Original TMDL
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Upper San Antonio River Watershed Protection Plan SSaa nn AAnnttoonniioo RRiivveerr AAuutthhoorriittyy BBeexxaarr RReeggiioonnaall WWaatteerrsshheedd MMaannaaggeemmeenntt PPaarrttnneerrsshhiipp TTeexxaass CCoommmmiissssiioonn oonn EEnnvviirroonnmmeennttaall QQuuaalliittyy James Miertschin & Associates, Inc. Parsons, Inc. JAMES MIERTSCHIN & ASSOCIATES, INC. ENVIRONMENTAL ENGINEERING P.O. BOX 162305 • AUSTIN, TEXAS 78716-2305 • (512) 327-2708 UPPER SAN ANTONIO RIVER WATERSHED PROTECTION PLAN Prepared For: San Antonio River Authority 100 East Guenther Street San Antonio, Texas 78204 and Bexar Regional Watershed Management Partnership Prepared in Cooperation With: Texas Commission on Environmental Quality The preparation of this report was financed through grants from the Texas Commission on Environmental Quality. Prepared By: James Miertschin & Associates, Inc. Parsons, Inc. December 2006 The Seal appearing on this document was authorized by Dr. James D. Miertschin, P.E. 43900 on 14 Dec 2006. TABLE OF CONTENTS Section Page LIST OF TABLES...............................................................................................................v LIST OF FIGURES ........................................................................................................... vi LIST OF ABREVIATIONS ............................................................................................. vii I. WPP SUMMARY...........................................................................................................1 1.0 INTRODUCTION ...................................................................................................1 1.1 WATERSHED PROTECTION PLAN CONCEPT ................................................1 1.2 PROJECT DEVELOPMENT ..................................................................................1 1.3 PROJECT BACKGROUND ...................................................................................2 1.3.1 Upper San Antonio River Basin ..............................................................................2 1.3.2 Water Quality Criteria for Bacteria..........................................................................6 1.3.3 Assessment of Bacteria Impairment ........................................................................6 1.4 REVIEW OF TMDL RESULTS .............................................................................6 1.4.1 Source Identification................................................................................................6 1.4.2 Linkage Between Sources and Receiving Waters ...................................................7 1.4.3 Required Load Reductions.......................................................................................8 1.5 STAKEHOLDER INVOLVMENT.........................................................................9 1.5.1 Stakeholder Groups, Roles, & Input........................................................................9 1.5.2 Public Outreach......................................................................................................11 2.0 WPP KEY ELEMENTS ........................................................................................14 2.1 MANAGEMENT MEASURES FOR POINT SOURCES....................................14 2.1.1 San Antonio Zoo Point Source ..............................................................................14 2.1.2 Stormwater Runoff Point Sources .........................................................................15 2.2 MANAGEMENT MEASURES FOR NONPOINT SOURCES ...........................17 2.2.1 Direct Nonpoint Sources – Wildlife ......................................................................17 2.2.2 Direct Nonpoint Sources – Human Origin.............................................................19 2.2.3 Direct Nonpoint Sources – Flow Augmentation....................................................19 2.4 NINE ELEMENT SUMMARY TABLE...............................................................20 2.5 SUMMARY TIMETABLE FOR IMPLEMENTATION......................................29 II. SUPPLEMENTAL SECTIONS ................................................................................30 3.0 WATER QUALITY DATA REVIEW..................................................................30 3.1 HISTORICAL SAMPLING ..................................................................................30 3.1.1 Routine River Sampling.........................................................................................30 ii 3.1.2 Urban Runoff Sampling.........................................................................................32 3.1.3 Zoo Discharge Sampling........................................................................................36 3.1.4 Bacterial Source Tracking......................................................................................36 3.2 VERFICATION SAMPLING ...............................................................................38 3.2.1 General Assessment Survey...................................................................................38 3.2.2 Baseline Surveys....................................................................................................47 3.2.3 Runoff Survey........................................................................................................53 4.0 WATER QUALITY MODEL ENHANCEMENTS..............................................55 4.1 WATERSHED BOUNDARY ADJUSTMENTS..................................................55 4.2 REVISED LAND USE DATA..............................................................................58 4.3 SAN ANTONIO RIVER TUNNEL ......................................................................62 5.0 MANAGEMENT MEASURES FOR POINT SOURCES....................................64 5.1 ZOO EXISTING CONDITIONS ..........................................................................64 5.1.1 Dry Weather Conditions ........................................................................................64 5.1.2 Wet Weather Conditions........................................................................................66 5.1.3 Water Quality.........................................................................................................66 5.2 ZOO TREATMENT ALTERNATIVES ...............................................................67 5.2.1 Chlorination ...........................................................................................................67 5.2.2 Chloramination ......................................................................................................68 5.2.3 Ultraviolet (UV) Disinfection................................................................................68 5.2.4 Ozonation...............................................................................................................71 5.2.5 Treatment Wetlands...............................................................................................73 5.2.6 Diversion to Sanitary Sewer ..................................................................................77 5.2.7 BMPs Inside the Zoo .............................................................................................78 5.2.8 Treatment of Stormwater Flows ............................................................................79 5.2.9 Water Recycling.....................................................................................................80 5.3 SUMMARY OF ZOO TREATMENT ALTERNATIVES ...................................81 6.0 MANAGEMENT MEASURES FOR NONPOINT & RUNOFF SOURCES ......82 6.1 INTRODUCTION .................................................................................................82 6.2 ASSESSMENT OF POTENTIAL SOURCES......................................................82 6.2.1 Urban Runoff .........................................................................................................82 6.2.2 Direct Animal Deposition......................................................................................83 6.2.3 Septic Systems .......................................................................................................83 6.2.4 Wastewater Collection Systems.............................................................................83 6.2.5 Homeless/Transient Population .............................................................................84 6.3 ASSESSMENT OF BMPS FOR WW COLLECTION INFRASTRUCTURE ....84 6.3.1 Rehabilitation, Replacement, and Maintenance of City Sewers............................84 6.3.2 Rehabilitation, Replacement, and Maintenance of Private Sewer Laterals...........85 6.4 ASSESSMENT OF BMPS FOR SEPTIC SYSTEMS ..........................................86 iii 6.4.1 Public Education ....................................................................................................86 6.4.2 Inspection and Maintenance ..................................................................................87 6.4.3 Upgrade or Replacement of Failing Systems.........................................................87 6.4.4 Chemical Additive Restrictions.............................................................................88 6.4.5 Connect Customer to Sewer System......................................................................88 6.5 ASSESSMENT OF BMPS FOR DIRECT ANIMAL DEPOSITION ..................88 6.5.1 Wildlife ..................................................................................................................89 6.5.2 Domestic Pets.........................................................................................................90