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format, along with interpretation of the data. fdentification of acute sources of nutrients <br />(human waste) to the Animas River, both surface and subsurface will be the major <br />deliverable of this task. <br />Task 3- Rapid Geomorphic Assessment <br />Subtask 3.1 Subproject Lead - Rapid Geomorphic Analysis <br />The geomorphic assessment will quantify present-day characteristics of the river channel <br />and adjoining flood plains through the use of various field methods. This information is <br />required in order to evaluate the present-day condition of the channel relative to its <br />stable forms, cause(s) of instability, sources and indicators of increased sediment and <br />degraded assimilative/functioning capacity, and potential improvement opportunities <br />and stabilization-restoration techniques. This information will be compiled, summarized <br />and presented on a reach-by-reach basis. When combined with nutrient and aquatic <br />assessments, sources of impairment will be documented and specific opportunities (Best <br />Management Practices) for water quality improvement measures can be identified. <br />The river will be divided into reaches that exhibit similar geomorphic features, based on <br />aerial photography and channel/ftood plain characteristics. Geomorphic assessments <br />performed on a reach by reach basis will determine stream type, channel stability, <br />channel bank erosion potential and adjoining flood plain characteristics. Geomorphic <br />assessments performed at representative riffle sections, in conjunction with nutrient, <br />SMI and periphyton sampling, will quantify channet bankfull dimensions, wetted-channel <br />water depth and velocity, and channel bed composition (e.g., cobble, gravet, sand). <br />The methods and a description of results for each geomorphic parameter to be evaluated <br />are provided below. Assessment work will be performed by Basin Hydrology, Inc. <br />Performed on a reach-bv-reach basis <br />• Stream Type <br />o Determine stream type for each reach using criteria presented by Rosgen <br />in Applied River Morpholo�y (1996, see attached Classification Key). <br />• Channel Stability Rating <br />o Evaluate each reach's condition at upper bank, lower bank and bottom of <br />channel using Pfankuch evaluation criteria (see attached Channel Stability <br />(Pfankuch) Evaluation and Stream Classification Summary form). <br />o Determine overall channel stability rating based on stream type. <br />• Channel Bank Erosion Potential <br />o Evaluate representative banks within each reach using Bank Erosion <br />Potential evaluation criteria (see attached Bank Erosion Potential form) <br />o Identify on maps highly eroded and degraded bank sections <br />o Identify on maps where bank stabitization measures have occurred and <br />their condition <br />o Determine overall bank erosion rating for each reach <br />• Flood Plain Composition <br />o Identify general land use(s) on active flood plain and any potential adverse <br />impacts <br />o Identify dominant riparian ve�etation, condition of vegetation and <br />estimated percent ground cover <br />o Summarize flood plain characteristics for each reach <br />0 <br />