Stormwater lessons from Southern California – Groundwater recharge and water reuse

The Chino Creek Wetlands and Educational Park filters 1 million gallons of stormwater on an average day. Source: Inland Empire Utilities Agency.

This is the second in a three part series by MPC research assistant Matt Nichols.

As discussed in the first installment of this series, responsible water planning in cases of scarcity – like southern California’s arid climate or the record drought Illinois experienced in 2012 – requires action on both the supply and demand sides of the problem. One way to increase the available supply of water is through what experts call “conjunctive use,” or the “deliberate combined use of groundwater and surface water.” Southern Californians have recognized that surface water, including rivers and lakes but also rain and runoff, must be managed in a way that more effectively recharges aquifers, an inherent challenge in an urban setting where most rain ends up in sewers that eventually discharge to the ocean.  On the flip side, reusing rain or greywater for non-potable uses can significantly reduce how much water we pump out of those aquifers to flush toilets or water landscaping.

Municipal governments across southern California have incorporated best management practices into the permitting conditions for all new land developments, specifically the permits needed to connect to the municipal separate storm sewer system, or MS4.  The regulations now require that all new construction and major renovations incorporate elements of low impact development (LID) to manage stormwater better.

On the supply side, LID might take the form of the permeable features at the new Inland Empire Utilities Agency (IEUA) headquarters in Chino, Calif. which direct rainwater back into the underground aquifer that feeds the region’s drinking wells.  Together, a permeable parking lot, retention pond, and constructed wetland at the facility can naturally filter and infiltrate nearly 40 million gallons of rain during major storms. Additionally, the system also keeps that water out of nearby Chino Creek, helping prevent floods and erosion.

On the demand side, the 216,000 gallon cistern at the TreePeople Center for Community Forestry in Studio City, Calif. holds enough captured rain from the center’s various buildings and parking lots to provide all the water needed for landscaping, completely eliminating one of the largest segments of the center’s water bill.  Closer to home, the visitor center at Ryerson Conservation Center has taken similar steps, using a cistern to collect rain water for landscaping and flushing toilets, as has an intrepid homeowner in Oak Park (whose project you can read all about in next month’s WOWW Newsletter).

Unfortunately, in Illinois, the state’s outdated plumbing code currently prohibits greywater reuse systems, and the aforementioned property owners had to complete an arduous process to apply for a variance from the Illinois Department of Public Health. Fortunately, it looks like 2013 will be the year when Illinois legislators finally bring the plumbing code into the 21st century, opening the floodgates for a host of water-savvy property owners and entrepreneurial manufacturers and installers to benefit from the opportunity.

As the projects mentioned above demonstrate, green infrastructure offers a wide variety of scales and price-points for improving water efficiency on private properties.  In the third and final installment in this series, we’ll examine what these case studies indicate about the most cost-effective and high-performing green infrastructure practices.


This entry was posted in Stream of Consciousness. Bookmark the permalink.

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>