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Skip Navigation LinksDNREC : Division of Watershed Stewardship : Watershed Assessment & Management : Watershed Assessment

Watershed Assessment and Management Section

DNREC Water Quality Monitoring Network Data Portal 
Here you can search for monitoring stations near you, see the latest water
quality conditions, generate graphs of data, and download data reports!

We all live in a watershed! Watersheds are the land areas that drain to water bodies like ponds, streams, estuaries, and oceans. What we do on the land affects the quality of those waters. To protect water from nonpoint source pollution, it is important to think about management actions to improve water quality on a watershed scale.

Delaware has four larger scale watersheds, or drainage basins. In northern Delaware, water flows through the Piedmont Drainage, which is named after the local geology. Streams and ponds in western Delaware drain to the Chesapeake Bay, while in eastern Delaware they drain to the Delaware Bay. In southeastern Delaware, water flows to the Inland Bays and the Atlantic Ocean. These larger scale watersheds can be broken down into smaller watersheds, which are named after the main water features within each. There are 45 of these watersheds in Delaware.

Delaware's major basins. The state has 45 of them.The Watershed Assessment and Management Section oversees the health of the State's water resources and takes actions to protect and improve water quality for aquatic life and human use. In order to protect the water for plants, animals, and people, Water Quality Standards are set to establish tolerable levels of pollutants. Each year, this section develops a water quality monitoring plan, which lays out the locations and frequency of sampling and determines the parameters that will be measured in each sample. This data is compared to standards to assess if water quality is good or needs improvement. These evaluations are presented to the EPA every other year in a two-part document, called a Combined 305 (b) Report and 303 (d) List. The first part of the document is the Watershed Assessment Report, also called a 305(b) Report. The second part of the document contains a list of all the waters in the state that are considered impaired because they do not achieve water quality standards, and is called the 303(d) List.

When waters are classified as impaired, a Total Maximum Daily Load (TMDL) must be established. TMDLs are regulations that place limits on the amount of a pollutant that can enter a water body from point and nonpoint sources. Since the late 1980's, this section has been busy modeling our watersheds to established TMDLs for nitrogen, phosphorus, and bacteria for all of the waters in Delaware impaired by these parameters. To clean up the waters, however, you have to do more than just place a limit on the pollution: you have to take action.

UPDATE: With respect to toxics substances that affect Delaware’s water resources, the Division of Waste and Hazardous Substances and the Division of Watershed Stewardship have developed a Watershed Approach to Toxics Assessment and Restoration (WATAR). WATAR is a holistic (watershed scale), integrated, and systematic approach to the evaluation of contaminant sources, transport pathways, and receptors, and a mechanism to implement restoration actions based upon site prioritization.

Delaware's Tributary Action Teams, or groups of stakeholders, have been working together to recommend a list of actions to reduce nonpoint source pollution in several TMDL watersheds. These recommendations, which include both voluntary and regulatory actions, are used to develop pollution control strategies. In addition to these documents, other watershed plans and strategies have been developed over the years. Some of the actions to improve water quality are simple things anyone can do!

The Delaware Nonpoint Source Program addresses nonpoint source pollution through educational programs, publications, and partnerships with other Delaware organizations. The Delaware NPS Program also administers a competitive grant made possible through Section 319 of the Clean Water Act, providing funding for projects designed to reduce NPS pollution.

Click here to find resources of information, support, and guidance for reducing nutrient and sediment pollution.

In addition, the Watershed Assessment and Management Section performs many other functions to help protect water resources and the plants, animals, and people who rely on them. 

The Watershed Assessment and Management Section houses the Wetland Monitoring and Assessment Program, whose goal is to assess the condition, or health, of wetlands and the functions and ecosystem services that wetlands provide. This information will then be used to inform the citizens of Delaware and to improve existing education, restoration, protection, and land use planning efforts. For more information about the Watershed Assessment and Management Section’s and DNREC’s wetland initiatives visit: Delaware Wetlands.    

The Watershed Assessment and Management Section also houses Delaware's Shellfish and Recreational Water Programs. These programs are charged with protecting public health by reducing the risk of human illness caused by the consumption of shellfish and recreational water activities. 

Delaware Shellfish Program: Because shellfish can become unsafe for human consumption due to high levels of bacteria and viruses, we routinely survey pollution sources for indicator bacteria levels. Data from sampling stations are analyzed and the information facilitates program operating procedures and health standards that protect shellfish consumers. Delaware is a member of the National Shellfish Sanitation Program (NSSP), a cooperative of state, federal, and industry representatives responsible for establishing the national guidelines that protect consumer health in all certified state programs. The program is responsible for monitoring and classifying shellfish growing areas to determine if recreational and commercial shellfish harvesting is safe. The program also inspects and ensures certification of all commercial shellfish shippers and processors within the state.

Recreational Water Program:  At all beach areas guarded by State or local governments, water quality is monitored weekly during the swimming season to better protect your health. If it is determined that an area is unsafe for water contact activities, we advise the beach owner to not allow swimming. The state, in conjunction with the University of Delaware’s Citizen Monitoring Program, monitors for the presence of potentially Harmful Algal Blooms (HABS) which could impact our inland and coastal beaches. The Recreational Water Program also monitors for other coastal hazards, such as floatable debris, oil slicks, etc., to further our surveillance and protection of all of the state’s recreational waters. Please take pride in our inland and coastal waters and help maintain the high level of water quality that our state’s residents and visitors expect and deserve!

The Watershed Assessment and Management Section also performs soil surveys and provides technical support to other programs and agencies who deal with water quality issues. For more information, please see Watershed Assessment and Management's Frequently Asked Questions.

Section Manager: John W. Schneider
Phone: 302-739-9939

Related Links:

  • Murderkill River Study Reports
  • The Watershed Assessment and Management Section has partnered with the University of Delaware, Institute for Public Administration, Water Resources Agency on a new website dedicated to providing detailed information about all of our 45 watersheds within the state. Check out to find what watershed you live in and ways you can help to protect our waterways!
  • DNREC staff recently participated in a day-long symposium sponsored by the Delaware Chapter of the American Water Resources Association (DEAWRA) featuring current activities and future trends in the organization, regulations, and funding opportunities. Click on this link to see the presentations and learn more about the DEAWRA.
  • Report: Aquatic Life Declines at Early Stages of Urban Development! The Center for Watershed Protection and the US Geological Survey have investigated the Effects of Urbanization on Stream Ecosystems, and the study findings and a short video podcast are now available.

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