Site work for a water / sewer project in Enumclaw, Washington. Completed plans call for site work for a water / sewer project.

1.1 Background. Mud Mountain Dam is a zoned earth and rockfill structure with an 810- foot-long crest and a maximum height of 432 feet above bedrock. The structural height of 427 feet is measured from the bottom of a structural depression located approximately 170 feet upstream of the cutoff wall to the new top of dam at 1,257 feet NGVD29. The dam is 1,600 feet wide at the base, 25.5 feet wide at the crest, with a design crest elevation of 1,257 feet NGVD29. A concrete seepage cutoff wall extends from the crest into bedrock in the core of the dam. Mud Mountain Dam is constructed in a narrow canyon where rock walls on both sides of the gorge rise almost vertically to a height of nearly 275 feet above the White River channel. The upstream hillside slope at the left abutment is steep (approximately1:1). Lower Cascade Creek (LCC) drains into an existing Water Control System (WCS) consisting of debris screens, a concrete lined catch basin and pipes which convey flow along the upstream left groin to the pool. The upstream groin is armored with shotcrete to approximate EL 1167.8 feet (NAVD88). The catch basin and embankment abutment tie-in are separated by roughly 51 feet of sandy-gravel fill between EL 1,267.8 feet (NAVD88) (basin) and 1,264.3 feet (NAVD88) (crest). The current WCS was not designed to a handle a specific flow or event with a defined return interval, because there is very little available hydrologic data on flow-frequency for LCC. Rather, the existing inlet basin was constructed to address recurring erosion caused by flows from past events along the upstream groin. This lack of a specific design event or flow has led to failure to control flows at the inlet even without debris accumulation. The LCC watershed is approximately 0.4 square miles or 0.1 percent of the Mud Mountain Dam watershed. Additionally, the watershed for LCC is immediately adjacent to the dam making it very likely that a large precipitation event would load both watersheds as it moves across the region. Due to the size and nature of the watershed, peak flows on LCC occur sooner and have a shorter duration than those observed on the White River. Consequently, high flows occur on LCC before much of the precipitation in the White River basin concentrates and begins to raise the reservoir. 1.2 Purpose. The purpose of this project is to replace an outdated and inefficient water control structure incapable of containing high water volumes from LCC. In 2009, a flood event overtopped the water control structure, and uncontrolled creek flows eroded both the upstream and downstream left groin of the dam causing extended disruption to project operations. 1.3 Facility Overview. The project takes place entirely within fee owned Corps of Engineers lands associated with Mud Mountain Dam. Primary work will occur on the left abutment of MMD and the upstream slope. Storage and equipment yards will be located within MMD property. Egress routes will be along nearby established highways and paved access roads. The facility does not have on site manufacturing facilities such as concrete batch plants and milling equipment. 1.4 Facility Component Description. The project can be broken down into several key components, notably the collection system, pipe transport system and energy dissipation system. See section 2.0 for description of the principal construction elements. 1.5 Scope of Work. The contractor shall provide all personnel, equipment, supplies, facilities, transportation, tools, materials, supervision, and other items necessary to as defined in the SOW and Specifications. The contractor shall perform to the standards in this contract, including environmental standards. 1.6 Contract Summary. This acquisition will result in an IFB Contract for the repair and maintenance of the construction of a water control system for Lower Cascade Creek at Mud Mountain Dam, WA.In accordance with DFARS 236.204(ii) "Disclosure of the Magnitude of Construction Projects," Magnitude of Construction is estimated to be between $5,000,000 and $10,000,000. *The value for this project is based on a financial range. The value is listed as the highest possible cost from the range provided by a stakeholder or official project document. MBE (7.2%), WBE (6.9%)