SD3 - Recurrent Flooding Study for Tidewater Virginia

Executive Summary:
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. 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.

The stakeholder advisory panel assembled for this report consisted of 25 individuals selected to provide a broad representation of the Virginia coastal localities and agencies working within the region. The panel focused on the roles of the state and localities in addressing flooding and sea level rise issues. The advisory panel felt strongly that Virginia localities are not adequately empowered to address the issues through policy and management actions, and localities do not have the necessary financial resources for many accommodation or protection strategies. Therefore, the advisory panel felt the state should take a strong leadership role, incorporating flood and sea level rise management into state purviews. They specifically believed localities should be enabled to implement adaptation strategies, but did not want the state to mandate specific adaptation strategies. The advisory panel recommended state authorization and support that would allow each locality the opportunity to address flooding and sea level rise in their own way.

To begin the process of addressing recurrent flooding at the state and local levels, we offer the following recommendations:

1. Given the long time frame necessary to effectively address recurrent flooding and sea level rise issues and given the speed at which risks are projected to increase, Virginia and its coastal localities should immediately begin comprehensive and coordinated planning efforts.

2. The State should initiate identification, collection and analysis of data needed to support effective planning for response to recurrent flooding issues in Virginia.

3. The State should take a lead role in addressing recurrent flooding in Virginia for the following reasons:

a. Accessing relevant federal resources for planning and mitigation may be enhanced through state mediation.

b. Flooding problems are linked to water bodies and therefore often transcend locality boundaries.

c. Resource prioritization efforts will require consistent or standardized assessment protocols across all localities and regions.

d. Localities do not feel enabled to address all flooding and sea level rise issues.

4. The State should request an expert review of local government legal authority to address current and projected flooding risks and what levels of evidence are likely to be required to justify locality action. The State should then enact any enabling authority needed to allow localities to address current and projected flooding issues.

5. The State should develop a comprehensive strategy for addressing recurrent flooding issues throughout Tidewater Virginia.

a. Part of that strategy should include prioritization of areas for flood management actions based (in part) on risk.

b. Detailed studies should be done of prioritized areas to determine:

i. Potential adaptation strategies appropriate to the area
ii. Implementation feasibility of identified strategies
iii. Cost/benefit of identified strategies