WATERSHED MANAGEMENT PLAN FOR THE SPRING CREEK WATERSHED Topical Report RSI-2416 prepared for Pennington County 315 Saint Joseph Street, Suite 118 Rapid City, South Dakota 57701 April 2015 WATERSHED MANAGEMENT PLAN FOR THE SPRING CREEK WATERSHED Topical Report RSI-2416 by Peter P. Rausch Justin W. Krajewski RESPEC P.O. Box 725 Rapid City, South Dakota 57709 prepared for Pennington County 315 Saint Joseph Street, Suite 118 Rapid City, South Dakota 57701 April 2015 ACKNOWLEDGEMENTS The Watershed Management Plan for the Spring Creek Watershed was developed as part of Segment 1 of the Spring Creek Watershed Management and Implementation Project. Funding for this project has been provided through an agreement with the South Dakota Department of Environment and Natural Resources (SD DENR) with grant funding from the U.S. Environmental Protection Agency Section 319(h) of the Clean Water Act. The Spring Creek Watershed Management and Implementation Project is sponsored by the Pennington County Board of Commissioners with support from the following organizations: city of Hill City; South Dakota School of Mines and Technology (SDSM&T); West Dakota Water Development District; city of Rapid City; U.S. Forest Service’s Black Hills National Forest; South Dakota Game, Fish and Parks; Black Hills Resource Conservation and Development Association; Pennington Conservation District; Black Hills Flyfishers; and the Natural Resources Conservation Service. Specific individuals involved in gathering, analyzing, and interpreting data for this plan include Ms. Brittney Molitor, Ms. Lysann Zeller, Ms. Kelsey Rausch, Ms. Mandi Schmierer, and Mr. Aaron Olson with Pennington County; Mr. Art Anderson and Mr. Brett McMacken with the city of Hill City; Mr. Chris Nichols with Custer County; Mr. Scott Hipple and Mr. Lee Baron with the SD DENR; Mr. Pete Rausch, Mr. Tom Schmitz, Mr. Tyler French, and Dr. Scott Kenner with the SDSM&T; and Ms. Teresa Whitney, Mr. Eric Krantz, Mr. Cory Foreman, Ms. Cindie McCutcheon, and Mr. Jared Oswald with RESPEC. In addition to the individuals and organizations mentioned above, special recognition and acknowledgement is reserved for the members of the Spring Creek Watershed Advisory Group and the residents and property owners within the project area who shared their information, thoughts and insights regarding their properties and the watershed. i TABLE OF CONTENTS 1.0 INTRODUCTION ................................................................................................................ 1 1.1 PROJECT AREA ........................................................................................................... 2 1.2 ADVISORY GROUP ..................................................................................................... 4 1.3 WATERSHED MANAGEMENT AND IMPLEMENTATION ................................... 4 1.3.1 Mission Statement ............................................................................................. 4 1.3.2 Goals ................................................................................................................... 4 1.3.3 Project Accomplishments................................................................................... 5 1.3.3.1 Segment 1 (2010–2012) ......................................................................... 5 1.3.3.2 Segment 2 (2012–Current).................................................................... 5 1.4 WATERSHED DESCRIPTION ................................................................................... 5 1.4.1 History ................................................................................................................ 6 1.4.2 Climate................................................................................................................ 7 1.4.3 Hydrology ............................................................................................................ 8 1.4.4 Geology ................................................................................................................ 12 1.4.5 Soils ..................................................................................................................... 16 1.4.6 Septic Absorption Field Soil Ratings ................................................................ 16 1.4.7 Vegetation ........................................................................................................... 19 1.4.8 Land Ownership and Land Use ........................................................................ 21 1.4.9 Addressed Structures ........................................................................................ 23 1.4.10 Population and Growth ..................................................................................... 25 1.4.11 Tourism and Recreation .................................................................................... 33 1.4.12 Motel, Hotel, and Campground Use ................................................................. 36 1.4.13 Forest and Timber.............................................................................................. 38 1.4.14 Pets and Domestic Animals............................................................................... 39 1.4.15 Grazing and Livestock ....................................................................................... 40 1.4.15.1 Black Hills National Forest Grazing Allotments .............................. 41 1.4.15.2 Private Land Grazing .......................................................................... 45 1.4.16 Wildlife and Fisheries ........................................................................................ 45 1.4.16.1 Wildlife ................................................................................................. 45 1.4.16.2 Fisheries ............................................................................................... 45 1.4.16.3 Sensitive Species ................................................................................. 47 1.4.16.4 Proposed, Threatened, and Endangered Species .............................. 51 1.5 WATER QUALITY........................................................................................................ 51 1.5.1 Beneficial Uses and Water Quality Standards ................................................ 51 1.5.2 303(d) Lists and Integrated Reports ................................................................. 53 1.6 PAST STUDIES AND ASSESSMENTS ..................................................................... 54 ii TABLE OF CONTENTS (Continued) 1.6.1 Total Maximum Daily Loads ............................................................................. 55 1.6.2 Watershed Modeling .......................................................................................... 56 1.7 WATER QUALITY MONITORING ............................................................................. 58 1.7.1 Monitoring Sites ................................................................................................. 59 1.7.2 Monitoring Results............................................................................................. 59 1.7.2.1 Fecal Coliform Bacteria ........................................................................ 63 1.7.2.2 E. coli ...................................................................................................... 86 2.0 ON-SITE WASTEWATER TREATMENT SYSTEMS .................................................... 90 2.1 ASSESSMENT OF ON-SITE WASTEWATER TREATMENT SYSTEMS .............. 91 2.1.1 Estimated Number of On-Site Wastewater Treatment Systems by Subwatershed ..................................................................................................... 93 2.1.2 Structure Types With Assessed On-Site Wastewater Treatment Systems ... 93 2.1.3 Types of Systems for Assessed On-Site Wastewater Treatment Systems ..... 93 2.1.4 Types of Septic Tanks for Assessed On-Site Wastewater Treatment Systems ............................................................................................................... 99 2.1.5 Permit Years and Estimated Ages for On-Site Wastewater Treatment Systems ............................................................................................................... 99 2.1.6 On-Site Wastewater Treatment System Repair Data ..................................... 102 2.1.7 Estimated On-Site Wastewater Treatment Systems Failure Rates .............. 105 2.2 PROXIMITY OF ON-SITE WASTEWATER TREATMENT SYSTEMS TO SPRING CREEK AND TRIBUTARIES ...................................................................... 106 2.3 ESTIMATED ON-SITE WASTEWATER TREATMENT SYSTEMS BACTERIA LOAD CONTRIBUTIONS ........................................................................................... 108 2.4 RULES AND REGULATIONS, CODES, AND ORDINANCES ................................ 111 2.5 PROBLEMS, ISSUES, AND CONCERNS ................................................................. 111 2.5.1 Managing Voluntary and Regulatory On-Site Wastewater Treatment System Approaches ............................................................................................ 112 2.5.2 Identifying Suitable On-Site Wastewater Treatment System Sites .............. 113 2.5.3 Affording the Cost of Replacing or Installing an On-Site Wastewater Treatment System.............................................................................................. 113 2.5.4 Obtaining Available Information About an Existing On-Site Wastewater Treatment System.............................................................................................