W Q R P ATER UALITY ESTORATION LAN AND T M D L (TMDL) OTAL AXIMUM AILY OADS FOR B C W THE OBTAIL REEK ATERSHED January, 2005 Technical Leads: Heidi Lindgren, Montana Department of Environmental Quality Bob Anderson, Hydrometrics, Inc. Contributors: Montana Department of Environmental Quality Water Quality Planning Bureau Hydrometrics, Inc. Brian Sugden, Plum Creek Timber Company Steve Wegner, USFS, Kootenai National Forest Bobtail Creek Watershed Group Confluence Consulting EXECUTIVE SUMMARY This document presents a Water Quality Protection Plan and Total Maximum Daily Load (TMDL) for the Bobtail Creek Watershed in Montana. A TMDL is a pollutant budget identifying the maximum amount of a particular pollutant that a waterbody can assimilate without causing applicable water quality standards to be exceeded. Section 303 of the Federal Clean Water Act and the Montana Water Quality Act (Section 75-5-703) require development of TMDLs for impaired waterbodies that do not meet Montana water quality standards. Section 303(d) also requires identification of impaired waterbodies on a list, referred to as the 303(d) list. This 303(d) list is updated every two years and submitted to the U. S. Environmental Protection Agency (EPA) by the Montana Department of Environmental Quality (MDEQ). Bobtail Creek supports a coldwater fishery that is geographically important to native fish. The development of the water quality plan and TMDL included an in-depth analysis of water quality in Bobtail Creek. The analysis focused on physical parameters linked to excess sediment loading. Results were compared to information from reference streams throughout western Montana and reference literature values to help identify potential aquatic life or cold-water fish limitations. Bobtail Creek was identified as having habitat and fishery limitations linked to excess sediment loading. These limitations were linked to a lack of pools, overly wide channels, excessive eroding banks, and a reduction in the health of the riparian corridor linked to forest and agriculture practices. These limitations were sufficient to justify the impairment determination for Bobtail Creek thus requiring development of a sediment TMDL. Many stakeholders are working toward improved water quality in this watershed and have implemented projects toward water quality improvement. This plan includes the development of TMDL targets and other beneficial use support indicators that must be satisfied to meet Montana Water Quality Standards. These targets focus on water quality limitations such as pool frequency or width to depth. Targets measuring sediment include Wolman pebble counts and Mc Neil core samples. Restoration objectives, including TMDL and sediment load allocations are developed to address the sediment sources that are contributing to the impairment conditions. These sources include loads of sediment from rain-on-snow events, mass wasting, and other activities mostly linked to timber harvest, forest and private road erosion, and human induced bank erosion. This plan also includes strategies for implementation and monitoring. Implementation focuses on a continuation of many the ongoing water quality protection activities in the watershed. The Kootenai National Forest, Plum Creek Timber Company, other private landowners, and other agencies play an important role in effective implementation of this plan and water quality protection and restoration. The monitoring strategy focuses on tracking progress toward meeting TMDL targets and other goals. An important component of the monitoring strategy is to provide for adaptive management to address uncertainties that tend to exist when developing numeric goals and applying them to TMDL targets and load allocations. The monitoring strategy also includes tracking implementation projects and pursuing a better understanding of the water quality and habitat capabilities and limitations in the Bobtail Creek Watershed. January, 2005 i Table E-1. Summary of Required TMDL Elements for the Bobtail Creek TMDL Planning Area. Water Body and Bobtail Creek Pollutants of Concern Pollutants: Siltation and Turbidity - addressed as sediment in the TMDL. Impaired Beneficial Uses Bobtail Creek Impaired Uses: Partially supporting aquatic life and cold-water fishery. Pollutant Sources Sediment (including siltation, turbidity, bank erosion, and other habitat alteration): from silviculture, logging road construction and maintenance, and “other” sources. Target Development • The current water quality impairment status of each of the waters originally listed on the Strategies 2000 and 2002 303(d) list was evaluated using a suite of targets and supplemental indicators. • Targets for the Bobtail Creek watershed include threshold values for width-to-depth ratios, pool frequency, riffle stability index, Wolman pebble counts, and McNeil core samples. TMDL A 95% reduction of total suspended solids during high flow conditions. Allocation Strategies • 90% application of road best management practices (BMP) to minimize surface erosion from existing roads. • 75% reduction in bank erosion rates. • No sediment loading from preventable mass wasting events. • No sediment loading from culvert failures where culverts are not up to BMP standards or not maintained. • No sediment loading increases (other than potential, minor, predicted, short-term increases associated with full implementation of applicable BMPs) related to future development. • No sediment loading increases (other than potential, minor, predicted, short-term increases associated with full implementation of applicable BMPs) related to future timber roads and timber harvest. Restoration Strategies • Utilize existing restoration programs and plans of the U.S. Forest Service and Plum Creek Timber Company. • Encourage additional restoration actives and BMP implementation by private landowners. Margin of Safety For the Bobtail Creek watershed, a margin of safety is provided by conservative assumptions and proposed additional studies to address uncertainties. Seasonal Considerations Sediment TMDL and targets consider seasonal variations by setting, related habitat targets and biological targets that are affected by year round processes. January, 2005 ii January, 2005 i D:\BobtailTMDL\FinalBobtailCoverDoc.doc January, 2005 iii Table of Contents Executive Summary.......................................................................Error! Bookmark not defined. Section 1.0 Introduction.................................................................Error! Bookmark not defined. 1.1 Background and Purpose.....................................................Error! Bookmark not defined. 1.2 Water Quality Restoration Planning Process.......................Error! Bookmark not defined. Section 2.0 Watershed Characterization........................................Error! Bookmark not defined. 2.1 Location and Regional Description.....................................Error! Bookmark not defined. 2.2 Geological Setting................................................................Error! Bookmark not defined. 2.3 Land Types and Soils...........................................................Error! Bookmark not defined. 2.4 Climate.................................................................................Error! Bookmark not defined. 2.5 Vegetation............................................................................Error! Bookmark not defined. 2.6 Land Ownership...................................................................Error! Bookmark not defined. 2.7 Land Use..............................................................................Error! Bookmark not defined. 2.8 Hydrology............................................................................Error! Bookmark not defined. 2.8.1 Stream Flow Data.........................................................Error! Bookmark not defined. 2.8.2 Equivalent Clear-cut Area Model.................................Error! Bookmark not defined. 2.9 Fisheries and Aquatic Life...................................................Error! Bookmark not defined. 2.9.1 Fisheries........................................................................Error! Bookmark not defined. 2.9.2 Macroinvertebrates.......................................................Error! Bookmark not defined. Section 3.0 Water Quality Impairment Status...............................Error! Bookmark not defined. 3.1 303(d) List Status.................................................................Error! Bookmark not defined. 3.2 Applicable Water Quality Standards...................................Error! Bookmark not defined. 3.2.1 Classification and Beneficial Uses................................Error! Bookmark not defined. 3.2.2 Standards.......................................................................Error! Bookmark not defined. 3.3 Water Quality Targets and Supplemental Indicators...........Error! Bookmark not defined. 3.3.1 Sediment Targets..........................................................Error! Bookmark not defined. 3.3.2 Supplemental Indicators................................................Error! Bookmark not defined. 3.3.3 Uncertainty Associated with Targets and Supplemental Indicators..Error! Bookmark not defined. 3.4 Current Water Quality Impairment Status for Bobtail Creek............Error! Bookmark not defined. 3.4.1 Summary of the 303(d) List..........................................Error! Bookmark not defined. 3.4.2 Target and Supplemental Indicator Data......................Error! Bookmark not defined. 3.5 Bobtail Creek Water Quality Impairment Status SummaryError! Bookmark not defined. Section 4.0 Source Assessment......................................................Error! Bookmark not defined. 4.1 USFS Information................................................................Error! Bookmark not defined. 4.2 Plum Creek Sediment Delivery Analysis............................Error! Bookmark not defined. 4.3 Field Review of Residential Reaches – Eroding Banks.......Error! Bookmark not defined. 4.4 Other Potential Sources........................................................Error! Bookmark not defined. 4.5 Source Assessment Uncertainty...........................................Error! Bookmark not defined. 4.6 Source Assessment Summary..............................................Error! Bookmark not defined. Section 5.0 Total Maximum Daily Load, Allocations, and Uncertainty.....Error! Bookmark not defined. 5.1 Total Maximum Daily Load................................................Error! Bookmark not defined. 5.1.1 TMDL for Total Suspended Sediment (TSS)...............Error! Bookmark not defined. 5.2 Load Allocations..................................................................Error! Bookmark not defined. January, 2005 iii 5.2.1. Surface Erosion from Performance Based Roads Allocations..Error! Bookmark not defined. 5.2.2 Eroding Banks Allocation.............................................Error! Bookmark not defined. 5.2.3 Mass Wasting from Timber Harvest Activities or Other Development...............Error! Bookmark not defined. 5.2.4 Culvert Failures.............................................................Error! Bookmark not defined. 5.2.5 Future Development......................................................Error! Bookmark not defined. 5.2.6 Future Roads and Timber Harvest................................Error! Bookmark not defined. 5.2.7 Future Performance-Based Allocations........................Error! Bookmark not defined. 5.3 TMDL and Load Allocation Uncertainty............................Error! Bookmark not defined. 5.3.1 Margin of Safety...........................................................Error! Bookmark not defined. 5.3.2 Seasonality....................................................................Error! Bookmark not defined. Section 6.0 Restoration Strategy....................................................Error! Bookmark not defined. 6.1 USFS Restoration Plans and Responsibilities.....................Error! Bookmark not defined. 6.2 Plum Creek Timber Company Restoration Plans and Responsibilities....Error! Bookmark not defined. 6.3 Other Private Landowner Restoration Plans and Responsibilities....Error! Bookmark not defined. Section 7.0 Monitoring Strategy....................................................Error! Bookmark not defined. 7.1 Monitoring Plan...................................................................Error! Bookmark not defined. 7.2 Trend Monitoring of Target Variables.................................Error! Bookmark not defined. 7.3 Trend Monitoring of Supplemental Indicators....................Error! Bookmark not defined. 7.4 Beneficial Use Linkage Indicators.......................................Error! Bookmark not defined. 7.5 Condition Monitoring..........................................................Error! Bookmark not defined. 7.6 Reference Monitoring..........................................................Error! Bookmark not defined. 7.7 Data Gaps.............................................................................Error! Bookmark not defined. 7.8 Adaptive Management Strategy...........................................Error! Bookmark not defined. Section 8.0 Public Involvement.....................................................Error! Bookmark not defined. References......................................................................................Error! Bookmark not defined. Appendices Appendix A Streamflow and Total Suspended Solids Data Appendix B McNeil Core Data for Bobtail Creek Appendix C Total Suspended Solids and Turbidity Data Appendix D Severity of Ill Effects Analysis Appendix E Bobtail Creek Road Sediment Delivery Analysis Appendix F Responses to Public Comments List of Figures Figure 1-1. Bobtail Creek Watershed – Location Map..................Error! Bookmark not defined. Figure 2-1. Geology of the Bobtail Creek Watershed...................Error! Bookmark not defined. Figure 2-2. Land Types of the Bobtail Creek Watershed..............Error! Bookmark not defined. Figure 2-3. Average Precipitation in the Bobtail Creek Watershed............Error! Bookmark not defined. Figure 2-4. Vegetation Cover Types in the Bobtail Creek Watershed........Error! Bookmark not defined. January, 2005 iv Figure 2-5. Land Ownership in the Bobtail Creek Watershed.......Error! Bookmark not defined. Figure 2-6. Daily Stream flow and TSS Data from Mouth of Bobtail Creek (Bobtail 1) Water Years 2001-2003....................................................................Error! Bookmark not defined. Figure 3-1. Weight-of-Evidence Approach for Determining Beneficial Use Impairments...Error! Bookmark not defined. Figure 3-2. Methodology for Determining Compliance with Water Quality Standards.......Error! Bookmark not defined. Figure 3-3. Comparison of Simultaneous Measurements of TSS and Turbidity in Bobtail Creek. ................................................................................................Error! Bookmark not defined. Figure 3-4. U. S. Forest Service Riparian Management Objectives Sites...Error! Bookmark not defined. Figure 3-5. Pebble Count Results for Bobtail Creek Watershed...Error! Bookmark not defined. Figure 3-6. Bobtail Creek Watershed Sampling Sites...................Error! Bookmark not defined. Figure 3-7. Calculated SEV for Concentrations of TSS Sampled on Bobtail Creek for Hypothetical Durations Using Model 1 (Adults and Juvenile Salmonids).Error! Bookmark not defined. Figure 4-1. TSS Concentrations and Flow on Bobtail Creek During a ROS Event, February 23, 2002........................................................................................Error! Bookmark not defined. Figure 4-2. TSS and Flow Measured on Tributary Streams in the Bobtail Creek Watershed During the ROS Event, February 23, 2002............................Error! Bookmark not defined. Figure 4-3. Sites Evaluated by Plum Creek Timber Company in the Road Sediment Delivery Analysis..................................................................................Error! Bookmark not defined. Figure 4-4. Area of Unstable Stream Reach..................................Error! Bookmark not defined. Figure 6-1 Restoration Projects in the Bobtail Creek Watershed..Error! Bookmark not defined. List of Tables Table E-1. Summary of Required TMDL Elements for the Bobtail Creek TMDL Planning Area. ................................................................................................Error! Bookmark not defined. Table 1-1. Summary of 303(d) Listings for Bobtail Creek............Error! Bookmark not defined. Table 1-2. Status of Beneficial Uses from 303(d) Lists.................Error! Bookmark not defined. Table 2-1. Land Types, Expected Response of the Soil Resource to Different Activities, Resultant Soil Erosion, and Delivery Efficiency to Surface Waters in the Project Area (Kuennen and Nielsen-Gerhardt, 1995).................................Error! Bookmark not defined. Table 2-2. Descriptions of Land Types Occurring in the Bobtail Creek Watershed (Kuennen and Nielsen-Gerhardt, 1995)........................................................Error! Bookmark not defined. Table 2-3. Measured Stream Flow and Stream Stage Data Pairs at River Road Near Mouth of Bobtail Creek, 1995-2003......................................................Error! Bookmark not defined. Table 2-4. Vertebrate Species in Bobtail Creek and its Tributaries............Error! Bookmark not defined. Table 2-5. Trout Estimates for 1976 and 1997 Electro Fishing Sections in Bobtail Creek...Error! Bookmark not defined. Table 2-6. Bobtail Creek Macroinvertebrate Sampling Results....Error! Bookmark not defined. Table 3-1. Summary of 303(d) Listings for Bobtail Creek............Error! Bookmark not defined. Table 3-2. Status of Beneficial Uses from 303(d) Lists.................Error! Bookmark not defined. Table 3-3. Montana Surface Water Classifications and Designated Beneficial Uses...........Error! Bookmark not defined. January, 2005 v Table 3-4. Applicable Rules for Sediment Related Pollutants......Error! Bookmark not defined. Table 3-5 Proposed Sediment Targets and Supplemental Indicators for the Bobtail Creek Watershed..............................................................................Error! Bookmark not defined. Table 3-6. Riparian Management Objective for Pool Frequency..Error! Bookmark not defined. Table 3-7. Reference Data for Substrate Fines..............................Error! Bookmark not defined. Table 3-8. Summary of TSS data used in evaluating TSS and impairment condition of Bobtail Creek......................................................................................Error! Bookmark not defined. Table 3-9. 303(d) List Status for Bobtail Creek............................Error! Bookmark not defined. Table 3-10 Riparian Management Objectives Assessed in the Bobtail Creek Watershed....Error! Bookmark not defined. Table 3-11. Summary of Percent Fine Sediment in McNeil Core Samples on Bobtail Creek. ................................................................................................Error! Bookmark not defined. Table 3-12. Summary of 2001 through 2003 Daily TSS Data Collected Near the Mouth of Bobtail Creek.........................................................................Error! Bookmark not defined. Table 3-13. Results of February 23, 2003 TSS and Flow Monitoring During Rain –On –Snow for Main stem Sites......................................................................Error! Bookmark not defined. Table 3-14. Models Developed to Predict SEV for Different Life History Stages and Particle Sizes (Newcombe and Jenson 1996)......................................Error! Bookmark not defined. Table 3-15. Bank Stability Values in the Bobtail Creek Watershed............Error! Bookmark not defined. Table 3-16. Bobtail Creek Macroinvertebrate Sampling Results..Error! Bookmark not defined. Table 4-1. Results of Watershed and Fisheries NFMA Screening Process. Error! Bookmark not defined. Table 4-2. Bobtail Creek Road Sediment Delivery Analysis on PCTC Property (Sugden and Richeal 2000, Unpublished Data)..........................................Error! Bookmark not defined. Table 5-1. Allocations for Identified Sediment Loading Sources in Bobtail Creek Watershed. ................................................................................................Error! Bookmark not defined. Table 5-2. Road Density Risk Ratings in Miles per Square Mile..Error! Bookmark not defined. Table 5-3. Future Performance-Based Allocations........................Error! Bookmark not defined. D:\BobtailTMDL\FinalBobtailSection1.doc D:\BobtailTMDL\FinalBobtailSection2.doc D:\BobtailTMDL\FinalBobtailSection3.doc D:\BobtailTMDL\FinalBobtailSection4.doc D:\BobtailTMDL\FinalBobtailSection5.doc D:\BobtailTMDL\FinalBobtailSection6.doc D:\BobtailTMDL\FinalBobtailSection7.doc D:\BobtailTMDL\FinalBobtailSection8.doc D:\BobtailTMDL\FinalBobtailReferences.doc January, 2005 vi