Slide 11 of 36
Notes:
The first step to getting a retrofit in the ground is the process of locating and identifying where it is feasible and appropriate to put them. This involves a process of identifying as many potential sites as rapidly as possible. Usually this step is completed in the office
Two important office tasks need to be conducted during this step. First, the drainage area to each retrofit should be delineated and second, the potential surface area of the facility measured. The drainage area is used to compute a capture ratio. This is the percentage of the overall watershed that is being managed by all retrofit projects. The surface area is used to compute a preliminary storage volume of the facility. A short cut storage volume can be computed by multiplying two-thirds of the facility surface area times an estimated depth. These two bits of information can be used as a quick screening tool. In general, an effective retrofitting strategy must capture at least 50% of the watershed and a minimum target storage volume for each retrofit is approximately � inch per impervious acre.