Many times a drywell is undersized for the volume of water that is directed into it. Another factor is soil make-up. If the drywell was not installed into well-draining granular material and the backfill material around the outside of the rings does not drain well, this will affect the leaching abilities. In this case, the drywell becomes nothing more than a holding tank with limited capacity. Many towns now require the installation of drywells for the construction of new homes. Drywells sometimes serve dual purposes; to collect roof runoff and surface water from driveway and lawn areas. The collection of sediment (leaves, silty soil, debris and lawn clippings) at the bottom of the drywell can also effect the leaching ability of the drywell and over the period of just a few years the drywell can become overwhelmed during heavy rains.
A 30 year old drywell structure installed in well draining material that failed due to silt
and sediment migration into the surrounding soils b/o lack of maintenance.
Catch basins serve as collection points for surface water and are also the first place where debris is deposited. Annual service and inspection is the best way to keep this critical part of the drainage system functioning at its peak performance. The grate or surface inlet of the catch basin can become restricted during periods of heavy rain or late in the fall when the leaves cover the ground, the catch basin can be rendered useless. Serious consideration should be given to the size and depth of the structure. The volume of water and handling of debris that enters through the open grate dictate how well the structure will perform under peak demand. Consider what would happen in the event the structure was obstructed or otherwise could not move water from the area, where will the water go? Will the water simply pond on the lawn or is a cellar entryway or basement window well the next lowest area that will take water?
A below grade window well that's back pitched
towards the house with no drainage system.
The pipe used to connect the roof drains, catch basins and drywells should be sized appropriately to accommodate large volumes of water in the event of a flooding condition. Flexible corrugated pipe works well in many cases because it’s easy to work with and adapts easily to changing site conditions. However, the corrugations in the pipe make it susceptible to debris becoming lodged and thus restricting flow rates. Smooth interior pipe works the best but the cost differential sometimes doesn’t outweigh the performance of the pipe. When corrugated pipe is used it is best to have it inspected once a year to be sure that the pipe is structurally sound and free of obstructions. We offer video pipeline inspection to properly locate and diagnose underground pipe problems combined with high pressure water jetting to clear pipes from 3"-12" in diameter.