Water Quality and Climate Change

Improving Water Quality in Maryland’s Coastal Waters

Maryland’s Chesapeake and Coastal Bays are vital components of Maryland’s culture, economy, and coastal ecosystems. To protect the fisheries, habitats, and communities that these waters support, the Maryland Department of Natural Resources has invested in water quality monitoring and management of nitrogen, phosphorus, and sediment loads. Water quality goals have been set through EPA’s Chesapeake Bay Total Maximum Daily Load (TMDL) framework, and the means to meet those goals have been addressed through the state’s Watershed Implementation Plan. While many practices are necessary to meet these goals, natural filter best management practices (BMPs) are of particular interest because they provide habitat benefits while filtering state waters.


What are natural filters?

A natural filter is exactly as it sounds – a natural habitat element that slows surface, subsurface and ground water, consequently filtering pollutants as water flows downstream. Natural filters consist of riparian forests, grasses, vegetation, wetlands, and living shorelines. Because these on-the-ground solutions require space, time, and money, they inherently bring about coastal and marine use conflicts. In order to address potential conflicts and plan for a healthier watershed, the Chesapeake and Coastal Service has invested in marine spatial planning techniques to evaluate estuarine and ocean uses.


Focusing State Restoration Efforts

In 2012, the Chesapeake and Coastal Service (CCS) initiated a project titled “Integrating Water Quality and Coastal Resources into Marine Spatial Planning in the Chesapeake and Atlantic Coastal Bays.” The overarching goal of this project is to help meet Maryland’s TMDL goals through natural filter BMP planning and implementation. CCS staff will:

  • Identify opportunities for wetland restoration, riparian buffers, and living shorelines;
  • Prioritize BMP sites that align with DNR conservation/restoration priorities and that exhibit greater nutrient reduction potential;
  • Evaluate the eastern oyster as an in-situ natural filter practice, identify potential oyster aquaculture sites, and estimate nutrient reduction benefits from on-bottom, caged, and floating oyster aquaculture;
  • Engage local stakeholders through participatory GIS meetings to identify potential coastal and marine use conflicts with natural filter practices; and
  • Develop a framework for considering climate change when planning restoration projects (see below).


Habitat Restoration in a Changing Climate

Natural filters are usually implemented to address existing conditions. Yet, climate models predict changes in sea level rise, precipitation patterns, temperature, and ocean acidification over the next century and beyond. These changes may impact the functionality and survivability of natural filter practices by altering soil characteristics, erosion dynamics, hydrology, water quality or salinity, among other factors. To invest in restoration sites that will reap water quality benefits over the long term, climate change must be considered during the targeting, planning, and design phases of these practices. To initiate this integration, CCS staff will 1) compile best management practices and principles for incorporating climate change into restoration, and 2) develop an evaluation process for targeting restoration sites in the future.


Additional Resources

DNR Restoration/Conservation priorities:


Restoration Efforts:


Climate Change Vulnerability:


Natural Filter Targeting Fact Sheet

Natural Filter Targeting Fact Sheet

HRC Climate Fact Sheet

HRC Climate Fact Sheet

Contact Information

Nicole Carlozo, NOAA Coastal Fellow

Chesapeake & Coastal Service

Maryland Department of Natural Resources

Tawes State Office Building E-2

580 Taylor Avenue

Annapolis, Maryland 21401

Phone 410-260-8726

Fax 410-260-8739

ncarlozo@dnr.state.md.us