WESTFIELD – The state Department of Transportation is seeking the approval of the Conservation Commission to change the scope of erosion control on Little River.
Gene Crouch of VHB, the DOT’s engineering consultant, presented details of the revised project at the rear of the DOT’s facility located at 219 East Main Street.
The Conservation Commission had approved orders of conditions for a project to stabilize the bank of Little River with rip rap, large processed rock. The erosion is occurring on a bank where the river curves around the DOT road maintenance facility.
“The DOT maintenance yard is used to store sand and salt during the winter,” Crouch said. “Little River loops around the site which has experienced erosion over the years. So now the edge of the pavement is crumbling down into the river and a ravine is being forged.
“This has been an on-going problem and the original order of conditions was to armor the bank, put down a lot of rip rap,” he said during the public hearing.
Crouch said the project was reviewed by various state and federal agencies for its environmental impact.
“The Army Corps of Engineers requested the DOT to consider installation of “j” hooks in the river,” Crouch said. “We were asked to re-investigate the situation and re-engineer the project.”
The “j” hook are rock structures attached to the bank being protected and jut out upstream into the river at a 15 to 20 degree angle. The length of each hook is determined based on the speed of the current and depth of the river at that point. The hooks terminate with the loop of the “j” pointing downstream at the opposite bank.
The “j” hooks are graded from the high point on the bank down into the river bottom.
“They direct the water away from the bank and slow down the velocity of the current along the bank, which is the cause of the erosion,” Crouch said. “The hooks also create fishery habitat benefits.”
“This is a significant change from what was originally approved by this board and is being done at the request of the Corps of Engineers,” Crouch said. “It is a technology being used all over the country in stream restoration projects.”
“We look at this as a resource enhancement, putting features out into the river that improve habitat, while at the same time stabilizing the bank.” he said.
The “j” hook structures are frequently used in North Carolina and Virginia, where VHB has offices, and is a technology familiar to the staff. Crouch said the environmental protection agencies in those states have approved the engineering requirements for installation of the structures and have offered to provide those documents to the local board.
The Conservation Commission continued the hearing to its Nov. 8, 2011 session.
