Stormwater management practices have evolved dramatically since the implementation of the Clean Water Act in 1972. Despite these changes, the precast concrete industry remains at the forefront of product development, providing technology and housing solutions that meet ever-changing regulations. But as more precast products are specified on stormwater projects, there is an increasing need for maintenance plans for the Best Management Practices that have been designed and installed.
NPCA file photo.
A variety of techniques can be used to remove pollutants, but settling vessels will fill, filters and screens will clog, and chemicals will become exhausted. In short, every BMP will eventually need to be cleaned, renewed, replaced or removed. All of the activities and the inspections needed to determine the condition of a BMP fall under the loose definition of “maintenance.”
Field crews have found that a major shortcoming of water quality efforts stems from a lack of proper maintenance or poor maintenance access. A good maintenance program is vital to the success of every BMP. However, many products do not allow for proper maintenance to be performed due to a lack of access.
For example, detention systems made from competing materials are often too short for a person to enter and perform an inspection or maintenance. As a courtesy, they offer “inspection ports” that are little more than ventilation shafts that allow maintenance personnel to visually inspect the portion of the BMP that is directly under their feet. Any obstructions or debris upstream or downstream remain a mystery. Maintenance can be performed with a jet wash or vacuum cleaning, but that will only be as thorough as washing or vacuuming in the dark.
When maintenance access is limited, excessive cost for the owner can be added long after installation is complete. Some systems, such as the one shown, restrict flow and can even obstruct the detention system, preventing it from operating.
When flow is restricted, the detention system can be prevented from operating. Photo courtesy of CrystalStream Technologies.
Typically, thanks to its structural qualities, precast concrete offers the best solution for ease of access related to inspection and maintenance throughout the life of a BMP, as can be seen in the following examples.
Photo courtesy of CrystalStream Technologies.
The above photo shows a precast concrete vault with steps embedded into its walls. With installed steps, maintenance workers can easily access deep vaults, inspecting them for debris and trash build-up.
Photo courtesy of CrystalStream Technologies.
This photo depicts a vacuum hose being lowered into a vault to allow for quick and easy maintenance. It’s important to note that the debris gathers along the flat floor and does not stick to the vertical walls. Additionally, a ladder on the opposite side provides simple access into and out of the vault.
Photo courtesy of CrystalStream Technologies.
The final photo shows a new system being installed. This vault is divided into multiple chambers, including a forebay, sedimentation area and clearwell outlet. Each chamber was manufactured long and wide for hassle-free inspection and maintenance.
As stormwater projects grow ever-larger and more complex, precast concrete – with its reliable performance, durability and ease of maintenance – offers the best solution for specifiers looking for an optimal building material in any situation.
I run into “Raintank” plastic chambers all the time, particularly in N Central Florida (Gainesville – Ocala areas) and have seen failures, especially with Auto-Carriers at car dealerships. One instance the Carrier went down through the parking lot.