Stormwater: retention basins, drainage ditches, and oil separators
Torrential rains overload existing infrastructure. On-site stormwater management—through retention, drainage, and treatment—protects both your investment and the environment.
Every hectare of land covered with concrete or asphalt sends water into the drainage system that natural land would otherwise absorb. The result is evident every time there is a torrential downpour: overburdened storm drains, flooded streets, and water damage to basements. That is why building permits are increasingly requiring on-site stormwater management solutions.
Retention: Regulating Flow, Not Eliminating Water
A retention basin does not make the water disappear. It captures the peak flow from rainfall and releases it into the drainage system in a controlled manner over a longer period. The drainage system is no longer overloaded, and the risk of flooding decreases.
Sizing is based on the site’s impervious area, the design rainfall with the return period specified in the permit, and the maximum flow rate accepted by the operator. From these, the usable volume and the outlet flow control device are determined.
Collection: Gutters and Drain Inlets
Even the best retention system is useless if the water doesn’t reach it. Concrete gutters, drain inlets, and diversion channels collect water from road surfaces and direct it in a controlled manner.
A common mistake here is skimping on the number of drains: too few storm drains mean water accumulates on the roadway and flows where it shouldn’t. They should be positioned at actual low points, verified on-site, not just on the grade plan.
Hydrocarbon separators: mandatory on traffic-bearing surfaces
Water from parking lots, platforms, and roads carries oils, fuel, and particles. Direct discharge into a natural watercourse or a stormwater system is prohibited. The separator retains hydrocarbons and sediments before discharge.
The selection is based on the design flow rate and the treatment class required by the permit, and the installation must allow access for pumping and inspection—a separator that cannot be reached cannot be maintained and will soon cease to function.
Maintenance: The Factor That Determines Service Life
- Periodic cleaning of drain inlets, especially in the fall
- Pumping out separators according to schedule
- Checking the flow-limiting device at the basin outlet
- Inspect the gutters after every heavy rain during the first year
A well-designed and maintained stormwater system is characterized by the fact that, after a heavy rain, no water remains on the property.