Here Come the Rains

While we wait and pray to the rain gods for some love down in southern California, being prepared for a rain storm to hit is becoming ever more important.

Even though the state of California is no longer in a drought emergency, climate change continues to threaten southern California’s water availability with changes in our winter weather.  Overall, less rain is falling and the storms we do see are very intense and short.  Along with rising temperatures, increased evaporation rates further strain our water supply (What Climate Change Means for California, EPA).

To top it all off, Los Angeles is covered in lovely concrete and asphalt, totaling a whopping 45% of land cover that is impervious (USDA Forest Service 2010).  So, what happens to all this rain that falls on impervious surfaces?  Where does it go and what can you do to help? It is now nearing the end of February and we’ve gotten a single storm so far with nothing but clear skies in the forecast. Rain will get to us at some point though and we Angelinos have got to be prepared for it.

I don’t mean whipping out your rain boots that you finally got to shake the dust off of during last year’s winter–now that was some good rain.  I’m talking about getting ready to catch that rainfall and keep it where it fell.  Instead of being taken up by soil and vegetation or sinking further to recharge our groundwater supply, the rain we get runs off into storm drains–taking bacteria and contaminants with it—going straight into the Santa Monica Bay.

Ever hear of the three-day rule about not taking a swim at the beach after a rain storm?  Check it out here and here, because you really do not want to be in that beach water—your immune system will be eternally grateful.

The Los Angeles County Department of Public Works estimates that last winter from January 18-31, 2017, 25 billion gallons of stormwater runoff drained into the ocean from the Los Angeles River alone.  That’s not including runoff from Ballona Creek, Malibu Creek, Topanga Creek, and all the other smaller systems across the Santa Monica Mountains.  That is a crazy amount of water runoff for just one of the many multi-day storms we had last winter.

Government entities all over LA have made huge strides to reduce the amount of runoff we see hitting the ocean after a rain event.  Check out this article written in January 2017 about the implementation of spreading basins and catchment requirements for development in LA.  Despite these efforts, there is still so much lost potential when it comes to catching that rain and keeping it from hitting the storm drain.

What Can You Do?

And that’s where YOU come in. Every action an individual takes can make a difference with water use. The Save the Drop campaign is a great place to start to learn the ins and outs of water conservation.

Whether you rent or own a place in LA, there is something you can do to help.

1) Set up a rainwater catchment/harvesting system

Getting a rain barrel or a cistern is a super easy way to catch some extra gallons that you can use to water plants when the rainy season ends, help take pressure off the amount of imported water we use, and save you money.  Rain barrels and cisterns are essentially the same thing-storage tanks that capture runoff from a catchment area, which in this case is your roof.  Rain barrels are smaller, typically holding 55 gallons of water and are the option normal households usually go for.  Cisterns are much larger (200-1000+ gallons), and are normally used in industrial settings to capture large amounts of runoff, but residential cisterns are out there for large properties.  This is also a good source of emergency water during a water disruption or natural disaster.  LA’s Watershed Protection program has put together a great page about rain barrels—where to get them, how to install them and how to cash in on a rebate offered by the Metropolitan Water District.  Most 55-gallon rain barrels are under $100 and the rebates offered for them often cover their cost entirely! Score!

Image: Rain barrels connected to the rain gutter of a home (Hayneedle.com, left barrel- 55 gal, $105.99; right barrel- 40 gal, $75.55

Image: Two high volume cisterns collecting runoff at a building in Philadelphia (Philadelphia Water Department Stormwater Plan Review)

2) Replace your lawn with a rain garden

Want to go all out and make a bigger impact?  Property owners can cash in on LADWP’s landscaping incentive to turn your lawn into a rain infiltration beast!  (That was a compliment in every way possible!) You can get a $2 per square foot rebate (as of Feb. 2018) for tearing out a boring, water-wasting lawn and replacing it with native vegetation, a rain garden, or a vegetation swale. California Native Plant Society estimates that traditional lawns require about an inch of water per week. Changing to a low water alternative like a rain garden with native plants cuts the amount of water you need to use between 50-75%. So if your lawn is 1,000 square feet, that means you can save 8,000-12,000 gallons of water per year!  Check out LADWP’s website to see what the current rebate rate is and how you can qualify.

Image: The Nature Conservancy, Rain Gardens

What is a Rain Garden?

A rain garden incorporates shallow, constructed depressions with deep-rooted native plants and grasses in order to divert runoff from impervious surfaces like a driveways or sidewalks. The water is diverted to a pervious area where it can infiltrate. During and just after a storm, a rain garden may fill with several inches of water, but over time, the water will soak into the adjacent soil. A rain garden is able to mimic the pollution removal abilities of a natural system like a forest or a meadow, helping to recharge groundwater with water that has been filtered of pollutants. Additionally, runoff absorption is 30-40% more efficient with a rain garden in comparison to a standard lawn (NRCS, USDA 2014).

There are many landscaping companies that offer expertise on converting your lawn to a more sustainable alternative, so web search your heart out…unless you want a DIY project, because Pinterest and Tumblr and Instagram have endless inspiration at your fingertips. Stick to native vegetation and not only will your new rain garden be more likely to withstand seasons of drought, but it will also increase habitat for butterflies, birds, and insects known to reduce the abundance of pests. Tree People, LADWP, and the Las Pilitas Nursery have all put together great lists of native plants for the Los Angeles area.

Maintaining a rain garden is much easier than maintaining a lawn: there is less water use and no need to mow every week. Yet, there are still some housekeeping duties that need to occur on a regular basis. In the first several weeks after planting, an inch of water per week and regular weeding will help your newly planted natives to establish. Once plants get bigger, they will be able to push out weeds better so only occasional weeding will be needed as time goes on. Periodic pruning for any dead vegetation or plants that have gotten too big, occasional raking of mulch, and yearly replenishment of mulch will be the extent of maintenance.

So, what are you waiting for?  Go catch that rainwater…when it eventually rains!