Date: Jun 9, 2017 5:58 PM
Subject: RE: Idaho Department of Environmental Quality - Palouse River Subbasin: 2017 Temperature Total Maximum Daily Load (TMDL)
Good Afternoon Benjamin,
The final Palouse River Subbasin Temperature TMDL document is on the Idaho DEQ website at http://www.deq.idaho.gov/ water-quality/surface-water/ tmdls/table-of-sbas-tmdls/ palouse-river-subbasin/, links to the document are at the bottom of the page. Response to comments can be found in Appendix D. That you for submitting your comments and please feel free to contact me with any additional questions.
Water Quality Analyst
Idaho Department of Environmental Quality
Excerpt from Palouse River Subbasin Temperature TMDL, Appendix D of the Comments Provided By: Electronic Review for the Environment, Inc.
Comment 1: Table of Contents – The list of tables relies heavily on shade data but doesn’t show data for temperature. Please consider adding water temperature data; it may help validate the other data, show useful information and potentially help identify inconsistencies or areas of special concern. Response: This comment will be considered in future temperature TMDL reviews in the subbasin.
Comment 2: Page 18 Sec 5.1.1 - Turbidity can be a factor that increases temperature from solar radiation due to suspended sediment absorbing heat from sunlight. This is a target factor of the Palouse Clearwater Environmental Institute projects that should be restated here for the purpose of explaining the importance of erosion control and riparian restoration pursuant to decreasing sediment load. Since it is unclear from this document how significant the turbidity affects temperature, the relative significance of this factor should be discussed. The discussion of the load capacity equation shown on page 17 section 5.0 should also consider the absorbance of heat attributable to this factor. If controlling turbidity is significant compared to shading, that information would be important for making decisions for priority-based allocation of resources (i.e. balancing efforts toward reducing turbidity and increasing shade). Response: This TMDL is written looking at system potential vegetation; we acknowledge that turbidity can be a factor that can add to the increase of stream temperature. However, by implementing riparian planting and other land management practices that increase shade, turbidity will also be reduced through stabilization of banks, filtering of runoff, etc.
Comment 3: Pages 25-26 - The design conditions for the Palouse River tributaries and South Fork Palouse River have no mention of measures to sustain the proposed potential natural vegetation (PNV) recommendations. Sustainable management strategies should reduce overgrazing in low shade areas and possibly utilize small net fencing to block grazing herbivores. A comprehensive ecological approach may improve sustainability for plant growth, foster beneficial animals, shade, and decreased water temperature. Palouse River Subbasin Temperature TMDL 105 Response: DEQ works with land management agencies in the subbasin to develop implementation plans that include sustainable management strategies for the assessment units in the TMDL. Assessment units in this TMDL are included in implementation plans that can be found at www.deq.idaho.gov/water-quality/surface-water/tmdls/table-of-sbas-tmdls/palouseriver-subbasin.aspx. DEQ is working with the Palouse River Subbasin WAG and additional land management agencies to review and update the implementation plans in the Palouse River subbasin.
- 2/20/2017 at 12:49 PM