z c Long Prairie River Watershed Stressor Identification Report August 2014 Authors The Minnesota Pollution Control Agency (MPCA) is reducing printing and mailing costs by using the Chuck Johnson Internet to distribute reports and information to wider audience. Visit our website for more Contributors / acknowledgements information. Jeff Jasperson MPCA reports are printed on 100% post-consumer Tiffany Schauls recycled content paper manufactured without Bonnie Finnerty chlorine or chlorine derivatives. Laurel Mezner Crystal Payment (MDNR) Eric Altena (MDNR) Project dollars provided by the Clean Water Fund (from the Clean Water, Land and Legacy Amendment). 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-ws5-07010108 Table of Contents Figures .................................................................................................................................. 3 Tables .................................................................................................................................... 5 Executive summary ................................................................................................................ 1 Stressors in the Long Prairie Watershed (8-digit HUC) .................................................................................... 1 Low dissolved oxygen concentrations.............................................................................................................. 1 Loss of habitat due to excess bedded sediment .............................................................................................. 1 Altered hydrology/channelization ................................................................................................................... 1 Loss of connectivity (impoundments/improper placement of culverts) ......................................................... 2 Lack of woody debris ........................................................................................................................................ 2 Introduction .......................................................................................................................... 3 Organization framework of stressor identification .......................................................................................... 3 Overview of watershed impairments ............................................................................................................... 4 Long Prairie Watershed .................................................................................................................................... 7 Watershed background and description .................................................................................. 9 Ecological and administrative regions of the LP Watershed ............................................................................ 9 Biological assessment ....................................................................................................................................... 9 Summary of biological impairments .............................................................................................................. 10 Candidate causes for biological impairment .......................................................................... 12 Candidate Cause: Flow alteration (channelization/ditching) ........................................................................ 12 Candidate Cause: Suspended sediment (TSS)/bedded sediment ................................................................. 14 Candidate Cause: Nitrate-Nitrite ................................................................................................................... 19 Candidate Cause: Pesticide toxicity ............................................................................................................... 20 Candidate Cause: Chloride toxicity................................................................................................................ 22 Candidate Cause: Low dissolved oxygen ....................................................................................................... 23 Candidate Cause: Loss of connectivity and habitat ....................................................................................... 25 Middle Long Prairie River 11-digit HUC .................................................................................. 28 Venewitz Creek AUID (07010108-568) fish impairment only ........................................................................ 28 Evidence of causal pathways-DO flux, chlorophyll-a, and oxygen demand ................................................... 30 Low dissolved oxygen ..................................................................................................................................... 31 Sediment: Total suspended solids ................................................................................................................. 33 Sediment: Bedded sediment ......................................................................................................................... 33 Nitrate toxicity................................................................................................................................................ 34 Connectivity ................................................................................................................................................... 34 Conclusion ...................................................................................................................................................... 35 Eagle Creek 11-Digit HUC (07010108030) .............................................................................. 36 Harris Creek AUID 07010108-592 .................................................................................................................. 36 Evidence of causal pathways-DO flux, chlorophyll-a, and oxygen demand ................................................... 37 Sediment: Total suspended solids and bedded sediment............................................................................. 39 Dissolved oxygen ............................................................................................................................................ 40 Nitrate-nitrite toxicity .................................................................................................................................... 40 Connectivity/habitat ...................................................................................................................................... 41 Conclusion ...................................................................................................................................................... 43 Headwaters Long Prairie River 11-Digit HUC (07010108010) .................................................. 44 Unnamed Creek to Lake Miltona AUID 07010108-595 (fish and invert NS) .................................................. 44 Evidence of causal pathways-DO flux, chlorophyll-a, and oxygen demand ................................................... 45 Sediment: Total suspended solids and bedded sediment............................................................................. 46 Nitrate toxicity................................................................................................................................................ 47 Connectivity/altered hydrology ..................................................................................................................... 47 Conclusion ...................................................................................................................................................... 49 Spruce Creek 11-Digit HUC (07010108020) ............................................................................ 50 Nutrients ........................................................................................................................................................ 51 Chlorophyll-a .................................................................................................................................................. 51 Sediment: Total suspended solids and bedded sediment............................................................................. 51 Dissolved oxygen ............................................................................................................................................ 53 Connectivity ................................................................................................................................................... 54 Conclusion ...................................................................................................................................................... 54 Summary of stressors to biology ........................................................................................... 56 Additional data collected in 2012 and 2013 in LP Watershed.................................................. 57 AUID 07010108-505 Long Prairie River .......................................................................................................... 57 AUID 07010108-534 Long Prairie River .........................................................................................................