System Wide Monitoring


Water samples are collected for nutrient analysis

The System-wide Monitoring Program (SWMP, pronounced “swamp”) is a key component of every National Estuarine Research Reserve.  The program measures short and long-term change in estuarine conditions, tracking the health of the nation’s coastal areas.  SWMP currently has three major components: (1) abiotic indicators of water quality and weather; (2) biological monitoring; and (3) watershed, habitat, and land use mapping and analysis.

The Program’s long-term data collection efforts serve as a nationally standardized network of reference sites, as well as sentinels for future change, and have facilitated a better understanding of how basic environmental components affect estuarine habitats.  Grand Bay’s SWMP program has captured significant real-time water quality events including a chemical spill in Bangs Lake (page 7) and Hurricane Katrina’s storm surge at Bayou Cumbest.

For more information about the National SWMP program read the 10th Anniversary SWMP Report.

Interested in downloading the data? Read our Quick Guide to Understanding SWMP data.


Water Quality and Weather

weather station

Weather station in Crooked Bayou


Water Quality   
Since 2004, essential physical and chemical water quality variables have been collected at four long-term monitoring stations across the Grand Bay NERR: Bayou Heron, Point aux Chenes, Bayou Cumbest, and Bangs Lake.  These stations capture the variability of water conditions within the Reserve’s sub-watersheds, including differences in freshwater input (Bayou Heron receives the most freshwater input, Point aux Chenes the least) and development (Bayou Heron is relatively pristine whereas Bayou Cumbest is impacted by residential development and Bangs Lake is impacted by industrial development). Specific conductivity, dissolved oxygen, temperature, turbidity, salinity depth, and pH are recorded every 15 minutes.

{Current Conditions: Bayou HeronBangs Lake}


Weather conditions have a strong influence on water quality conditions in estuaries and meteorological monitoring is an important component of the SWMP program.  Grand Bay’s meteorological station is located near the center of the Reserve, in Crooked Bayou.  Relative humidity, barometric pressure, wind direction and speed, temperature, rainfall, and photosynthetically available radiation (PAR) are reported every 15 minutes.

{Current Conditions: Crooked Bayou}


Monthly nutrient samples are collected to monitor chlorophyll-a, reactive phosphates, total phosphates, ammonia, nitrates, and nitrites.  Samples are collected at each of the four water quality sites and a diel (24-hour cycle) set of samples are collected at one site to examine day/night and tidal changes.  Nutrient monitoring is important because nutrient concentrations affect overall water quality and plant (e.g. algae) growth.


Biological Monitoring {Stewardship & Research}

Seagrass beds are sampled in local waters


The Grand Bay Reserve Site Profile, completed in 2007, reviews and synthesizes existing knowledge of the Reserve’s natural history, ecological processes, biological resources, and impacts on the ecosystem.  In addition, the Site Profile identifies research and monitoring needs for future efforts.

Reserve biological monitoring builds on the existing Site Profile information and characterizes patterns of variability and distribution in estuarine communities.  SWMP biological monitoring efforts include characterizing the diversity of multiple habitats and communities including: submerged aquatic vegetation (e.g. seagrasses), emergent vegetation (e.g. salt marshes), nekton, and invasive species.

View Current projects at Grand Bay


Land Use and Habitat Change  {GIS & Maps}

The Land Use and Habitat Change component of SWMP focuses on understanding relationships between land use and habitat change, anthropogenic influences, and climate change.  By using state of the art technology, short-term variability and long-term change are tracked and evaluated.View Current GIS projects at Grand Bay