Flood control dams worked
On Thursday, September 5, The Morgan Messenger sat down with Kate Lehman of the Warm Springs Watershed Association and Jim Michael of the Eastern Panhandle Conservation District to talk about the flash flood of Saturday, September 1.
Six inches of rain fell in four hours between 3 p.m. and 7 p.m. causing Warm Springs Run to flood the U.S. 522 south corridor and the town of Berkeley Springs.
“I don’t think anything could have been done to totally avoid the flooding with so much rain falling in such a short period of time,” Lehman said.
Flood control plans
Michael said the original plan to control floods on Warm Springs Run was written in 1954. The “Flood Prevention Plan” was authored by the U.S. Department of Agriculture Soil Conservation Service.
One of the recommendations in the plan was to build eight flood control dams on tributaries to
Warm Springs Run. Those dams were built on easements donated by landowners between 1955 and 1961.
“The dams were designed to catch the 100 year storm and studies showed the dams would catch about 50 percent of the runoff,” Michael said.
Another study was done by the USDA Soil Conservation Service in 1991 titled “Flood Plain Management Study.”
It proposed a culvert be installed under the town to divert the stream from Route 9 to North Berkeley. The plan was nixed because businesses didn’t want the disruption, Michael said.
Both the 1954 and 1991 studies suggested a measure that was never implemented to control flooding on the stream - a large dam south of Widmyer Elementary School, Michael said.
The latest plan for the Warm Springs Run watershed is the “Comprehensive Watershed Management Plan” of 2012.
The Warm Springs Watershed Association commissioned the study and writing of the document through a Chesapeake Bay Accountability and Regulatory Program grant. The primary author was geologist Robert K. Denton of GeoConcepts Engineering.
The plan deals with improving the quality of the water in the run as well as reducing stormwater runoff.
Although the plan is not specifically aimed at preventing flooding, the plan does address many flood issues such as stream bank erosion, uncontrolled stormwater runoff and sedimentation causing shallow stream beds that increase the chance of flooding.
The current West Virginia Watershed Implementation Plan for the Chesapeake Bay initiative calls for voluntary stormwater management measures to be put into place to capture the first one inch of runoff. These measures will eventually become mandatory.
“The Warm Springs Watershed Association is looking at ways to capture the first one inch of runoff from impervious surfaces,” Lehman said.
Talking about the recent flash flood, she added, “Even if you captured the first inch, five inches wouldn’t have been captured.”
Looking for the cause
Both Michael and Lehman agree the eight flood control dams did their job. They toured the dams after the flood and took pictures showing the high water mark never reached the top of the overflow pipes at any of the dams.
“We had a long way to go before the water ran over the spillways,” Michael said.
The dams were built long before any development was done along the U.S. 522 corridor south of Berkeley Springs. Michael and Lehman attribute much of the flooding problems to the runoff from impervious surfaces.
Lehman said 17 percent of the watershed is now covered with impervious surfaces, mostly from Morgan Square through town. Michael said only two percent of the watershed is agricultural.
“It appears the storm fell mostly on areas of impervious surfaces,” Lehman said.
“All landowners need to practice good land and stormwater management practices,” Michael said.
Lehman said parking lots need to incorporate filter strips of vegetation to soak up rain water, remove curbs and put in permeable parking areas where water runs off.
She said individuals can help by installing rain gardens, using rain barrels and raised garden beds to trap runoff.
“It is important to look at the entire picture. If you are looking at a solution in town, you also have to look upstream and vice-versa,” Lehman said.
The Morgan County Planning Commission does enforce the counties Stormwater Management ordinance, requiring commercial buildings and developments with over 3,000 square feet of impervious surfaces to install stormwater retention ponds, County Planner Alma Gorse said.
A consulting engineer reviews builder’s plans to insure stormwater management practices are incorporated into builder’s designs and they meet all county requirements.
The Stormwater Management ordinance is currently being reviewed to determine how the ordinance needs to be modified to bring it into compliance with the state’s Watershed Implementation Plan, Gorse said.