Most modern cities, industrial parks and residential lots utilize the same general strategy for managing storm water runoff: Collect and transport the water away from these areas as quickly and efficiently as possible.

The problem with this approach is that along the way, runoff water collects surface pollutants – such as sediments, phosphates, pesticides and debris – and carries it to the final discharge location, which is usually a lake, river or ocean.

This paradigm not only creates serious environmental problems, but such systems are expensive to install and maintain. Fortunately, a relatively new approach – called low impact development (LID) – offers an environmentally friendly alternative. Additionally, systems that rely on LID principles usually cost less to install and maintain than conventional drainage solutions do.

What distinguishes LID systems from traditional storm water management strategies?

Whereas traditional drainage solutions try to remove the water from given areas, systems employing low impact development principles seek to retain the water on site, where it can be put to good use. They convert a liability into an asset. 

LID strategies emphasize the use of plants, soil and trees to absorb and store water. This helps to reduce construction costs and provide supplementary benefits, such as improved aesthetics and the lowering of local temperatures via the process of transpiration.

What are some examples of LID techniques?

For example, rather than relying on a drainage channel to guide water into a municipal sewer, a property built with LID principles may channel water into a rain garden, full of flood-tolerant plants. As the water flows across the garden, the soil and plants absorb and store large quantities of water, eliminating the need to transport the water elsewhere.

Another LID technique seeks to reduce the quantity of water traveling along cement curbs. Rather than keeping the water confined to these channels, gaps – called curb cuts – can be placed along the length of the curb. When the water reaches these gaps, it travels through the empty space, and infiltrates into the nearby soil. This reduces the amount of water that ultimately reaches storm drains, thereby reducing the amount of pollutants reaching important water bodies.

Another LID solution to drainage and runoff water problems is to collect the water in a rain barrel or cistern. Usually, these devices attach to the gutter system of a house, which allows them to collect most of the water falling on the roof. Once collected, the water can be used to irrigate lawns, wash windows or any other outdoor task.

How do LID strategies handle the pollutants carried by runoff water?

As pollutant-laden waters flow across soil or vegetated areas, the ground and roots help to filter out pollutants. This keeps the water trickling into the local water supply clean and healthy. Additionally, microorganisms in the soil help to breakdown many harmful chemicals and pathogens present. Vegetated areas also strain other pollutants, such as trash and sediment, from the water flowing over the surface.   

To learn more about this option, contact professionals , such as Michael Bellantoni