Watershed-Based Management Plan for the Upper Illinois River Watershed, Northwest Arkansas
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Watershed-Based Management Plan for the Upper Illinois River Watershed, Northwest Arkansas Prepared for Illinois River Watershed Partnership and Arkansas Natural Resources Commission Prepared by FTN Associates, Ltd. July 17, 2102 Accepted by EPA November 2012 This page intentionally left blank November 30, 2012 Executive Summary Executive Summary The Upper Illinois River Watershed lies in Benton and Washington counties, as well as a small portion of Crawford County, in northwest Arkansas. The Illinois River originates near Hogeye, Arkansas, approximately 15 miles southwest of Fayetteville. The river flows westerly, crossing the Ozarks of northwest Arkansas and into Oklahoma, 5 miles south of Siloam Springs, Arkansas, near Watts, Oklahoma. Land use in the UIRW is diverse with about 46% pasture, 41% forest, and 13% urban. The watershed is characterized by rapidly growing urban centers from south Fayetteville to Rogers and Bentonville, Arkansas, in the headwaters, with more rural areas to the west, along the Oklahoma border. The Illinois River and its major tributaries in Arkansas (Osage Creek, Clear Creek, Baron Fork, and the Muddy Fork) exhibit a range of conditions, from areas with dense riparian forest buffers illustrating exceptional beauty and ecological value, to areas of exposed and eroding stream banks with no vegetated buffers. The Illinois River and its tributaries have many designated uses set forth by the Arkansas Pollution Control and Ecology Commission (APCEC), including fisheries, primary and secondary contact recreation, drinking water supply, and agricultural and industrial water supply. However, portions of the Illinois River and its tributaries have been cited as not meeting these designated uses due to impairment from bacteria, sediment, and/or nutrients. The goal of this watershed-based plan is to improve water quality in the Illinois River and its tributaries so that all waters meet their designated uses both now and in the future. The watershed-based management strategy described within this document considers watershed land use, current water quality conditions, and existing and potential pollutant sources. The management strategies for the Upper Illinois River Watershed were developed based on water quality conditions at the sub-watershed level. Based on the identified priorities, recommended best management practices specific to each priority sub-watershed should be implemented to improve water and watershed environmental quality. Since no single management option can “fix” the watershed, a suite of practices is recommended. Since watershed processes and systems are dynamic, adaptive management is the best means of achieving sustainable watershed management. Stakeholders should expect the implementation of this management plan to be a cooperative, evolving, ongoing process. i November 30, 2012 Table of Contents Executive Summary .................................................................................................................................................................. i List of Tables ............................................................................................................................................................................ vi List of Figures ............................................................................................................................................................................ ix Glossary of Terms and Acronyms ...................................................................................................................................... x 1 Plan Guidance ........................................................................................................................................................ 1-1 1.1 A Vision for the Upper Illinois River Watershed..................................................................... 1-1 1.2 Watershed Based Plan Funding Sources and Management ............................................... 1-1 1.3 Development Team ............................................................................................................................. 1-2 1.4 Nine Elements of the Watershed-Based Management Plan ............................................... 1-2 1.5 Implementation Process ................................................................................................................... 1-2 1.6 Adaptive Watershed Management ............................................................................................... 1-3 2 Watershed Description ..................................................................................................................................... 2-1 2.1 Geography .............................................................................................................................................. 2-2 2.2 Geology ..................................................................................................................................................... 2-2 2.3 Climate...................................................................................................................................................... 2-4 2.4 Soils ............................................................................................................................................................ 2-5 2.5 Hydrology ................................................................................................................................................ 2-6 2.6 Land Use/Land Cover....................................................................................................................... 2-14 2.7 Socioeconomics .................................................................................................................................. 2-18 2.8 Water Quality and Monitoring...................................................................................................... 2-19 2.9 Wildlife Resources—Endangered and Threatened Species and Fisheries ................ 2-28 3 Regulations of the UIRW ................................................................................................................................... 3-1 3.1 Federal Regulatory Drivers ............................................................................................................. 3-1 ii November 30, 2012 Table of Contents (continued) 3.2 State Regulatory Drivers ................................................................................................................... 3-2 3.3 Local Regulatory Drivers .................................................................................................................. 3-5 3.4 Water Quality Standards ................................................................................................................... 3-7 3.5 Regulated Activities .......................................................................................................................... 3-10 4 Element 1: Identification of Causes and Sources of Impairment ..................................................... 4-1 4.1 Impaired Stream Reaches in the Illinois River ........................................................................ 4-1 4.2 Causes of Water Quality Impairment .......................................................................................... 4-1 4.3 Sources of Pollutants Causing Water Quality Impairment ................................................. 4-6 5 Element 3: Management Measures .............................................................................................................. 5-1 5.1 Objective .................................................................................................................................................. 5-1 5.2 Target Pollutants .................................................................................................................................. 5-1 5.3 Management Units ............................................................................................................................... 5-2 5.4 Watershed Prioritization .................................................................................................................. 5-2 5.5 Management Measures for Urban Sources ............................................................................... 5-8 5.6 Management Measures for Surface Erosion ........................................................................... 5-17 5.7 Management Measures for Rural Sources ............................................................................... 5-22 5.8 Watershed Implementation Plans .............................................................................................. 5-28 5.9 Adaptive Management ..................................................................................................................... 5-29 6 Element 2: Expected Load Reductions........................................................................................................ 6-1 6.1 Environmental Goals .......................................................................................................................... 6-1 6.2 Non-Target Pollutants and Issues ................................................................................................. 6-2 6.3 Estimated Pathogen Reductions for Management Measures ............................................ 6-2 iii November 30, 2012 Table of Contents (continued) 6.4 Estimated Sediment Load Reductions