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Assessing the suitability of lakes and reservoirs for recreation using Landsat 8
Citation:
Keith, Darryl J., W. Salls, Blake A. Schaeffer, AND P. Werdell. Assessing the suitability of lakes and reservoirs for recreation using Landsat 8. ENVIRONMENTAL MONITORING AND ASSESSMENT. Springer, New York, NY, 195:1353, (2023). https://doi.org/10.1007/s10661-023-11830-5
Impact/Purpose:
This study represents a new way to assess the suitability of lakes, ponds and drinking water reservoirs to provide recreational benefits based on water clarity and remote sensing. Water clarity has long been used by aquatic monitoring programs as a visual indicator of the condition of water quality. Water clarity is often monitored in these environments monitored by federal and state agencies, tribal nations, and citizen-volunteer groups using an inexpensive Secchi disk, a 20-centimeter (8 inch) diameter metal or weighted plastic disk, normally black and white, which is attached to a measured line and lowered into the water until it can be no longer seen. The depth of disappearance is recorded as the Secchi depth (ZSD). While the Secchi disk and measurement process to collect this information are relatively inexpensive, extending this type of monitoring to the thousands of lakes in the conterminous US is costly and logistically prohibitive. We demonstrated that Secchi depths can be derived from the optical properties of 278 lakes, ponds, and drinking water reservoirs across the continental US from the Operational Land Imager (OLI) sensor on the Landsat 8 satellite. We also demonstrated that this information can be used to assess the suitability of these water bodies using frameworks based on public perception of water clarity. This suggests that operational land-based satellite sensor systems such as the OLI can be repurposed to monitor water quality of recreational lakes and drinking water supplies for public use and consumption. This provides an added value and promising opportunity for the use of publicly available, no cost, high resolution satellite data to assist in evaluating, over multiple temporal and spatial scales, and making decisions on lake, pond and reservoir management for recreational, aesthetic, and public health benefits.
Description:
Water clarity has long been used as a visual indicator of the condition of water quality. The clarity of waters is generally valued for esthetic and recreational purposes. Water clarity is often assessed using a Secchi disk attached to a measured line and lowered to a depth where it can be no longer seen. We have applied an approach which uses atmospherically corrected Landsat 8 data to estimate the water clarity in freshwater bodies by using the quasi-analytical algorithm (QAA) and Contrast Theory to predict Secchi depths for more than 270 lakes and reservoirs across the continental US. We found that incorporating Landsat 8 spectral data into methodologies created to retrieve the inherent optical properties (IOP) of coastal waters was effective at predicting in situ measures of the clarity of inland water bodies. The predicted Secchi depths were used to evaluate the recreational suitability for swimming and recreation using an assessment framework developed from public perception of water clarity. Results showed approximately 54% of the water bodies in our dataset were classified as “marginally suitable to suitable” with approximately 31% classed as “eminently suitable” and approximately 15% classed as “totally unsuitable–unsuitable”. The implications are that satellites engineered for terrestrial applications can be successfully used with traditional ocean color algorithms and methods to measure the water quality of freshwater environments. Furthermore, operational land-based satellite sensors have the temporal repeat cycles, spectral resolution, wavebands, and signal-to-noise ratios to be repurposed to monitor water quality for public use and trophic status of complex inland waters.
URLs/Downloads:
DOI: Assessing the suitability of lakes and reservoirs for recreation using Landsat 8