sustainability Z
Harvesting Monsoons By Jeff Gardner
JULY AND AUGUST hold special places in our desert. The sky tears apart with more thunder and lightning than any other point in time, and with that fury comes the majority of our rainfall. Tucson receives an average of 10 to 15 inches of rain every year. And despite the rest of the seasons being typically dry, Tucson turns out to be a pretty great place for rainwater catchment. Luckily for locals, rainwater catchment isn’t only environmentally beneficial, Tucson Water also offers up to $2000 in rebates for water catchment systems. Applicants can apply for rebates for both “passive” and “active” catchment systems, and for those in need of financial capital to start, Tucson Water also offers grant and loan programs to help. Passive catchment, or a rain garden, includes water distribution systems such as downspouts and ditches for more effectively using rainwater to aid a natural area. Active catchment, or a rain tank, includes directing water from a catchment area into a storage tank for controlled use. Both are beneficial and viable options, depending on the homeowner’s needs. After submitting a plan and passing inspection, residents can be on their way to that two grand. But there is one final – and educational – catch for receiving the rainy rebate: Attending a free rainwater harvesting workshop offered by a local nature institute, such as the Watershed Management Group. “We’re figuring out how to fix the problems we have here, not steal more water from somewhere else,” said Bill Wilkening, board president of Watershed Management Group. “You need good clean water, and you need it every day.” Watershed Management Group started here in Tucson to create communitybased solutions for environmental problems on both a local and global scale. They offer sustainability classes on subjects like green living, gardening, and of course, rainwater harvesting. “Tucson is such a powerful place for catchment because our storms are so localized and isolated,” Wilkening said. “We can make the most of them.” With a catchment system, for every 1000 square feet of roof, one inch of rain will generate 600 gallons of water. This can be harvested into a tank, or passively rerouted into a rain garden with the help of berms and swales lined with mulch. “The best part about passive systems is instead of building a tank, you let the ground be your tank.” Wilkening said. While active water tank systems require more work, they are also more
efficient. Passive systems, on the other hand, are easier to make over larger areas, but are less efficient. An active system of 1000 square feet on a roof has the potential for 6000 gallons of water annually, whereas a passive system of 1000 square feet in the landscape has the potential for 3000 gallons of water annually. “It’s a resource that we’re just allowing to flow away,” Wilkening said. Tucson Water gives rebates for up to 50 percent of the cost, or 500 dollars, for passive systems. This includes costs for labor, terraces, mulch and curb cuts. For active systems, Tucson Water will give up to 2000 dollars, depending on the tank size: 25 cents a gallon for 50 - 799 gallon rain tanks, and a dollar a gallon for 800+ gallon rain tanks. Contrary to what some might think, having a rainwater catchment system doesn’t entirely rob downhill areas of water. Properly caught rainwater pools to nurture plant life and replenishes the surrounding area, whereas normal rainwater in a city spreads out across concrete and quickly evaporates. “If you think that water is going to naturally flow through an urban environment and replenish the aquifer, think about it as if you were trying to dig a hole,” Wilkening said. “You want the water to go deep into the ground and be absorbed. Sure, you can thinly spread it over a large area, but it will dry up fast.” When water deeply penetrates soil, vegetation blooms and makes the area cooler. This leads to water being able to slowly trickle through a landscape instead of quickly flowing and evaporating. The natural plants mitigate heat island effect, add carbon to the soil and suppress evaporation, all while allowing for percolation. “We only need people to reduce their water use by ten percent,” Wilkening said. “And we’ll start to see little creeks popping up. This is one of the most important steps to having a sustainable community.” There are many ways to harvest rainwater, and endless best practice tips: Which kinds of piping to use, selecting collection tanks, using “first flush” systems, olla balls, overflow routes and more. But there are many local services right here in Tucson that offer education and even help set up water tanks. “Go outside when it rains,” Wilkening said. “And just see what’s going on.” For more information, visit tucsonaz.gov/water or watershedmg.org
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July & August 2018 | ZOCALOMAGAZINE.com 9