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2024 Hennepin County All -Jurisdiction Hazard Mitigation Plan <br />Volume 2 — Hazard Inventory <br />• Minneapolis Park Board, $6.8M: Mudslide behind Fairview -Riverside affecting 100' x 250' <br />slope and exposing facility oxygen tanks and require extensive re -engineering and <br />restoration. <br />• Minnehaha Creek Watershed District, $180k: Lake Minnetonka reached record high water <br />mark of 931.11 feet, and Minnehaha creek exceeded 100-year flow at Hiawatha (with 893 <br />cu ft.). The entire creek watershed was severely impacted, as were many of the MCWD's <br />capital projects. <br />• Minnetonka, $55k: unspecified damages to municipal property <br />• Minnetonka Independent School District, $NA: Destruction/failure of retaining wall at <br />high school. <br />• Mound, $1M: unspecified damages to streets, culverts, sewers, parks, and infrastructure <br />• Orono, $150k: severe damage to Starkey Road and Balder Park Road <br />• Park Nicollet Methodist Hospital, $3.6M: Drainage system destroyed; sunken grade <br />creating sinkhole risk; low-lying electrical circuitry inundated and damaged, pumping, <br />sandbagging and dewatering required; barriers construction. <br />• Richfield, $70-75k: Power failure at sanitary lift station, damage to pumps, trails and paths <br />inundated, littered with debris, and damaged. <br />• St. Louis Park, $50-55k: severe damage on Louisiana Ave <br />• Wayzata, $70-75k: city marina flooded and damaged; culverts damaged, requiring <br />emergency repairs. <br />August 18-20, 2007 - worst <br />rainfall event on record in MN <br />Perhaps the most extraordinary <br />precipitation event in <br />Minnesota's modern history <br />shattered Minnesota's 24-hour <br />rainfall record. The 15.10" total <br />recorded at 8:00 AM on Sunday, <br />August 19, 2007, near Hokah in <br />Houston County is the largest <br />24-hour rainfall total ever <br />measured at an official National <br />Weather Service observing <br />station in Minnesota, breaking <br />the old record of 10.84 inches <br />by an astonishing 39%. <br />Rainfall Totals for Southern Minnesota <br />August 18through August 20 (8:00 AM CDT), 2007 <br />0 1 2 3 4 5 6 7 8 101214 inches <br />State Climatology Office- DNR Waters <br />Rainfall totals for entire 3-day rainfall event in southern Minnesota in <br />august of 2007. In most areas, 80-90% of the totals came within the <br />first 24 hours of the event. <br />The storm also obliterated the state's "unofficial" rainfall record, when a non -National Weather <br />Service rainfall observer near La Crescent (Houston County) reported 17.21 inches for the 24-hour <br />period ending 7:00 AM, Sunday, August 19. This is the largest 24-hour value in the Minnesota State <br />Climatology Office database and broke the previous statewide non-NWS observer record 12.75" <br />by a margin of 35%. Both new records far exceeded expected totals, even for record -breaking <br />events, and are so large, a true return period estimation is virtually impossible. <br />124 <br />