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<br />distinguish these species. It may be that more spectral information at lower spatial <br />resolution (without texture) might provide bener species separation. or that correctly <br />calibrated four-band image data can provide adequate vegetation mapping. This issue <br />needs to be resolved by additional evaluation of existing or new airbome data that <br />examines vegetation species instead of vegetation communities. <br /> <br />Remote-sensing technologies were evaluated for several physical characteristics <br />of the aquatic environment: (I) chlorophyll; (2) total suspended sediment; (3) turbidity; <br />(4) wann backwater areas amenable to fish habitats; (5) sediment storage; and (6) <br />substrate grain,size distribution. Remote-sensing technologies were found useful in <br />mapping all of these characteristics, Digital (\2-bit), high-gain CIR image data and <br />thermal-infrared image data can provide large-area maps of chlorophyll. total suspended <br />sediment, turbidity, wann backwater areas amenable to fish habitats, sediment storage, <br />and substrate grain-size distribution. All of these characteristics can be mapped with an <br />airborne sensor having a few visible/near-infrared bands and a thermal-infrared band. <br />However, the cost for this data in orthorectified fonn is about $625 per river km. Thus, <br />these remote-sensing data cannot economically provide high-frequency data that are <br />currently obtained by ground collection, but ground collection cannot achieve the rapid, <br />wide-area coverage provided by the airbome data. Image autocorrelation software could <br />reduce rectification costs of these data, as long as the surface in a previous controlled <br />image mosaic has not changed appreciably. For mapping channel substrate <br />geomorphology, airborne technology easily surpasses side-scan sonar surveys in all <br />aspects, but the water needs to be relatively clear for the airborne approach to work well <br />and its depth of penetration in clear water is limited to about 20 m. An unanticipated <br />result of our evaluations of low,resolution L1DAR elevation data was that the data <br />actually mapped the elevation of the water's surface over the main stem, which compared <br />with historical elevation profiles of the main stem indicated changes in submerged cobble <br />bars since the historical measurements. Remote sensing data are generally not useful for <br />monitoring the chemical characteristics of running water because chemical <br />concentrations are too low. <br /> <br />Overall, the remote-sensing initiative has resulted in establishing the basic <br />requirements on remote-sensing data and the technologies that can meet these <br />requirements and has produced the most functional data sets to date. As a result, program <br />scientists are making more and better use of these data each month, which has increased <br />productivity and monitoring accuracy, made monitoring less invasive, and opened new <br />avenues for improved ecological studies. Additional positive outcomes of this initiative <br />are listed at the end of this report. Remote-sensing technology continually advances and <br />improves in tenns of capability and cost. eRE monitoring can benefit even more in the <br />future from these improvements, but the technologies need to be thoroughly understood <br />and evaluated for their potential benefits and against GCMRC monitoring requirements. <br /> <br />4 <br />