White Rock Lake Watershed Data Report July 2013 The preparation of this report was prepared in cooperation with, and financed through, grants from the Texas Commission on Environmental Quality and the U.S. Environmental Protection Agency. Table of Contents Introduction .................................................................................................................................................. 4 White Rock Lake Watershed Characterization ............................................................................................. 5 Location and Climate ................................................................................................................................ 5 Physical Description and Land Use .......................................................................................................... 6 History ...................................................................................................................................................... 6 Water Quality Parameters ............................................................................................................................. 6 Water Temperature ................................................................................................................................... 6 Dissolved Oxygen ..................................................................................................................................... 7 Specific Conductivity and Total Dissolved Solids .................................................................................... 7 pH ............................................................................................................................................................. 7 Secchi disk and total depth........................................................................................................................ 8 Texas Surface Water Quality Standards .................................................................................................... 8 Data Analysis Methodologies ..................................................................................................................... 10 Data Collection ....................................................................................................................................... 10 Processes to Prevent Contamination ................................................................................................... 10 Documentation of Field Sampling Activities ...................................................................................... 10 Data Entry and Quality Assurance .......................................................................................................... 11 Data Entry ........................................................................................................................................... 11 Quality Assurance & Quality Control ................................................................................................. 11 Data Analysis Methods ........................................................................................................................... 11 Standards & Exceedances ................................................................................................................... 12 Methods of Analysis ........................................................................................................................... 12 White Rock Lake Watershed Data Analysis ............................................................................................... 13 White Rock Lake Watershed Maps ......................................................................................................... 13 White Rock Lake Watershed Trends over Time ..................................................................................... 13 Sampling Trends over Time ................................................................................................................ 13 Descriptive Parameters over Time ...................................................................................................... 14 Trend Analysis over Time....................................................................................................................... 15 Air and water temperature ................................................................................................................... 15 Total Dissolved Solids ........................................................................................................................ 16 Dissolved Oxygen ............................................................................................................................... 17 pH ....................................................................................................................................................... 20 1 | P a g e Secchi disk and total depth .................................................................................................................. 21 Field Observations .............................................................................................................................. 22 White Rock Lake Watershed Site by Site Analysis .................................................................................... 22 Site 14415 – White Rock Lake at Mockingbird Lane near the West Bank on South Side of Road ......... 23 Site Description................................................................................................................................... 23 Sampling Information ......................................................................................................................... 23 Air and water temperature ................................................................................................................... 24 Total Dissolved Solids ........................................................................................................................ 24 Dissolved Oxygen ............................................................................................................................... 25 pH ....................................................................................................................................................... 25 Secchi disk and total depth .................................................................................................................. 25 Field Observations .............................................................................................................................. 25 Site 13485 – Mockingbird Lake at White Rock Lake ............................................................................. 25 Site Description................................................................................................................................... 25 Sampling Information ......................................................................................................................... 25 Air and water temperature ................................................................................................................... 26 Total Dissolved Solids ........................................................................................................................ 26 Dissolved Oxygen ............................................................................................................................... 26 pH ....................................................................................................................................................... 26 Transparency Tube and Total Depth ................................................................................................... 27 Field Observations .............................................................................................................................. 27 Site 80333 – Rush Creek at Fisher/Branchfield near White Rock Lake .................................................. 27 Site Description................................................................................................................................... 27 Sampling Information ......................................................................................................................... 27 Air and water temperature ................................................................................................................... 28 Total Dissolved Solids and Salinity .................................................................................................... 28 Dissolved Oxygen ............................................................................................................................... 28 pH ....................................................................................................................................................... 29 Secchi disk and total depth .................................................................................................................. 29 Field Observations .............................................................................................................................. 29 Site 80272 – Williamson Creek at W. Lawther Bridge on White Rock Lake.......................................... 29 Site Description................................................................................................................................... 29 Sampling Information ........................................................................................................................