Loading...
HomeMy WebLinkAboutWWP273062 (12)STREAM BANK STABILIZATION AND FISH HABITAT RESTORATION Recent Projects ENGINEERS I ARCHITECTS I PLANNERS I APPLIED SCIENTISTS Tetra Tech / KICK Inc. Related Project: Fifth Street Waterway Improvements Client: Toum of Steilacoom, Department of Public Works The Problem: In October 1993, Tt/KCM prepared a Comprehensive Stormwater Management Plan for the Town of Steilacoom, Washington. The plan identified various nonpoint pollution sources that contributed contaminants such as sediment and nutrients to surface water runoff, ultimately affecting the water quality of Puget Sound. The Fifth Street Waterway was identified as a major contributor of fine, silty sediment due to streambank erosion and channel downcutting. 1 ne cnannel naci clowncut nearly J teet through the Bellingham silty clay soil and bank erosion threatened Typical channel before construction roadways. High flowrates and stream velocities began to destabilize the steep hillslopes of a large wooded ravine in the lower reaches, threatening homes above. The Solution: In order to stabilize the stream banks and improve water quality, TdKCM proposed modifications to the stream alignment, backwater storage areas, and channel stabilization. Longterm streambank erosion and undercutting will be reduced by shallow stormwater detention areas. Flow velocities will be further reduced by reconstructed meander bends, regraded sideslopes, widened floodways, log and rock instream structures, and rock toe protection in critical stress areas. Exposed streambank soils were covered with coir woven blanket material or SoilGuard, a biodegradable spray -on material. Custom native seed mixes were used for short term erosion control until the planted native shrubs, trees and groundcover become established. Eventually this restored riparian area will protect the stream channel by providing long-term erosion control, improving water quality by filtering runoff before it enters the stream, and providing both aquatic and terrestrial habitat. I --7 Finished channel prior to planting Cost Information: TdKCM produced design plans, specifications, estimates, and bid documents for project construction in 1997. Construction of the $250,000 project was substantially completed by September 1997. Reference: Jim Richards (253) 581-1912 Town of Steilacoom DPW 1030 Loc Street, Steilacoom, WA 98388 ' Related Project: Indian Creek Relocation and Fish Habitat Restoration Client: City of Olympia The Problem: Urbanization of the Indian Creek watershed transformed this once forested land into heavily developed residential, commercial, and downtown core areas. Impervious surfaces such as roads and parking lots overloaded the creek flows with undetained and untreated storm water runoff. Flood flows during large storm events frequently overtopped streambanks exceeded pipe capacities and caused extensive property damage. Early solutions to the flooding problems resulted in blockages to upstream migration and loss of salmonid spawning habitat. Project Description: The solution to problems in this multiple -use stream included restoration of fish passage to upstream habitat, diversion of base flows to a new channel that supports spawning habitat, routing of high flows to the old stream channel, restoration of Indian Creek one year after construction riparian vegetation, and replacement of undersized culverts to alleviate backwater flooding. Tetra Tech's role was to create an innovative design for the stream diversion, culvert replacement, fish passage, fish spawning, and riparian habitat restoration. At the same time Tetra Tech assisted the City in the development of unique educational opportunities at the entryway to downtown Olympia. ' Project Highlights: ♦ Fish have returned to the stream and it is again supporting a native salmon fishery ♦ Flooding under normal storm flow conditions are no longer a threat to businesses and transportation routes ♦ The Indian Creek relocation and fish habitat restoration project was selected by the National Park Service as 1 of 19 examples of multiple -use project throughout the United States in their 1996 book, Floods, Floodplains and Folks: A Casebook in Managing Rivers for Multiple Uses Key Features: Culvert replacement Fisheries passage improvements Creation of spawning habitat Streambank stabilization Flood protection Reference: Charles L. Main, Construction Supervisor, City of Olympia DPW (360)753-8490 Related Project: Kokanee Creek Restoration Client: City of Lake Stevens ' The Problem: Kokanee Creek was a healthy tributary to Lake Stevens providing excellent spawning habitat for kokanee salmon. Then the road ' was built, and the stream was straightened, and the watershed was logged and developed. By 1993, the deeply incised creek had become little more than a roadside ditch with severe water quality problems and less than 100 feet of spawnable channel during only moderate flows. Sediment and nutrient concentrations approached 200 times the state standards. A constructed spawning channel was no longer effective and every ' driveway and roadway culvert in the lower reach had become a severe blockage for upstream fish migration. ' Project Description: In 1992, the City of Lake Stevens and Snohomish County asked Tetra Tech to design a rehabilitation plan for Kokanee Creek that would improve water quality to Lake Stevens and provide ' passage for fish to spawning areas in the upper reaches of the creek. - ' One of the main obstacles to 4, - upstream fish migration was _ an 80 foot long, 24 inch diameter, steep gradient 4 culvert that ran diagonally under a residential roadway. ' Tetra Tech designed a unique cast -in -place, 6-foot wide, 65- 4�; i'�,- foot long, bottomless box culvert that contains four concrete notched weirs. Three of the four weirs accommodate existing water and sewer lines. The interior was backfilled with river rock and streambed gravel to form pools and a low -flow channel. Key Features: Custom designed, 6 foot wide cast - in -place bottomless box culvert contains 4 weirs, water and sewer lines, access hatches, river rock and streambed gravel Four bottomless concrete box culverts with modifications for residential access ♦ Twenty-two log weir structures for step -pool formation Severe easement and utility constraints for design and construction Bank stabilization using hand - placed rock, coir, and live plant ' Four driveway culverts were replaced with bottomless precast culverts and rockery headwalls. Interiors of each of these culverts were backfilled with suitable stream gravel. Other elements of the project included sloping the vertical streambanks where possible. Severe easement limitations required that the creek remain within a 20 foot right-of-way, in some places only 2 feet from the edge of the road. Log weirs were used to establish a step -pool formation through steep gradients. Vortex rock weirs with wood y debris were used in the upstrear i transition area and hand placed rock was used to protect exposed cutbanks at the toe and provide roughness. Project Highlights: ♦ Over 200 kokanee were counted by WDFW during the first spawning season after construction ♦ Fish now have access to spawning areas previously unreachable for nearly 40 years ♦ Instream sediment sources were reduced by over 90 percent; monitoring indicates reduction of TSS and TP to state standards, increase in benthic invertebrate number and diversity Related Project: Lake Stevens Watershed Water Quality Management Plan Client: City of Lake Stevens, Washington I tie Problem: Lake Stevens is the largest recreational lake in Snohomish County. Declining water quality was recognized as a serious problem over 20 years ago when persistent algal blooms and mats of decaying filamentous algae developed. Phosphorus was determined to be the limiting nutrient in Lake Stevens and low dissolved oxygen concentrations were hypothesized to be the reason for the decline of the kokanee fishery. The Solution: In the summer of 1988, Tetra Tech began working with the City of Lake Stevens and Snohomish County to assemble the comprehensive water quality plan for the Lake Stevens watershed, following the recommendations of the Phase Ha study. The plan was the first of its kind and provided a guideline for long-term water quality protection and enhancement. Tetra Tech was involved in four of the six elements which composed the project: watershed inventory, water quality plan, public awareness, and administration. The watershed water quality plan was completed in June 1989 and included an inventory of the watershed's surface resources, a catalog of surface water system characteristics, and a plan for reduction of watershed -generated nonpoint source pollutants. The Lake Stevens Watershed Quality Plan represents one of the most sophisticated, comprehensive approaches to watershed management in the nation. Adoption of the plan has led to designation of the entire watershed as a critical area, requiring all new development to provide detailed drainage plans with specific water quality protection strategies. In addition, the plan recommended creation of a watershed keeper position. The watershed keeper serves as the focal point for implementation of the plan and coordinates intedurisdictional involvement. Role of Tetra Tech Team Members: Harry Gibbons, Project Manager i „. «: v vst .1nrVr i Ia LIVII: Tetra Tech fee was $80,000 Schedule: 1988-1989 Reference: Jim Craig (425) 334-1012 r� Related Project: Lundeen Creek Restoration Client: Snohomish County Surface Water Management The Problem: Nearly 800 feet of the main stem of Lundeen I ....� �•. Creek through an older residential area had been~�'�`� converted to a roadside P- ditch. Stormwater monitoring within this section indicated consistently high concentrations of total phosphorus (54 mg/L average), orthophosphate (19 mg/L average) and nitrate+nitrite-nitrogen (1,712 mg/L average). While Kokanee salmon and cutthroat trout were often seen within the ditch, most of them could not migrate to spawning areas above due to dense vegetation, extremes in flow rates, and culvert obstructions. The goals of the Lundeen Creek Restoration project were to reduce Typical channel before construction flooding of abandoned septic system drain fields; reduce bank erosion; improve the biofiltration potential of the channel during storm events; improve conditions for salmonid migration, resting, rearing and feeding habitat; and encourage awareness of water quality issues among residents. The Solution: ' Design drawings, details, planting plans, field instructions, and materials specifications were produced by Tetra Tech to be used by Snohomish County crews for construction of the improvements. Project elements included ' replacement of five undersized culverts, bank stabilization using bioengineering techniques, and enlargement of the channel cross -sectional area. Habitat enhancement features included constructing a low -flow channel ' with pools and woody debris, rock structures, streambed gravel, and Noonu R N 12.1. ,.1BER CURS overhanging vegetation. E 1pJ0.SS ,! NOpeON 809E 10 swx C5 Channel realignment, shaping, and _ — cm instream structures were performed ®® 0 - by County crews in September -�„— -- 1995. Citizen volunteers from 6, a County staff planted native grasses, ' N 1102.OJ 10 RRN N 10,�]0.l1 herbaceous plants and shrubs as E E !MZ7 the materials became available ' through the County native plant salvage program. Reference: Bob Aldrich ' Principal Watershed Steward Snohomish County Public Works (360)334-1012 Contract Amount: $20,000 Finished channel prior to planting Tetra Tech Project Manager: Harry Gibbons, Ph.D. Tetra Tech Project Engineer: Caroline Barnes, P.E. r� Related Project: Swamp Creek Watershed Water Quality Management Plan Client: Snohomish County Like many of the watersheds that comprise Puget Sound basin, Swamp Creek Watershed has been severely impacted by urbanization. Between 1986 and 1990 the population in the Upper Swamp Creek Subbasin increased by 80 percent. Forests, wetlands, and small farms were transformed into high density residential and commercial developments, hobby farms, and roads. As a result, the volume and peak flow of stormwater increased, and water quality was degraded. Tetra Tech assisted the County in preparing a comprehensive management plan in 1992 that is currently being implemented. Tetra Tech collected existing information, reviewed current procedures, and performed a detailed inventory of the watershed and nonpoint source evaluations. A hydrologic model of the North Creek Watershed was calculated based on the existing HSPF model after refining and verifying it using available data. Armed with this information Tetra Tech developed specific solutions to existing problems and BMP's to prevent future problems from developing. The products included watershed characterization, watershed biological inventories, water assessments, nonpoint problem definitions, nonpoint source control program. The format of the report was easily administered, including elements for capital improvements and public involvement programs with specific references to BMPs. Related Project: North Creek Watershed Water Quality Management Plan Client: Snohomish County • As population increased in the Puget Sound region, North Creek _ • ; —..-- watershed land use converted from rural to urban. With growth ,wR,� • � al ` predicted to continue at a rapid rate, a watershed water quality plan was needed to solve existing problems and prepare for the future. Tetra Tech prepared a comprehensive management plan in 1992 that is currently being implemented. Tetra Tech collected existing information, reviewed current procedures, and performed a detailed inventory of the watershed and nonpoint r source evaluations. Hydrologic model of the North Creek Watershed was calculated based on the existing HSPF model_ after refining and verifying it using available data. Armed with this information, Tetra Tech developed specific solutions to existing problems, and BMPs to prevent future problems from developing. The products included watershed characterization, watershed biological inventories, water assessments, ' nonpoint problem definitions, and nonpoint source control program. The format of the report was easily administered and includes elements for capital improvements, as well as public involvement programs with specific references to BMPs. Reference: Mike McGuiness, (425) 388-3464 Related Project: Peters Creek Restoration Client: City of Redmond, Washington The Problem: Upper reaches of Peters Creek in the City of Redmond are commonly incised and unstable due to increasing flow rates from the developing watershed. Sediment from these areas has destroyed much of the salmonid habitat within the lower reaches of this tributary to the Sammamish River. Tetra Tech/KCM completed the Phase I Habitat and Geotechnical Investigation for the entire stream corridor in 1997 and was subsequently asked to assist the City with the design to stabilize a portion of the upper main branch of Peters Creek. The Solution: Striving to utilize the talents of their maintenance crew, Redmond will construct the first of 29 projects identified in the Phase I investigation. The main branch, upper reach project comprises 1,200 linear feet of channel within a heavily wooded ravine. Difficult access conditions required creative design and construction feasibility considerations. Working with the maintenance supervisor, Tt/KCM developed a design with construction sequence to fit the available equipment and materials, crew size and experience. Incised channels and eroding streambanks threaten homes Design costs were minimized by planning to build "in-house". Topographic survey information and channel cross sections provided the detail necessary for Tt/KCM to develop specific designs for stabilization of slope failure areas and head cuts. Locations for structures to provide grade control, channel complexity, and habitat enhancement features were ' � �ars�,eiaeaa.e� Sao identified with reference to typical details developed in Phase I �u�ar�at•t + of the project. Plan drawings were provided for temporary erosion control, planting, and construction sequence to ' minimize disturbance. Material descriptions and quantities were provided to the City for acquisition and stockpiling. Tt/KCM also completed all documents necessary to obtain State soma VK and Federal regulatory agency authorization through the Joint X61" us Aquatic Resource Permit Application and SEPA review. Phase II, Design was completed in June,1998. As part of Phase III, ' SEMI Construction, Tetra Tech will provide full-time onsite field -- -- -- — direction for the duration of the project. AOpt".1El�GJ'10wYli ' Contract Amount: Reference: $24,400 Jon Spangler, P.E. Tetra Tech Project Manager: Natural Resources Division Manager Tony Melone, Ph.D., P.E. City Red ity of Redmond 23 Tetra Tech Project Engineer: Caroline Barnes, P.E. �© N Related Project. San Juan and Aliso Creeks Watershed Study (General Investigation, Reconnaissance Phase) Client: U.S. Army Corns of Engineers Los Angeles District Tetra Tech provided planning and technical support during the Reconnaissance Phase, including turn key services for two Project Study Plans (PSP's), and the facilitation of cost -sharing negotiations with over a dozen public entities. The San Juan Creek and Aliso Creek watersheds are paired coastal watersheds that encompass several hundred square miles in southern Orange County, California. Long-term aggregate resources development, agricultural use, urban runoff, channelization and piece -meal bank protection have caused significant degradation of the channel system, impacting water quality, beach sand supplies, and the functions and values of the ecosystem. Tetra Tech's support of this study has helped facilitate HQUSACE approval and certification of the reconnaissance report, recommending that two (one for each watershed) cost -shared feasibility studies be pursued at a total cost of $3.4 million. Tetra Tech provided an in- depth literature survey and review of existing baseline data, culminating this information into a Corps without - project condition report (CESPD R3 Milestone). Technical support was provided in developing a concept design and functional analysis of six multi -purpose (detention basin/wetland complex with ecosystem restoration and passive recreation components) watershed restoration projects situated throughout both watersheds. The plan is formulated to: • Control costs such as LERRD's, mitigation, and O&M ♦ Meet the planning goals and objectives established by local, state, and federal stakeholders ♦ Ensure consistency with Corps planning criteria (ER-1105-100 and relevant Planning Guidance Letters). The proposed plan includes the removal of large drop structures and levee impoundments that are an impediment to aquatic species migration (such as steelhead and black bass) and adversely impact stream temperature, turbidity, and oxygen levels. Other features include re-establishment of a riffle -pool sequence with frequent, gentle low drops protected by rip -rap as well as the re-establishment of riparian and wetland vegetation between riffles, development of gabion, riprap or articulated revetment bank protection to protect existing infrastructure. Offline multi -purpose detention basin facilities developed for selected locations to reduce peak discharges, control sediment, and provide opportunities for wetland development and groundwater recharge. In addition to the above, the team prepared with and without - project river hydrologic and hydraulic studies to screen project -mot performance and aid in the selection of watershed restoration 01 plans. Technical and planning support was provided to the District during the RRC and during the completion of the RGM. Tetra Tech also was contracted to develop the draft and final PSP's and FCSA's for both watersheds. Services included the a n� development of a detailed project study plan for each watershed, including cost estimates for the feasibility phase of study. Efforts also included identifying potential cost -sharing partners and facilitating negotiations of in -kind support Over a dozen agencies were involved in the negotiations including Orange County Public Facilities (departments of flood control, harbors/beaches/parks) local cities, water purveyors, sanitary districts, state regional water quality control board, state parks, school districts, land developers and toll road agencies. All parties have endorsed the two proposed feasibility studies scheduled for initiation in January 1998. O Related Project: Subbasin F Storm Drainage Improvements Client City of Auburn The Problem: Subbasin F in Auburn is an 85-acre, highly urbanized area that drains to the Green River. The area was subject to chronic flooding, even during moderate rainfall events. The City's Comprehensive Drainage Plan called for upsizing the storm drainage trunk system and construction of new stormwater pump station to alleviate flooding when high water in the Green River limits gravity flow in the storm drainage system. The Solution: Tetra Tech first performed a predesign study to establish required pipeline improvements and further investigate the feasibility of constructing the stormwater pump station. A SWMM analysis indicated that the vast majority of flooding would be alleviated by upsizing the existing storm drain network and constructing a new outfall to the Green River. The study revealed the pump station was not warranted, saving over a million dollars in construction cost. 6�J Outfall to Green River shortly after construction, prior to revegetation. Certification. ' Project Team Personnel: Jeff Lykken, Project Manager Doug Gen linger, Senior Civil Engineer ' Cost Information: Tetra Tech Design Fee: $100,000 Construction Cost: $900,000 ' Schedule: Construction Completed in 1994 Reference: City of Auburn: Tim Carlaw (253) 804-5060 The upgraded storm drainage system alleviated chronic flooding even during periods of high Green River stage. Role of Tetra Tech: The second phase of the project included development of plans, specifications, and construction cost estimates for replacing 4,000 feet of storm drainage pipe in the subbasin, and adding a new 42-inch diameter outfall to the Green River. Tetra Tech was responsible for permitting and regulatory approvals on the project, securing the Shoreline Substantial Development permit, Hydraulic Project Approval, Corps of Engineers Section 10 permit, Short Term Modification of Water Quality permit, and Section 404 Water Quality Key Features: New 42-inch diameter outfall to the Green River PS&E for replacement of 4,000 feet storm drainage pipeline Bio-engineering techniques used to stabilize the river bank at the new outfaIl and enhance fish habitat in the river Tetra Tech worked closely with the Department of Fish and Wildlife and Ecology during design development to ensure compliance with agency standards and facilitate approval of permits. M% Lightning Fast Design Project: Hylebos Creek Restoration Client: City of Federal Way, Washington Key Thanks to active partnering, Tetra Features: Tech 's Hylebos Creek Restoration project took only 16 weeks from concept through permitting, bidding, and construction. ylebos Creek is one of the most productive systems for chum salmon in the southern Puget Sound region. Forty-five feet of 18-inch culvert on the North Fork of Hylebos Creek was the last remaining barrier to the migration of chum and other salmonid species from excellent spawning and rearing habitat in the upper watershed. The recreated channel uses log weirs. large woody debris and rocks to stabilize the steep slope of the stream bed and develop pools. riffles and backwater areas for fish habitat. In May 1999, the City of Federal Way asked Tetra Tech to develop a design for removing the culvert and restoring about 200 feet of stream channel. Design documents had to be completed in time to secure This 18-inch culvert prevented the migration of salmon to the upper North Fork Hyleb: system for o,, 30 yea permits, attain funding, and receive bids for construction in July. In addition to performing this speedy design work, Tetra Tech provided construction assistance for placement of log weirs, woody debris and rock to recreate the stream channel and repair failing sections upstream. The City is now planning to develop a trail system through this open space property and create a live camera web site to observe migrating salmon at the project location. For R".or Information: Contact Tetra Tech/KCM, Inc. 1917 First Avenue Seattle, Washington 98101 (206)443-5300 or Visit Our Web Site www.tetratech.com TETRA TECH Innovative Construction Techniques Project: Peters Creek Restoration Client: City of Redmond, Washington Key Tetra Tech and the City ofRedmond Featu res: cooperated as a design -build team to carry out restoration of a stream reach with limited access for construction ncreased stormwater runoff from watershed development had created deeply incised channels and failing slopes throughout the upper ravine of Peters Creek in Redmond, Washington. The city's Natural Resources Division hired Tetra Tech to design stream and slope stabilization measures that could be constructed by city crews. Working with Redmond's engineers and equipment operators, Tetra Tech designed a restoration plan for 1,200 feet of channel that could be completed from only one access point. Teaming up for construction, the city and Tetra Tech completed nearly 500 feet of channel reconstruction in less than two weeks, raising the streambed three feet with clay Eroding stream banks and failing slopes threatened homes above Peters Creek Restored to its original elevation, the stream's channel and slopes are stabilized with nprap, large woody debris, and native plants subgrade and streambed gravel and stabilizing banks and slopes with 400 tons of riprap and river rock and over 300 pieces of large woody debris. Volunteers and city crew will complete the design by seeding and planting the restored banks with native plants. Limited access to the channel required a unique stream - flow bypass and step -key construction sequence For Mor Information: Contact Tetra Tech/KCM, Inc. 1917 First Avenue Seattle, Washington 98101 (206)443-5300 or Visit Our Web Site www.tetratech.com TETRA TECH � Quick Response Capabilities 0 Project: West Point Wetland B Repairs Client: King County Department of Natural Resources Key To quickly address the washing out Features: of a mitigation wetland, Tetra Tech developed, designed and implemented bioengineering improvements in one month onstruction of the West Point Treatment Plant in Seattle required several acres of mitigation wetlands. One of the these, Wetland B, was constructed along the northeast side of the plant at the base of the Magnolia Park bluff. Heavy rainfall during the spring of 1996 eroded nearly 90 percent of the wetland, making a large gully up to 5 feet deep, 20 feet wide and nearly 500 feet long. Most of the topsoil, plant materials, and native soil were washed into Puget Sound. King County asked Tetra Tech to propose a quick solution to stabilize the channel and reduce the likelihood of A rainy spring virtually destroyed a wetland that had been established ' as part of mitigation for construction of a wastewater treatment plant continuing washouts through the gully. After evaluating the channel hydraulics, Tetra Tech recommended a strategy using a bioengineering technique of constructing low dams with posts and live shrub cuttings backfrlled with soil (post -brush dams). This method would restore the original ground elevation, reinforce the 12 percent slopes, and establish a scrub -shrub wetland. Bioengineenng techniques restored vegetation and stability to the wetland quickly and efficiently Eleven variable -height, variable -width "post -brush" dams were designed and spaced through the channel based on the flow hydraulics and desired extents of wetland area. Bioengineering techniques were used throughout the site to stabilize slopes. Design sketches with detailed field instructions and material quantities were produced within ten days and construction was completed within one month. For "ore Information: Contact Tetra Tech/KCM, Inc. 1917 First Avenue Seattle, Washington 98101 (206)443-5300 or Visit Our Web Site www.tetratech.com � � TETRA TECH Hands-on Skills in the Field Project: Strandley/Manning Stream Restoration and Habitat Enhancement ' Client: Seattle City Light Key Tetra Tech not only performed the Features: field monitoring to define improvement needs for a damaged stream but also participated in the repair work Battle City Light's Strandley/Manning property contains a small, unnamed, spring -fed stream that discharges to the head of Burley Lagoon, a tidal inlet connected to Henderson Bay, which is an arm of Puget Sound. In the winter of 1995-96, heavy rains severely damage 900 feet of the stream and associated habitat areas. Repairs were made during the summer and fall of 1996. Seattle City Light hired Tetra Tech in the spring of 1997 to monitor the stream's aquatic macroinvertebrate population and the Tetra Tech's repair design has restored stability to the severely damaged stream structural stability of the in -stream repair structures. The first site visit revealed that several grade control structures had failed or were failing, banks were actively eroding, and over 600 feet of channelneeded immediate repair. The utility asked Tetra Tech to design repairs to be completed before the next winter's rains. damage from heavy winter rains Within a month, a repair plan was developed that accommodated the site's sensitive nature. Soft soil conditions, existing plantings, and a short construction window required all work to be performed by hand. ,� 1e t,: � I r d h. Working directly with three City Light crewmen, Tetra Tech directed field design and assisted with the installation of log weirs, rock bank stabilization, rock habitat features, streambed gravel, and native species vegetation. Using wheelbarrows and a slide chute to the stream, four weirs were replaced, two were repaired, and one new weir was installed within three days. All structures were backfilled with quarry spalls and gravel. Topsoil and coir fabric completed the repairs. r_.. AA_-- rV! f Vf V Information: Contact Tetra Tech/KCM, Inc. 1917 First Avenue Seattle, Washington 98101 (206)443-5300 or Nsit Our Web Site www.tetratech.com C1 TETRA TECH