Storm drain system inventory and inspection is an important part of NPDES permit compliance. When heavy rains fall, storm drains help handle the excess water and keep paved surfaces like our streets and parking lots from flooding. Most storm drain inlets have metal grates to prevent people, pets or other large objects from falling into the drain. However, smaller items like leaves, mud, sticks, and garbage often find their way into the storm drain system. A buildup of these objects can clog the storm drain system and cause a backup. To avoid this, routine storm drain system inventory and inspection can help identify potential issues before they become a problem.
The US Environmental Protection Agency (EPA) regulates stormwater through a National Pollutant Discharge Elimination System (NPDES) Permit, which is required by the Federal Water Pollution Control Act (or, Clean Water Act). While many NPDES permits require permittees to map the regulated portions of their storm drain infrastructure, the benefit of having a complete asset inventory and condition assessment has proven to be a valuable maintenance tool for both stormwater quality and structural integrity. Therefore, many municipalities and state and local governments are currently committing resources to collect this invaluable data.
Using a custom data collection application on Panasonic Toughbook computers, KCI field crews inventory and inspect the storm drain infrastructure throughout Delaware. Global Positioning System (GPS) equipment linked to the Toughbook computers are used to locate stormwater structures (e.g., manholes, inlets, outfalls), conveyances (e.g., pipes, ditches), and Best Management Practices (BMPs) (e.g., ponds, bioswales). This data collection application allows the user to input a description (e.g., type, size, material) and the condition (e.g., good, fair, poor) for individual storm drain components, such as the grate of an inlet. If the structural component is given a “poor” rating, the field crews then input the necessary data to create a work order that can be formatted to a client’s specific maintenance work order system.
Issues related to stormwater quality are often encountered inside an enclosed pipe conveying stormwater underground. A buildup of organic matter, trash and sediment in pipes is difficult to quantify without a camera system. Closed Circuit TV (CCTV) is an option, but it can be time consuming, expensive, and not feasible on an everyday basis. Our crews inspect pipe conditions using a high-zoom pole-mounted camera linked to a Toughbook computer, allowing the operator to look 200 feet into a pipe, without having to perform confined space entry. The pole-mounted camera is easy to carry and is used daily by our field crews to inspect all underground stormwater pipes.
To date, KCI has inventoried and inspected more than seven million linear feet of stormwater pipe throughout Delaware. Our routine inspections have aided in the identification of maintenance issues and have pin-pointed non-stormwater discharges and other pollutants. This ability to target specific areas of the storm drain system that require cleaning, or those with non-stormwater discharges, has greatly reduced the overall impact of stormwater on local streams, rivers, and estuaries.
Check out the video below to see how our storm drain system inventory and inspection process works.