A watershed is a contained land area that channels rainfall and snowmelt downward from the highest ridge top to the lowest creeks, streams, rivers and lakes. The USGS classifies watersheds by a number called the hydrologic unit code, or HUC. See Hydrologic Units (scroll to end of page)
2-digit HUC: The larger the watershed, the smaller the number. Moniteau County is located in the huge Missouri River 2-digit HUC 10. This HUC 10 is further divided into smaller HUCs.
8-digit HUC: Missouri contains sixty-six 8-digit HUCS. This is the scale MDNR frequently uses to monitor water quality and identify locations of impaired waters. Moniteau County is located in the 8-digit HUC #10300102 Lower Missouri-Moreau Rivers Watershed. Read More about the watershed.
12-digit HUC: The 8-digit HUC watersheds are further divided into 1,900 smaller 12-digit HUCs. Moniteau County has all or parts of twelve 12-digit HUCs within its borders. This scale is used for communities to develop Watershed Management Plans and implement Conservation Practices.
In the new 2023 CAFO operating permit, MDNR begins monitoring where and in what quantities animal waste is applied to the land at the HUC-12 scale.
Hydrologic Unit Code (HUC) boundary maps from MDNR
Contact MCNA if you need help using the maps.
EPA How’s My Waterway? - Learn about about the water quality in your watershed.
EPA Healthy Watershed Protections – Comprehensive overview of watersheds, and how to assess and protect them.
USGS StreamStats – Access to spatial analytical tools that are useful for water-resources planning and management.
Missouri’s thousands of miles of rivers, streams and lakes, along with underground aquifers, supply our state’s 6 million residents with water. Half of the residents receive drinking water from the Missouri River and its alluvium. About 1.4 million residents acquire drinking water from more than 400,000 private wells. Both MDNR and the Missouri Department of Health and Human Services (DHSS) report on drinking water quality
Private Drinking Water (DHSS)
Public Drinking Water (MDNR)
The MDNR Water Protection Program conducts water quality monitoring of surface waters as part of its responsibility to implement the federal Clean Water Act. The USGS in cooperation with MDNR, collects data from about 71 sites as part of the Missouri Ambient Water-Quality Monitoring Network (AWQMN).
MDNR consolidates AWQMN data with Missouri Stream Team data and others to determine if the waters of the state meet Water Quality Standards (WQS). Use the MDNR WQ Search below to access all of MDNR's water quality data.
The USGS Report: 1993-2017 Water Quality Trends in the AWQMN is a valuable study of Missouri's water quality over time.
Missouri Stream Teams Voluntary Water Quality Monitoring Program began in 1993. Since then thousands of Stream Team volunteers have been trained to collect samples from the state's waterways to report on their water quality.
The Missouri Stream Team Water Quality Report 1993-2016 compiles and summarizes data from over 40,000 sampling events in each of the 13 regions in the state.
Missouri Stream Teams United is a 501(c)3 nonprofit that supports the Stream Team Program. See: Weekly Water News, and the Legislative Outlook
The Missouri Geological Survey (MGS) Water Resources Center hydrologists, geologists and engineers investigate and monitor surface water and groundwater resource characteristics, availability and use, but do not monitor groundwater quality. Through the MDNR Public Drinking Water Program, public systems acquiring drinking water from wells are required to monitor water quality. For private wells, the Department of Health and Human Services (DHSS) provides monitoring upon request.
Ensuring Missouri waters are safe to enjoy today, as well as for future generations, is a challenge as any material applied to the Earth’s surface can runoff and pollute the waterways.
Wherever pollution enters a waterway upstream, the people, plants, and animals living downstream are put at risk from contamination.
Point Source (PS) Pollution: About 15% of all water pollution in Missouri. Comes from an identified source, like a wastewater treatment facility. Regulated by MDNR.
Nonpoint Source (NPS) Pollution: About 85% of water pollution. Comes from diverse sources difficult to identify and monitor. Unregulated by the MDNR. NPS pollution derives from organic materials (like animal waste, human bio solids, and food processing residues) and non-organic materials (like chemical fertilizers). These materials are routinely “land applied” all over Missouri. Rain and snow cause runoff of the materials into waterways, which then travel “downstream,” ending up in the Gulf of Mexico where they contribute to the Dead Zone. Protection of waterbodies from NPS pollution relies totally on voluntary efforts. See: MDNR NPS Pollution
The federal Clean Water Act (CWA) goal is "to restore and maintain the chemical, physical, and biological integrity of the Nation's waters." The CWA requires MDNR to provide the following Water Quality Reports to the EPA every two years:
See Water Quality Standards Map Viewer
Missouri’s WQS describe the desired condition of Missouri's waterbodies and the means by which those conditions will be protected or reached.
Water Quality Standards consist of:
1) Designated use or uses of a waterbody that classify the protection given to a stream, river or lake including:
2) Criteria necessary to protect the designated uses in the form of concentrations, loads, or narrative statements. For example, E-coli bacteria is a common water pollutant from animal and human waste. The designated use of whole body contact recreation cannot be achieved if water quality monitoring shows E. coli colonies over 126 per 100 milliliters of water during the April 1 through Oct. 31 recreation season.
3) Antidegradation policy requires actions to maintain and protect high quality waters and existing water quality.
If a waterbody cannot meet its designated use, the MDNR is required to complete a restoration plan that includes a Total Maximum Daily Load (TMDL). The TMDL Report determines the load (amount) of pollutant entering the waterway, where it is coming from, and how much that load must be reduced for the water body to meet the WQS associated with the designated use.
The TMDL Report is used by communities that develop a Watershed Management Plan to voluntarily restore the quality of their local waters. The TMDL sets targets for reducing NPS and PS pollution. Communities can access MDNR 319 funds, and other sources of funding, to develop their plan and pay for “conservation practices” to reduce pollution.
Organizations involved in water quality issues:
Association of State Drinking Water Administrators is the professional association serving state drinking water programs.
Missouri Confluence Waterkeeper is a grassroots, citizen-led conservation organization focused on clean water and dedicated to protecting fishable, swimmable, drinkable water for all Missourians.
North Central Region Water Network is an Extension-led partnership of 12 land-grant universities, ensuring safe and sufficient water supplies and sustainable, resilient communities.
MDNR maps at either: 1) GeoPlatform, or 2) MDNR GIS Office of Geospatial Information