue to prevail. New lot development would be curtailed; therefore, no new con- struction would take place and associated increases in suspended partic- ulates would be minimal. Treatment Facility Location: Split Facility~ Existing and New Site Under this alternative, a new site location would result in operational and vehicular impacts similar to the proposed action. Due to more site modification and a longer construction period, this option would create greater construction impacts. The air quality impacts associated with construction would be dispersed between the two sites. Treatment Process: Land Treatment Construction of pipelines, lift stations, and the primary treatment lagoon would result in temporary increases in suspended particulates. The majority of the construction activities would be conducted outside of the developed area of Port Ludlow. The land treatment.process would reduce the level of oxygen in the sludge and thus increase the hydrogen sulfide and ammonia by-products. These by-products, characterized as obtrusive odors, would have little adverse effect as no residents are located in the immediate area of the land application s~te. It is estimated the land treatment alternative would require hauling sludge to a landfill about once every five years. This is not expected to have an adverse impact on air quality. Treatment Process: t~ Disinfection This type of disinfection ~ould have no effect on air quality~ The use of b~ disinfection would eliminate any chlorine odors generated under the proposed action. Outfall Locatfon: Extend Existing to South Discharge Point Outfall alternatives would have no impact on air quality. -54- MITIGATING MEASURES Proposed Action Impacts to air quality could be reduced by implementing mitigating measures. Fugitive dust generated during construction could be mitigated through the use of control measures, including watering or oiling of dusty areas and turning off idling equipment. Increased treatment plant capacity and careful operation by a certified licensed operator would eliminate obtrusive odors. If odors do persist at the treatment plant, odor control devices may be installed. Odors from sludge could be reduced by discing and applying oxidizing agents, such as potassium permanganate. Alternatives Treatment Facility Size: Retain Existin~ Facilitv (No Action) No mitigating measures are suggested. Treatment Facility Location: Split Facility~ Existing and New Site Mitigating measures proposed with this alternative are the same as the proposed action. Treatment Process: Land Treatment Mitigating measures to reduce construction impacts are the same as the proposed action. Treatment Process: Aerobic Digestion Since no air quality impacts are likely to occur under this alternative, no mitigating measures are suggested. Treatment Process: b%' Disinfection Since no air quality impacts are likely to occur under this alternative, no mitigating measures are suggested. Outfal! Locaticn' Ex?and Existing to South Discharge Point Since no air ebalitv impacts are likely to occtzr under this alternative, no mitigating measures arc suggested. b~AVOIDABLE ADVERSE IMPACTS Proposed Action During the construction period, temporary increases of suspended particulate levels will occur. Vehicular traffic resulting from ingress and egress of construction vehicles and sludge hauling transport trucks, as well as increases in population as vacant lots are developed, would increase ambient levels of carbon monoxide hydrocarbons and photochemical oxidants. _ ' Alternatives Treatment Facility Size' Retain Existing Facility (No Action) Minimal increases of suspended particulates would occur as individual septic systems are constructed. Obtrusive odOrs may increase as the existing WWTP reaches its full capacity. Treatment Facility Location' Split Facilit¥~ Existing and New Site Unavoidable construction impacts, similar to those described in the proposed action, would occur. Increased vehicular traffic would occur as a result of new lot development and hauling of sludge from the existing and new facility sites. Treatment Process: Land Treatment Unavoidable construction impacts would result in similar effects as the proposed action. Obtrusive odors are likely to occur; however, their adverse effect on residents is unlikely. Treatment Process' Aerobic Digestion No unavoidable adverse impacts are anticipated. Treatment Process' Ih? Disinfection No unavoidable adverse impacts are anticipated. Outfall Location: Expand ExistinG to South Discharge Point No unavoidable adverse impacts are anticipated. -56- WATER AFFECTED ENVIRONMENT Physical Settin$ Port Ludlow Bay is a 2.2-square-mile J-shaped area that opens into Admiralty Inlet near the northern most portion of Hood Canal (see Figure 2). The bay begins at the mouth of Ludlow Creek and extends 3.5 miles to the bay's entrance where a low headland protrudes into the bay from the north shore. The entrance to Port Ludlow Bay is defined by an imaginary line that extends northerly from Tala Point to the area of Colvos Rocks and then west through Snake Rock to the mainland. Figure 11 delineates the bay's boundary, as well as the areas referred to as the inner and outer bay. The eastern approach to the bay, between Tala Point and Colvos Rocks, is characterized by a submerged sill having an average depth of 24 feet mean sea level (MSL). This sill forms a submerged basin open to the north. The average depth of the opening between Colvos Rocks and Snake Rock is 82 feet (MSL). From this point, the bottom of the basin slopes upward for a distance of 0.5 mile to a depth of 50 to 60 feet. From here, the depth of the bay remains fairly uniform between 50 and 60 feet throughout most of its length to within 0.5 mile of Ludlow Creek. The innermost 0.5 mile of the bay has an average depth of 16 feet (MSL). The Port Ludlow k~TP is located on the western shoreline, midway up the bay. The W~P outfali extends approximately 400 feet from the western shoreline and discharges through a single port. Water depth at the existing discharge point is 13 feet at mean lower low water (MLLW) (see Figure 11). Currents and Circulation Various methods were employed to determine the current and circulation patterns in Fort Ludlow Bay. Detailed description of those studies is provided in two documents (Harper-Owes, 1985a, Harper-Owes et al, 1986). In the first study a drogue (parachute-type device) was used to estimate current velocities and to reveal the general pattern of cir- culation in the bay. Submers~b!e current ~,-~eters were also used to measure current velocities at various depths. In the second study, surface drifters were used at two proposed outfall sites to determine surface currents under various wind conditions; current meter reading were also taken. Flushing rates (the time it takes to replace portions or the entire volume of the bay's water with new water from Admiralty Inlet) were determined in both cases by the use of the Salt Balance Equation. This method allows calculations of flushing rates by comparing the relative salt content of waters inside and outside the bay. Results of the salt balance equation were consistent with drifter and drogue study observations. The use of all these methods enables the dominant processes controlling the current and circulation patterns and flushing characteristics of Port Ludlow Bay to be described. -57- .~rFECTED EhWIROM~iENT This section was prepared from a site visit conducted in April ]985, information provided in the existing Port Ludlow South Bay Community EIS (Jefferson County, 1975), marine bird censuses completed by Wahl, et al. (1983), and existing literature on wildlife resources of the Pacific Northwest. Marine biological resources of the Port Ludlow area in the vicinity of the existing ~fP outfall were inventoried through a litera- ture review and field surveys conducted in March 1985 and April 1986 (see Figure ]8). In addition, staff of the Washington Department of Fisheries (WI)F) were interviewed for updated information on commercially important resources. Appendix A presents a detailed discussion of the marine biological resources based on literature review, field survey, and interviews. The Port Ludlow area was surveyed for marine bird use during December 1982 and February ]983 (Wahl, et al., ]983) and as part of this ElS during March 1985. Terrestrial Vegetation and Wildlife The ~P is located along the western shoreline of Port Ludlow' Bay. There are n~erous residential dwellings and condomini~s located along the shoreline around the bav. The surrounding upland area is a mixture of deciduous and coniferous forest with riparian habitat along the streams. Dominant tree and shrub species ~n~lude red alder, black cottonwood, Douglas fir, western hemlock, western red cedar, salal, sw~rd ferns, Oregon grape, and sa!monberry. The area provides habitat for ~ wide variety of wildlife. The following species are known to occur en the upland habitat surrounding the ~P' deer, coyotes, squirrels, skunks, raccoons, weasels, beavers, mice hawks ~ '~ woodpeckers upland game birds, and nmmerous song birds. The existing facility is located on a quarter acre site bordered by a residential neighborhood to the west and north, ccndomini~s to the south, and Port LUdlow Bay to the east. The entire site is fenced. Approximately one-third of the site is covered by impervious surfaces. There are steep banks (up to 40 feet high on the northern boundary: su~~- rounding the treatment fac ]~tv mh~c-~ c-~r,~~ ere ~ab~iy~d ~v ~? ....... horsetails, blackberz-ics, ~:-:-ar.~, ~azm:.nz~c :-ic~ anJ ~ ~' b:' . There are several patches :,f ~,-foot tall yoang red a]oer s~ools at the top of the banks. Seversl 3-foot ta]_] j,,~Sper trees have been planted along the roadway. Along the sou'chern bank, several sword fern plants are growing. Outside the fence line, to the south, are dense young red alder trees up to 30 feet tall. The overall wildlife value of the Y~P site is limited by the following factors: the small size, the amount of urban development and roadways surrounding the site, the fact that the site is totally fenced, and the lack of vegetative diversity. The site does not provide the necessary life requirements of food, shelter, and cover for most terrestrial wildlife. . -82- Crows are probably the only common wildlife visitor to the WWTP. Approximately 20 crows were observed at the sewage pond. Other common birds typically associated with urban areas that could be using the site are robins, starlings, swallows, rock doves, sparrows, and gulls. Few mammals are likely to reside in the project area. Shrew, moles, and mice could inhabit the landscaped areas of the semi-flat portions of the site. Most likely, raccoons could be found feeding on invertebrates along the shoreline, outside of the fenced area. Marine Birds and Mammals Marine birds and mammals are commonly found in Port Ludlow Bay throughout the entire year. Marine bird abundance is generally higher in the fall and winter and lowest in summer, because few species breed in the Puget Sound area. Bird species richness is generally higher in protected areas of Puget Sound, such as Port Ludlow Bay, than in open water (Long, 1983). The Port Ludlow area was ranked 19 out of 28 in importance for marine bird habitat in the lower Puget Sound and Hood Canal areas (Wahl, et al., 1983) ' Approximately 44 species of marine and shorebirds, out of 80 common species (Long, 1983) that regularly occur in Puget Sound, have been observed in Port Ludlow Bay. This includes two loon species, four grebe species, two cormorant species, great blue heron, 16 duck species, seven gull species, four alcid species, and nine shorebird species. In April 1985, the most common species observed were white-winged and surf scoters, western and horned grebes, American wigeons, glacous-winged gulls, red-breasted mergansers, and greater scaups. The total number of birds observed in December 1982, February 1983, and April 1985 are presented in Table 3. Table 6 T,~T~r NLPIBERS ~Y _i?~q . .. v.^~ ,v,,-N=&RiN~ R_ _ OBSERi.~D IN POPT LUDLOW BAY Daze' December i982 February i983 April 1985 Area Sampled' (!.' mi-) (0.3 mi2) ( 1.5 mi~) F~'l i LY Loon ~ 9 5 Grebe 147 2! 77 Cormorant 17 2 2 Great blue heron 1 0 0 Duck 625 19 127 Gull 47 51 35 Alcid 17 11 13 Total 855 113 259 Large numbers of birds are found in areas where prey species concen- trate, such as tidal fronts and eddies .... ~s occurs in passages such as at the mouth of Port Ludlow Bay. Diving birds (e.g., grebes, loons, Brandt's cormorants, scorers, marbled murrelets, rhinoceros auklets, and common murres) that feed on small fish and invertebrates are the most common species. Dabbling ducks (e.g., American wigeons, mallards) and shorebirds (e.g., sandpipers, killdeers) are common in the intertidal areas where they feed on exposed surfaces. Great blue herons wade along the tide line feeding on fish. Gulls are found in all these habitats. Harbor seals commonly occur in Port Ludlow Bay. A commonly used haul out site is located north of Port Ludlow Bay (Natural Heritage Data Program, 1985). River otters also have been observed in Port Ludlow Bay (Natural Heritage Data Program, 1985). Although they have not been reported, several other marine mammals species could use these waters, including' California sea lions, Stellar's sea lions, minke whales, killer whales, grey whales; harbor porpoises, and Dali's porpoises. Whales and porpoises usually forage in open water and rarely use intertidal or shallow subtida! habitats. The present WWTP outfall into Port Ludlow Bay does not appear to affect marine invertebrates or fish resources of the area (see Marine Invertebrate and Fisheries sections). Since the aquatic resources have not been affected, it is presumed no subsequent effect on marine bird and mammal use has occurred. Threatened and Endangered Species Bald eagles, a threatened species, have been observed year-round in the Port Ludlow area. Eagles are probably feeding on waterfowl, fish, and marine birds. There are large trees available for roosting all along the shoreline of Pert. Ludlow Bay. There .~re two bald eagle's nests and an osprey nest located !ess than a mile from the project site (Natural Heritage Data Program, 19851). Plankton The planktonic assemblage %hat would probably be most affected by the proposed project ~ou!d be the phytoplankton. The only known study on nutrients and chlorophyll a levels in ?oru Ludlow Bay was conducted by Harpe--~w~~ ...... ~!~~'~,~...., ' ?ki~' ~tudv ~,'~ _..,~,,~._ theft nut~ier~t~ ~ :;!'re£en and · ' . '~--' ~he ?cr~ Ludlow Bay phv~oplankton are nearby Admiralty inlet limited by nitrogen levels. Harper-Owes also found the existing effluent apparently has little effect on nutrient levels, even under worst case situations. This is presumably due :o relatively rapid flushing rates and large dilutions. In addition to relatively low nutrient levels in Port Ludlow Bay, Harper-Owes also recorded a lack of substantial suspended algal growth relative to areas in Admiralty Inlet. Port Ludlow Bay is a comparatively clear, well-flushed bay. These conditions encourage growth of attached benthic plants rather than suspended phytoplankton (Harper-Owes, 1985). -85- Marine Benthic Habitats The intertidal and subtidal marine habitats in the vicinitv of the Port Ludlow WWTP outfall are predominantly sand and si]tv sand substrates. Occasional areas of harder substrate are present, mostly in the form of boulders or patches of mixed coarse sand, gravel, and cobbles. The sandy sediment gradually becomes more rocky to the north, where the upper and middle portions of the beach are mixed coarse habitat consisting of gravel, cobbles, and boulders in a Sandy matrix. The most important habitat in Port Ludlow Bay is probably the extensive eelgrass beds (Zostera marina and ~. japonica) prevalent throughout the lower intertidal and upper subtidal areas. No extensive beds of benthic algae, such as kelp, are reported in Port Ludlow Bay. Marine Plants The extensive eelgrass beds in Port Ludlow Bay form a distinct biological habitat. An introduced species of eelgrass, ~. japonica, forms a bed with occasional small interrupting patches of bare sand 800 yards to the south and ] 000 yards north of the existing outfal] Den- .sities of the intertidal beds are approximately 280 plants per square meter. The width of the beds range from about 6 to over 60 feet with an average width of 44 feet. The ~. japonica is replaced in the shallow subtidal by narrow beds of ~. marina, the native eelgrass. A dense cover of sea lettuce (U2va 2actuca) is present at the top of the underwater slope and extends shoreward to the lower edge of the eelgrass bed. This algae covers approximately 50 to 100 percent of the bottom. Interspersed with the sea lettuce is the red algae Neo~ardhieiia baileFi. The sand under and between the sea lettuce and red algae is covered with brown filamentous diatoms. Marine Invertebr.ates The intertidal beaches along the Tala Point shore opposite the existing ~r~F outfaii are_~u~ct~ to large amounts of mebile sand and fresh water, apparently originating from the bluffs behind the beaches. In addition to normal conditions of desiccation, temperature variations, and wave shock, the stresses imposed on the intertidal biological comm. uni~y by the s~nd and fresh water .apFe~~ tc~ have significantly inhibited the development of kigh abundan.::e and diversity i~ the intertidal assemblages. Only where t. he movement of sand and the flows of fresh water are reduced does the diversity and abundance of animals living within the sediment approach expected normal levels. The clam genus ~acoma is specifically adapted to these conditions, and is well represented in Port Ludlow Bay. Also present in Port Ludlow Bay are mobile polychaete worms, occasional horse clams (Tresus sp.), and two tube worms, Spiochaetopte~us costarum and Diopatra ornata; none of these species are plentiful (Appendix A). On the South Bay shore, across the bay from the marina, a small patch of sulphur bacteria was noted on the sandy substrate below MLLW. These bacteria are generally found at sites of buried decomposing materials, such as an animal carcass or leachate from a failiug septic tank. -86- At a few locations on both beaches, hard substrate composed of rocks, debris, and pilings are present. The biological community on these hard substrate materials appears to be heavily influenced by the predominate sand and fresh water and by the effects of logs floating in the bay. Normal encrusting assemblages in Port Ludlow Bay, however, are similar to those found throughout Puget Sound in small embayments on stable substrates. For instance, on an old shipwreck opposite the Port Ludlow resort, a well-established encrusting assemblage of barnacles and blue mussels was observed in March 1985. The adults and juveniles comprising this assemblage indicate that the community has been covering this substrate for a number of years. The subtidal animal community is much more diverse and abundant than the intertidal, a common situation in Puget Sound. Seapens, burrowing anemones, small hermit crabs, and sand shrimp characterize the deeper areas at the outer end of the proposed outfall corridor (Appendix A). In shallower water, at the level of the existing outfall, the subtidal animal community is characterized by small snails associated with the macroalgae, nudibranchs, and abundant burrowing shrimp. Chitons, tube worms, whelks, sea cucumbers, nudibranchs, and seastars were observed on the rocks associated with the existing sewer pipeline (Appendix A). No invertebrate populations capable of supporting a substantial fishery were observed, nor have any been reported in existing literature (Appendix A). At the base of the submerged slope, a population of geoduck clams (Panope ~enerosa) is present with an estimated density of 326 to 365 per 900 square feet (this unit is used in WI)F surveys). The geoducks are restricted to depths below approximately -25 feet (MLLW) throughout the outer bay area. Surveys conducted by W~F found no commercially important geoduck populations or other hardshell clams in Port Ludlow Bay (Appendix A). The~ observed geoduck population may be extensive enough to be commercially harvestable. The nearest co~merciat!y important shellfish (hardsheil clam, geoduck, and oyster) beds are located between Tala Point and Colvos Rocks. These have been commercially harvested for up to 15 years, producing an average $!,000 pounds annually (Goodwin, 19~5; Hoyser, 1985). In !984, this average harvest was ~orth about $!2 000 (Ward, 1985; Hoyser, 1985). Because of ~he ]~,-i< cf an~.' s!~'~if~'~ ~he]l~i~n re~c~.rcc-s west of ~ala ro ~ iht aha Ccl',cs ':-,ceiL2 LA :i~r% _kiLl.'-.' c,~','~ is probahiv not affecting any fiskers: resources. ?}~e szudy by Harper- Owes (!985) found that residual chlorine levels potentially harmful to the biological ¢omaunity are limited to = circle with a radius of about 120 to 200 feet around the existing outfall. The o~tfal! is located too far from the substantial clam beds at Colvos Rocks to affect any fisheries. Prior to recent ~w~P improvements and during periods of high recrea- tional boating activity, the effluent discharge from the W~P and the wastewater discharge from recreational boaters contributed about equally to the high fecal coliform counts in the bay (Harper-Owes, 1985). After WWTP improvements, water quality studies indicated that fecal coliform -87-