Laserfiche WebLink
<br />1.3 <br /> <br />. Field Reconnaissance and Survey <br />Field reconnaissance involved site inspection of the watershed and alluvial <br />fan, identification and measurement of pertinent hydraulic structures, a cross- <br />sectional survey of the Cornet Creek channel, and collection of historic flood <br />information. Information concerning past floods along Cornet Creek was collected <br />from newspapers, city records, and individual accounts. <br /> <br />. Hydroloqic Analysis <br />Flood hydrographs for the Cornet Creek watershed were developed for 10-, <br />2!i-, 50-, 100-, and SOD-year return periods for use in the FIS. Both water <br />n ood and mud flow hydrographs were developed" <br /> <br />. Hydraulic Analysis <br />Hydraulic analysis of hyperconcentrated sediment flows on t.he Cornet Creek <br />alluvial fan was performed using the MUDFLOlli 2-D flow-routing model, Flow <br />depths, velocities and areas of inundation were established for various scen- <br />arios of water flood and mud flow. <br /> <br />. Flood-Hazard Maps <br />Results of the hydraulic analysis were used t.o prepare maps delineating <br />maximum flood depths, flow velocities, and ar~as of inundation. <br /> <br />1.3 Principal Investiqators and Proiect Te,llIn <br />The project manager for this investigation was Mr. Thomas R. Grindeland, <br />P,E., SLA Senior Civil Engineer. Dr. J. S. O'Brien, P.E., acted as a special <br />consultant to SLA. Dr. O'Brien adapted the U.S. Geological Survey's 2-D OHM <br />model (Hromadka, 1988) to specifically accommodate hyperconcentrated sediment <br />flow properties and applied it to the Cornet. Creek watershed and alluvial fan. <br />Additionally, Mr. Paul E. Clopper', P"E., SLA Senior Water Resources <br />Engi neer, developed a computer graph i cs interface to the MUDFLOW model for <br />interpretation and plotting of model results. Ms. Kathleen E. Cohan, SLA <br />Geologist, contributed the geologic and soils assessments used in the study. <br />