Water Runs Through It

Years of recurring drought and soaring water rates finally have convinced homeowners to embrace waterwise landscapes. But there’s much more to be done to improve water conservation. 

One increasingly popular option is to reduce runoff with the use of permeable paving.

“Why let water run off your property?” questions landscape designer Steve Harbour of Alpine-based Steve Harbour Landscapes. “With water rates rising about
10 percent a year, it’s like throw-ing money down the drain.” Plus, in the future, he predicts, “taking steps to control storm or irrigation runoff will be required.”

Permeable paving helps make the most of sparse rainfall and expensive irrigation by allowing water to percolate into the soil.  Among options to traditional hardscape are decomposed granite and gravel, as well as
permeable concrete and pavers.

“Permeable paving is cost effective and affordable,” Steve says. “Aesthetically, it fits with naturalistic landscapes; it’s a softer, more natural look.”

Some common permeable paving options are do-it-yourself friendly. Others are best installed by landscape pros. Examples of most can be found at the Water Conservation Garden on the campus of Cuyamaca College in El Cajon. Consider the following:

Decomposed granite. Finely ground rock is compacted or hardened to create a firm, weed-free surface for paths, driveways, patios and auxiliary parking areas. It is available in a half-dozen colors and is relatively inexpensive — about one-third the cost of colored and textured concrete.

Gravel. Popular for centuries, washed and cleaned crushed rock is a highly permeable surface for small patios, paths and auxiliary parking areas. Avoid rounded pebbles, Steve cautions, because “they are like walking on marbles.” Gravel can be combined with steppingstones. Choose from a wide range of colors. Depending on the rock chosen, this can
be an inexpensive option.

Pavers of stone or concrete set on sand. “This is a popular and good-looking driveway and patio option,” Steve says. Bricks or pavers are packed tightly or interlocked on a bed of sand, minus any concrete, so water seeps through. Professional installation is recommended to avoid future sinking and buckling. There are dozens of style and color choices. This option costs slightly more than colored and textured concrete.

Flagstone set on sand. Seams between irregular pieces of flagstone set on sand are filled with decomposed granite, gravel or plants (see sidebar). This method is ideal for paths and patios. “A patio can begin with a solid base and be more permeable around the edges,” Steve says. Depending on the flagstone selected, the cost is about one-third more than concrete.

Permeable concrete. Permeable concrete uses larger aggregates and lacks the gap-filling fines
in standard concrete, so water
passes through. Steve describes the surface as “rough, resem-bling cottage cheese or seeded concrete.” Color options are available, and professional installation is recommended. Permeable concrete costs 15 to 20 percent more than standard concrete. 

Photo caption: Ruth E. Wolfe designed a decomposed granite and flagstone path for Burton and Mary Enquist of Escondido. 

Garden Guide: By Mary James Photography by Bob Wigand