Agreement - US Army Corps of Engineers - Flood Induation Mapper for SB

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TASK 4. RIVER CROSS SECTION SURVEY The USGS will use an Acoustic Doppler Current Profiler (ADCP) to collect the bathymetry of the river cross sections. The City of South Bend will provide the as -built drawings with elevations for the bridges in the study area. If as -built drawings are not available then the bridge or bridges will be surveyed by the City of South Bend. There are 24 bridges within the study area. There is also the East Race Whitewater Rafting Canal that as -built drawings will need to be provided by the City of South Bend. It is estimated that the ADCP survey will be $20,000 and the bridge surveys will be $10,000. The estimated cost/value of the Task 4 work is $30,000.00. TASK 5. WATER LEVEL STAGE GAGE INSTALL The USGS will install a new water level stage gage at the WWTP. The USGS will develop the rating curve at the gage to relate stage and discharge. The rating curve is what will be used for the steady state hydraulic model. This will be used to set and calibrate the flood stages used in the FIM. The estimated cost/value of the Task 5 work is $18,000.00. TASK 6. GAGE OPERATIONS — 2 YEARS The USGS will operate the new gage for two years in order to develop a sufficient rating curve that can be used in modeling. The gage costs $14,000 per year to operate and maintain. The City of South Bend will have to pay the USGS to continue to operate and maintain the gage after the initial two year period, that is, if the City chooses to continue to operate the gage after the initially required first two years. The estimated cost/value of the Task 6 work is $28,000.00. TASK 7. HYDROLOGIC ANALYSIS The USACE will provide a hydrologic analysis for the study. This cost estimate assumes that the gage that is measured on the Saint Joseph River near South Bend, where there is a NOAA Advanced Hydrologic Prediction (AHP) gage, becomes a continuous automated USGS gage. A hydrologic analysis of the nearby gages with a long period of record will be used to get some flood frequency statistics, but the rating curve that will be developed by the USGS using data collected for the first year after the gage is installed is what will be used for the steady state hydraulic model. Multiple flow rates to simulate approximate bank full stage to the highest rated stage (most likely at 1 ft intervals) will be determined and coordinated with USGS and the City of South Bend. The estimated cost/value of the Task 7 work is $4,000.00, .n