Municipalities with natural or manmade waterways offer convenient opportunities for dealing with storm water. In less developed areas, run off is often nearly clean and has relatively little effect on the water quality. Dense urban areas and industrial zones are less appropriate settings for direct discharge systems. If you’re considering a direct connection to a local waterway for affordable discharging, consider these facts first.
Convenient Discharge Options
In most areas, direct discharge to existing waterways is the cheapest method for management. Holding ponds and water treatment plants require maintenance and staff to ensure they’re running properly. If storm water flows directly down the pipes straight to the ocean or a lake, human labor is only needed for occasional cleaning and repairs. For rural areas with limited budgets for upgrading and maintaining advanced storm water treatment options, direct discharge is still the best option.
High Flow Capacity
Systems based around ocean or large river discharge can handle very large amounts of water at a time. Spikes in flow, caused by releases from power generating dams or drainage systems, won’t overwhelm these designs. However, this is all made possible by the high absorption capacity of the waterway. A smaller river or lake with a fixed volume can’t withstand the same kind of changes in flow. For reliable, high flow performance in areas with flood risks, retention ponds are often recommended instead. A combination of direct release drains and pond connections may also work best for some situations.
Risk of Short-term and Long-term Damage
By allowing untreated run off and storm water to mix into living bodies of water, there’s always a risk of both short and long-term damage. Environmental impacts can last for years after the initial release, even with today’s most advanced remediation methods. Preventing the contamination in the first place is always recommended. Most direct discharge systems are located in areas where oils, paints, greases, and chemicals are rarely mixed into the water. Yet there’s always a risk of something new getting introduced into the flow. Weigh these risks before choosing one of these systems.
Impermeable Liners to Prevent Contamination
Since there’s no opportunity for further treatment in a direct discharge system, preventing water loss and water entry is essential to control contamination. If water escapes the basins or pipes as it travels to the discharge point, it could contaminate the surrounding soil and water before it has a chance to become diluted by the waterway. Water entering the drainage system from surrounding soil also creates a risk for contamination. To keep the system functioning as designed, use liners and durable pipe materials wherever possible for leak and seepage control.
Other Options
Direct connections are common for storm water systems, but they’re far from the only option. It’s also possible to funnel the storm water into some kind of storage unit like a retaining pond or tank. Tanks are all too easy to overfill during a flood, so more adaptive retaining ponds are generally favored. It’s rare, but some areas with high levels of run off contamination may opt to connect storm drain systems to a treatment plant. This will be either the same plant used for sewage or a separate treatment facility. Since storm water surges can overwhelm a facility, separate treatment plants are often required to ensure the sewage system isn’t disrupted.
With a direct connection system requiring different designs and features than one that connects to a pond or treatment plant, it’s important to choose your discharge method from the start. Switching an existing drainage system from one type of discharge to the other may require extensive pipe replacement and improvements for basins and related equipment. Make sure any liners you choose come from BTL Liners to ensure you get reliable performance and minimal maintenance requirements from the storm water system.
