Spokane Combined Sewer Overflow Abatement Project

Author : Lisa Koefod Humphreys
Publisher :
ISBN 13 :
Total Pages : 252 pages
Book Rating : 4.:/5 (246 download)

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Download or read book Impact of Combined Sewer/stormwater Overflows on the Spokane River, Washington written by Lisa Koefod Humphreys and published by . This book was released on 1991 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Spokane River, WA, has its source at the outlet of Lake Coeur d'Alene, Idaho, and runs 112 miles (180 km) downstream into the Columbia River. The river flows through the heart of Spokane, WA, encountering municipal and industrial discharges outside and within its corporate boundaries. The City's wastewater collection system has at times become hydraulically overloaded with heavy precipitation and/or snowmelt runoff. Overflow pipes were established to accommodate excess wastewater volume by releasing it into the river as combined sewer overflow (CSO). Spokane has separated two major collection systems, eliminating 84 percent of CSO that annually reached the river, deteriorating water quality. In these separated systems, sanitary sewage now flows to the Advanced Wastewater Treatment Plant and only stormwater exits from the original outfalls. The primary purpose of this study was to determine what impact selected CSO (from outfalls remaining) and stormwater discharges have on river quality. Four CSO outfalls, one storm sewer outfall, and nine river stations were monitored. Parameters included: dissolved oxygen concentrations; conductance; total Kjeldahl, ammonia and nitrate nitrogen concentrations; total and soluble reactive phosphorus levels; total suspended solids, turbidity and fecal coliform density. During wet weather, the water quality of the river was seriously degraded by CSO and the influence of Hangman Creek (a tributary). Several unmonitored CSO's may have also contributed to the observed poor quality. A recommendation was made that the City of Spokane consider taking measures to prevent CSO introduction into the river from the monitored sites--Document.