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Title: ASSESSING FRESHWATER INFLOWS TO THE SUBTROPICAL LOWER LAGUNA MADRE OF TEXASUSING IN SITU PHYSICOCHEMISTRY, SPECTRAL RADIOMETRY AND AERIAL VIDEOGRAPHY

Author
item WEBSTER, CHARLES - TEXAS NAT RES CONS COM
item REPIC, RANDALL - UNIV OF MICHIGAN - FLINT
item Everitt, James
item Escobar, David
item Davis, Michael

Submitted to: Geocarto International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/15/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: The Lower Laguna Madre is a biologically productive, subtropical, hypersaline estuary on the southmost Texas coast. Its shallow waters serve as important nursery areas for many Gulf of Mexico species and as food for the largest wintering population of redhead ducks (Aytha americana) in North America. The Arroyo Colorado and its distributary arm, the North Floodway, are the only two freshwater streams that deliver significant particulate, nutrient and chlorophyll/pheophytin loads to the estuary. Water reflectance, airborne videography and in situ physicochemical data of water surfaces were acquired from the Arroyo Colorado and Lower Laguna Madre. Analysis of the spectral, video, and physicochemistry data confirmed that near-surface chlorophyllous aggregates (chlorophyll a and phenophytin) can be imaged, yielding both qualitative and quantitative results. This study demonstrated the potentials of using aerial video imagery to locate, identify, track and assess the seston composition of effluents in turbid rivers, streams and estuaries.

Technical Abstract: Water reflectance, airborne videography and in situ physicochemical data were acquired from two above-tidal and two tidal stations in the Arroyo Colorado and from one station in the estuary, at the confluence of the Arroyo Colorado with the Gulf Intracoastal Waterway (GIWW), during the summer of 1995. Analysis of the collected imagery, spectral data and physicochemistry confirm that near-surface chlorophyllous aggregates (chlorophyll a and pheophytin) can be imaged, yielding both qualitative and quantitative results. Correlation coefficients greater than 0.90 were obtained when digital data from specified spectral bands and band ratios were compared to chlorophyll a, total suspended solids and total dissolved solids concentration. This study demonstrated the potentials of using aerial video imagery to locate, identify, track and assess the seston composition of effluents in turbid rivers, streams and estuaries. With additional research, aerial videography could be developed for use as an environmental monitoring tool by government agencies, managers, planners and others needing to make informed decisions about land and water use, disposition and development.