Rain Garden Expert Speaks
Virginia Department of Forestry expert Judy Okay answered questions about rain gardens at the Planning Commission work session Monday night.
The commissioners and residents were reacting to the proposed Elkins Heights development that recommends rain gardens for the site's storm water management.
Concerns included how effectively they will drain in the predominantly clay-based soil and how much time will be spent maintaining the gardens.
Okay said rain gardens are designed to look like a landscaped part of the lawn, as a bio-retention pit. They will act as a filtration system for the storm water run-off of roofs and yards that contain everyday pollutants. They are designed to hold about six inches of water, and drain in about 24- to 48-hours. Because the soil in the Herndon area is primarily clay, according to the developer, the proposed rain gardens will have an underground pipe that will take the filtered water directly to the streams.
Okay said tree overhangs are important to rain gardens, specifically willow, willow oak, river birch or sweetbay magnolia which are better for smaller gardens.
Maintenance is not too extensive, but home owners need to make sure the gardens are filtering properly by checking the retention and the pipe to verify it has not clogged. Okay added because rain gardens are so new, it is hard to estimate how long they will last. Although there have been some reports that they last 20 to 30 years, she admitted that wasn't for sure, and that when rain gardens expire they will need to be rebuilt, which could cost around $1,500.
Elkins Heights Development
The Planning Commission reviewed a letter submitted to the town from Paciulli Simmons and Associates, the agent for the proposed Elkins Heights development. The letter addressed the concerns raised about the location of the permanent road entrance. the construction entrance and the proposed rain gardens during the Aug. 2 public hearing.
The proposed location for the road into the development will stay as planned. The developers said they evaluated residents' concerns and revisited the plan, but because of the layout of the lots and the surrounding land, the location they chose was the most effective for the site. Based on residents' requests, the developers have moved the location of the construction entrance road to the western end of the site.
Landowner Responsibilities Clarified
The Planning Commission reviewed a proposed agreement presented by town staff that would bind home owners to maintain the bio-retention facilities, or rain gardens, on their property. The agreement is almost exactly the same as the existing storm water management agreement that states home owners are responsible for the maintenance of the storm water run-off that accumulates on their property, so that the town does not have to come onto private property and maintain the land. The addition to this agreement states the landowner shall notify the town when they transfer the property by sale or conveyance and provide a copy of the document of transfer between the parties involved.
Trail Improvements Sought
Members of the planning Commission reviewed two of the town's applications that will be submitted to the Northern Virginia Transportation Authority Sept. 24, requesting funding for W&OD Trail crossing improvements and pedestrian and transit access improvements. These requests are a part of the Congestion Mitigation-Air Quality/Regional Surface Transportation Program funding cycle for 2006.
The Planning Commission reviewed a staff report proposing improvements to the Chestnut Grove Cemetery including mausoleum area improvements, a memorial garden monument area, the widening of existing driveways, construction of a new driveway, 18 standard parking spaces and two handicapped spaces, a fuel tank and dumpster enclosure, a storm water management pond, an administration building and a maintenance building. There are other changes proposed to the site plan including the removal of three internal driveways, the removal of an existing maintenance building, the substitution of paver walkways for concrete walkways and an additional screening around the storm water management pond. The costs were already budgeted into the Town of Herndon 2001 bond program, along with additional funds that were provided in this year's Capital Improvements Program through a loan from the general fund.