WILLOW CREEK WATERSHED ASSESSMENT AND MANAGEMENT PLAN Final Report Submitted by Watershed Consulting, LLC P.O. Box 1701 Kalispell, MT 59903 Submitted to Blackfeet Environmental Office 457 Hospital Road Browning, MT 59417 September, 2010 This project was conducted in cooperation with the Blackfeet Tribe Environmental Office and the EPA Region 8 1 Table of Contents Table of Contents....................................................................................................................... i List of Tables ............................................................................................................................ ii List of Figures..........................................................................................................................iii List of Maps .............................................................................................................................iii List of Appendices ................................................................................................................... iv 1. Executive Summary.................................................................................................................. 1 1.1 Summary of Accomplishments........................................................................................... 1 1.2 Summary of Results............................................................................................................ 2 2.0 Standards................................................................................................................................. 4 3.0 Site Description and Project Overview................................................................................. 6 3.1 Project Description.............................................................................................................. 8 3.2 Objectives ........................................................................................................................... 8 3.2 Site and Source Description................................................................................................ 9 3.2.1 Primary Pollution Sources in the Watershed ............................................................. 9 3.2.2 Description of Listed Segments and Sources............................................................. 9 3.2.4 Listed Segment Summary........................................................................................ 13 4.0 Methods.................................................................................................................................. 15 4.1 Aerial photo interpretation and GIS analysis.................................................................... 15 4.2 Field Data Collection ........................................................................................................ 15 4.2.1 Sediment .................................................................................................................. 18 4.2.2 Physical Stream Characteristics............................................................................... 19 4.2.2 Nutrients................................................................................................................... 21 4.3 Community Outreach and Restoration Planning .............................................................. 21 5.0 Results and Analysis ............................................................................................................. 22 5.1 Aerial Photo Interpretation Results................................................................................... 22 5.2 Field Results: Sediment .................................................................................................... 22 5.2.1 Stream Condition Assessment ................................................................................. 22 5.2.1 Road Inventory Assessment..................................................................................... 24 5.2.2 Channel Morphology ............................................................................................... 25 5.2.3 Streambank Erosion................................................................................................. 26 5.2.4 Total Suspended Solids............................................................................................ 28 5.2.5 Turbidity .................................................................................................................. 29 5.4 Field Results: Nutrients..................................................................................................... 32 5.4.1 Nitrogen ................................................................................................................... 32 5.4.2 Total Phosphorous ................................................................................................... 36 5.4.3 Dissolved Oxygen.................................................................................................... 37 5.5 Field Results: Temperature............................................................................................... 39 5.6 Field Results: Pathogens................................................................................................... 40 5.6.1 Total Coliform ......................................................................................................... 40 5.7 Water Quality Data Analysis Summary............................................................................ 41 5.7.1 Pollutant Reduction Targets..................................................................................... 44 5.8 Temporal Analysis............................................................................................................ 47 5.9 Data Gaps.......................................................................................................................... 48 6.0 Discussion and Management Recommendations ............................................................... 49 6.1 Influences on Stream Segment Condition......................................................................... 49 6.2 Restoration Priorities and Recommendations................................................................... 51 i 6.3 Monitoring Recommendations.......................................................................................... 54 6.3.1 Filling data gaps....................................................................................................... 54 6.3.2 Effectiveness Monitoring......................................................................................... 55 6.3.3 Monitoring to support additional efforts.................................................................. 58 6.3.4 Budget for Proposed Monitoring Approach ............................................................ 59 6.4 Adaptive Management...................................................................................................... 60 7.0 References.............................................................................................................................. 61 List of Tables Table 1. Pollutant Standards ........................................................................................................... 4 Table 2. Dissolved Oxygen Criteria Fisheries and Associated Aquatic Life ................................. 5 Table 3. Land Use and Pollution Source Assessment.................................................................. 13 Table 4. Willow Creek Watershed Listed Segments and Designated Uses*................................ 13 Table 5. Data collected by Watershed Consulting and BEO (05/2008 – 08/2008) ...................... 16 Table 6. Existing BEO Water Quality Sites and Years of Existing Data ..................................... 17 Table 7. Potential pollution sources from aerial photo interpretation ......................................... 22 Table 8. RAF scores...................................................................................................................... 23 Table 9. Road-related Sediment Sources with Highest Sediment Contributions ......................... 24 Table 10. Culverts displaying at least one indicator of higher risk of failure............................... 25 Table 11. Stream Type and Morphology ...................................................................................... 26 Table 12. Eroding area of streambank for each reach, normalized to rate/1000ft........................ 27 Table 13. Total Suspended Solids Summary Data........................................................................ 28 Table 14. Upper Willow Creek Total Suspended Solids Results by Reach. ................................ 28 Table 15. Lower Willow Creek Total Suspended Solids by Reach.............................................. 29 Table 16. Depot Creek Total Suspended Solids by Reach ........................................................... 29 Table 17. Turbidity Summary Data .............................................................................................. 29 Table 18. Upper Willow Creek Turbidity by Reach..................................................................... 30 Table 19. Depot Creek Turbidity by Reach.................................................................................. 31 Table 20. Lower Willow Turbidity by Reach............................................................................... 32 Table 21. Total Nitrogen by Listed Segment...............................................................................