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<br /> C; <br /> c..~ <br /> (-..., <br />( I~ <br />~~ <br /> 00 <br /> <br />San Juan Ichthyological Investigations <br /> <br />WORK STATEMENT/PROTOCOL <br />HABITAT/FLOW RELATIONSHIPS <br /> <br />Background: <br />Habitat availability at different flows is an important facet of the overall <br />research plan which seeks to determine the biological response of target species <br />to more II natural II flows in the San Juan River. Determination of habitat/flaw <br />relationships is integrally related to other ongoing research which deals with <br />habitat use by target species. Riverine habitats must be quantified in order to <br />determine the relationship between habitat availability, habitat use by target <br />species and the impact of flows on target species. <br /> <br />Airbome videography has proven useful for determining habitat to riverflow <br />correlations on several rivers in the upper and lower Colorado River basins. <br />Airborne videography provides a cost effective method for long term monitoring <br />of habitat changes over time and with different flows. <br /> <br />( <br /> <br />Methods: <br />The study area chosen for habitat mapping using videography is the San Juan River <br />from the Hogback diversion near Farmington, New Mexico to Mexican Hat, Utah. <br />During FY91 the river was filmed five times to determine changes in" riverine <br />habitat related to different flows. video was acquired once prior to spring <br />runoff, once during the peak runoff, and three additional times as the flow subs. <br /> <br />Video of the San Juan River was acquired using a 3/4 inch CCD video camera <br />mounted to a Tyler mount on the nose of a helicopter. The helicopter utilizes <br />a radar altimeter to maintain a constant altitude of 2,000 feet above the river <br />which provided coverage of the entire river width for the majority of the reach. <br />Widely braided areas were filmed using two passes. Using an altitude of 2,000 <br />feet above ground level yields a resolution of approximately one meter. <br />The video. imagery is interpreted using MIPS (Map and Image Processing System), <br />a PC based digitizing image software. Several bridges along the reach have been <br />measured to provide a calibration standard for measurements done with the <br />computer. Individual frames of the video are grabbed by the computer to be <br />analyzed by the investigator. Using the software, each portion of river <br />contained in a frame is categorized and delineated by a polygon that yields the <br />area of a feature. The data will be interpreted for the following categories; <br />backwaters, side channels, isolated pools, main channel and total open water. <br />Abutting frames of the entire study reach will be analyzed using this <br />methodology. The resulting numerical data will then be evaluated for habitat to <br />flow relationships using spreadsheet software and statistical methods. <br /> <br />During FY 1992 video data collected during 1991 will be interpreted using MIPS. <br />A report will be generated in early March that will include tabular data giving <br />acreage and number by river mile for the following categories: backwaters, side <br />channels, isolated pools, total open water. <br /> <br />Also in FY 92, the data acquisition schedule of the previous year will be <br />repeated to verify the flow habitat relationships developed with the first year's <br />field data. In addition, an attempt will be made to collect video imagery of <br />winter habitat conditions. <br /> <br /><- <br /> <br />A29 <br />