It’s no news that the Golden State is potentially facing its most serious drought ever. The topic has been a media staple since NASA released an alarming report revealing that California has one year of water left in its surface water reservoirs.
With water resources already being stressed—increased population growth and a decrease in available surface water supplies are putting a squeeze on communities across the state—future trends will only compound existing conditions. As the most populous state, California is expected to reach 50 million people by 2050. According to the Intergovernmental Panel on Climate Change (IPCC) report from 2013, California will continue to experience reduced snow packs and warmer temperatures. These conditions will lead to increased evaporation and a reduction in available water for both urban areas and agriculture. Food security for Californians and the multitudes of other Americans who depend on its food and wine production, will be further challenged.
Of the total precipitation which falls in California, 50 percent is infiltrated into soils in rural areas or piped to the ocean in urban areas. The other 50 percent is appropriated for human use. Of the latter, 80 percent is channeled to agriculture and the rest is diverted for residential use. The hydrologic cycle in California needs to be understood and used as a formative system in urban planning and design to ensure resiliency for our communities and for the state’s economy.
First we need to maximize the capture and storage of the 50 percent that returns to the environment. In order to retain and improve rainfall for future years, we need to allow precipitation to infiltrate into soils for uptake by plants and release back to the atmosphere through evapotranspiration. We can capture 100 percent of rainfall events up to a 100-year-storm level at the neighborhood and city scale through high-performing open spaces, which include bioswales, rain gardens, and detention ponds. For 100-year+ events, the regional scale can be used to lay out a matrix of large, interconnected open spaces.
The next 50 percent has the big finger pointing at agriculture. Yet, by arranging our cities based on the water cycle we can reduce our use of potable water. Currently, recycled water is used to irrigate vast areas of ornamental landscapes that surround our urban environs. What if we reconfigure these decorative landscapes and turn them into productive members of society by creating a heterogonous patchwork of agricultural open spaces stitching together our communities—places where recycled water becomes the formative system. Graywater from residential areas can then be filtered to acceptable agricultural levels and used to either offset or replace surface water demands. Instead of fields of stagnant groundcovers and static trees, the landscape will come to life with shifts in seasons, workers, and harvests and people will become connected to their food, farmers, and water use. A local food network will be generated, with grocery stores, farmers markets, and restaurants all benefiting from the local supplies. Local food brings local jobs, and local spending compounds the multiplier effect.
Farm areas in close proximity to sources of recycled water are at a unique advantage over others especially in time of drought and in a future that is anticipated to be far more water-scarce. Agriculture is part of the identity and economy of California. A radical shift in everyone’s way of life is required. As the population in California continues to grow, so will the demand for water, food, and land. Our ability to offer ingenious solutions to these issues will be essential to sustaining the places we live.
Image courtesy of Michael McCullough via Flickr: http://tinyurl.com/mu9fo37
Posted by Paul Peters in Ecology, Urban Ecologies on