As a kid scrambling around in the Vermont woods, I never thought much about water: where it came from, where it went, whether there was enough of it. It was all around me, all the time, and I gave it as little thought as I gave to air. It wasn’t until I moved to the stark desert mountains of eastern California that I suddenly understood the power of water to shape and explain a place. This magic force could carve huge canyons, nurture narrow ribbons of cottonwoods and willows, fill the saline basins of inland seas, and – it seemed to me – dictate the course of politics, culture, and human endeavor.
Woods Creek in the Sierra Nevada.
Water in California is both highly visible and desperately scarce. Throughout history, water conflict has played out as the principal drama of the California stage. Farmers have dynamited aqueducts, cities have battled one another through decades of litigation, and governments have imposed restrictions on water consumption that would be unthinkable in the East1, but the problems have only intensified. While drought has plagued the state off and on for all of American memory, the last four years were among the warmest and driest in more than a century of record-keeping2,3. Increasing population pressure and a greater understanding of global climate change have brought water shortage to the tip of every tongue in the state.
Human ingenuity is spurred by crises, and California’s plight has prompted widespread brainstorming. Proposed solutions range from the prosaic (mandatory water rationing, public education about water conservation) to the resourceful (desalinization, improved stormwater retention and treatment) to the bizarre (cloud-seeding, harvesting fog, or reducing evaporation from an open-water reservoir in Los Angeles by filling it with 96 million plastic “shade balls”4). While idea generation is rampant, actual implementation lags behind.
Shade ball deployment in August 2015.
The Los Angeles basin is home to almost twenty million people5 and has a long history of redirecting water to suit its needs, from the aqueduct that drains 1,600 cubic feet per second of the Colorado River into the coffers of the Metropolitan Water District6, to the gravity-fed pipeline that appropriates Sierra Nevada snowmelt to fill the taps of city customers7. Today, in the face of the latest drought, Los Angeles is contemplating increased reliance on water that reaches the city in another form: rain.
Not long ago, stormwater was seen only as a threat to infrastructure. Cities were built to funnel rain out of the streets and into the ocean as efficiently as possible. But as reservoirs shrink and snowmelt dwindles, city planners have turned their attention toward salvaging the water that falls out of the sky. In August 2015, the Los Angeles Department of Water and Power (LADWP) published a Stormwater Capture Master Plan that proposes to increase the amount of captured stormwater in the basin by as much as 114,000 acre-feet each year8. For reference, a California household’s average water use clocks in at less than one acre-foot per year9. The savings may seem insignificant, but the message is clear: water must be saved however and wherever it can be. There are no more rivers to divert or lakes to drain. Los Angeles must search for and exploit any possible source of increase to its water stores.
The Stormwater Capture Master Plan is ambitious and far-reaching. The plan identifies potential water-saving initiatives from the level of a single house (rebates for rainwater barrels) to that of several-hundred-acre spreading grounds where stormwater is trapped in shallow ponds to encourage its infiltration into underground aquifers. LADWP lays out a twenty-year implementation schedule and promises “immediate, significant, and sustained efforts” in pursuit of these goals8.
Los Angeles River in 2014
Yet there are those who find this approach unsatisfactory. LADWP’s plan is too broad to pick up on every fine-scale opportunity for stormwater retention in the basin, and the plan does little to promote public awareness of and involvement in the process. Peter and Hadley Arnold, architects at the Arid Lands Institute in Burbank, CA, have another idea.
“How do we craft cities and buildings that consciously and visibly mitigate, anticipate, and even celebrate, hydrologic variability?” This is the question the Arnolds pose in their 2013 article “Pivot: Reconceiving Water Scarcity as Design Opportunity“10. Their answer: a geospatial model of the San Fernando Valley that blends runoff predictions with detailed surface mapping to identify where – at the scale of individual rooftops, gutters, sidewalks, and curbs – stormwater can be trapped or transported most efficiently. The model traces the likely path of water through the city, pinpoints ideal locations for cisterns or permeable substrates, and even accounts for contaminated areas where stormwater should be channeled off-site and prevented from entering a polluted aquifer. They call the software Hazel, after the wood traditionally used in divining rods. The Arnolds estimate that if the model became reality, it could save the San Fernando Valley 92,000 acre-feet per year of runoff water11. The Valley is about 260 square miles in area12; imagine those savings at the scale of the 4,850 square mile Los Angeles metropolitan area5.
Sample output from the Arnolds’ model.
The Arnolds’ intention is not simply to create a more detailed stormwater retention plan. They envision a paradigm shift. As Hadley put it in a 2014 interview with Architect Magazine, “We first have to break through the invisibility of water systems…the idea that water is just something that shows up in a pipe”13. Instead, water availability and consumption should be transparent public knowledge. Woven into the Arnolds’ design are schemes to prompt a new consciousness of water: water meters as urban art installations, a “smart water grid” that helps private homeowners optimize their water collection, a house that showcases stored water in its walls. They hope for a new generation of planners, builders, and citizens whose eyes are trained to understand the water retention possibilities of a landscape, just as we’re trained to orient our windows toward the sun or build our foundations on level ground13.
For many people in urban Los Angeles, water has always been exactly what it was to me as a child in Vermont: something that comes from who knows where to pour out of the tap, and goes down the drain to who knows where when you’re done with it. Perhaps it’s time to recognize that water, while powerful, is not so mysterious. We have the technology to understand its trajectory in minute detail. The next task is to embrace an approach that capitalizes on that technology. Water can shape not only our creekbeds and canyons, but also the way we design our cities and homes. This new ideology could be a path to extraordinary and unlooked-for solutions.
1. Hanak, E., J. Lund, A. Dinar, B. Gray, R. Howitt, J. Mount, P. Moyle, B. Thompson. 2011. Managing California’s water: from conflict to resolution. Public Policy Institute of California.
2. United States Geological Survey. The California Drought.
3. California Department of Water Resources. 2015. California’s most significant droughts: comparing historical and recent conditions. State of California.
4. Howard, B.C. 2015. Why did L.A. drop 96 million ‘shade balls’ into its water? National Geographic.
5. Wikipedia. Los Angeles metropolitan area.
6. Wikipedia. Colorado River Aqueduct.
7. Wikipedia. Los Angeles Aqueduct.
8. Los Angeles Department of Water and Power in collaboration with TreePeople. 2015. Stormwater Capture Master Plan.
9. Water Education Foundation. What’s an acre-foot?
10. Arnold, H. and P. Arnold. 2013. Pivot: reconceiving water scarcity as design opportunity: mapping a more absorbent landscape. Boom: The Journal of California 3:95-101.
11. Tory, S. 2015. Could Los Angeles design its way to water independence? High Country News.
12. Wikipedia. San Fernando Valley.
13. Karaim, R. 2014. Woodbury’s Arid Lands Institute rethinks water in the west with “Divining LA.” Architect Magazine.