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Newman Lake Total Phosphorus TMDL| WRIA | 57 |
| County | Spokane |
| Parameter | Phosphorus |
| Current Status | TMDL submittal approved by EPA Implementation plan completed |
| TMDL Approval Date | February 27, 2008 |
| # of TMDLs | 1 |
| TMDL Leads |
David Moore, WQP-ERO Tony Whiley, WQP-HQ |
Newman Lake is located in Spokane County, Washington, 26 kilometers northeast of the city of Spokane. It is approximately nine meters deep and contains about 26 million cubic meters of water. The lake is fed primarily by Thompson Creek.
The main land use around Newman Lake is forestry, but also pastureland and residential housing. Residential use is generally highest during the summer months.
Water quality studies of Newman Lake show that the high availability of the nutrient phosphorus has lead to increased algae growth during the summer months. The algae growth has, in turn, lead to reduced water clarity and decreased available oxygen in the deeper portions of the lake during the summer. These changes result in impacts to the majority of aquatic resources that were adapted to a lower phosphorus condition.
Other studies determined that there are two sources for phosphorus to Newman Lake: that within the bottom sediments (internal), and phosphorus brought to the lake, for example from surface water runoff (external).
As part of the water quality improvement report (WQIR) a total maximum daily load (TMDL) study was performed on Newman Lake. The TMDL addressed impairment of Newman Lake’s characteristic uses and aesthetic qualities caused by phosphorus. It examined and quantified the pathways that bring phosphorus to the water column of Newman Lake. As a result of the study, the WQIR established limits for external phosphorus sources. The underlying strategy is that algae growth can be controlled by limiting the introduction of phosphorus to Newman Lake from the various external sources identified, along with management controls already in place to control phosphorus recycling within the lake.
Ecology submitted the WQIR to EPA on December 19, 2007. EPA approved the WQIR on February 27, 2008.
The Newman Lake TMDL Water Quality Implementation Plan is currently under development and scheduled to be complete by September 2009. An TMDL advisory committee has been formed and is providing input on necessary actions to meet the TMDL. The public comment period for the draft WQIP ended on June 22, 2009. The finalized WQIP will be sent to EPA in July 2009.
Newman Lake Total Phosphorus Total Maximum Daily Load: Water Quality Improvement Report (Ecology Publication)
Newman Lake Total Phosphorus Total Maximum Daily Load: Water Quality Implementation Plan (Ecology publication)
Watershed Information for WRIA 57 (Environmental Assessment Program website)
Reducing Phosphorus Pollution to Improve Water Quality (Water Quality website)
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David Moore Water Quality Program-Eastern Regional Office WA Department of Ecology Phone: 509-329-3514 Email: dmoo461@ecy.wa.gov |
Tony Whiley Water Quality Program-HQ WA Department of Ecology Phone: 360-407-7241 Email: twhi461@ecy.wa.gov |
Copyright © Washington State Department of Ecology. See http://www.ecy.wa.gov/copyright.html.
