DELAWARE NUTRIENT MANAGEMENT NOTES

"TMDLs"

The Delaware Nutrient Management Act (Title 3, Chapter 22 of the Delaware Code) was enacted in June, 1999 as part of an effort to address water quality concerns in Delaware (for more information on this Act see Nutrient Notes, January 2000). One of the factors that led to the drafting of this legislation is the 1972 Federal Clean Water Act (CWA), as amended. In particular, the CWA requires the establishment of Total Maximum Daily Loads (TMDLs) for waters that have significant water quality "impairments." The purpose of this Note is to describe TMDLs and show how they are related to nutrient management in Delaware.

WHAT IS A TMDL?

· A TMDL is the maximum daily amount, or load, of a pollutant that can enter a body of water while still meeting water quality standards. Pollutants may be such things as nutrients, bacteria, sediments, or even heat. The Delaware Nutrient Management Act specifically addresses nutrients, so implementation of the Act will help Delaware meet water quality goals for waters that are impaired by nutrients. Meeting these water quality goals will allow the waters to support finfish and shellfish.

· The CWA requires that a TMDL include, 1) a Wasteload Allocation (nutrients, or other pollutants, that can come from point sources such as wastewater treatment plant discharges); 2) a Load Allocation (such as nutrients from nonpoint sources like lawns, golf courses or agricultural fields); and, 3) a Margin of Safety.

WHO IS RESPONSIBLE FOR ESTABLISHING AND IMPLEMENTING A TMDL?

· Section 303(d) of the CWA requires States to develop a list of waterbodies that need to reduce pollutants to meet water quality standards. The list of these "impaired" waters is commonly referred to as the "303(d) list." This list identifies the waterbodies that require a TMDL process. In Delaware, the responsible agency is the Department of Natural Resources and Environmental Control (DNREC).

· Although the DNREC is responsible for establishing the 303(d) list, and associated TMDLs, the ultimate responsibility falls on the EPA through the CWA. This means that if the DNREC does not complete a TMDL process the EPA is required to do this directly. When this happens, it is generally the result of a lawsuit filed against EPA for failure to comply with the CWA. Approximately 45 of these suits have been filed in 34 different states.

· TMDL water quality goals will be met via the implementation of a Pollution Control Strategy. Such Strategies identify specific reduction activities and timeframes. The DNREC will adopt Pollution Control Strategies as regulations.

HOW ARE TMDLs USED IN THE NUTRIENT MANAGEMENT PROGRAM?

· The Delaware Nutrient Management Program will draw on the TMDL process in three main ways: 1) identifying nutrient load reduction goals; 2) targeting priority areas for nutrient management activities; and 3) tracking water quality improvements from those activities.

· For waters impaired by nutrients, information generated in the TMDL process will provide guidance as to the type of nutrient and the extent of nutrient load-reduction necessary to achieve water quality standards.

· As a part of the TMDL process, watersheds are identified in terms of "critical" water quality issues. The Delaware Nutrient Management Commission will use this information to decide where to focus their Nutrient Management Planning and Nutrient Relocation programs.

· The TMDL process includes collection of water quality data. The Delaware Nutrient Management Program will use the data as a baseline to help monitor water quality improvements that may occur as a result of this, or other, initiatives.

ADDITIONAL FACTS ABOUT THE TMDL PROCESS

· Water quality standards for TMDLs are based on the designated use of the water. There often are questions as to why some standards for streams, lakes, or bays are more stringent than similar standards for drinking water. This can be true for nutrients like nitrogen that have both human health and environmental health consequences. This happens because the negative environmental effects of nitrogen occur at much lower concentrations than human health effects. Relatively low concentrations of nitrogen (or phosphorus) in lakes, streams, and bays can induce rapid growth of water plants or algae. When these plants die and decompose, oxygen levels decrease and the result is the death of fish or bottom-dwelling organisms. This explains why acceptable concentrations of nitrogen are lower for aquatic habitats than for drinking water.

· In a recent court case in California (Pronsolino et al. vs. Marcus et al.), a U.S. District Judge ruled that the TMDL process was "intended to be applied differently" for nonpoint sources. The ruling concludes that the States have a "large degree of discretion" in how the information is used. However, this ruling also confirmed that the EPA must establish TMDLs for all impaired waters, including those impaired only by nonpoint sources. This ruling should not impact the Delaware Nutrient Management Program.

· To date, DNREC has promulgated TMDLs for the following watersheds:

_ 1998 - Rehoboth Bay, Indian River, Indian River Bay - (impaired by nitrogen and phosphorous)

_ 1998 - Nanticoke River & Broad Creek - (impaired by nitrogen and phosphorus)

_ 1999 - Red Clay Creek - (Impaired by zinc)

_ 1999 - White Clay Creek - (impaired by zinc)

· The TMDL process is underway in the Delaware Inland Bays, and will be completed for all "impaired" watersheds by 2007.

Prepared by Dave Hansen, LID Cooperative Extension, with input from

DNREC, The Delaware Nutrient Management Program, and DDA

Cooperative Extension Education in Agriculture and Home Economics, University of Delaware, Delaware State University and the United States Department of Agriculture cooperating. John C. Nye, Dean and Director. Distributed in furtherance of Acts of Congress of May 8 and June 30, 1914. It is the policy of the Delaware Cooperative Extension System that no person shall be subjected to discrimination on the grounds of race, color, sex, disability, age or national origin.

Last Updated: Monday, 19-Mar-2007 09:37:32 EDT