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<br />botanic information from past floods preserved in stream channels and is <br />particularly useful in providing hydrometeorologic data in ungaged basins <br />(Jarrett, 1990, 1991). Data collection consists of determining rainfall, <br />peak flow, and sedimentologic data for most streams in the Buffalo Creek <br />area. Monitoring is planned until water and sediment runoff in the burned <br />area has retumed to near-normal. <br /> <br />In 1996, rainfall-bucket survey data were obtained in areas outside of the <br />burned areas for each rainstorm; homes were destroyed within the burned. <br />In addition, paleoflood and sedimentologic data were used to estimate <br />rainfall amounts and spatial variability. Rainfall amounts on sparsely <br />vegetated (burned or unburned) can be inferred from the amount of hillslope <br />erosion (rills, gullies, and headcuts), maximum size of sediments <br />transported, and depositional characteristics. The paleoflood rainfall <br />estimates can be compared with other sources of rainfall data (gaged, <br />bucket survey, and radar) or they can provide rainfall data when no other <br />source exists. <br /> <br />Because of hazards measuring flash floods, peak discharges were estimated <br />using the slope-conveyance method (Barnes and Davidian, 1978) for streams <br />in the Buffalo Creek area after each rainstorm. Sites were selected <br />primarily where bedrock is exposed across the channel. A few sites were <br />located in alluvial channels; reaches selected were relatively straight and <br />uniform, which reduces potential errors due to channel change. In such <br />reaches, net change in total-flow area probably are small for one flood, <br />although sediment loads may be large. Cross section data were collected <br />for channels in burned and adjacent unburned basins. Monitored basins <br />range from about 0.1 km2 to the total storm contributing area of about 75 <br />km2 (mostly burned) at the South Platte River at South Platte <br />streamflow-gaging station (06707500). The July 12, 1996 peak stage in the <br />gage stilling well was 1.52 m lower than excellent high-water marks (HWMs) <br />probably due to an insufficient size intake for flash floods; it is likely <br />the entire flood hydrograph is suspect. Incorrect gage recordings are a <br />serious concern for flash-flood detection and issuing warnings to the <br />public. Peak-discharge data were estimated for 75 subbasins in the study <br />area having different basin characteristics such as vegetation cover, burn <br />intensity, watershed aspect and slope, sediment sizes, and <br />watershed-rehabilitation measures. Onsite data also were collected for <br />subsequent storms that produced runoff. <br /> <br />For burned and unburned basins, data also were collected to: a.) estimate <br />hillslope erosion; b.) estimate channel agradation and degradation; c.) <br />approximate volumes of channel and alluvial-fan deposits; and d.) identify <br />past fire and flood deposit sequences in the alluvial stratigraphy. This <br />monitoring complements sediment studies being conducted by other USGS and <br />USFS scientists and to help validate channel changes from aerial <br />photographs taken before and after the fire. <br /> <br />Results and Discussion <br /> <br />Most efforts have concentrated on monitoring numerous floods and to provide <br />preliminary information for hazard-mitigation efforts and for forest <br />managers. Results are presented for the storm and flood of July 12, 1996, <br />the effects of the fire on flooding, and assessing watershed-rehabilitation <br />efforts. <br /> <br />July 12,1996 Storm and Flood <br /> <br />Maximum rainfall from bucket-survey data for the July 12, 1996 storm was <br />about 80 mm in an hour in the community of Buffalo Creek and headwaters of <br />Page 4 <br />