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<br />.-. <br /> <br />(Hunt, <br />;ists of <br />os, and <br />-ucture <br />.ainage <br />nonga- <br />. Engi- <br /> <br />Cheat <br />Ibright <br />eloped <br />turns <br />imately <br />hrough <br />1996). <br />sons to <br /> <br />bin the <br /> <br />outh Side <br /> <br />i <br /> <br />G.S. Springer. J.S. Kile /Geomorphology 18(1997) 91-100 <br /> <br />canyon. The most significant of these include Corn- <br />well Cave and the caves of lower Coliseum Rapids. <br />All solutional caves in the canyon are developed in <br />the Mississippian-age Greenbrier Formation which is <br />46 m thick. <br /> <br />3, Previous research <br /> <br />Slackwater deposits consist of relatively fine- <br />grained sediments (typically fme sand and coarse <br />silt) deposited in sheltered, low-energy floodplain <br />areas by sediment-laden floodwaters (Kochel and <br />Baker, 1988). Within arid portions of the western <br />United States, flood records have been extended <br />along several major rivers by examination of slack- <br />water sediments. Pertinent works include those by <br />Patton and Dibble (1982), Kochel and Baker (1982), <br />and Kochel and Baker (1988). <br />Linton (J992) and Kite and Linton (1993) exam- <br />ine sediments deposited by the November 1985 flood <br />along Cheat River. Linton (1992) repotts that slack- <br />water deposits within sheltered tributary mouths were <br />similar to one another, though the detailed stratigra- <br />phy varies from site to site. Linton recognizes four <br />stratigraphic units: a basal gravel and sand, sandy <br />loam, silt loam, and fine sandy loam. Deposits at <br />each site typically contain at least two of the four. <br />The sandy loam is the most common deposit in <br />tributary mouths (Linton, 1992). <br />Using the Manning equation, Linton (1992) calcu- <br /> <br />93 <br /> <br />lates estimates of discharge from the elevations of l <br />1985 slackwater deposits and high water marks. The <br />high water marks are veneers of silt or trash adhering <br />to natural objects or human structures. Most high <br />water marks are destroyed quickly and, therefore, i <br />slackwater sediments are often used to calculate bt <br />discharge. Unfortunately, slackwater sediments typi- I <br />cally lie at elevations beneath those of the high water J <br />mark and are sources of error in calculating flood <br />discharges. Linton (1992) repotts that slackwater <br />sediments along Cheat River underestimate dis- <br />charge by at least 50% relative to high water marks. <br />Springer et al. (1996) examine cave development <br />and cave sediments within the Cheat River canyon. <br />They recognize three classes of cave sediments in <br />caves of the canyon: phreatic, vadose, and residual <br />(Table I). The phreatic sediments are deposited in <br />maze caves with elliptical passage cross-sections. <br />S.ediments are fine-grained (sand to clay) and be- <br />come fmer away from Cheat River. Vadose sedi- <br />ments are derived from ihe overlying valley wall or <br />overbank flooding of the nearby river and are sepa- <br />rated from the phreatic facies class by scour surfaces. <br /> <br />4. Overbank sediments <br /> <br />Vadose-deposited. overbank. facies in caves of the <br />Cheat River canyon are blanket-like deposits of <br />loamy silt, sand, and organics. Individual deposits <br /> <br />Table 1 <br />Two of the three facies classes present in caves of the Cheat River canyon. Phreatic facies are associated with anastomotic maze caves. <br />Vadose facies are generally separated from p~tic facies by a scour surface. Modified from Springer et aI. (1996) <br /> <br />Phreatic facies class: Vadose facies class: <br />Sediments deposited beneath base level in maze caves. Includes Sediments deposited above base level. Includes the facies described <br />the facies described below below <br /> <br />Diamiction: Gleyed. matrix-supported. bouldery gravel to loam <br />diamict. Becomes finer away from river <br /> <br />Laminated sand: Laminated sands and sandy loams with em-thick <br />beds and some silt interbeds <br /> <br />Silt-day rhythmite: Silty loams. loamy, silts. and loamy clays <br />displaying rhythmic laminations. Fill elliptica1~shaped passages <br /> <br />Sandy clay loam: Gleyed, massive sandy clay loarns with <br />laminated clay interbeds. Sand uains are frosted and well rounded <br /> <br />Gravity: Poorly sorted. course colluvial deposits from overlying <br />valley wall. Includes-collapse deposits <br /> <br />Travertine: Chemically precipitated calcite and aragonile derived from <br />overlying bedrock and soil <br /> <br />Overbank.: Thin. blanket-like: deposits of laminar silt, sand. and <br />organics bounded by scour surfaces. Mudcracks and surge marks <br />present <br /> <br />Cave Stream: Soned fines and gravels with directional flow indicators <br />or cut and fill reatures. Associated with dicrete input source <br />