We analyzed 27 established and new simple and therefore perhaps portable satellite phycocyanin pigment reflectance algorithms for estimating cyanobacterial values in a temperate 8.9 km2 reservoir in southwest Ohio using coincident hyperspectral aircraft imagery and dense coincident water surface observations collected from 44 sites within 1 h of image acquisition. The algorithms were adapted to real Compact Airborne Spectrographic Imager (CASI), synthetic WorldView-2, Sentinel-2, Landsat-8, MODIS and Sentinel-3/MERIS/OLCI imagery resulting in 184 variants and corresponding image products. Image products were compared to the cyanobacterial coincident surface observation measurements to identify groups of promising algorithms for operational algal bloom monitoring. Several of the algorithms were found useful for estimating phycocyanin values with each sensor type except MODIS in this small lake. In situ phycocyanin measurements correlated strongly (r2 = 0.757) with cyanobacterial sum of total biovolume (CSTB) allowing us to estimate both phycocyanin values and CSTB for all of the satellites considered except MODIS in this situation.
9 February 2009 in Civil Engineering and Environmental Systems
An integrated watershed hydrologic model, the Soil and Water Assessment Tool (SWAT) was adopted in this study to simulate the water quality conditions under the current and the future land-use configurations. The findings were compared to determine the hydrologic consequences of future land-use changes. Results indicate that as the land use in the watershed shifts from predominantly agricultural to mixed rural and residential lands, a reduction in flow, sediments, and nutrients is detected. Although the projected average daily concentration of phosphorus is reduced by 47% under the future land-use scenario, it will still exceed the daily limit suggested by the US Environmental Protection Agency. From this study, it is evident that SWAT is a reliable water quality model, capable of producing accurate information for environmental decision-making. The model has a GIS interface and is coupled with the Better Assessment Science Integrating Point and Nonpoint Sources system. It is, therefore, a valuable tool for environmental informatics.