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Stormwater Management

There are a variety of stormwater management techniques used to manage excess stormwater runoff. Typical stormwater management is through the use of a stormwater basin, which collects stormwater and slowly releases it to prevent erosion and flooding. The two types of stormwater basins are retention and detention. A detention basin, commonly called a dry basin, does not have a permanent pool of water or pond. A detention basin releases its collected stormwater at a controlled rate, which allows the basin to dry up between storm events. A retention basin or wet pond collects stormwater into a permanent pool or pond. A low flow orifice controls the water level in each type of basin. An orifice installed level with the bottom of the basin allows for all the water to drain from a detention basin, while an orifice at a raised elevation maintains a water level in a retention basin. The third type of stormwater basin is an infiltration basin, which directs stormwater to groundwater through permeable soils.

Advantages of Underground Stormwater Management

Considering the above options, what are the choices when the real estate required for either a wet or dry pond is not available or preferred? Underground stormwater management has a major advantage in that it collects a high volume of stormwater runoff within a smaller footprint as compared to a detention or retention pond. Underground stormwater management also has the advantage of being buried under a parking lot, parking garage, building, park or other areas to prevent the need for dedicated space for the management of stormwater runoff. With limited site space available, the real estate intended for stormwater management can be used for dual purposes. Other advantages of underground stormwater management is the elimination of landscape maintenance of the area around a wet or dry basin, elimination of a standing pool of water in the case of a wet pond, thereby increasing public safety, and elimination of unwanted insects, waterfowl, or other animals.

Advantages of Underground Traffic-rated Precast Concrete Stormwater Management

Underground stormwater management products are manufactured in a variety of materials - corrugated metal, plastic, fiberglass, precast concrete, and poured-in-place concrete. Traffic-rated precast concrete offers advantages over other materials, specifically in construction safety, schedule and labor. Upon initial review, an underground traffic-rated precast concrete stormwater management system may seem more costly than other options. However, when construction labor and schedules are compared versus other methods, traffic-rated precast concrete comes out ahead. When burying stormwater management structures under a traffic or construction area, there are significant advantages to using traffic-rated precast concrete - no concerns about cave-ins or crushing the underground structures which allow continued equipment access prior to final paving and a reduction in the base rock required. With the use of non-traffic rated materials, heavy equipment cannot drive on the site during installation, and manual labor may be required for back-fill activities. The traffic-rated precast structures can be installed immediately after delivery, and construction activities can resume. For future planning, the underground traffic-rated precast concrete stormwater management system can be left undisturbed if the primary use of the site is changed or expanded. For example, if an area where an underground traffic-rated precast stormwater management system is converted to additional parking, the system can be left in place, and parking lot expansion activities can proceed.

Underground Traffic-Rated Precast Concrete Stormwater Detention

An underground stormwater detention system’s purpose is to collect stormwater runoff and slowly release the water at a controlled rate until the structure empties. With the variety of sizes available in traffic-rated precast box culvert, the underground detention system can be arranged in a multitude of ways to accommodate the underground site space available. Either three-sided box culvert on a stone base for infiltration back into the ground or four-sided traffic-rated box culvert can be used for underground stormwater detention.

Underground Traffic-Rated Precast Concrete Stormwater Retention

An underground stormwater retention system’s purpose is to collect stormwater runoff and store the water before discharge. With the variety of sizes available in traffic-rated watertight tanks, the underground retention system can be arranged in a multitude of ways to accommodate the underground site space available.