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Wet Meadow #7a: Halting or reversing channel <br />degradation benefits adjacent wet meadow hydrology <br />N <br />M 3 <br />c <br />? o ? <br />? L (n <br />cn 0) c <br />? a c? <br />? 1 L <br />L <br />cu <br />cu <br />? <br />cu a) <br />> <br />cu O <br />? <br />Q <br />? •? a) <br />-o <br />(a •> C <br />a) <br />? <br />m <br />cu I <br />? a O <br />? ? ca <br />c o <br />ca *. <br />Channel aggradation resulting <br />from sediment augmentation or <br />other factors <br />_ At what point is this sffect detectable? <br />0 <br />V ? Decrease <br />Channel degradation <br />resulting from sediment <br />deficiency or other factors <br />-5 ft 0 +5 ft <br />Change in local Platte channel bed elevation <br />over 13 years (ft) <br />Sediment augmentation (est. 225,000 tons/year in the reach near Overton) <br />will balance the sediment budget in sediment-deficient reaches, restoring <br />channel bed elevations and/or preventing future channel degradation in <br />certain reaches between Overton and Grand Island. In such areas with <br />adjacent bottomland grasslands, higher river bed elevations will support <br />higher river stages for a given quantity of flow, which will support higher water <br />tables in these areas (all other factors held constant). (Question: in what <br />areas and at what threshold would this effect be detectable? Detectability will <br />vary with site conditions, period of ineasurement, definition of `detectability; <br />etc. )