From the Boulder Daily Camera (Carol O’Meara):
Before bemoaning the lack of rain barrels, consider an alternative, says landscape designer, Alison Peck. What you can do is channel rainwater coming off your roof into the landscape so that it flows to thirsty plants and stores in the soil. There, plants can access the water as summer heat dries the land.
“The interesting thing is that we’ve always been told you can’t use rainwater, but there’s nothing illegal about collecting rainwater in the landscape, storing it in the soil,” says Peck, a founding member of the Front Range Sustainable Coalition. “You can’t put rainwater in containers, but are they really helpful? Think about how small an area can survive on rain barrels, which only hold about 30 to 50 gallons.”
Generally, you can store between a 1/4-21/2 inches of water in your soil, but to make use of it you need plants with deep root systems, like natives, says Peck, an Associated Landscape Contractors of Colorado member (alcc.org). As you plan your rain redirection, look over your landscape for the location of the plants with big root systems — perennials, grasses, shrubs and trees.
More conservation coverage here.