In drought-wracked California, efforts to conserve every bit of available water are prompting ambitious solutions. But while the state looks to major infrastructure projects to meet future demand, researchers at the Arid Lands Institute are working on a software mapping tool, Divining LA, to give urban planners, architects and engineers a better view of a region's water profile to maximize use.
Combining information gleaned from digital terrain models, geotechnical data sets, multi-spectral satellite imagery and historical surveys, Divining LA may one day provide a model of a region's stormwater drainage and water availability to a high level of detail.
Work on the tool began in early 2013, with a Metropolitan Water District of Southern California grant to find ways to reduce dependency on imported water supplies. Currently, it models an area of more than 460 sq miles, down to a resolution of about 300 sq ft. "The tool is trying to work multi-scalar: regional scale, municipal scale, even small-lot scale," says Peter Arnold, co-founder and research director of the Arid Lands Institute, Woodbury University, Burbank, Calif. "The central challenge for us is to link all of this data together."
Armed with rich data on stormwater runoff, geology, soil chemistry and the built environment, Arnold says city planners, architects and engineers will be able to model how their proposed structures will alter the hydrological landscape. Further, the tool will have the capability to update its model to show the effects of proposed construction.
Now in the prototype stage, Divining LA models only the San Fernando Valley region of the Greater Los Angeles area. Using computer models to track and predict stormwater runoff is not a new concept, but Divining LA is far more ambitious in its goals. "Our hope is that by putting together this data, we can move beyond blanket policies and blanket procedures for resources," says Hadley Arnold, co-founder and executive director of the Arid Lands Institute. "We can move into an era in which every act of construction or in-fill or remodeling is done by designers and developers who are aware of the hydrological duties that a building has to perform for the area to be at its optimal hydrological function."
While there is still much work to be done on Divining LA, the city of Los Angeles already has expressed interest. "As the primary engineering organization for the city of Los Angeles, we are interested in tools that facilitate effective water-infiltration designs," says Deborah Weintraub, city engineer with the Bureau of Engineering. "Divining LA … can provide quick feedback on localized opportunities for water capture and infiltration, which are critical to sustainable practices." The Bureau of Engineering provides the Arid Lands Institute with the detailed GIS information that forms a crucial segment of Divining LA's data set. Weintraub expects immediate benefits from adopting it, saying, "The tool can be used by our engineering and design staff for initial assessments of the opportunities for stormwater capture and reuse."
What sets Divining LA apart from similar solutions is its emphasis on finding small, distributed solutions to wasted water runoff, says Peter Arnold. "In the San Fernando Valley, up to 82% of water needs within the metropolitan water district service area could be met through three strategies: increased end-user efficiency, recycling water and increasing its use, and capturing more and using more locally available stormwater."
The program is able to model the impacts of not only large construction projects but many small changes, too. "What we're trying to do is show the connection between the land surface and the built fabric and how changing it incrementally can actually make huge changes," says Peter Arnold. "With this information, we can start to evaluate where resources are best spent, the impact on city planning, the water cycle, ecosystems, and economic costs and benefits. That's what's unique about Divining LA, and that's why there so much interest in this tool."
"It's exciting. We'll be stretching water further and making places more intelligently," says Hadley Arnold. "Fifty years from now, if Divining LA or a similar tool were part of an overall hydrologic overview of the city that designers, architects and engineers had to use, you would have a city that is visibly legible as a sort of Swiss cheese, where certain parts of the city are designed to be absorbent and others are designed to retain water, and it would be shown on a fine-grain scale."
The tool also has its fans in major engineering firms. "Divining LA is very GIS-focused, looking at data layers of geological topography and land uses," says Rowan Roderick-Jones, associate civil and environmental engineer with Arup, which has served in an advisory role in the water-mapping tool's development. Arup has developed its own internal software tools for modeling the water and energy profiles of a region and sees publicly available tools such as Divining LA fitting into its workflows. "Divining LA is about finding new sources of water. Combined with our models, we can see how it fits in with other regional planning goals, such as California's carbon targets."
According to Roderick-Jones, Arup's push to build these tools isn't due simply to regulations or owner demands. "For us, we don't necessarily see a regulatory driver for this, but we see this contributing to how California wants to solve its energy and water problems. If we wait for this to hit the regulatory world, it's probably too late. We need to be ahead of the process. So, when those regulations do hit, we'll be ready."
While the final version is still a few years out, Hadley Arnold has high hopes for what planners, architects and engineers will do with the tool. "It's not about just having a piece of engineering at the end of a street or a rain barrel under a gutter. We'd like to see the surfaces of buildings and sites manipulated to their fullest advantage, both functionally and aesthetically," she says. "Distributed water infrastructure is gaining traction, but one thing we've found in working on Divining LA is that there is no one-size-fits-all solution. We have to be strategic and technical in working with this wide range of geologies. Divining LA can map that in a way it becomes easy to understand. We're looking to optimize design in a holistic way."