Avoiding and Minimizing Risk of Flood Damage to State Assets: A Guide for Delaware State Agencies
Prepared by Delaware’s Flood Avoidance Workgroup, this report outlines a set of principles and instructions for ensuring that existing and future flood risks are considered during site selection and project design, as required by Executive Order 41.
The primary guidance principles as detailed further in the report are:
- Understand flood risk at each site under consideration.
- Avoid sites with existing or future flood risk. If not feasible, minimize flood risks by choosing locations outside of hazard zones and where flood depths are shallowest.
- Where avoidance is not possible, design to decrease risk of flood damage.
- Incorporate green infrastructure techniques at the site scale and landscape scale.
- Document flood risk reduction measures.
Noting that flood avoidance can be difficult for infrastructure, since designs and locations are constrained by necessity - the guidance offers different recommendations for buildings and infrastructure. Detailed information on avoiding or reducing flood risk for structures and infrastructure is included in Appendix A -Instructions for Avoiding and Minimizing Risk of Flood Damage to State Assets. As an example, to avoid flood damage the report suggests: obtaining the base flood elevation, determining if the site is tidally influenced, determining the exposure to wave action, and assessing the future flood risks due to sea level rise based on the expected life-span of the structure. Some of the best management practices listed for infrastructure design include: sizing culverts to accommodate anticipated future flows, burying power lines, and raising electrical components for pumping stations above the future flood elevations.
The report also provides an overview of prior legislation and state agency action to address flood risks. It also summarizes the main findings from past sea level rise and climate change research; and offers Mapping Tools for Assessing Flood Risk in Appendix B.
The Flood Avoidance Workgroup was convened to assist state agencies in meeting the flood avoidance directions included in Executive Order 41.
Publication Date: March 2016
- Agency guidance/policy
- Best practice