Sauk River Watershed Stressor Identification Report
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Sauk River Watershed Stressor Identification Report Conditions causing deterioration of aquatic biological communities in the SRW August 2012 Legislative Charge Minn. Statutes § 116.011 Annual Pollution Report A goal of the Pollution Control Agency is to reduce the amount of pollution that is emitted in the state. By April 1 of each year, the MPCA shall report the best estimate of the agency of the total volume of water and air pollution that was emitted in the state the previous calendar year for which data are available. The agency shall report its findings for both water and air pollution, etc, etc. HIST: 1995 c 247 art 1 s 36; 2001 c 187 s 3 Authors Estimated cost of preparing this report (as Principal Author Chuck Johnson required by Minn. Stat. § 3.197) Other author Jeff Jasperson Total staff time: 500 hrs. $15,000 Other author Production/duplication $x,xxx Contributors / acknowledgements (if any) Total $xx,xxx Kevin Stroom The MPCA is reducing printing and mailing costs Nolan Baratona by using the Internet to distribute reports and Greg Van Eeckhout information to wider audience. Visit our web site Laurel Mezner for more information. Editing and Graphic Design (if any) MPCA reports are printed on 100% post-consumer PIO staff recycled content paper manufactured without Graphic design staff chlorine or chlorine derivatives. Administrative staff Cover photo: Minnesota Pollution Control Agency 520 Lafayette Road North | Saint Paul, MN 55155-4194 | www.pca.state.mn.us | 651-296-6300 Toll free 800-657-3864 | TTY 651-282-5332 This report is available in alternative formats upon request, and online at www.pca.state.mn.us Document number: wq-iw8-38n Contents Legislative Charge ................................................................................................................................................................... 2 Authors ................................................................................................................................................................................... 2 Contributors / acknowledgements (if any) ............................................................................................................................ 2 Editing and Graphic Design (if any) ........................................................................................................................................ 2 Estimated cost of preparing this report (as required by Minn. Stat. § 3.197) ........................................................................ 2 Executive Summary for the Sauk River Watershed Stressor Identification Report ................... 1 Stressors in the Sauk River Watershed (8 Digit HUC) .............................................................................. 2 Low dissolved oxygen concentrations ................................................................................................... 3 Loss of habitat due to excess bedded sediment ..................................................................................... 3 Increased nutrients .............................................................................................................................. 3 Altered hydrology/channelization ........................................................................................................ 3 Loss of woody habitat .......................................................................................................................... 3 Loss of connectivity (impoundments/improper placement of culverts) ................................................... 4 Elevated concentration of total suspended solids .................................................................................. 4 Sauk River Watershed Monitoring Sites and known impairments .......................................................... 4 Recommendations for implementation strategies ................................................................................. 4 Introduction .......................................................................................................................... 7 Overview of watershed impairments .................................................................................................... 7 Organization Framework of Stressor Identification ................................................................ 8 Sauk River ............................................................................................................................. 9 Definition of Sauk River Watershed Management Units (Minors) .......................................................... 9 Division of Minors .................................................................................................................................................................. 9 Minnesota Department of Natural Resources Watershed assessment tool ........................................... 11 Candidate causes for biological impairment ........................................................................................ 12 Candidate cause #1: ditching/channelization ...................................................................................... 13 Background .......................................................................................................................................................................... 13 Conceptual mModel ............................................................................................................................................................. 15 Casual analysis ...................................................................................................................................................................... 16 Biological effects -- fish ........................................................................................................................................................ 16 Tolerance metrics ................................................................................................................................................................. 17 Trophic response .................................................................................................................................................................. 18 Biological effects -- macroinvertebrates .............................................................................................................................. 19 Strength of evidence summary – channelization/ditching ................................................................................................... 20 Candidate Causes #2-4: Total Suspended Solids /Turbidity/Bedded Sediment ....................................... 22 Biological effects of TSS, turbidity, and bedded sediment ................................................................................................... 22 Turbidity/TSS standard ......................................................................................................................................................... 22 Sources and pathways of deposited and bedded sediment riparian grazing/bank erosion ................................................. 23 Overland runoff .................................................................................................................................................................... 24 Total suspended volatile solids ............................................................................................................................................ 25 Specific effects of TSS on fish and macroinvertebrates ........................................................................................................ 25 Conceptual model ................................................................................................................................................................ 26 Strength of evidence summary for TSS ................................................................................................................................ 26 Bedded (deposited) sediment ............................................................................................................. 28 Biological effects of TSS, turbidity, and bedded sediment ................................................................................................... 28 Assessment of bedded sediment ......................................................................................................................................... 28 Causal analysis – bedded sediment ..................................................................................................... 30 Strength of evidence summary for deposited and bedded sediment ..................................................... 32 Nitrate toxicity ................................................................................................................................... 32 NO2 – NO3 water quality standards/ecoregion expectations ............................................................................................... 32 Effects of nitrate-N toxicity on aquatic organisms ............................................................................... 33 Sources and causal pathways of NO3 - NO2 toxicity .............................................................................. 34 Toxicity from insecticides and herbicides ............................................................................................. 37 Pesticide monitoring in Minnesota and