Salem, NH- SFC Engineering Partnership has designed an expanded parking area for Canobie Lake Park with a focus on being environmentally friendly.
Parking capacity is being increased to improve patron convenience while minimizing the use of busses to transport employees from off-site parking areas. This expansion will add over 2½ acres of new pavement surface.
Many factors must be considered: soil erosion, aesthetics, traffic, tree removal, lighting, and noise. Each aspect is carefully orchestrated to insure that the only effects of this project on the community are positive.
Perhaps the most recognized effect of a project of this magnitude is on stormwater. When 2½ acres of pavement is created, stormwater water volume increases and water flows faster than before.
SFC met the design challenge with pervious pavement and a gravel wetland to control and clean the stormwater.
Pervious pavement controls stormwater even before it becomes a factor. Rainwater falling on pervious pavement behaves not unlike rainfall on a grassy meadow. The rain infiltrates right into the pavement. It does not run across the pavement surface, and therefore, eliminates negative effects of stormwater runoff. A portion of the Canobie Lake Park project where soils are suitable for infiltration is being constructed with pervious pavement to take advantage of these benefits.
Other portions of the site drain to a gravel wetland. The gravel wetland is a constructed facility using a stone filter media and a wetland environment to detain and filter stormwater. The gravel wetland proved to be a relatively compact and efficient facility that allows maximum parking yield in the available space.
Additionally, offline infiltration chambers are used to increase the rate of infiltratration back into the ground and decrease the volume of stormwater flowing from the site.
SFC worked with Canobie Lake Park to design these solutions. The net result – no negative impacts to stormwater quality, no increase in stormwater volume nor stormwater rate of flow. It is the hope of both SFC and Canobie Lake Park that this gravel wetland will become an outdoor classroom for future stewards of the environment.