Lincoln Street Stormwater Gardens

The Manito Cannon Hill Neighborhood Council worked closely with City staff to address a number of concerns raised by the community regarding the City’s plans to rehabilitate Lincoln Street from 17th to 29th Avenue.

Close cooperation between a host of City departments has crafted an innovative solution to a number of challenges facing the City’s Administration.  Engineering Services was planning on rehabilitating Lincoln Street, between 17th Avenue and 29th Avenue, under the City’s 2004 Street Bond Project during the summer of 2009.  The City’s legal department crafted a settlement agreement with local environmental groups who were threatening to sue the City over perceived violations of the federal Clean Water Act.  The issue was the City’s handling of combined sewer overflow (CSO) events that dump raw sewage into the Spokane River during large storm events.  The City’s wastewater management department has been constructing CSO overflow facilities to capture the stormwater surge that occurs during storm events (with an overall price-tag of over 250 million dollars).  That effort has been accelerated with this settlement agreement.

The end result of the interplay between all these issues is the City’s CLASS proposal:  Cannon-Lincoln Alternative Stormwater Solution  to be added to the streetscape when the City reconstructs Lincoln Street next summer.  Street bond monies will be used to rehabilitate the pavement.  Stormwater monies will be used to construct curb extensions into a portion of the existing street currently used as on-street parking spaces on Lincoln.  Instead of sending all stormwater collected along Lincoln Street to the CSO facilities at the bottom of the hill, the first 130,000 gallons of runoff will be detained in the curb extensions. The proposed curb extensions will reduce both contaminates and water volume entering the combined sewer. Plants and soils will capture pollutants to prevent them from traveling downstream. Plants in the curb extensions will reduce the amount of stormwater runoff entering the traditional piped stormwater system by absorbing water in their leaves, branches and roots. These plants also slow down the runoff. The slower runoff will enter the combined sewer later, minimizing the overflow to the Spokane River. Stormwater will leave the curb extension cleaner and at a slower rate.

Average Weekday Traffic counts along Lincoln have remained essentially the same since the 1970s. The City recognized that effectively narrowing the street width along Lincoln (with stormwater curb extensions) would not compromise the viability of the City’s arterial grid.

The Neighborhood Council recognizes that this stormwater solution is an opportunity for their neighborhood to achieve some of the objectives they have identified as being important to maintaining the livability of their neighborhood.

Curb extensions will allow the development of additional street tree canopy which will create additional storage capacity for precipitation, create shade which will protect and prolong the life of street pavement, filter out air pollution, reduce summer air conditioning costs for homeowners, increase property values, and calm traffic.

Here are some supporting documents: Maintenance Brochure

Storm Garden Information Letter

Lincoln Street Curb Extension Location

Council Resolution to fund stormwater on Lincoln

Here is a photo gallery of the finished product: