Low Impact Development Delivers Huge Water and Energy Savings

NRDC's new report, "A Clear Blue Future" explores the benefits of low impact development in California. Download it at: http://www.nrdc.org/water/lid/)
Author: Bevan Griffiths-Sattenspiel

The Natural Resources Defense Council in partnership with UC Santa Barbara's Bren School of Environmental Science and Management released a new report last week that found that by simply implementing low impact development (LID) practices - such as bioswales, green roofs, rainwater harvesting, rain gardens and green streets - California could create a huge new water supply and put a significant dent in their energy demands and greenhouse gas emissions.

The new report, called A Clear Blue Future: How Greening California Cities Can Address Water Resources and Climate Challenges in the 21st Century, is an excellent piece of research that examines the numerous benefits of LID strategies in California. Of course, the piece I'm most interested in are the energy benefits and according to this analysis they are huge.

The idea of implementing LID techniques as a water supply and energy saving strategy is relatively new. Initially, LID was designed with water quality in mind and the end goal was to restore a site's pre-development hydrologic regime by managing stormwater onsite. These techniques have been found to effectively reduce nonpoint source pollution and harmful stormwater surges by allowing water to naturally filter through the aquifer before slowly entering nearby surface waters. But the same techniques can provide new, low energy water supplies by recharging aquifers and collecting rainwater for a variety of potable or nonpotable uses.

Using LID techniques to augment water supplies makes a good deal of sense--especially when a community's only available alternatives are energy intensive water supplies, such as desalinated seawater or water pumped from great distances. As Noah Garrison explains in an NRDC press release:

“Across the arid west, we’re facing depleted or threatened water supplies for millions of people. We need to be smarter with our water use. Low impact development maximizes water and energy savings while reducing global warming pollution. Water can easily be collected and used on-site instead of being dumped into local waterways, where it’s not only wasted, but contributes to unnecessary water pollution.”

How much water and energy can be saved through LID? The answer is a hell of a lot. According to the report (emphasis added):

Implementing LID practices that emphasize rainwater harvesting, which includes infiltration of water into the ground as well as capture in rain barrels or cisterns for later use onsite, at new and redeveloped residential and commercial properties in the urbanized areas of southern California and limited portions of the San Francisco Bay area has the potential to increase local water supplies by up to 405,000 acre-feet (af ) of water per year by 2030. This volume represents roughly two-thirds of the volume of water used by the entire City of Los Angeles each year. The water savings translate into electricity savings of up to 1,225,500 megawatt hours (MWh), avoiding the release of as much as 535,500 metric tons of CO2 per year, as the increase in energy-efficient local water supply from LID results in a decrease in the need to obtain water from imported sources of water such as the California State Water Project (SWP) or the use of processes such as ocean desalination, both of which require tremendous amounts of energy. These benefits would increase in each year thereafter.

That means that LID can provide California - a state currently considering water rationing - with enough water for 810,000 households. This in turn would save 1.2 billion kilowatt hours of electricity and reduce the same amount of greenhouse gas emissions as taking nearly 100,000 cars off the road. And the best part: the benefits would increase each year thereafter.

As Dr. Robert Wilkinson, a coauthor of the report and all around water-energy sage, explains in the press release:

“Our analysis found that significant opportunities exist to improve local water supply reliability in both southern and northern California by capturing rainwater for beneficial use. While LID is only part of the answer to our water supply needs in the state, the energy, climate, water supply, and pollution prevention benefits of LID applications is an opportunity to be tapped.”

For more information, check out: A Clear Blue Future: How Greening California Cities Can Address Water Resources and Climate Challenges in the 21st Century

LID

This is a great introduction into the idea of low impact development and how it can help us all. It would be incredible to not have to rely on our Refrigerator Water Filter to get all the contaminants out of the water. If this was a more routine planning formula, we might have a considerably better overall water quality. This would be huge as so many surface lakes are in such bad condition. Thanks again for putting this together.

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