Water: Watershed Central
Characterize the Watershed - Gather Existing Data and Create a Watershed Inventory
More info on Characterize the Watershed
- Gather Existing Data and Create a Watershed Inventory
- Identify Data Gaps and Collect Additional Data
- Analyze Data
- Identify Causes and Sources That Need to Be Controlled
- Estimate Pollutant Loads
- Results and Next Steps
The variety and quantity of data available vary by watershed, making it difficult to decide which data (and analyses) are necessary. To make these decisions easier, your data-gathering efforts should be guided by your earlier scoping efforts, based on the conceptual model, preliminary watershed goals, and stakeholder concerns.
To keep your effort focused on essential information, use the conceptual model that was developed while establishing partnerships and tailor your data gathering efforts accordingly. Gathering non-essential data can cost you extra money and distract you from the established scope of the planning effort.
In general, there are five broad categories of data used to characterize watersheds:
- Physical and natural features - Information on the physical and natural characteristics of your watershed will allow you to define the watershed boundary and can provide you with a basic understanding of the watershed features that can influence watershed sources and pollutant loading. Section 5.4 (PDF) (56 pp, 1.4MB, About PDF) on page 5-9 of EPA's Watershed Planning Handbook provides complete lists of data sources of physical and natural features.
- Land use and population characteristics - This information can help you to understand the potential growth of the area and possible changes in land uses and sources, providing a logical basis for identifying or evaluating sources. Evaluating land use distribution and associated sources also facilitates the development of future implementation efforts. Demographic information can be used to help design public outreach strategies, identify specific subpopulations to target during the implementation phase, or help determine future trends and needs of the populations. Section 5.5 (PDF) (56 pp, 1.4MB, About PDF) on page 5-18 of EPA's Watershed Planning Handbook provides additional information on land use and population characteristics.
- Waterbody conditions - You will need to obtain the all applicable (and current) water quality standards for your watershed to understand existing and designated uses established for the waterbodies and to compare instream monitoring data with standards to evaluate impairment. You should also document the criteria set for the waterbodies and any relevant criteria for evaluating waterbody conditions. Section 5.6 (PDF) (56 pp, 1.4MB, About PDF) on page 5-26 of EPA's Watershed Planning Handbook provides additional information on waterbody and watershed conditions.
- Pollutant sources - Characterizing and quantifying watershed pollutant sources can provide information on the relative magnitude and influence of each source and its impact on instream water quality conditions. Watershed-specific sources will typically be identified and characterized through a combination of generation, collection, and evaluation of GIS data, instream data and local information. Section 5.7 (PDF) (56 pp, 1.4MB, About PDF) on page 5-30 of EPA's Watershed Planning Handbook provides additional information on identifying and characterizing pollutant sources.
- Waterbody monitoring data - This information is used to evaluate the condition of the water bodies in your watershed. Section 5.8 (PDF) (56 pp, 1.4MB, About PDF) on page 5-35 of EPA's Watershed Planning Handbook provides additional information on finding and using waterbody monitoring data.
For more information on types of data typically collected for watershed characterization and the data's potential uses see Table 5-1 (PDF) (56 pp, 1.4MB, About PDF) on page 5-8 of EPA's Watershed Planning Handbook.
Data sources may come from local, state, tribal, or federal sources:
- Local sources of information will support the watershed characterization and any major changes expected to occur in the watershed. To know what is available and how to get county-level information, be familiar with state-, county-, and city-level agencies and the authority and jurisdictions of the agencies in the watershed. Other local data sources include universities and environmental non-governmental organizations (NGOs).
- State sources of information can provide biological, hydrological, and water quality information for the waters in the state. Go to your state's environmental agency's Web site to learn which types of offices work in your state and identify potential sources of relevant information.
- Tribal sources of information are important in watersheds that include tribal land. First search the Web to see if the specific tribe has a Web site with historical data or background information or reports.
- Federal sources of information are available from several federal agencies, including EPA, USDA, and USGS. Within the various offices, divisions, and agencies in the federal government, there are likely several federal sources of every type of data used in watershed characterization.
USEPA Biological Criteria: Technical Guidance for Survey Design and Statistical Evaluation of Biosurvey Data - Full Technical Guidance document is available in PDF format.
EPA / Monitoring and Assessing Water Quality / Rapid Bioassessment Protocols for Use in Streams and Wadeable Rivers: Periphyton, Benthic Macroinvertebrates, and Fish - This Web site provides information about the evaluation of community assemblages (e.g., macroinvertebrates, fish, periphyton)¡ªa critical measure of the overall effectiveness of habitat protection management measures.
USDA 2007 Census of Agriculture - FAQ for the Census of Agriculture.