Urban Heat Mitigation

Valerisa Gaddy now serves as the community conservation director at the Watershed Management Group, helping communities thrive in the Sonoran Desert. (Credit: Courtesy of Valerisa Gaddy) Editor's note: Meet all five winners of our 2024 Women In Science Incentive Prize here. Valerisa Gaddy grew up on the border of Arizona and New Mexico – in Navajo Nation. “I was constantly back and forth between res and non-res communities, because my parents wanted me to attend schools that weren’t on the reservation,” the research scientist remembers. The huge disparities between these two communities didn’t hit her until she was at college, though. “I saw how easy it was for people to call and ask their parents for help – my parents just couldn't do that. I never had that net where, if I fell, they’d be able to catch me, because they were struggling themselves.” As an Indigenous student, Gaddy came up against a number of other challenges. “Indigenous knowledge is still not recognized as science, and my dissertation kept getting sent back because there was ‘too much Indigenous knowledge’ in it. I was told if I want to be taken seriously as a scientist, I have to reduce the amount of Indigenous knowledge in there.” Against the odds – and in spite of the discrimination she received – Gaddy defended her dissertation, receiving a PhD and master of science in environmental science from the University of Arizona, as well as a bachelors in microbiology from New Mexico State University. She now works as the community conservation director at the nonprofit Watershed Management Group, helping communities across Southern Arizona thrive in the Sonoran Desert. One of Gaddy’s projects is Cool Tucson, which aims to reduce the city’s temperature by 5 degrees. The average temperature has increased by 11 degrees over the past century, with half of that increase attributable to the urban heat island effect: Streets and buildings absorb more heat than green spaces, making cities hotter than rural areas. Urban heat islands disproportionately impact low-income people and people of color, and the project plants tree canopies in these neighbourhoods, helping lower the temperatures. “A lot of these heat indexes are quite high on Native American land because of how the government built the houses – on these huge slabs of concrete that are impossible to have gardens on.” Gaddy has also launched a plan to work with the Pascua Yaqui Nation, which is currently experiencing both extreme flooding and heat stress, to develop rain gardens. “The reservation is hot and dry, and when they do have rain they get flooded so badly that even their one emergency road is underwater, and they can’t go in or out.” A rain garden is a cost-effective, long-term solution that provides shade and cools the ground – as well as alleviates flooding. Gaddy’s project hosts workshops for tribal members and distributes kits made up of native grasses, shade trees, shrubs and mulch so that the community can build their own garden. “We teach people how to ‘plant the rain,’” she explains, “by first digging a basin and then incorporating the tree and plants within it.” By digging a basin no more than 12 inches deep, a pocket is created where water can collect. The tree and plants added to the basin help absorb the water, and the mulch helps prevent unwanted weeds and keeps the basin hydrated by slowing evaporation. A workshop held this past spring built 15 basins throughout the Pascua Yaqui Nation, which varied from 3 feet to 25 feet in size. The workshop’s success has led to requests for Gaddy to host workshops for other tribes. Holding onto her Indigenous knowledge has been a driving force for Gaddy. “There’s a need for it to be recognized and acknowledged as scientifically valid, and that keeps me going as a professional – making sure that I intertwine that knowledge with my work.” ◼️

Urban Heat Mitigation

Her ‘Indigenous Knowledge’ Almost Cost Her a PhD. Now, She’s Using It to Help Desert Communities

The Story Exchange

Urban Heat Mitigation

Her ‘Indigenous Knowledge’ Almost Cost Her a PhD. Now, She’s Using It to Help Desert Communities

The Story Exchange

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