Lessons Learned from Monitoring of a Natural Drainage System in West Seattle's High Point Neighborhood

• Published in: Low Impact Development for Urban Ecosystem and Habitat Protection pp. 1 - 9
• Main Authors: Rheaume, Andy, Lenth, John, Tackett, Tracy
• Format: Book Chapter
• Language: English
• Published: 2009
• Subjects: Drainage; Monitoring; Washington
• ISBN: 0784410097; 9780784410097
• DOI: 10.1061/41009(333)6

Seattle Public Utilities (SPU) is implementing a large scale Natural Drainage System (NDS) project in conjunction with the redevelopment of the High Point neighborhood in West Seattle. When developing the design concept for the High Point NDS project, one of the primary challenges SPU faced was modeling the interactions between the various NDS components in order to predict flow attenuation through the entire system. Key inputs to the model were the infiltration rates for the engineered soil layer of the NDS and the underlying native soil. The infiltration rate for the engineered soil layer was assumed to be 2 inches/hour based on results from laboratory testing. Based on geotechnical reports for the project, the infiltration rate for the underlying till soils was assumed to be so low as to be insubstantial.