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The Underground
Shirley King | Avenida Primavera

Jim Kennedy and Teddy on the patio stones made by Jim that cover the containment system. To the right is the access pipe. Photo by Shirley KingClick on image to enlarge.

Two previous columns in November and December illustrated how Del Mar Garden Club members conserve outdoor water use by forcing lawns into an abstinence program or removing turf altogether. Another active conservationist, resident Jim Kennedy, explains his storage system to collect rainwater - an in-ground catchment.

What was your primary reason for installing an in-ground rainwater/water catchment system?
I had noticed for years that when it rains there are torrents going unused down our gutters and into the sea. I enjoy some water features and (with my irrigation turned off half the year ) I sometimes need to water plants before turning the City-water irrigation back on. It seemed like a good idea to capture the rainwater that was already falling on my property rather than use more of our City’s limited water resources.

What is the greatest benefit that you achieve with your catchment system that otherwise you would not receive?
Ever since I participated in designing my home I have enjoyed making better use of my home and garden’s potential. Of course it is also gratifying to make better use of a limited resource and lower one’s water bill. Finally I get to enjoy my water features more and hope not to need my City-water irrigation as much going forward.

Describe the basic design of your system? How long did it take to install? Did you have to sacrifice any use of your yard?

Time to install: Aside from locating and addressing the various pipes and conduits underground, digging the hole and arranging the materials delivery and electricity availability, it took about three days to install the containment system.

Basic Design: My Landscaper used a concept similar to his “pondless” waterfall systems. A hole in the earth was lined with a fabric and rubber liner, with the “cavity” (with all of my surface drainpipes feeding into it) filled with very strong commercial (corrugated plastic) horizontal storm water pipes with one additional vertical pipe to the surface containing an underwater “sump” pump, power wire, and a lockable metal access grate).The top of the storage cavity (except for the grated access pipe) was covered with another liner, and earth and stepping- stones were put on top of that. The border to the walkways and adjacent beds were reconfigured so that the access pipe is well within the bed - barely noticed, and out of the way of pedestrians. The remainder of the underground storage is unnoticeable to those walking by. The pump (separate from to my City-water irrigation system) is connected to a booster pump and a separate pipe which runs the water uphill to the various waterfall reservoirs and to some hose bibs to permit hand-watering.

Sacrifice: None aside from the cost, I reconfigured my walkway’s borders and my adjacent beds so that the whole system will go unnoticed. I am still looking for the perfect “fake rock” to cover the access pipe’s grate, but I have a big flagstone that does the job for now.

In what kinds of yards is your system most usable?
A flat area is best, although a sloped area like mine can be made to work with a stronger pump. If a walkway is involved, the system should be configured so that the access pipe is located in an adjacent bed of plants well away from pedestrian traffic. It helps to have an area that is free of underground lines of any kind with electricity nearby, and of course, a use for the water.

The Del Mar Garden Club will host a talk “Reusing, Capturing and Conserving Water with Candace Vanderhoff, Monday February 23rd at 9:30 am at the Powerhouse. Light refreshments will be served.


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