Accession Number ADA581209
Title Missouri River Flood 2011 Vulnerabilities Assessment Report. Volume 2 - Technical Report.
Publication Date Oct 2012
Media Count 227p
Personal Author N/A
Abstract The duration and magnitude of the 2011 Missouri River runoff event exceeded all other events in the recorded gage history of the river. The thaw of an unusually heavy snowpack coincided with heavy rain throughout the upper and middle portions of the basin. Almost a years average precipitation fell in 2 weeks in May, in the upper basin. This combination and continuing rainfall raised pool levels at the mainstem reservoirs, reaching record elevations at three reservoirs, and requiring record releases from all six dams from late May through late September. Discharges reached 150,000 cfs cubic feet per second (cfs) at Gavins Point Dam June 1, 2011 and continued through September, peaking at 160,700 cfs June 27. Emergency spillways were operated at all the dams except Oahe, and flood tunnels were used at 3 dams. The inflows exceeded those estimated for the design storm by 20 percent. Total inflow would have exceeded the entire storage capacity of the Corps reservoir system if it had started empty. Flows peaked in the Omaha area at 217,000 cfs. Fortunately for the reach downstream of Gavins Point Dam, the runoff occurred upstream of the dams and had to pass through the dam system, allowing prevention of much greater peak flows in the river (examples include 313,100 cfs at Omaha and 338,000 cfs at Rulo, Nebraska) and prevention of more disastrous damages. In managing the record runoff of more than 61 Million Acre-Feet in 2011 and record releases from Corps Projects, the Corps flood risk management facilities and actions were effective. The handling of inflow and the releases in preventing even more damage than occurred, but the facilities themselves were damaged but still intact and fully functional. While many key repairs have been accomplished and many more will be complete within a year, other vulnerabilities in facilities and operations will take longer to address. Some have yet to be fully assessed, and others would require large commitments of funds not readily available. The purpose of this report is to present results of evaluations, assessments, and repairs that have been done, will be done, or still need to be done for facilities and infrastructure that are under Corps of Engineers jurisdiction or responsibility. It is a snapshot in time, as some evaluations and assessments are yet to be completed, but this effort provides an overall picture of immediate and longer term needs to bring flood risk management on the Missouri River to its fullest potential. In the near term, repair of facilities damaged during the flood is our priority effort. Other actions will be necessary to restore many features of reservoir and river corridor infrastructure to their originally designed, or intended, level of function. And in the long term, enhancements can be made subject to feasibility, authority and funding, that will increase the flood risk reduction capability of federal and non-federal infrastructure and related governance in the Missouri basin.
Keywords Cultural resources
Dams
Economic impact
Erosion
Flooding
Infrastructure
Levees
Missouri river
Repair
Repair-restore-enhance
Reservoirs
Risk management
Runoff
Spillways
Tribal relations
Water management


 
Source Agency Non Paid ADAS
NTIS Subject Category 48G - Hydrology & Limnology
50B - Civil Engineering
Corporate Author Corps of Engineers, Omaha, NE. Missouri River Div. Lab.
Document Type Technical report
Title Note N/A
NTIS Issue Number 1325
Contract Number N/A

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