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A Total Maximum Daily Load Evaluation for Arsenic in the Similkameen River

Publication number Date Published
02-03-044November 2002
VIEW NOW A Total Maximum Daily Load Evaluation for Arsenic in the Similkameen River (Number of pages: 124) (Publication Size: 3MB)

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Author(s) Johnson, A.
Description A TMDL evaluation was conducted for arsenic in the Similkameen River. The major source appears to be tailings from historical mining activity in British Columbia between Hedley and the U.S. border. The only significant sources identified in Washington were: 1) Palmer Lake, likely arising from periodic flooding by the Similkameen River and perhaps inputs from Sinlahekin Creek, and 2) resuspension of contaminated sediments.

It was determined that the Similkameen naturally exceeds EPA human health criteria for arsenic upstream of Hedley. Water quality targets of 0.4 - 0.6 ug/L total recoverable arsenic are therefore proposed and estimates provided of the load reductions needed to meet the targets. An arsenic monitoring plan is suggested.
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Keywords creek, flow, fish, 303(d), section 303, evaluation, study, river, plan, water, water quality, Total Maximum Daily Load, lake, flood, arsenic
WATERSHED Water Resource Inventory Area 49 Okanogan
DATA Environmental Information Management (EIM) #AJOH0016


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