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Coal Creek Enhancement Project View of Coal Creek reservoir Coal Creek drains a 1,087-acre watershed that has nearly three miles of salmon spawning and rearing habitat. The creek flows through second growth and mature timber, owned by Tillamook County, before reaching private agricultural land and emptying into the Kilchis River in the Tillamook Bay Watershed. A fish passage barrier dam on Coal Creek at rivermile 1.7 terminates all fish passage to the remaining one mile of habitat. Coal Creek supports coho, chinook, steelhead, cutthroat, and is one of the biggest chum producers in Tillamook County. According to Oregon Department of Fish and Wildlife (ODFW) 2002 spawning surveys, one surveyor observed 809 live chum and 263 redds in the 1.7 miles between the dam and Coal Creek's confluence with the Kilchis River. The dam, 4 drainage culverts, several forest roads, a failed waterline in the riparian area, lack of riparian vegetation around the reservoir, and degraded salmon spawning and rearing habitat all contribute to less than optimal watershed conditions. THE PROBLEMSThe Dam In 1949, the Tillamook County Creamery Association (TCCA) built a 30' high, 80' wide dam to supply water to the TCCA cheese plant and surrounding community.  Coal Creek Dam In 1951, TCCA entered into an agreement with Tillamook County to lease the 566 acres of forestland surrounding the dam, with the purpose of protecting the community's water supply and TCCA's investment in the dam. When local municipalities extended their water line distribution, TCCA and the community discontinued using water from the 2.5 million gallon reservoir for drinking and cheese making. However, water from the reservoir was still used in other capacities until the waterline failed in the late 1990's. TCCA has since transferred 1.33 of the 2 cfs water right to instream uses on Coal Creek. Due to these changes, TCCA has no reason for retaining the dam and desires to terminate the lease and return the property to Tillamook County. The County has made it clear that as a condition of terminating the lease, TCCA must remove the dam. TCCA has requested TEP's assistance. The dam was flushed in 1975 and dredged in 1986. ODFW engineers surveyed Coal Creek from the mouth upstream through the reservoir and determined sediment volumes behind the dam to be low. Based on transects at the reservoir and the delta flowing into the reservoir, they determined approximately 2,000 cubic yards of sediment is accumulated behind the dam. In March 2005, six samples were collected throughout the reservoir and analyzed for volatile organic compounds, arsenic, and pesticides (DDT). Compounds identified in the analysis were well below EPA standards. Scoured Stream Channel In addition to blocking fish migration and downstream wood transport, the dam has trapped spawning gravels and scoured the reach immediately below the dam down to bedrock, resulting in decreased spawning gravels. According to an ODFW 2003 Aquatic Inventory Survey, although wood volume in the reach below the dam is moderate (19.6m3 per 100 m), the channel is heavily scoured from the dam, demonstrating that spawning gravels are not being recruited or retained. Stream substrate is comprised of silt and sand (26%), gravel (32%), boulder (17%), and bedrock (25%). Failed Waterline and Drainage Culvert The failed TCCA 12" waterline still extends from the base of the dam and downstream toward the Kilchis River. The uppermost section of this steel waterline parallels the stream closely for 250' before going subsurface. Drainage Culverts Three culverts drain into the north side of the reservoir and one culvert drains into Coal Creek 250' downstream of the dam (where the waterline goes subsurface). With the dam demolition and waterline removal, the culverts are no longer needed. Dam Access Road A 0.30-mile long spur road splits from the main forest road and ends at the dam. After the dam demolition, this road will serve no purpose. Lack of Riparian Vegitation Riparian vegetation on the north side of the reservoir, where the dam is accessed, has been lacking since the dam was built and allows direct sun exposure to heat the reservoir. Currently, this doesn't pose a problem to downstream water temperatures since water in the summer is discharged from the bottom of the reservoir. However, once the dam is removed, the barren riparian area may contribute to increased stream temperatures. THE SOLUTIONSThe proposed solution is estimated to cost $140,000. In collaboration with ODFW and TCCA, TEP intends to implement the project in 2007-2008. TEP is the overall project manager, which includes managing grants, permits, and contracts. Task 1) Construct log/boulder structures throughout approximately 1,000' of Coal Creek Under the design and guidance of ODFW biologists, approximately 1,000' of instream habitat on Coal Creek will be enhanced through the addition of 60 logs and 110 boulders to the stream. The active channel width in the reach below the dam averages 19', which requires the logs to be a minimum diameter of 16", and a minimum of 29' long with rootwads and 38' long without rootwads. Some logs may still bear their rootwad. The boulders will average 1 cubic yard each. Structures will not need to be cabled or pinned. The placement of trees and boulders, from the dam downstream 1,000', will stabilize the channel gradient after the dam removal and facilitate gravel retention, rather than allowing gravels to flush through the system. Structures will also improve channel complexity, provide habitat, and enhance stream productivity. Project benefits to chum, coho, chinook, steelhead, and cutthroat include enhanced spawning and rearing habitat, and escape cover from predation. Task 2) Remove 250' of the failed waterline paralleling Coal Creek Under the guidance of ODFW, the upper 250' section of failed waterline will be removed. The waterline end will be cut or disconnected cleanly and capped. Waterline segments will be hauled off the leased property and recycled. Task 3) Remove four drainage culverts The four drainage culverts will be permanently removed and hauled to a disposal site off the leased property. All removed fill will either be spread on stable upland areas near the culvert removals or hauled to one of the disposal sites on the leased property. Task 4) Remove the Coal Creek dam  Coal Creek Dam A small barge will be built adjacent to the dam to float drill equipment and drill the full length of the structure in preparation for explosive charges. TEP will then coordinate with TCCA and ODFW to slowly begin the reservoir drawdown. Once the reservoir has been significantly lowered, fish will be seined and relocated below the dam. A gravity-fed water diversion will be installed above the reservoir to isolate the work area in preparation for the final reservoir drawdown. A check dam lined with sand bags and straw bales will be constructed immediately upstream and downstream of the dam to control concrete dust, sediments, and exclude fish attempting to migrate into the project reach. Of the estimated 2,000 cubic yards, ODFW engineers estimate that up to 500 cubic yards of fine sediments may need to be removed to prevent substantial sediment mobilization downstream. After the final drawdown, fine sediments will be excavated until gravels and cobbles are exposed and the dam will be demolished with explosives. All sediments and dam rubble will be hauled to disposal sites on the leased property. Task 5) Plant native trees and shrubs All disturbed areas, including the disposal site, will be seeded with native grass seed and mulched to control immediate erosion and deter invasive vegetation establishment. Native trees and shrubs will be planted in the winter following project completion. WATERSHED BENEFITSThis project aims to enhance the overall function of the watershed using several enhancement techniques. The project will restore salmon spawning and rearing habitat and fish passage to the upper watershed. Hydrologic processes and gravel and large wood transporting processes will also be restored. Additionally, riparian areas will be enhanced through native tree plantings. Project Objectives:
 Coal Creek Reservoir after being drained  Coal Creek Reservoir at full capacity
MONITORINGTEP and ODFW are committed to conducting project monitoring as described below: TEP Photo Points: TEP will take annual photos to document changes within the enhancement reach. TEP Snorkel Surveys: In 2005, TEP hired Bio-Surveys, Inc. to conduct a snorkel survey (read about the Rapid Bio-Assessment here) throughout the Tillamook Bay Watershed. Ending in 2007, this three-year survey will provide baseline juvenile salmon abundance and distribution data for the project area before the dam removal. ODFW Habitat Surveys: ODFW conducted an Aquatic Inventory Survey on Coal Creek in Summer 2003, which evaluated current habitat conditions in the watershed (including upstream of the dam). ODFW or TEP will conduct post-restoration habitat surveys in Summer 2009 and 2012. Habitat surveys will document stream channel changes after the dam removal and instream enhancements, including gravel recruitment. ODFW Spawning Surveys: ODFW conducts annual spawning surveys from the mouth of Coal Creek upstream to the dam. ODFW or TEP will conduct annual spawning surveys above the dam beginning in Winter 2008 (the first spawning season following the dam removal and instream structure placement). These surveys will monitor adult presence and use of spawning gravels upstream of the dam and in the enhanced reach just below the dam. PARTNERSTillamook County Creamery Association: funding for dam demolition |
