With the weather warming up and homeowners working on spring cleaning and yard maintenance, don’t forget about those stormwater BMPs! Most improvements involving the addition of impervious surfaces require stormwater management. For small residential jobs such as house additions, patios, or swimming pools, this usually means a subsurface stone seepage bed. Larger projects may utilize rain gardens or detention basins.
Municipalities will often require homeowners to sign into an agreement to maintain the required stormwater management features. These agreements include regular inspections of these features. No two agreements are the same, but they typically require the following.
Starting with what you can see from the surface, the grading and drainage patterns will be examined to ensure stormwater runoff drains to the appropriate inlets/yard drains with no erosion or ponding. Roof drains need to be checked for clogging so that they drain adequality, whether it’s to a splash block or directly to a subsurface bed. Inlets and yard drains should be inspected for debris and sediment accumulation. For above-ground basins and rain gardens, the bottom, side slopes, and piping are inspected for erosion and adequate vegetation. If there are any trees near the stormwater BMPs, it is important to make sure there is no intrusion from root growth.
Seepage beds are designed with cleanouts and/or maintenance ports to access the subsurface features of the bed and perform visual inspections. We review water and sediment levels through these maintenance ports. Ideally, the bed will be empty. But if there is standing water and the most recent rainfall was more than 72 hours prior to the inspection, then infiltration problems exist, and further investigation is needed. If the stormwater system has an outlet structure, then it will be reviewed for sediment or water accumulation and to confirm the individual pieces (weir, orifice, or other flow control feature) are intact and undamaged.
The requirements for operation, maintenance, and inspections depend on the type of system and the agreements with the municipality. I always say this, but every township is a little different. If you have a stormwater management system on your property that needs inspection but aren't exactly sure what is required, don't hesitate to reach out to DLHowell so we can take care of it!