Monday, March 22, 2021 is World Water Day, a time to bring awareness to this vital resource! This year’s theme is Valuing Water, and the City of Encinitas is celebrating by hosting an online event with Surfrider’s 2011 Water Warrior Award winner Brook Sarson, a local rainwater catchment and greywater expert. The event will feature EcoFest's Amelie Catheline hosting a short interview/Q&A session with Brook on all things catching water as recently presented at EcoRotary. Here’s a preview of what you’ll learn:
Before you dive into your project it’s helpful to identify your goal. Catchment projects are relatively inexpensive but water is cheap in San Diego so simple payback is hard to justify. Other reasons include reduce water use, prevent storm drain pollution, grow abundant landscapes with no municipal water, create onsite backup for emergencies, prevent foundation flooding, reduce strain on wastewater treatment facilities, or simply because you hate to see water wasted!
Since San Diegans use 75% of their water outdoors, Brook focuses on integrated strategies for more abundant landscapes using rainwater and greywater. Rainwater is captured from the roof, while greywater comes from the shower and bathroom sink, NOT the toilet or the kitchen sink for health reasons.
A popular way to capture rainwater is with 55 gallon rain barrels, but as little as 1” of rain generates 600 gallons of runoff water from a 1,000 square foot roof. With just a slightly larger footprint, a 500 gallon tank holds 10 times as much water as a rain barrel and is a better choice in San Diego which can receive as much as 10” of rain a year. Rebates available at www.socalwatersmart.com.
Plants enjoy both nutrient rich greywater and relatively pure rainwater. Since greywater creates better soil systems, shower water is often diverted to fruit trees while laundry water is used around the site perimeter for flowers and herbs. Rainwater is typically diverted to the vegetable garden, but greywater may also be used if the plants are upright and the greywater doesn’t splash on the food to be consumed.
Growing plants in a mulched, Xeriscape garden has multiple benefits including shade and habitat for wildlife as opposed to a Zeroscape constructed with decomposed granite (DG). Brook has experience constructing planted landscapes that thrive with no tending and only use water diverted from the premises. However, greywater isn’t allowed to surface flow on lawns or ground cover, and should not be applied to sensitive plants.
Begin assessing your water resources by calculating the flow from showers and washing machines. If the shower head flows 2 gallons per minute (GPM), then each 10 minute shower will generate 20 gallons of water. A family of four showering once a day will generate over 500 gallons of water!
Greywater systems for washing machines are permit free and use 10-35 gallons per load. Washing machine detergents can be a good source of plant nutrients such as nitrogen, phosphorus and potassium (NPK), but can also include bad ingredients such as sodium. Read the labels carefully!
On-site water capturing isn’t rocket science, it’s not expensive, and parts are readily available at hardware stores. New buildings need a permit, but retrofits often can avoid permitting. There are many resources available including those listed here:
https://www.harvestingrainwater.com/
https://www.sdsustainable.org/
To learn more about Brook Sarson visit:
http://www.h2o-me.com/our-team
https://www.urbanfarm.org/2018/07/31/372-brook-sarson/
To view the EcoRotary Meeting Recording click on the link below and use Access Passcode: 3uRnc&3p