Modifications
Early modifications of Boeing Creek include the logging of the creek's watershed, the creation of Hidden Lake, and the construction of the Seattle Country Club Golf Course Dam. The creek's mouth was crossed by railway tracks, today owned by BNSF, running along the edge of Puget Sound.
In the 1960s a Sears mall complex was built at Aurora Avenue and 160th Street, covering Boeing Creek's wetland headwaters. This and other urban development placed about 2 miles (3.2 km) of what had been upper Boeing Creek into a patchwork of pipes, most of which are on private property. Within this area there is one 400-foot (120 m) segment that flows free from pipes, located in Darnell Park. However a lack of detention facilities and an undersized pipe causes flooding in the vicinity of Darnell Park and contributes to erosive flows downstream. The City of Shoreline is planning on improving the drainage and reducing downstream erosion by building a detention basin and replacing the pipe.
The creek's watershed was heavily urbanized after World War II, altering the runoff and discharge patterns. Increased runoff into Boeing Creek during rainy weather has caused more intense erosion and sediment transport, leading to the build-up of sediment in Hidden Lake. In the 1970s heavy rains flushed enough sediment down the creek to completely fill Hidden Lake, which became a meadow. Subsequently, King County Surface Water Division began efforts to control stormwater runoff in Boeing Creek's watershed. In 1996 dredging work restored Hidden Lake. On January 1, 1997, a winter storm created a large sinkhole which ruptured sewer lines on 175th Street, resulting in the Hidden Lake being filled with sediment again. The lake was dredged and restored again. The city of Shoreline budgets money for dredging Hidden Lake as needed and continues to seek a long-term solution to the problems of increased storm surge runoff, erosion, and sedimentation.
King County built a stormwater control system in Boeing Creek Park. A large detention basin stores water during storms, reducing the creek's flood risk. The detention basin is augmented by an underground storage pipe designed to temporarily store up to 500,000 gallons of wastewater during large storms. This storage pipe is located under the detention basin in Boeing Creek Park. The pipe is 12 feet (3.7 m) in diameter and about 640 feet (200 m) long. Completed in 2007 by King County Public Works, the pipe's purpose is to help keep wastewater within the sewer system and reduce overflows into Puget Sound. The pipe conveys wastewater to the Hidden Lake Pump Station. At the same time the Hidden Lake Pump Station, located on Hidden Lake, was replaced in order to increase capacity. The old pump station lacked capacity, resulting in about three overflows into Puget Sound per year. Another related wastewater projet is the Boeing Creek Trunk Sewer Replacement. A major wastewater conveyance pipe, the Boeing Creek Trunk (BCT) was under capacity and had deteriorated with age. During heavy rain storms wastewater sometimes overflowed from manholes and into Puget Sound. These projects were all part of the Hidden Lake Pump Station replacement and sewer improvement project. Construction of this overall project began in 2006. The underground storage pipe in Boeing Creek Park was finished in 2007, Boeing Creek Trunk in 2008, and the Hidden Lake Pump Station in 2009. All of these wastewater systems are located very close to Boeing Creek, although the Boeing Creek Trunk extends north out of the creek's watershed. The City of Shoreline is planning additional stormwater management projects to reduce flooding and improve Boeing Creek's hydrology. Construction of the Pan Terra Pond and Pump Improvement Project began in 2009.
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