Madison Valley Stormwater Park

Madison Valley Stormwater Park May 2012

Madison Valley Stormwater Park May 2012 

Madison Valley Stormwater Park May 2012 

Lupine in the Madison Valley Stormwater Park May 2012

 Madison Valley Stormwater Park May 2012

The Madison Valley Stormwater Park, also known as the Phase 1 of the Madison Valley Stormwater Project & the Madison Valley Drainage Basin, is a response to flooding in Madison Valley during times of heavy rain fall.  Tragically, a Madison Valley woman, Kate Fleming, died when a flash flood trapped her inside her basement studio in December 2006.  The nicely landscaped basin makes a very pleasant park.  

From the Seattle Public Utilities website:  The Madison Valley drainage basin in Seattle is an area that is located east of Capitol Hill, west and south of Washington Park, and north of the Central District. Shaped by a glacier and eroded by floods, the valley has steep hillsides and was once drained by a stream that emptied into Union Bay via what is now the University of Washington Arboretum. In the late 1860s, a wagon road was cut through from downtown to Madison Park along the current route of E Madison St. In the 1880s, a cable railway with a trestle across the valley was constructed to provide better access to Madison Park and environs. In the early 1900s, the trestle was replaced with fill, which blocked the natural watercourse, and a combined sewer trunk pipe was built to carry sewage and stormwater under the fill and northward. 

Over the past several decades, there have been a number of instances of flooding in Madison Valley. On August 22, 2004 and December 14, 2006, storm events which hit the city and the Madison Valley neighborhood were especially severe, causing some residents around 30th Ave. E and E John St. to have up to 5 feet of water in their basements and flooding in their backyards. Seattle Public Utilities built an interim stormwater holding area at 30th Ave. E and E John St. which was completed in late December 2006 and holds up to 1 million gallons of stormwater during large rain storms. As the alternatives for the long-term solution were considered, improving stormwater infrastructure on E Madison St. near 29th Ave. E also was an important consideration. Seattle Public Utilities undertook an extensive public involvement effort through the development and selection of the preferred alternative, which was approved for implementation by Seattle City Council and the mayor in June 2008. 

Phase 1 of the Madison Valley Stormwater Project included the expansion of the 1 million gallon above-ground stormwater holding area at 30th Ave. E and E John Street. This facility now has the capacity to hold 1.7 million gallons of stormwater during very large storms. Construction of Phase 1 began in summer 2009 and the expanded stormwater holding area was operational by the end 2009.  Click here for a plan of the park.

High Point Natural Drainage System

High Point Natural Drainage System February 2013. Storm water is stored in this large, permanent pond before it empties into Longfellow Creek.

High Point Natural Drainage System February 2013. A cut in the curb allows water from the street to flow into a swale.

High Point Natural Drainage System February 2013. Nearly all the parking strips at High Point have been built as swales.

High Point Natural Drainage System February 2013. A small temporary retention pond.

High Point Natural Drainage System February 2013. A drain at the bottom of a swale.

Because of its size & relationship to Longfellow Creek, the redevelopment of High Point in West Seattle offered Seattle Public Utilities an opportunity to contruct a large natural drainage system, the largest built by the City of Seattle & the first natural drainage system of this scale used in a high-density Seattle neighborhood. Designed in partnership with the Seattle Housing Authority, the system treats about 10 percent of the watershed feeding Longfellow Creek, which flows into the Duwamish River, then Puget Sound. The natural drainage system mimics nature by using swales to capture & naturally filter storm water. Landscaped ponds hold the overflow. All 34 blocks of the High Point community are part of this system. In addition, porous surfaces make up a significant part of the sidewalks & parking spaces. 

High Point was originally developed during World War II to provide government housing. It remained a district of predominantly low-income housing through the 1990s. In 2003, the Seattle Housing Authority began work on the first phase of a 6-year project to redevelop High Point into a mixed-income community. All existing housing, roads & utilities were replaced. High Point now has approximately 1,600 housing units, about half of them low-income rentals owned by the Seattle Housing Authority. The other half are single family homes, condominiums & town homes sold to private owners. 

The need to improve the water quality of Longfellow Creek drove the plan to connect High Point with the surrounding environment. The City of Seattle is required by the US Environmental Protection Agency to dramatically cut sewage overflows by 2025. Natural drainage systems are an effective method for curbing storm water, which can trigger overflows of raw sewage. The swales & temporary retention ponds (also known as rain gardens) are planted with red-twig dogwood, evergreen huckleberry, sword fern, grasses, sedges & other plants. Rainwater soaks into the ground rather than flowing into the (unfortunately combined) storm water & sewer system. Oil, pesticides & other pollutants are filtered out to decompose & be consumed by micro-organisms in the soil.  Not long after a heavy rainfall, swales & shallow ponds are mostly empty of water.  Before flowing on to Longfellow Creek, water is stored in a large pond, often used by migratory waterfowl, located at the lower edge of the development. Following the path of the water through High Point is a pleasant & interesting walk.