On Dec. 3 I joined an unusual garden tour guided by the Salmon Protection and Watershed Network's (SPAWN) Water Sustainability Coordinator Lisa Chipkin. The group did not gather to ogle floral or edible gardens, but rather to check out a few of Ross Valley's demonstration rain gardens created via the 10,000 Rain Gardens Project, a joint project of SPAWN and the Marin Municipal Water District (MMWD).

"We're nowhere near 10,000 rain gardens," said Chipkin. "It's a lofty goal worth striving for."

The majority of tour participants were water-conservation-conscious locals who want to incorporate or expand upon already existing water harvesting in their own personal or professional landscape and garden designs. Activist Kathy Coldiron drove all the way down from St. Helena, where water rates are about to increase 70-100 percent. She hoped to return home with information for the St. Helena Town Council that will help lessen her town's growing water problems.

Most of us on the tour simply wanted to learn how to better use and save rainwater for our gardens rather than watch it disappear down a hill or drain somewhere. "Water is life," said landscape designer Lora Amara. It is too precious to waste or be unconscious about.

"We send [water] away and don't think twice about it," Chipkin said. "If we all captured 5 percent of our runoff, what kind of difference could we make?"

In urban and suburban settings, water runs off paved and hard surfaces so fast that it doesn't have time to sink into the natural landscape, thereby creating greater flood risks, greater erosion, increased stream pollution and endangered ecosystems. The 10,000 Rain Gardens Project encourages Marin residents to take meaningful steps towards slowing down runoff erosion and pollution, as well as reducing the use of treated water supplies for landscaping.

The tour's first demonstration garden at the Marin Art and Garden Center featured a 2,500 gallon polyurethane cistern that captured rainwater runoff from one side of a potting shed roof and irrigated a modest community of native plants. The garden was subtle in the sense that it didn't look much like a typical garden, just a slight indent in the earth (a swale) full of leaf mulch bordered by some raised earth (a berm) with a smattering of inconspicuous native plants.

Among the interesting facts we learned at this site was that one inch of rainfall on 1,000 sq. ft. of roof equals approximately 600 gallons of water. Multiply that figure by the Marin average rainfall of 44 inches per year and you get approximately 26,400 gallons per year. That's a lot of water.

My mind floated back to my own 8 x 15 sq. ft. vegetable garden perched nearly at the same level as the roof of my house. A cistern below the garden would require a pump to get the water back up to its destination. The roof of my garage could capture water, but I would have to remove precious trees to fit in a cistern. Perhaps it will be easier to use the roof capture solely for the plants downhill of my house and roof. Each property clearly has its own particulars to be dealt with.

Master composter Ruth Beckner threw out the bright idea that fences should be designed to capture and store water. Someone else noted that at least one fence-capture systems is already on the market. That would probably work better than roof capture in my upper garden.

From the Marin Art and Garden Center, the group carpooled over to the San Anselmo Library, where we viewed a roof rain capture system, a cistern and the concrete-lined beds where the library's rain garden will soon be installed. The projected average yearly rainfall capture for the San Anselmo Library is 60,000 gallons. Considering the $30 million worth of damage done to San Anselmo businesses, residences and town buildings in the 2005 flood it is fitting that the town would make this significant effort towards reducing rainwater runoff. "If everyone held back some water, maybe it would make a difference [in terms of flooding]," said Chipkin.

From the library, we traveled to the grounds behind Fairfax's Town Hall to see a cistern-less, roof capture rain garden. The garden itself looked a bit like the first rain garden, i.e. a swale and berm construction bordered by rocks and filled with permeable mulch. The berm was dotted with sage-colored shrubbery. The town hall's roof and garden is expected to capture an average of 20,000 gallons of water per year.

The tour ended at Sustainable Fairfax's magical, luscious and beautifully designed rainwater garden, where one could sit on a bench and ponder the meaning of life for hours. Sustainable Fairfax captures their roof runoff in a 1,000 gallon cistern and also in the blue claw-foot bathtub turned rain garden that graces their storefront.

Visiting the four demonstration gardens felt like an appetizer. I now want to see more gardens, more of what people were doing in this field, and I want one at my house. Chipkin said a good way to start is to simply observe the flow of water on one's land and "see where it goes."

For information on self-touring Marin's rainwater harvesting projects and starting a rain garden, visit SPAWN's site.