Many cities are now pushing reinvestments in the urban core, prompting people to live, eat, and play in walkable city centers.
Unlike in the past, cities today have challenges associated with adequately housing greater numbers of people while balancing scarce and threatened natural resources. In particular, cities must meet demands around public transit, water, infrastructure improvements, and even open, community spaces.
And in some ways, the most rapidly growing cities and regions—Phoenix, Denver, and Seattle, and cities such as Portland and Salt Lake City on the Forbes 2017 list of America’s fastest-growing cities—already are overextended, says Philip A. Stoker, assistant professor in the College of Architecture, Planning, and Landscape Architecture at the University of Arizona.
For example, the Denver Regional Council of Governments reports that, by 2040, the city will likely see rush-hour traffic extended by hours, adding risk for traffic backups and collisions. In San Diego, renting and buying have become increasingly difficult, contributing to the region’s growing homelessness problem. San Francisco historically has experienced limited space, high congestion, and housing costs at about three times the national average.
In response, cities have begun to adopt more mixed-use development, where single buildings or blocks contain not only housing, but also restaurants, grocery stores, cultural centers and the like. Also, some are placing a greater emphasis on walkability, which carries financial, environmental, health-related, and social benefits.
Stoker works to best integrate land-use planning with the management of natural resources—with a specific focus on water.
“The importance of the environment on our economy, social well-being, and humanity cannot be overstated,” he says.
Stoker and researchers from the University of Utah created a typology of urban neighborhoods that share distinctive combinations of natural, built, and social structures expected to shape water system dynamics. Typology isn’t usually part of urban planning, but the data can help planners create water systems that encourage social, economic, and environmental sustainability.
Stoker, coauthor of a new study in the journal Science of the Total Environment, discusses the future of cities in the face of changes in climate and environment.
Q - What are some of the growth-related challenges facing the nation, especially cities in the Western region?
A - The way we build, design, and permit our cities should protect our natural resources. After all, urban areas in the United States are growing. The urbanized growth rates in the West are astonishing: Arizona, Utah, and Nevada all saw urban populations grow more than 25 percent from 2000 to 2010.
This growth is likely to continue, and at the same time our climate is going to change. These combined forces, changing climate and increasing urbanized populations will stress water supplies in cities. Therefore, we really need to be investigating every option available to urban water managers to sustainably manage water. One of those strategies will be to intentionally design and build cities with water in mind.
California is a top-of-mind place when it comes to issues related to urban water systems. Which other states and cities are you tracking that are working on major challenges and changes related to such systems?
My research has me on the phone with water managers and urban planners in Portland, Los Angeles, San Francisco, Cleveland, Las Vegas, Pittsburgh, Salt Lake City, Albuquerque…and the list goes on.
Really, every city in the nation has to consider water as a fundamental resource to support population and economic growth.
Q - What are some of the other new or emerging strategies for balancing water resources?
A - Tucson and Arizona have pioneered many innovative water strategies that are models for the rest of the nation. For example, the 1980 Groundwater Management Act regulates groundwater mining and requires 100-year water supplies for new development. That really would have been beneficial for California had they adopted similar legislation 30 years ago, but they are just now getting around to careful regulation of groundwater.
I also find myself telling people about the municipal ordinances in Tucson that limit turf grass, allow greywater reuse on landscapes, and require high efficiency plumbing in new developments. These are strategies to better manage urban water that can be adopted nationally, yet have not.
Also, water conservation at the consumer level contributes to citywide water efficiency and has the potential to generate substantial savings. Effective conservation will allow cities to grow without requiring new sources of water. There are many conservation strategies, such as education, rebates, and tiered water rates. All of these options should be pursued. In particular, tiered rates are important, but some cities are constrained by what they can charge because they have legal requirements to not charge at a rate higher than the cost of provision. Others have a hard time setting effective rates.
Q - The influence of built and natural environments on water demand and quality is dominantly researched and discussed. Why is it important to give heightened critical consideration to social characteristics and institutions in analyses?
A - There’s no doubt the design of built environment influences water demand and quality, but when it comes right down to it, it’s the people who are turning on the tap.
People are also responsible for making decisions about how to permit and build cities and neighborhoods. A holistic understanding of urban water use requires an examination of the physical characteristics of the built environment, the climatic conditions of a city, the social dimensions of the residents, and the institutions that manage water. A portion of my research focuses on how we can design houses, neighborhoods and cities to use water more efficiently. I complement this with research that focuses on the social drivers of consumption, as well as how water is managed in cities.
Also, higher-density urban development—to a point—is more efficient for water consumption. One explanation is that homes in higher-density neighborhoods have to be smaller, and therefore have fewer water-using appliances and smaller lawns. Development density is one reason per-capita water use is lower in European cities compared to many sprawling US cities. Cities such as Las Vegas recognize this, and water managers are trying to promote higher-density urban development. Interestingly, water managers don’t have the legal authority on land-use decisions, so they have to collaborate with municipal land-use planners.
If you took a 0.25-acre single-family residential property, and held all the physical characteristics of the property constant, that house is expected to use more water in a low-density suburban neighborhood than if it were in a mixed-use, higher-density neighborhood.
In other words, the density and land-use mix of a neighborhood are influencing how people use water in ways other than the physical characteristics of a property. We aren’t sure, but it could be related to how social norms are shared. For example, low-density suburban neighborhoods may promote expectations to have your house look like all the others, which might include a well-watered lawn.
But regardless of where people live, water systems can be strengthened by protecting water quality at the source above and below ground, maximizing the efficiency of water use in cities and recycling wastewater and storm water. Urban planning and the design of cities has a role to play at each of these stages.
Source: University of Arizona