Gathering Data on Your Watershed
- Data Needed for Watershed Characterization
Physical and Natural Features
- Watershed Boundaries
Land Use and Population Characteristics
- Land use and Land Cover
- Existing Management Practices
- Water Quality Standards
- TMDL reports
- 305(b) report & 303(d) list
- Source Water Assessments
- Point Sources (PS)
- Nonpoint Sources (NPS)
- How can Local Governments Assist?
County and City Planning Offices
- Master Plans
- Local Ordinances
- Stormwater Pollution Prevention Plans
- 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
- Water Quality Data
- Recycling Programs
Water and Sanitation Department
- Stormwater plans
- Maps of water and sewer
- Transportation master plan
- Road & bridge construction
Council of Governments
- Data & Information Including GIS Layers
- Grant Funding Programs
- Data Provided by State Agencies
- Water Quality Management Plans
- Dry Litter Poultry Operations
- Brush Control Program
- Silviculture (Forestry)
- Forest Management and Sustainable Forestry
- Urban Forestry and Pest Management
- Fire and Emergency Response
- Water Quality Data
- 305b reports and 303d Lists
- Previous reports such as TMDLs, waste load reports, source water protection and any other studies
- Wildlife Data, Deer Counts and Endangered Species
- Ecoregions and Habitat Data
- Kills and Spills Data
- Ground Water/Well Data
- Water and Wastewater Planning and Assessments
- Population Projections
- Texas Natural Resources
- Geographic information of Texas
- Aerial photos
- Satellite imagery
- Electronic or paper maps
- Data provided by Federal Agencies
- Farm and Crop Information
- Data from Federal Agencies
- USGS Water Data
- Real-Time Water Data for Texas
- Surface water
- Water quality
- Water Resources of the United States
- Water Resources of Texas
- Mapping your Watershed
Determine the boundaries of the watershed
- Derives slopes of stream segments and watershed areas to identify unstable areas and to characterize segments or subwatersheds to model
- Evaluate altitude changes
- Topo Maps:
- Identify locations of waterbodies
- Many databases are organized or referenced by HUC Codes
GIS coverages are available in:
- Daily Streamflow Conditions
- Soil characteristics will help identify high erosion prone areas, poor drainage & runoff
- STATSGO: State Soil Geographic Database, generalize the detailed soil maps at a scale of 1:250,000
- SSURGO: Soil Survey Geographic Database, at scale of 1:12,000 to 1:63,360, the most detailed level of soil mapping
- USDA-NRCS Web Soil Survey
- Texas Online Soil Survey Manuscripts
- 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
- 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
- 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
Steps in Designing Sampling Plans
- Select Monitoring Design
- Develop Data Quality Objectives
- Develop Measurement Quality Objectives & Performance Criteria
- Develop Plan for Data Management
- Develop QAPP
It is important to focus on immediate data collection needs for completing watershed characterization and consider long-term monitoring needs
- EPA QA/G-5S
- 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