Emergency repair work on the shoreline where the Ma & Pa Trail meets Winters Run is expected to be completed by Friday.
A crew from Environmental Quality Resources LLC, of Arbutus, worked this week to temporarily reroute the stream in the vicinity of the trail's boardwalk and bridge, where the east bank of Winters Run was being severely eroded and the shifting stream threatened to eventually undermine the boardwalk.
Paul Magness, chief of capital planning and development for the county Department of Parks and Recreation, said "several regular trail users" alerted the department about the problem less than a month ago.
About two years ago, he continued, the stream went under the bridge, shifted north and an island of sediment was created.
But since last year's storms, "Winters Run would come down, make a 90-degree turn, go toward the bridge, then make another 90-degree turn and go past the bridge," creating a whirlpool effect, Magness said. The action scoured the shoreline and deposited the sediment back into Winters Run, creating sandbars north and south of the trail bridge that also altered the stream flow.
"We have worked with one of our waterway engineering contractors, one of our waterway construction contractors, the Maryland Department of the Environment and the Army Corps of Engineers to develop an acceptable repair option," Magness said.
EQR crews began work Monday to create a channel where Winters Run used to be and then used sediment, rocks, stumps and fallen logs to create a new shoreline wall by the boardwalk. The work on the shoreline was finished by early Thursday morning, and the crew was in the process of covering the tracks of its equipment and restoring the surrounding woods before leaving the job.
"We had a very limited window to work," Sepehr Baharlou, an engineer with BayLand Consultants & Designers Inc., who designed the repair project, explained as he toured the site Thursday morning.
Any repairs had to be completed by March 1 because of federal regulations on stream disturbance during fish spawning season, he explained. The Corps of Engineers, the chief regulatory body for waterway disturbance activity, is very specific on what it will and won't allow, he added.
"We could only use materials found on site," he said. The stream diversion was accomplished only with sand, gravel, earth, wood and stone already there, and the equipment used was limited to a trackhoe and a Bobcat. Those were trailered in from the Edgeley Grove end of the trail, which is blacktopped, to the boardwalk and bridge.
Baharlou said the problem with the bank erosion appears to have been exacerbated by a large tree that fell across Winters Run north of the trail bridge and in turn caused the stream to alter its course more eastward, a process that was accelerated by the increased volume of water caused by Irene and Lee. The tree was cut up by the EQR crew and sections of the trunk were used in the bank stabilization.
Magness, of parks and recreation, said the emergency project cost $17,450.30, with funding coming from the department's capital fund that is for work on Edgeley Grove Park, where the section of the trail and the shoreline are.
Even though emergency repairs are near completion, parks and rec has also started working on a more permanent solution to the problem, which will be developed over the next few months.
Magness said the waterway engineer is under contract to come up with what will essentially be "some amount of stream restoration."
Baharlou, who said he has submitted a proposal to the county, explained the emergency repair should last long enough for the county to do a permanent repair, barring a major flooding event.
"Work will have to be done a few hundred feet upstream and downstream," he explained, pointing to a gravel bar that has built up south of the trail. "That bar even influences where the stream goes" on the north side of the bridge, he added.
Aegis staff member Allan Vought contributed to this article.