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2024 Hennepin County All -Jurisdiction Hazard Mitigation Plan <br />Volume 2 — Hazard Inventory <br />changes in ground water level can induce sinkholes. Ground water drawdown often increases <br />sinkhole activity. <br />4.1.2.11.7. Construction and development. Human development activities that add extra weight <br />and pressure to land surfaces by construction of new buildings and other infrastructure may <br />accelerate sinkhole formation. The alteration of surface and subsurface drainage flows due to <br />human development may also accelerate sinkhole formation by increasing the flow of water <br />through sinkhole drains. Water and sewer lines in karst areas are susceptible to damage from <br />sinkholes and other land subsidence. When water or sewer lines leak or break, the released water <br />may enter sinkhole systems and quickly enlarge voids, accelerating sinkhole formation. <br />4.1.2.12. Prevention <br />4.1.2.12.1. Avoidance The most effective prevention/mitigation measure against sinkhole <br />fatalities, injuries, infrastructure disruption and property loss are avoiding development and <br />certain human activities at sites prone to sinkholes. This is a preventive action. Avoidance may <br />be accomplished through evidence -based zoning policies that utilize local area sinkhole hazard <br />assessments that trigger site -specific sinkhole risk investigations when appropriate if <br />development or other uses are proposed at sites inside identified hazard areas. Zoning -based <br />measures would be challenging in Hennepin County because much of the karst areas have already <br />been developed. <br />4.1.2.13. Mitigation <br />4.1.2.13.1. Education. Education of zoning officials, landowners need accurate local information <br />to make sound decision regarding their development and activities in sinkhole susceptible terrain. <br />These require detailed sinkhole hazard maps. HCEM completed its Landslide Hazard Atlas to assist <br />in mitigation, avoidance, and planning response efforts. The atlas was release by 2020. <br />4.1.2.14. Response <br />With the completion of the Landslide Hazard Atlas in 2020. Response effort follows five key <br />principles: engage partnerships, have a tiered response, have a scalable, flexible, and adaptable <br />operational capability, unify your effort, and be ready to act. Scene stabilization will be achieved <br />when the immediate threat to life -safety and property damage at the scene have been stopped. <br />4.1.2.15. Recovery <br />The recovery process begins soon after the incident happens. The objective is to bring households <br />and communities back to normal activities post -disaster. Relief can come from a variety of ways. <br />Public Assistance, Individual Assistance, Emergency Repair, or Permanent Repair. <br />4.1.2.16. References <br />Hennepin County landslide Hazard Atlas. (July 2020). https://www.hennepin.us/- <br />/media/hennepinus/residents/emergencies/landslides/landslide-atlas-cover-contents.pdf <br />22 <br />