Town Center Subbasin Study Report - Bellingham Massachusetts

Proposed Designs for Drainage Area O24-A: Municipal CenterBEFORE: Photo of existing lawn behind the Municipal CenterAFTER: Visualization of proposed rain gardenO24-A Municipal Center: Rain GardenStormwater control Description:A small rain garden has been designed to captureoverland flow from a portion of the Municipal Centerroof, driveway, and vegetated lawn area to providewater quality treatment and infiltration. This systemwill enhance the beauty of this back courtyard areawhere a small, sparsely planted landscape area iscurrently sited. Many Municipal Center offices look outonto this courtyard area.O24-A Municipal Center: Rain GardenDrainage Area (acres) 0.11Impervious Area (acres) 0.11Estimated Infiltration Rate (in./hr) 4.46Target Phosphorus Removal 85.7%Water Quality Depth (in.) 0.70Water Quality Volume (ft3) 280±Stormwater Control Surface Area (ft2) 420±Estimated Construction Cost $1,670Plan and section details can be found in Appendix C.“Rain gardens provide a cost effective way of treatingstormwater as the ratio of cost to volume of runoff treatedis lower than many other stormwater controls.”23