FINAL 2014 BACTERIAL AND TURBIDITY TOTAL MAXIMUM DAILY LOADS FOR OKLAHOMA STREAMS IN THE LOWER ARKANSAS RIVER AREA (OK220100, OK220200, OK220600) Oklahoma Waterbody Identification Numbers Poteau River OK220100010010_00 Poteau River OK220100010010_40 Brazil Creek OK220100030010_00 Bandy Creek OK220100040080_00 Sallisaw Creek OK220200030010_20 Sans Bois Creek OK220200040010_10 Sans Bois Creek OK220200040010_40 Little Lee Creek OK220200050040_00 Canadian River OK220600010119_10 Prepared by: OKLAHOMA DEPARTMENT OF ENVIRONMENTAL QUALITY MARCH 2014 2014 Bacterial and Turbidity TMDLs in the Lower Arkansas River Area Table of Contents TABLE OF CONTENTS EXECUTIVE SUMMARY ................................................................................................... ES-1 ES - 1 Overview ................................................................................................................... ES-1 ES - 2 Problem Identification and Water Quality Target ................................................. ES-1 ES-2.1 Chapter 45: Definition of PBCR and Bacterial WQSs.............................. ES-2 ES-2.2 Chapter 46: Implementation of OWQS for PBCR ..................................... ES-4 ES-2.3 Chapter 45: Criteria for Turbidity .............................................................. ES-5 ES-2.4 Chapter 46: Implementation of OWQS for Fish and Wildlife Propagation ................................................................................................. ES-6 ES - 3 Pollutant Source Assessment ................................................................................ ES-7 ES - 4 Using Load Duration Curves to Develop TMDLs .................................................. ES-7 ES-4.1 Bacterial LDC ............................................................................................. ES-11 ES-4.2 TSS LDC ..................................................................................................... ES-11 ES-4.3 LDC Summary ........................................................................................... ES-11 ES - 5 TMDL Calculations ................................................................................................. ES-12 ES-5.1 Bacterial PRG ............................................................................................ ES-12 ES-5.2 TSS PRG .................................................................................................... ES-12 ES-5.3 MOS ............................................................................................................ ES-13 ES-5.4 PBCR Season ............................................................................................ ES-13 ES - 6 Reasonable Assurance ......................................................................................... ES-13 ES - 7 Public Participation................................................................................................ ES-14 SECTION 1 INTRODUCTION ........................................................................................... 1-1 1.1 TMDL Program Background ...................................................................................... 1-1 1.2 Watershed Description ............................................................................................... 1-4 1.2.1 General ............................................................................................................ 1-4 1.2.2 Climate ............................................................................................................. 1-5 1.2.3 Land Use .......................................................................................................... 1-6 1.3 Stream Flow Conditions ............................................................................................. 1-9 SECTION 2 PROBLEM IDENTIFICATION AND WATER QUALITY TARGET ................. 2-1 2.1 Oklahoma Water Quality Standards .......................................................................... 2-1 2.2 Problem Identification ................................................................................................ 2-6 2.2.1 Bacterial Data Summary .................................................................................. 2-6 2.2.2 Turbidity Data Summary .................................................................................. 2-7 2.3 Water Quality Target ................................................................................................. 2-10 SECTION 3 POLLUTANT SOURCE ASSESSMENT ........................................................ 3-1 3.1 Overview ...................................................................................................................... 3-1 3.2 NPDES-Permitted Facilities ....................................................................................... 3-1 3.2.1 Continuous Point Source Dischargers ............................................................. 3-3 3.2.2 Stormwater Permits ......................................................................................... 3-3 3.2.2.1 NPDES Municipal Separate Storm Sewer System ........................................ 3-3 3.2.2.1.1 Phase I MS4 ................................................................................................. 3-3 3.2.2.1.2 Phase II MS4 ................................................................................................ 3-3 3.2.2.2 Construction Activities .................................................................................... 3-4 3.2.2.3 Multi-Sector General Permits ......................................................................... 3-4 3.2.2.4 Rock, Sand and Gravel Quarries ................................................................... 3-5 FINAL ii March 2014 2014 Bacterial and Turbidity TMDLs in the Lower Arkansas River Area Table of Contents 3.2.3 No-Discharge Facilities and Sanitary Sewer Overflows .................................. 3-5 3.2.4 Concentrated Animal Feeding Operations ....................................................... 3-6 3.2.4.1 CAFO ............................................................................................................. 3-6 3.2.4.2 PFO ............................................................................................................... 3-7 3.2.5 Section 404 permits ....................................................................................... 3-13 3.3 Nonpoint Sources ..................................................................................................... 3-15 3.3.1 Wildlife ............................................................................................................ 3-15 3.3.2 Non-Permitted Agricultural Activities and Domesticated Animals ................. 3-16 3.3.3 Failing Onsite Wastewater Disposal Systems and Illicit Discharges ............. 3-19 3.3.4 Domestic Pets ................................................................................................ 3-20 3.4 Summary of Sources of Impairment ....................................................................... 3-21 3.4.1 Bacteria .......................................................................................................... 3-21 3.4.2 Turbidity ......................................................................................................... 3-22 SECTION 4 TECHNICAL APPROACH AND METHODS .................................................. 4-1 4.1 Determining a Surrogate Target for Turbidity .......................................................... 4-1 4.2 Using Load Duration Curves to Develop TMDLs ..................................................... 4-4 4.3 Development of Flow Duration Curves ..................................................................... 4-4 4.4 Estimating Existing Loading ...................................................................................... 4-6 4.4.1 Bacterial FDC ................................................................................................... 4-6 4.4.2 TSS FDC .......................................................................................................... 4-6 4.5 Development of TMDLs Using Load Duration Curves ............................................ 4-7 4.5.1 Step 1 - Generate LDCs .................................................................................. 4-7 4.5.1.1 Bacterial LDC ................................................................................................. 4-7 4.5.1.2 Turbidity LDC ................................................................................................. 4-8 4.5.2 Step 2 - Define MOS ........................................................................................ 4-8 4.5.3 Step 3 - Calculate WLA .................................................................................... 4-9 4.5.3.1 WLA for WWTF .............................................................................................. 4-9 4.5.3.1.1 WLA for Bacteria .......................................................................................... 4-9 4.5.3.1.2 WLA for TSS................................................................................................. 4-9 4.5.4 Step 4 - Calculate LA and WLA for MS4s ...................................................... 4-10 4.5.4.1 Bacterial WLA for MS4s ............................................................................... 4-10 4.5.4.2 Turbidity WLA for MS4s ............................................................................... 4-10