Devils Lake Flood Risk Management - Geotechnical Aspects Devils Lake, North Dakota

摘要

Devils Lake flooding has inundated thousands of acres of farmland and destroyed hundreds of homes and businesses. More than $ 1 billion has been spent in flood mitigation. Devils Lake lies within a closed basin with no natural outlet. Embankments have been constructed and roadways raised to "act" as dams, protecting people and resources from the lake, which has risen 54 feet since 1940. Dam safety analyses and designs were completed for embankments totaling over 13 miles in length. Designs include a zoned embankment with impervious core and impervious fill, and sand/toe drains and berms for seepage control. Constructabil-ity addressed excavation into existing embankments, and abandonment of drainage structures, while under head. Sequencing was critical to safely completing construction without compromising flood protection. Geotechnical aspects are presented and seepage and slope stability mitigation measures discussed. Construction observations are presented including means and methods adapted to meet disclosed subsurface and groundwater conditions.