RAIN GARDEN
What is a rain garden?
A rain garden is a depression in the ground that allows rain water runoff from rooftops, driveways, sidewalks, and other surfaces that shed rainfall to be absorbed by plants and the soil. Rain gardens keep pollution from entering our streams, rivers, lakes and ocean. They are cost effective and easy to build. They are beautiful to look at, require little to no maintenance, and supplemental irrigation; Rain gardens provide wildlife habitat where it is desperately needed.
Watch the Power Point Presentation video of Mark Abramson’s September 22nd “How to build a rain garden” presentation given to Rancho Los Cerritos Historic Site, to learn How to Build your own Rain Garden:
Rain garden’s filter pollution
Pollutants like oil, grease, and metals from our cars, weed killer, bug killer and fertilizers from our yards, pet waste, litter, and air pollution from factories and tailpipes are washed from our rooftops and streets into the our rivers, streams, and ocean during every rain storm. Rain gardens capture this polluted runoff and use the soil and plants to filter and clean the water. This clean water then slowly flows back into our streams, lakes, ocean, or into groundwater aquifers (storage chambers) where it can be used as clean water in the future.
Rain Garden’s create wildlife habitats
EcoMalibu recommends planting your rain garden with local native plants. Native plants are deep rooted allowing them to access water stored deep in the soil. Certain native plants will actually use pollutants for nourishment and require little to no supplemental irrigation after they become established. Local native plants provide food, and shelter to native wildlife, and will attract a host of birds, butterflies, and insects. Native gardens provide year round interest not only by watching the wildlife but by the incredible display of flowers throughout the year.
Rain gardens need almost no irrigation
Planting your rain garden with local native plants significantly reduces the need for supplemental irrigation. You will need to irrigate your plants when they are first installed but they will quickly be weaned off that irrigation. To give an example a typical 25 ft. x 40 ft. lawn watered with sprinklers 15 minutes 3 days per week in spring through fall and 2 days per week in winter will water 142 days per year. Once established your rain garden will be watered 2 days per month June-October or a total of 10 days. A significant water and money savings in drought prone southern California.
Rain gardens are low-maintenance, and don’t need fertilizer, weed killer or bug killer
Like in the forest, allow the leaves of your native plants to fall and protect the ground. The fallen leaves serve as natures free mulch that feeds soil and the beneficial organism in the soil, minimizes weed growth, and dramatically slows the evaporation of stored rain water. Imagine the extra free time you will have when you no longer mow and blow your yard every week. Imagine the quiet you can enjoy when you no longer hear the roar of lawn mower engines or leaf blowers.
To learn How to Build a Rain Garden view the video of Mark Abramson’s presentation at Rancho Los Cerritos Historic Park on September 22, 2018.
To help design and size your own Rain Garden, use our free Rain Garden calculators page.
DOWNLOADS
Download the raw PowerPoint Presentation given by Mark Abramson at Rancho Los Cerritos Historic Park. User must have PowerPoint and should be viewed as a slide show.
PDF plant list of approximately 60 different local native plants that are appropriate for use in Rain Gardens throughout Los Angeles, Orange, and Ventura Counties. This plant list was used in the Power Point Presentation and video of presentation.
Excel calculator (Microsoft Excel required) to determine Runoff Volume in Gallons from up to six different drainage areas to be captured in your rain garden. Useful for sizing and determining volume of water that can be treated in various size and shape rain gardens configurations. User must “Enable Editing” in Excel to properly view and use calculators. The Runoff Volume Calculator is also available on the EcoMalibu calculator web page (Microsoft Excel not required).
Excel calculator (Microsoft Excel required) to determine quantity of compost needed to mix with existing soils to a depth of 14-16 inches as described in PowerPoint Presentation. User must “Enable Editing” in Excel to properly view and use calculators. Compost Quantity Calculator is also available on the EcoMalibu calculator web page (Microsoft Excel not required).
Excel calculator (Microsoft Excel required) to determine quantity of mulch needed to provide minimum 4 inch mulch cover between plants as described in PowerPoint Presentation. User must “Enable Editing” in Excel to properly view and use calculators. Mulch Quantity Calculator is also available on the EcoMalibu calculator web page (Microsoft Excel not required).
