Six steps to better stormwater control
Four communities in Virginia’s Roanoke Valley, a region that has long suffered the effects of flooding disasters, are pursuing a cooperative approach to stormwater control. Coordinated by the Fifth Planning District Commission (Fifth PDC), the multi-jurisdictional effort became a top priority following the devastating November 1985 flood caused by the remnants of Hurricane Juan. Municipal leaders in the communities adjacent to the Roanoke River recognized that the proposed U.S. Army Corps of Engineers’ flood control project along the river would not solve existing flooding problems along its tributaries.
So the Fifth PDC organized a technical subcommittee to develop a plan studying historic flooding problems and develop remedial measures. A feasibility study in 1985 was completed shortly before the big flood, and the arrival of a Federal Emergency Management Agency (FEMA) interagency team after Hurricane Juan opened new funding possibilities through a Hazard Mitigation Program.
FEMA set a precedent by providing a 50 percent matching grant for development of a $690,000 stormwater management plan, with local governments providing the other 50 percent.
The Fifth PDC’s technical subcommittee selected Dewberry Davis, Fairfax, Va., to develop the plan and Ch2M Hill, Herndon, Va., to implement it.
The management project was divided into six phases:
* develop watershed plans;
* arrange remedial action plans;
* conduct water quality studies;
* adopt stormwater guidelines;
* provide environmental permitting; and
* implement the plan.
“Flooding doesn’t abide by manmade boundaries,” says Wayne Strickland, executive director of the Fifth PDC. “Our goal is to control stormwater in a cooperative manner that will be more effective than a piecemeal jurisdiction-by-jurisdiction approach. What we hope to achieve is a substantive means of responding to the impacts of flooding to save lives and property throughout the Roanoke Valley.”
As part of the plan, 16 priority watersheds, covering more than 365 square miles, are being studied. Watershed master plans are being prepared for each priority watershed to identify future projects that will lessen existing problems and/or minimize future increases in flooding. Such measures include culvert and bridge improvements, stream restoration and stormwater/flood control projects. Remedial action plans are being developed for several critical watersheds to identify projects that can immediately reduce flooding.
For example, hydraulic modeling will be conducted on 27 streams covering more than 112 linear miles. The hydraulic models are being developed by enhancing the accuracy of the HEC-2 models prepared by the U.S. Army Corps of Engineers for the 1993 FEMA FIS.
The studies will culminate in stormwater control recommendations for constructed projects that will either eliminate or greatly reduce repetitive flood losses. Projects may involve non-structural measures, such as greenways and floodproofing, as well as structural measures such as stream-crossing modifications and strategically located flood control facilities.
Funding for implementation is still uncertain. The agency recognizes that in the long run, money it now spends on mitigation will help eliminate flood recovery spending measures down the road. However, even with FEMA’s matching grant money, more is still needed.
One solution may be to establish a regional authority with the power to create stormwater utilities that can collect user fees. Receiving additional assistance from federal and state sources is another possibility as well.
“The new flood studies will be an invaluable tool for regional planning,”.says Greg Secrist, chairperson of the technical subcommittee for Vinton, Va. “Before the project, we had no consistent ideas
about stormwater impacts. Now we will have answers to questions about development so we can justify what we ask developers to do. This is about creating a balance between protecting downstream residents and ensuring the interests of economic development.”