BIG BEAR LAKE TMDL ACTION PLAN Prepared for Big Bear Lake Nutrient TMDL Task Force August 26, 2010 9665 Chesapeake Drive, Suite 201 San Diego, California 92123 THIS PAGE INTENTIONALLY LEFT BLANK Big Bear Lake TMDL Action Plan TABLE OF CONTENTS TABLE OF CONTENTS ................................................................................................................................................ III LIST OF FIGURES........................................................................................................................................................ V LIST OF TABLES ......................................................................................................................................................... VI LIST OF ABBREVIATIONS ......................................................................................................................................... VII EXECUTIVE SUMMARY ............................................................................................................................................... 1 1. INTRODUCTION..................................................................................................................................................... 1-1 1.1 Watershed Setting ........................................................................................................................................ 1-1 1.2 Big Bear Lake Watershed and Lake Characteristics .................................................................................... 1-5 1.3 Big Bear Lake Water Quality ........................................................................................................................ 1-7 1.4 Regulatory Context ....................................................................................................................................... 1-9 1.4.1 TMDL Development .......................................................................................................................... 1-9 1.4.2 Big Bear Lake Nutrient TMDL Task Force ...................................................................................... 1-11 1.5 Other Related Activities .............................................................................................................................. 1-11 1.5.1 Nuisance Aquatic Plant Management ............................................................................................. 1-11 1.5.2 Fisheries Management ................................................................................................................... 1-12 1.5.3 Model Updates ................................................................................................................................ 1-12 2. SEDIMENT NUTRIENT REDUCTION PLAN .......................................................................................................... 2-1 2.1 Approach ...................................................................................................................................................... 2-1 2.2 Findings ........................................................................................................................................................ 2-1 2.2.1 Water Level Management ................................................................................................................. 2-2 2.2.2 Dredging ........................................................................................................................................... 2-3 2.2.3 Lake Treatment ................................................................................................................................. 2-9 2.2.4 Aeration and Destratification ........................................................................................................... 2-14 2.2.5 Other Possible Activities ................................................................................................................. 2-24 2.3 Recommendations ...................................................................................................................................... 2-24 2.3.1 Alternatives Screening .................................................................................................................... 2-25 2.3.2 Sediment Disposal and Beneficial Re-use: Planning for the Future................................................ 2-26 2.3.3 Updates to Lake Monitoring Plan .................................................................................................... 2-28 2.3.4 Comprehensive Schedule ............................................................................................................... 2-28 2.3.5 Summary and Perspective .............................................................................................................. 2-29 3. WET WEATHER STRATEGIES FOR CONTROLLING NUTRIENT INPUTS TO BIG BEAR LAKE ....................... 3-1 3.1 Introduction ................................................................................................................................................... 3-1 3.2 Overview of Best Management Practices ..................................................................................................... 3-1 3.2.1 Overview of Nutrient Removal Mechanisms ..................................................................................... 3-1 3.2.2 BMPs for Nutrient Removal .............................................................................................................. 3-2 3.2.3 Performance Locally ......................................................................................................................... 3-4 iii Use of contents on this sheet is subject to the limitations specified at the end of this document. S01255.FINAL_Big Bear LakeTMDL Action Plan 8-26-2010 Table of Contents Big Bear Lake TMDL Action Plan 3.2.4 Nutrient Removal Efficiencies ........................................................................................................... 3-6 3.2.5 Nonstructural and Operational BMPs ............................................................................................... 3-7 3.3 Project Approach .......................................................................................................................................... 3-8 3.3.1 Review of BMP Documents .............................................................................................................. 3-8 3.4 Interview Findings ....................................................................................................................................... 3-11 3.4.1 City of Big Bear Lake ...................................................................................................................... 3-11 3.4.2 San Bernardino County Flood Control District ................................................................................ 3-12 3.4.3 San Bernardino County ................................................................................................................... 3-12 3.4.4 US Forest Service ........................................................................................................................... 3-12 3.4.5 Big Bear Mountain Resorts ............................................................................................................. 3-13 3.4.6 California Department of Transportation ......................................................................................... 3-13 3.5 Implementation of BMPs ............................................................................................................................. 3-14 3.5.1 Opportunities and Constraints ........................................................................................................ 3-14 3.5.2 Costs ............................................................................................................................................... 3-14 3.6 Conclusions ................................................................................................................................................ 3-17 4. NUSIANCE AND NOXIOUS AQUATIC PLANT MANAGEMENT PLAN ................................................................. 4-1 4.1 Introduction ................................................................................................................................................... 4-1 4.1.1 NAPMP Objectives ........................................................................................................................... 4-2 4.1.2 Problem Statement ........................................................................................................................... 4-3 4.2 Background ................................................................................................................................................... 4-3 4.2.1 Aquatic Plant Species in Big Bear Lake ............................................................................................ 4-4 4.2.2 Historical Aquatic Plant Management Efforts .................................................................................... 4-6 4.2.3 Pilot Programs to Eradicate Eurasian Water Milfoil .......................................................................... 4-7 4.3 Noxious and Nuisance Aquatic Plant Monitoring Program ........................................................................... 4-7 4.3.1 Aquatic Plant Monitoring Approach ..................................................................................................