Texas Watershed Planning

Gathering Data on Your Watershed

Data Needed for Watershed Characterization

Physical and Natural Features

  • Watershed Boundaries
  • Topography
  • Climate
  • Wildlife
  • Hydrology
  • Soils
  • Habitat

Land Use and Population Characteristics

  • Land use and Land Cover
  • Demographics
  • Existing Management Practices

Waterbody Conditions

  • Water Quality Standards
  • TMDL reports
  • 305(b) report & 303(d) list
  • Source Water Assessments

Pollutant Sources

  • Point Sources (PS)
  • Nonpoint Sources (NPS)
How can Local Governments Assist?

County and City Planning Offices

  • Master Plans
  • Local Ordinances
  • Stormwater Pollution Prevention Plans

Economic Development

  • Census Data & Demographics
  • Tax Records

Public Health Department

  • OSSF permits and violations
  • Records of outbreaks

Soil & Water Conservation Districts & USDA NRCS

  • Agricultural Land Use Information
  • Soil Surveys
  • Erosion Control Information
  • Flood Control Structures

Environmental Departments

  • Water Quality Data
  • Recycling Programs

Water and Sanitation Department

  • Stormwater plans
  • Maps of water and sewer

Transportation Department

  • Transportation master plan
  • Permits
  • Road & bridge construction

Council of Governments

  • Data & Information Including GIS Layers
  • Grant Funding Programs
Data Provided by State Agencies

Texas State Soil & Water Conservation Board

Texas Forest Service

Texas Commission on Environmental Quality

Texas Parks and Wildlife Data

  • Wildlife Data, Deer Counts and Endangered Species
  • Ecoregions and Habitat Data
  • Kills and Spills Data

Texas Water Development Board

The Railroad Commission of Texas

Data provided by Federal Agencies

U.S. Environmental Protection Agency

U.S. Fish & Wildlife Service

United States Department of Agriculture

USDA Natural Resources Conservation Service

USDA Farm Service Agency

U.S. Geological Survey

Mapping your Watershed

Determine the boundaries of the watershed





  • Determine climate conditions for your watershed including annual rainfall amounts, runoff, and evaporation amounts
  • Will help understand what drives the rainfall-runoff processes in watershed models
  • Online sites of weather data include:

Land Use & Land Cover

  • National Land Cover Database
  • USGS's LULC data
  • May be obtained from local and regional agencies such as Counties or Council of Governments
  • Land Use data can also be updated from aerial photographs, satellite images and ground surveys


Demographic data includes information on people in the watershed:

  • Persons or families
  • Household structure
  • Economic conditions
  • Commuting patterns
  • Age, Gender, and Race
  • Employment and Education

Water Quality Standards

  • Texas Surface Water Quality Standards
    • Establish explicit water quality goals throughout the state
    • Set to maintain the quality of water in Texas consistent with public health and enjoyment, protection of aquatic life, and the operation of existing industries and economic development of the state

Water Quality Reports

  • Determine locations of concerns and impairments within the watershed
  • Find reports completed on the watershed by others:
    • Water Quality Standards
    • TMDL Reports
    • Fish Kill Reports
    • 305(b) report & 303 (d) list
    • Source Water Assessments
    • Texas Commission on Environmental Quality, Texas Parks & Wildlife Department, Railroad Commission of Texas, Counties, Texas Water Development Board, River Authorities, Universities

Water Quality Data
Water Quality Data in tabular form can be obtained from:

Biannual 305(b) State Water Quality Report

  • Under Section 305(b) of the Clean Water Act, states are required to prepare a report describing the status of the water quality every two years
  • If your watershed has been monitored than the report should have:
    • Status of use support with descriptions of significant water quality impairments
    • Identification of problem parameters for impaired waters, along with potential sources of the stressors
    • Priority for TMDL development

303(d) List of Impaired Waters

  • Identify known pollutant impairments
  • Identify geographic extent of impaired segments
  • Identify potential causes and sources of impairments

How much data is enough?

How much data is enough? This is one of the biggest challenges because there is always more data to collect. You must balance resources, ability to reasonably characterize watershed and need to keep the process moving forward.

Conduct Data Review

Evaluate data you've compiled & assess:

  • Do you have the right types of data to identify causes and sources?
  • Evaluate the quality of the data.
Identify Data Gaps
  • Does my data include all types of information needed?
  • Does my data cover the time periods needed?
    • "Old data" (conditions have changed)
    • Season or hydrologic condition
  • Does my data provide good spatial coverage of the watershed?
    • Underrepresentation of specific areas
Evaluate Data Quality
  • What were the goals of the monitoring activity? Were they consistent with yours?
  • What types of data were collected? Are they relevant to your needs?
  • How were the data collected? Were the sites selected randomly or targeted?
Evaluate Measurement Quality

Measurement quality describes data characteristics like accuracy, precision, sensitivity, and detection limit, basically all the things that should be covered in a QAPP.

  • Was data collected under a Quality Assurance Project Plan?
  • How old is the data? Analysis methods different from today's methods?
  • Is the quality of the data known?
Decide if new data is needed

Compare your available resources against your tasks:

  • Can we identify & quantify water quality problems in the watershed?
  • Can we quantify pollutant loads where water quality problems exist?
  • Can we link water quality impairments to specific sources/source areas?
  • Do we know enough to select & target management measures to reduce pollutant loads & address water quality impairments?

If you answer YES to all of these questions, you are ready to move on to data analysis. If you answer NO, the next step is to design a sampling plan to fill the gaps.

In Texas, most watersheds do not have enough data available in to characterize sources and causes and quantify pollutant loads prior to the initiation of a watershed-based planning process.

Design Sampling Plan

Guidance on Choosing a Sampling Design for Environmental Data Collection

  • EPA QA/G-5S
    Steps in Designing Sampling Plans
    1. Select Monitoring Design
    2. Develop Data Quality Objectives
    3. Develop Measurement Quality Objectives & Performance Criteria
    4. Develop Plan for Data Management
    5. Develop QAPP

It is important to focus on immediate data collection needs for completing watershed characterization and consider long-term monitoring needs

Collect New Data

Data collection techniques

  • Watershed Overview/Visual Assessment
  • Physical Characterization
  • Geomorphic Assessment
  • Hydrological Assessments
  • Water Quality Assessment
  • Assessment of Habitat Quality
  • Biological Assessment
Watershed Survey/“Visual Assessment”

You can do this with very little resources and it has many benefits.
Walking, drive, and/or boat your watershed; and observe and photograph water and land conditions.


  • This gives you a good working knowledge of the watershed which will benefit you as you speak to local stakeholders.
  • It can help you begin to identify and verify pollutants and sources. Some sources such as streambank erosion won't show up in many routine monitoring or modeling analysis, but will using this approach.
  • Photographs for presentations and publications.
  • NRCS Visual Stream Assessment Protocol
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