One focus of the Missouri Department of Natural Resources has been on restoring impaired waters and reducing pollutant levels in waterways. Water quality restoration and protection requires a watershed approach to ensure healthy waters for drinking, recreation and other uses. Watershed planning and improvement is not a small task – the right tools and resources can make all the difference in successful watershed planning and implementation projects.


Planning helps prioritize impaired waters and watersheds on a federal and state level. These plans have strategies and goals to protect watersheds. 

Note: EPA's 2013 Nonpoint Source Program and Grants Guidelines for States and Territories allows for alternatives to nine-element watershed based plans under specific conditions, if they adequately meet guidance requirements and are approved by EPA.

Mapping and Modeling

Click on the image to access an interactive map depicting HUC-8 and HUC-12 watersheds that intersect Missouri.

Watershed boundaries are marked by landscape features that divide the direction of surface water flow, such as hills and ridge lines. In order to identify and organize our watersheds, the U.S. Geological Survey (USGS) divided and sub-divided our nation into successively smaller hydrologic units. Each unit is assigned a unique hydrologic unit code (HUC) consisting of two to twelve digits, based on the classification level in the hydrologic unit system

  • Locate Your Stream Site by 12-digit HUC - USGS: An interactive map that can be used to locate your 2-digit region, 4-digit subregion, 6-digit basin, 8-digit subbasin, 10-digit watershed and 12-digit subwatershed. It also provides basic information about the unit and a link to additional watershed information from your subwatershed.
  • How’s My Waterway - EPA: An online database that provides information about the condition of your local waters based on data that states, federal, tribal, local agencies and others have provided to EPA.

Watershed modeling is a useful way to help determine what areas of a watershed are most in need of best management practice (BMP) implementation to address, and which BMPs would be most effective. The modeling application chosen will depend on the needs of the project. If Section 319 funding is being used for watershed planning or implementation, watershed modeling will most likely be needed to calculate pollutant load reductions.

Water Quality Assessment

Click on the image to access an interactive map depicting stormwater outfalls, monitoring sites, CAFOs, toxic event locations, etc.

Knowing and measuring the quality of water can be challenging. In order to be able to address problems in a watershed, you need good information about the status of the water resources, potential and actual threats, options for addressing the threats and data on how effective management actions have been. 

  • Section 305(b) Integrated Water Quality Report: Missouri's report summarizing water quality issues and the status of Missouri's waters
  • Impaired Waters: Learn about how the department identifies waters not meeting Missouri's water quality standards. Includes a link to Missouri's 303(d) list of impaired waterbodies.
  • Total Maximum Daily Loads (TMDLs): Learn how the department calculates the maximum amount of a specific pollutant that a water body can absorb and still meet water quality standards.
  • Impaired Waters and Total Maximum Daily Loads (TMDL) Viewer: An online interactive map that shows locational data for Missouri's impaired water bodies or lakes. Includes links to approved TMDL documents and implementation plans to identify how pollutant loads will be reduced to a level that will protect water quality. 
  • Water Quality Data Sources: Includes links to online sources of water quality data on the department's website, as well as other organizations.
  • Who’s Monitoring Your Watershed?: Interactive map showing Missouri Stream Team Volunteer Water Quality Monitoring sites and associated data. Data can be requested from department staff.
  • Science in Your Watershed - USGS: These "Information Discovery" pages are designed to help you find links to research, planning, management and development activities at the watershed level.
  • How’s My Waterway - EPA: An online application that provides information about the condition of your local waters based on data that states, federal, tribal, local agencies and others have provided to EPA.
  • Healthy Watersheds Protection - EPA: Find watersheds data, integrated assessments, indexes, reports and references
  • WATERS (Watershed Assessment, Tracking & Environmental Results System) - EPA: A database system that unites water quality information from several independent and unconnected databases. Access comprehensive information about the quality of the nation's surface water, including: designated use(s) of a waterbody, water quality monitoring results, water quality assessments, causes and sources of impaired waters and discharge locations.
  • International Stormwater BMP Database: A partnership between EPA and other public, private and nonprofit groups, this database is a repository of best management practice (BMP) field studies and related web tools, performance summaries and monitoring guidance.


In order to ensure high quality data collection and analysis outcomes, both watershed based planning and implementation projects require a quality assurance project plan (QAPP) for any environmental data collection activities (e.g. water quality monitoring), use of secondary data, and watershed or water quality modeling. Since QAPPs must be approved by the department, they must follow departmental and EPA guidance and requirements.

Education and Outreach

Watershed groups need to develop and implement an effective watershed outreach plan to help address public perceptions, promote management activities and inform or motivate stakeholders.