In many cities, stormwater management is becoming increasingly
important. As infrastructures age,
managing stormwater on-site can reduce the load on storm systems and water
treatment plants. Many municipalities
require that stormwater be detained on-site, and then released to the storm
system slowly so as not to overwhelm the city storm system. This often means creating a storage space for
stormwater, that remains empty much of the time. Instead of simply detaining stormwater, why
not retain it, treat it and use it on site, turning the storage cistern into an
asset?
Most people have heard of rainwater
harvesting, but may be unfamiliar with the concept of stormwater harvesting. There
is a difference between “rainwater” and “stormwater.” They both begin with a
rain event. “Rainwater” is the relatively clean water coming from rooftops and
other above ground surfaces. But once that rainwater reaches the ground, it
becomes “stormwater” that may be contaminated with silt, hydrocarbons from
automobiles, road salt in northern climates, nitrates, other fertilizers from
landscaped areas and more. Because of this, additional filtration and cleaning
steps are required, but stormwater can still be an excellent harvested water
resource.
A stormwater collection system can receive water from impervious surfaces such
as sidewalks, driveways, and streets, which block precipitation from naturally penetratingthe
ground. Capturing this water not only helps to reduce the load on the city
storm system, but it has the added benefit of reducing polluted runoff. Once
harvested, the stormwatercan then be treated and used for non-potable purposes
such as irrigation, toilet flushing,
vehicle wash and more.
