Rainwater Catchment & Rain Gardens 101

Water-wise isn’t just about using less water, it’s also about being creative with the water we do have — especially the free kind that comes right from the sky. As evidenced by the memorable storms of recent winters, rain events are predicted to become more severe and less frequent in our area, meaning that we’ll receive occasional surges of valuable but potentially destructive water. How can we re-envision our developed landscapes to more effectively utilize the gift of rain?

Below are three methods for DIY rainwater catchment that can help you become a water-wise wizard and a model to your friends and neighbors.

1) ‘Slow it’ with rain catchment systems

The simple installation of rain barrels, tanks or cisterns off of your home’s rain gutters is becoming a relatively mainstream concept, with information and materials readily available in your local hardware store.  There are many ways to go about designing your system so that it can effectively store a whole season’s worth of rain, or just individual rain events. Depending on your storage capacity this free water source can be used for irrigating your landscape during dry months, reducing both your water bill easing your conscience at the same time. To give you a sense of how much rain you can collect: a 1000 square foot roof will shed 600 gallons for every inch of rain that falls!

2) ‘Spread it’ with mulch applications

The unsung hero in the garden landscape: mulch provides numerous benefits besides the aesthetically pleasing ‘finished look’. Adding a layer of mulch to your garden can help cut down on erosion, minimize compaction of soil during heavy rain events, maintain soil temperature, replenish organic content of soil as it breaks down and prevent weed growth. Organic mulches like woodchips have a high water-holding capacity, which creates additional storage space for excess water until it can be taken up by soil and plants. Generally applied to lawns, sheet mulching is a process in which compost, cardboard and woodchips are added to the landscape in thin layers, creating more surface area to spread and capture rainwater on-site, while reducing weeds and increasing soil fertility as it decomposes.

3) ‘Sink it’ through rain gardens and bio-swales

The addition of rain gardens and swales in your landscape offers two simple ways to increase stormwater capture and recharge our aquifers. These strategically designed low depressions and channels create holding places for water to collect and sink rather than run off over heavily saturated soils or impermeable surfaces. While both of these features can function well with a dry riverbed look, incorporating water-wise plantings will increase both the aesthetics and the benefits. The use of native plants in particular can provide much needed habitat, slowing the water and acting as bio-filters for harmful pollutants all at the same time. Be sure to place plants best suited to wet conditions in the center, moving from seasonally wet preferences into dry conditions towards the edges for best results. Check out this video tour of our rain garden at the Petaluma Library!

Where do you find the resources to make all your conservation dreams come true?

Many of our local municipalities in Sonoma County have incentive programs to help residents reduce water use both inside and outside the home. Programs like Petaluma’s ‘Mulch Madness’ (which delivers cardboard, mulch and compost to your door for free!), Cotati’s ‘Cash for Grass’ and Windsor’s ‘Efficiency PAYS’ program all provide incentives to reduce outdoor water use. The City of Santa Rosa’s ‘Green Exchange’ program also offers similar programs along with a rebate for installing a residential rain catchment system.

If you’re looking to grow your skills and gain some hands-on experience or guidance before taking the plunge, Daily Acts offers workshops throughout the year on rain catchment system design and installation, rain gardens, bio-swales and sheet mulching.

Watch this webinar recording on rainwater catchment with Jesse Savou of Blue Barrel Systems

Watch this recording of a conversation about sheet mulching and Petaluma’s Mulch Madness program