Alaska Department of Environmental Conservation 555 Cordova Street Anchorage, Alaska 99501 Total Maximum Daily Load (TMDL) for Residue Adjacent to the Waters of the Matanuska River in Palmer, Alaska Public Notice Draft July 2017 Draft TMDL for Residue Adjacent to the Matanuska River, AK July 2017 Table of Contents Executive Summary ........................................................................................................................................... 7 1 Overview ..................................................................................................................................................... 9 1.1 Location of TMDL Study Area ....................................................................................................... 9 1.2 Population ........................................................................................................................................ 13 1.3 Topography ...................................................................................................................................... 13 1.4 Land Use and Land Cover ............................................................................................................. 13 1.5 Soils and Geology ............................................................................................................................ 14 1.6 Climate .............................................................................................................................................. 17 1.7 Hydrology and Waterbody Characteristics .................................................................................. 17 1.8 Fish Populations .............................................................................................................................. 18 2 Water Quality Standards and TMDL Targets ..................................................................................... 19 2.1 Applicable Water Quality Standards ............................................................................................. 19 2.1.1 Designated Uses ...................................................................................................................... 19 2.1.2 Water Quality Criteria ............................................................................................................ 19 2.1.3 Antidegradation ....................................................................................................................... 19 2.2 Designated Use Impacts ................................................................................................................. 21 2.3 TMDL Target .................................................................................................................................. 21 3 Data Review and Analyses ..................................................................................................................... 22 3.1 Data Inventory ................................................................................................................................. 22 3.2 Debris Analysis ................................................................................................................................ 24 3.3 Water Quality, Sediment, and Soil Data Analysis ....................................................................... 25 3.3.1 Surface Water .......................................................................................................................... 25 3.3.2 Sediment ................................................................................................................................... 27 3.3.3 Soil ............................................................................................................................................. 29 3.3.4 Summary of Data Analysis .................................................................................................... 31 4 Source Assessment .................................................................................................................................. 32 4.1 Point Sources ................................................................................................................................... 32 4.1.1 Disposal Area .......................................................................................................................... 32 4.1.2 Natural Sources ....................................................................................................................... 33 5 TMDL Allocation Analysis .................................................................................................................... 34 5.1 Loading Capacity ............................................................................................................................. 34 5.2 Wasteload Allocations .................................................................................................................... 34 5.3 Load Allocations.............................................................................................................................. 34 5.4 Margin of Safety .............................................................................................................................. 34 5.5 Seasonal Variation and Critical Conditions ................................................................................. 35 5.6 Future Growth ................................................................................................................................. 35 5.7 Daily Load ........................................................................................................................................ 35 5.8 Reasonable Assurance .................................................................................................................... 35 1 Draft TMDL for Residue Adjacent to the Matanuska River, AK July 2017 6 Implementation and Monitoring Recommendations ......................................................................... 36 6.1 Prevention of Additional Dumping.............................................................................................. 36 6.1.1 Local Ordinances .................................................................................................................... 36 6.1.2 Leave Debris in Place ............................................................................................................. 37 6.2 Options for Debris Removal ......................................................................................................... 38 6.3 Enhancing Revegetation ................................................................................................................ 39 6.4 Monitoring Recommendations ..................................................................................................... 40 7 Public Participation ................................................................................................................................. 42 8 References................................................................................................................................................. 43 2 Draft TMDL for Residue Adjacent to the Matanuska River, AK July 2017 Figures Figure 1-1. Location of the impaired section of the Matanuska River, Alaska. ...................................... 11 Figure 1-2. Location of the debris disposal site along the Matanuska River........................................... 12 Figure 1-3. Land use and land cover in the Matanuska watershed. .......................................................... 14 Figure 1-4. Soil classification in the Matanuska River watershed. ............................................................ 16 Figure 1-5. Monthly average flow in the Matanuska River at USGS gage 15284000 (Matanuska River at Palmer, AK) (5/1/1949 to 9/30/2015). .................................................................................................. 18 Figure 3-1. Location of surface water, sediment, and soil samples collected from the disposal site and the Matanuska River in 2004. ................................................................................................................. 24 Figure 4-1. Photo of the debris site along the Matanuska River. .............................................................. 33 Tables Table 1-1. Matanuska River section 303(d) listing information from Alaska’s 2012 Integrated Report ............................................................................................................................................................................ 10 Table 1-2. Land use/land cover in the Matanuska River watershed and the debris site surrounding area ..................................................................................................................................................................... 13 Table 1-3. Characteristics of hydrologic soil groups ................................................................................... 15 Table 1-4. Soil distribution in the Matanuska River watershed and within a 1,000-foot area surrounding the debris site ............................................................................................................................. 16 Table 2-1. Alaska water quality standards for residues, applicable for TMDLsa .................................... 20 Table 3-1. Available data summary ..............................................................................................................