By Jondi Gumz, Santa Cruz Sentinel
CAPITOLA >> Local residents interested in water conservation got insights Friday into why the city’s temporary parking lot by City Hall cost $1.373 million, exceeding the $1 million estimate, and ideas they could use to save water as the drought persists.
The higher cost was due to new requirements on stormwater mitigation.
Project engineer Tai Chau of Bowman & Williams Consulting Civil Engineers, explained the design of the parking lot, which has an inch of gravel pavers with 8 to 24 inches of more porous drain rock below allowing rainwater to sink into the ground.
“The deeper the drain rock, the more storage,” he said.
The parking lot contains about 20 “control structures,” barely noticeable underfoot until Chau lifted one of the lids.
The structure holds water for 24 to 48 hours and releases it slowly. Like an oil separator, grease floats on top while the water flows out.
On one side of the lot, a bioswale lined with a graceful native grass feeds on the hydrocarbons and helps trap pollutants.
“That is a nice-looking swale,” said Elizabeth Burton, a Santa Cruz landscape designer.
She was equally intrigued by the gravel pavers.
A retaining wall made of cast concrete and stamped to look like wood shores up a hillside filled with horizontal subdrainage that is invisible to the eye.
“That’s the thing about drainage, it’s so subterranean,” said Burton.
“The city could recycle this material,” said Chau, pointing to the cast concrete panels.
“A lot of thought went into this,” said Paul Binding, Santa Cruz County Mosquito and Vector Control manager, who took the tour.
Danielle Uharriett, Capitola’s environmental projects manager, showed off a 50-gallon rain barrel installed on a city building, which provides enough water to irrigate a bit of landscaping.
Last year, the city teamed up with Santa Cruz to order rain barrels and offered them at discounted price of $50 to Capitola residents, with 80 being purchased.
Uharriet was pleased with the response to the first-time program. She hopes the City Council offer the rain barrels again.
“I’m fishing for more information,” said Alison Paul of Soquel, who has been considering rain barrels.
Vai Campbell of the Soquel Creek Water District, who came on the tour, said her agency offers rebates for rain catchment and downspout redirect systems.
She encouraged people to report water waste to help protect the groundwater supply.
The tour was organized by Laurie Egan of the Coastal Watershed Council, which offers free tours monthly to showcase best water practices and educate the public about water quality issues.
The tours have explored a new well in the Soquel Creek Water District and the Monterey Bay Trout and Salmon Project and the need for water in habitat for endangered species.