Satellite-based Water Quality Mapping at High Rock Lake, NC
The map below shows the North Carolina (NC) Lakes that are listed as impaired, many due to high levels of turbidity and Chlorophyll-a (Chl-a). These impairments are often attributed to high sediment and nutrient loads that originate from both point (i.e. water treatment plants) and non-point (i.e. agriculture, including swine and poultry farms) sources, the latter considered very challenging to quantify and regulate. Developing effective water quality improvement plans therefore requires input and commitment from a wide range of stakeholders, leading to the establishment of local advocacy groups. These groups include environmental scientists, engineers, and managers that employ data and models to make informed decisions on water quality planning. However, the ability of these groups to collectively develop and implement water quality improvement plans is limited by the sparsity of in-situ data and the accuracy of currently available decision-making tools.
Collecting in-situ water quality data can be extremely expensive, but satellite imagery can now be leveraged to monitor lake water quality holistically and cost-effectively. Satellites such as Landsat-8 and Sentinel-2 record images of the Earth about every five days and provide data products that contain the amount of radiance reflected from the water’s surface at different wavelengths. This information can be translated into estimates of Chl-a, Total Suspended Sediment (TSS), and color dissolved organic matter (CDOM) to produce water quality maps that cover the entire lake. Stakeholders can leverage satellite-based estimates of water quality to augment in-situ databases spatially and temporally and use this information to develop more comprehensive and data-driven water quality improvement plans.
NDCEQ 2020 Integrated Report Map (https://ncdenr.maps.arcgis.com/apps/webappviewer). All water bodies shown in red are listed as Category 5 waters on the 303(d) list and require a TMDL, designating limits on pollutant sources to return water bodies to a condition where beneficial uses can be sustained.
Research Goals and Objectives:
Results from a pilot study using historical water quality data and satellite imagery were presented at the 2021 American Geophysical Union (AGU) meeting in New Orleans. Here is the pre-recorded 15-minute presentation that was summarized at the meeting.
Learn about this project through Wake Forest 2022 summer research fellows - Amelia Suhocki & Michael Huang