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<br />...- < \-... <br /> <br />valuable insight into flood hydrology in the Front Range of Colorado. <br />The techniques being developed also have excellent transfer value when <br />studying paleofloods in other Colorado basins. <br /> <br />PLANS: <br /> <br />[A] Estimation of Paleoflood Discharqes. Paleoflood discharges will be <br />estimated for each of the four sites in Arthurs Rock Gulch. The method <br />of analysis includes step backwater, critical depth, and <br />reconstructions based on particle sizes in flood deposits. The <br />analyses will include the evaluation of channel erosion and deposition <br />and the effects of debris dams with dam-break modeling. These analyses <br />will be completed by February 1990. <br /> <br />[B] Flood-Frequency Analysis. Flood-frequency estimates will be made for <br />the paleoflood discharges using existing regional flood-frequency <br />methods. This estimates will be completed by March 1990. <br /> <br />[C] Precipitation-Runoff Modelinq. Precipitation-runoff modeling will be <br />done to evaluate different rainfall scenarios to complement paleoflood <br />estimates. This modeling will be completed by February 1990. <br /> <br />[0] Dendrochronoloqy. Studies pertaining to the use of tree rings for <br />determining the chronology of recent floods have not yet been made. We <br />have consulted with several local tree-ring experts and have developed <br />data-collection methods for the study area. Collection of tree-ring <br />data will begin during November 1989. <br /> <br />[E] Sediment Studies. Sediment samples will be submitted to a laboratory <br />for particle-size analysis, radiocarbon dating, clay mineralogy, and <br />iron determination. These analyses will help characterize the degree <br />of soil development and its relation to the age of the deposits. <br />Laboratory results are expected in late January or early February 1990. <br /> <br />[F] Data Compilation and Synthesis. Tables, graphs. and statistical <br />analysis of data collected during the fieldwork phase of the project <br />will be prepared during the winter months of 1990. This information <br />will be included in the final report either within the text of the <br />report or as appendices. <br /> <br />[G] Paleoflood History of Arthurs Rock Gulch. An outline of the paleoflood <br />sequence for Arthurs Rock Gulch will be developed based on the results <br />and findings discussed above. This outline will include discussions of <br />the types of deposits that occur in the basin, the estimated ages of <br />these deposits, and the estimated flood magnitudes associated with <br />respective deposits. The relation between flooding and paleoclimate <br />also will be discussed. <br /> <br />[H] Reports. A U.S. Geological Survey Water-Resources Investigation Report <br />(WRIR) summarizing research results will be prepared and provided to <br />the U.S. Bureau of Reclamation for comments in May 1990. The report <br />will provide a summary of the investigation and will provide an <br />overview of the paleohydrologic techniques developed and used. Two <br />journal articles also will be prepared after the WRIR is in review. <br />