Thesis
Retro-fitting conventional subdivisions with low impact development for Bellingham, Washington
Washington State University
Master of Science (MS), Washington State University
2010
Handle:
https://hdl.handle.net/2376/100473
Abstract
Subdivisions have been built the same way for decades. Developers try to maximize the buildable land in order to construct the most houses. With the majority of the land taken up by residential lots and impervious surfaces, large detention ponds are needed to handle the increased stormwater flow rates. As an alternative way to reduce peak flow rates, increase water clarity, and improve site aesthetics, Low Impact Development (LID) techniques are being used. LID methods are derived from nature's approach toward stormwater management which allows infiltration to occur at point of intersection. Various LID techniques can be applied: install rain gardens, green roofs, and rain barrels or cisterns, and/or reduce impervious surfaces. Developers have seen the advantages of LID in new construction, but the data for a retro-fit design is still needed. The Lazy E Ranch, located in Bellingham, Washington has been selected to test the feasibility of LID techniques as a retro-fit design for a conventional subdivision. The site was selected based on criteria developed using data from the City of Bellingham's geographical information system (GIS). The rational method was used to calculate runoff from pre-development (2.49 cfs - 5 year storm) and post-development (6.88 cfs - 5 year storm). The final retro-fit design utilizes twenty rain gardens and seven infiltration strips. The rain gardens are designed to handle runoff from rooftops and the infiltration strips deal with street runoff. The infiltration strips are patches of pervious concrete and, due to the slope, have check dams that slow down the stormwater and allow the runoff to infiltrate. The LID improvements reduce runoff by 4.42 cfs or 100% from post-development conditions. Due to the reduced runoff the existing detention pond can be replaced by a local gathering area that can be used for recreation by residents and close neighbors.
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Details
- Title
- Retro-fitting conventional subdivisions with low impact development for Bellingham, Washington
- Creators
- Eli John Kraft
- Contributors
- Phillip S. Waite (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Horticulture, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525110501842
- Language
- English
- Resource Type
- Thesis