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<br />Bed load - Sediment that moves by saltation (jumping), roll ing or <br />sl iding in the bed layer of a stream. <br />Bedrock - The solid rock underlying soi Is and overlying the mantle <br />rock, ranging from surface exposure to depths of several hundred <br />feet. <br /> <br />Bed slope - The inol ination of the channel bottom. <br /> <br />Bituminous mattress - An impermeable rock-, mesh-, or metal-reinforced <br />layer of asphalt or other bituminous material placed on a <br />streambank to prevent erosion. <br /> <br />Blanket - Material covering al I or portion of a streambank to prevent <br />erosion. <br /> <br />Braided stream - A relatively wide and shal low stream with multiple <br />channels formed by islands and bars in the waterway. <br /> <br />Buffer zones - Areas of trees, grass, or other vegetation located <br />between top bank and adjacent pastures or cultivated fields (also <br />ca II ed greenbe Its). <br /> <br />Bulkhead - A vertical or nearly vertical retaining wall or structure <br />supporting a natural or artificial streambank. <br /> <br />Cation-exchange capacity (CEC) - The sum total of exchangeable cations <br />that a soi I can absorb; expressed in *mi II iequivalents per gram <br />or 100 grams of so i I . <br /> <br />Caving - The.col lapse of a bank by undercutting due to wearing away <br />of the toe or an erod i b I e so i I I ayer above the toe. <br /> <br />Cellular-block mattress - Regularly cavitated interconnected concrete <br />blocks p I aced direct I y on a streambank or f i I ter to prevent <br />erosion. The cavities can permit bank drainage and the growth of <br />either volunteer or planted vegetation when fi Iter fabric is not <br />used between the mattress and bank. <br /> <br />Channel - A natural or man-made waterway that continuously or <br />per i od i ca II y passes f low. <br /> <br />Chemical stabilization - streambank protection technique involving the <br />appl ication of chemical substances to increase particle <br />cohesiveness and to shift the size distribution~oward the <br />coarser fraction. The net effect is to improve the erosion <br />resistance of the material. <br /> <br />Clay - Material passing the No. 200 (0.074 mm) U.S. Standard Sieve <br />that exhibits plasticity (putty-I ike properties) within a range <br />of water contents and has considerable strength when air-dry <br />(Unified soi I Classification System). <br /> <br />Clay blanket - Layer of compacted clay placed over cohesionless bank <br />soi Is to protect them against erosive streamflow. <br /> <br />74 <br /> <br />~ <br />I <br />~ <br /> <br />.~ <br /> <br />. <br />~ <br />~ <br />, <br />~ <br />~ <br />~ <br /> <br />~ <br />I <br />, <br /> <br />~ <br /> <br />t <br />, <br />., <br />~ <br />