You can learn about growing, preserving and eating nutritious food in the gardens and classrooms of the 78th Street Heritage Farm.
Soon, an area for cars will offer other environmentally related lessons. Work is underway on a new parking lot at the historic property at 1919 N.E. 78th St.
“It will help a lot,” said Doug Stienbarger, director of the Washington State University Clark County Extension, which is headquartered there. “For big events, (people) were parking in the grass.”
He added: “We have a small-acreage expo in the spring; we’ve had people get stuck and we’ve had to pull them out.”
In addition to providing space for 54 cars, the project has another role. It was designed as a demonstration site for parking-lot surfaces.
The main traffic lane will be asphalt, but four other types of paving surfaces are being used. They allow rainwater to seep right through the surface, rather than adding to the runoff problem created by Vancouver’s annual 41 inches of rain.
“Stormwater has two challenges,” said Jeff Schnabel, the county’s clean water infrastructure manager. “One is pollution. The other is the water itself. When it runs off quickly without being detained,” damaging erosion can result.
“Instead of taking water that falls and concentrating it, the idea is to have it dispersed and go into the ground right where it falls,” Schnabel said.
The state Department of Ecology is providing the $482,000 funding.
“They consider this a stormwater demonstration project,” said Matt Hall, who is the project manager for Clark County.
There will be four test areas at the site of the former county poor farm. One uses pervious concrete; containing much less sand than the standard product, pervious concrete can be up to 25 percent empty space, allowing water to trickle through.
Another pervious surfacing is porous asphalt, consisting of coarse stone aggregate and asphalt binder.
There also are low-impact concrete-block pavers. A section of W-shaped pavers create a honeycomblike design; the open spaces have been filled with a planting mix where grass will be grown, providing drainage. Another area is surfaced with solid concrete pavers; stormwater trickles through the gaps between the 6-inch squares.
“All are initially effective in letting water through. It has to do with how they hold up over time,” Hall said. “If maintained, they continue to have water permeate; some will plug up easier than others. The Department of Ecology can track the effectiveness of them over time.”
Along with water-holding landscaping features, they’re examples of low-impact development — an approach that is now required.
“It went into effect in January 2016,” Schnabel said. “There are times you can’t use it, if it’s not the right soil type or there is a high ground-water level. But you have to show that the site can’t do it.”
The alternate materials cost more than standard pavement or concrete, Hall said. “The trade-off is that when the soils are right, it’s less expensive than having to collect water, drain it off, and treat it.”
A link on a county stormwater website (www.stormwaterpartners.com/LID/sites.html) lists 13 featured locations that use low-impact techniques. One highlighted site is McCord’s Vancouver Toyota, 10455 N.E. 53rd St. More than 1.6 million pavers were used in the 325,000-square-foot sales and parking lot. That eliminated the need to connect the 7.6-acre site to a stormwater system, according to the county’s stormwater management website.
Even though the 78th Street Heritage Farm project won’t be finished for a week or two, Stienbarger has already seen it in action.
During some recent rainfall, the extension director said, “you could see water sitting on the regular asphalt, and the pervious stuff was dry.”
