Recurrent Flooding Study for Tidewater Virginia

Center for Coastal Resources Management, Virginia Institute of Marine Science
Molly Mitchell, Virginia Institute of Marine Science
Carl Hershner, Virginia Institute of Marine Science
Julie D. Herman, Virginia Institute of Marine Science
Daniel E. Schatt, Virginia Institute of Marine Science
Emily Eggington, Virginia Institute of Marine Science
Skip Stiles, Wetlands Watch

Abstract

Recurrent flooding is flooding that happens repeatedly in the same areas, typically leading to economic losses. Recurrent flooding is a problem throughout Tidewater Virginia, both in coastal areas (typically due to storm surge) and in inland areas (typically due to heavy rainfall). The Virginia General Assembly requested that in conducting its study, the Virginia Institute of Marine Science  review and develop a comprehensive list of ideas and examples of strategies used in similar settings around the United States and the world;  convene a stakeholder advisory panel for the purpose of discussing and assessing the feasibility of employing these strategies in Tidewater and Eastern Shore Virginia; and offer specific recommendations for the detailed investigation of preferred options for adapting to relative sea-level rise. The study was undertaken with the collaboration and assistance of Old Dominion University, the Hampton Roads Planning District Commission, Wetlands Watch, the University of Virginia Institute for Environmental Negotiation, the William and Mary Coastal Policy Clinic, and relevant state agencies. Data and analyses were collected from multiple local, state, and federal agencies, as well as NGOs and regional authorities. This Recurrent Flooding Study addresses all localities in Virginia’s coastal zone. It documents flooding risks based on available records of past road and infrastructure inundation as well as potential flooding risks based on the best available topographic information. It assesses future risk based on projections for sea level rise from the National Climate Assessment program modified to incorporate factors specific to Virginia’s coastal zone. The study also inventories adaptation options from regional, national, and international sources. Options include planning, management, and engineering strategies that merit particular consideration for application in Virginia. In preparing this report we found: 1. Recurrent flooding is a significant issue in Virginia coastal localities and one that is predicted to become worse over reasonable planning horizons (20-50 years). 2. The risks associated with recurrent flooding are not the same throughout all areas of Tidewater Virginia. 3. Data are often lacking for comprehensive and/or fine resolution analysis of flood risks in the region. 4. Review of global flood and sea level rise management strategies suggests that it is possible for Virginia to have an effective response to increasing flood issues BUT it takes time (20-30 years) to effectively plan and implement many of the adaptation strategies. vii There are a wide variety of adaptation strategies used throughout the world, many of which are suitable for use in some part of Tidewater Virginia. The optimal strategy is going to be development of flexible plans that match adaptation options to the unique circumstances of each coastal locality and link option implementation to the evolving risks. This is the strategy now employed by an increasing number of states and localities in the United States. It requires serious planning, commitment of resources, and careful analysis of evolving conditions. It reduces unnecessary expenses, ensures development decisions are informed, and recognizes the long lead times required for effective implementation of many adaptation options