Planning and Engineering Sustainable, Resilient Water Resource Systems
Covering more than 70 percent of the earth, water is essential to all forms of life. Water plays an important role in the world economy as civilization has typically grown and flourished around rivers and major waterways.
A clean and secure water supply is perhaps the most vital component of public health. Destruction of water supply, stormwater management and wastewater disposal infrastructure after major catastrophes, such as earthquakes or floods, and deterioration over time poses severe challenges to the affected population, including waterborne diseases that can be life-threatening, excessive operation and maintenance costs and significant environmental impacts.
Steven Burian, associate professor of civil and environmental engineering, is working on the issue of safe water by improving the resiliency of water resource systems in the United States and developing communities around the world. He uses computer modeling, simulation and data analysis to quantify implications of water infrastructure changes, such as decentralization, on system sustainability and to determine impacts of climate change on system resiliency. He seeks to develop and evaluate new designs and technologies that can improve water infrastructure system resiliency.
Integrated Urban Water Management
One of Burian’s projects seeks new ways to plan, design and manage urban water supply, stormwater, and wastewater collection and disposal as an integrated system. “This includes determining the implications of low-impact urban water infrastructure integration development and decentralization on environmental impact, energy demand, and life-cycle costs,” he says. “In general, we seek to find a balance of centralization and decentralization, conservation and reuse, and resiliency and cost for urban water management.”
Decentralization involves distributing the management of a resource throughout the system. Centralized urban water management, which involves large treatment facilities and extensive pipe and sewer networks, is reaching its limits due to rapid urban growth. In the future, the sustainability will be further challenged as urban water infrastructure systems are stretched further and resources become scarcer. Decentralized urban water management is one possible solution. It incorporates specific practices such as rainwater harvesting, graywater treatment, water reuse, stormwater infiltration and ecological wastewater treatment to distribute the management of water throughout the system. “The difficulty is quantifying the implications to public health risk, cost, and the environment from these shifts and ultimately finding the most effective combination of centralized and decentralized elements,” says Burian.
Burian and his team are working with cities across the country, and specifically with the City of San Diego and the American Society of Civil Engineers, to develop rainwater harvesting programs (accumulating and storing rainwater for use at the point of consumption) as one component of a decentralized urban water system. He is also leading a national committee in the development of guidelines for use of rainwater harvesting for stormwater management. “We are using simulation tools to show what a cost-effective size cistern would be and what would be the impacts on storm water runoff control and water supply,” he says. “We also demonstrate the sustainability and costs of the program and the benefits.”
In some states, including Utah, rainwater harvesting, graywater reuse, and other decentralized water management techniques are constrained by water rights. “Recent legislation in Utah has made rainwater harvesting possible within specified constraints,” says Burians. “Other states have gone much further to the point of requiring installation of rainwater harvesting and promoting decentralized stormwater management concepts, but there is uncertainty about what these changes may have on the water infrastructure system cost and performance as well as the receiving water bodies.”
Although it is difficult to determine the best approach to creating a decentralized urban water system, Burian says that new technologies can be developed to tailor a system to meet the area’s climate and geographical needs.
Flood Modeling and Consequence Assessment
For nearly a decade, Burian and his group have worked with researchers at Los Alamos National Laboratory in New Mexico to develop new approaches and tools to help analyze urban water infrastructure and to determine impacts of natural hazards, such as floods. One recent development has been the creation of faster flood computer modeling integrated with geospatial analysis and data management tools. “Our goal is to improve our ability to project flood impacts and quantify resiliency of water infrastructure to floods,” he says. “This will lead to improved approaches to plan and configure urban areas and the water infrastructure networks to be more sustainable.”
With more than 2.8 billion of the world’s population living within 10 miles of rivers, floods are one of the more frequently occurring, high-impact natural disasters. Every year on average approximately 200 million people in more than 90 countries are affected by catastrophic flooding. Between 1980 and 2000, there were more than 170,000 deaths reported worldwide due to floods-and this statistic is before the 2004 Indian Ocean earthquake and tsunami that is estimated to have killed more than 230,000 people or the recent earthquake and tsunami in Japan that resulted in the loss of thousands of lives. “This problem with flooding is being aggravated by population growth and movement into high-risk coastal and riparian areas, as well as climate change,” says Burian.
Burian and one of his Ph.D. students Alfred Kalyanapu have partnered with computer science professor Charles Hansen from the University of Utah’s Scientific Computing & Imaging (SCI) Institute to develop faster flood modeling. Together, they have integrated Burian’s group’s 2-D flood modeling capability with SCI’s graphics processing unit (GPU) parallel computing approach. GPUs are specialized hardware that rapidly control memory to accelerate the building of images when performing simulations. Parallel computing allows computations to run faster by running parallel to one another, instead of sequentially which is slower.
“Before we integrated GPUs, it would take hours just to do one simulation,” says Burian. “This fast model has reduced our model run times to seconds and permitted us to do hundreds of simulations in a much shorter amount of time to project flood impacts and analyze impacts faster than ever before.”
Using the fast modeling approach, Burian is working with Los Alamos National Laboratory to determine flood risk from hurricanes and other disasters in particular regions and cities. When hurricanes are forecasted, there is usually only a few days of lead time to simulate multiple possible flooding scenarios. With fast modeling, analysts can potentially run thousands of scenarios in minutes. “It’s important to be able to look at a potential flood area and simulate what might happen to the communications, energy, water and transportation infrastructure, which will help us assess potential damage and help guide policy to improve system resiliency,” says Burian.
Other projects in Burian’s group includes one funded by NASA that uses global hydrologic simulations and satellite precipitation observations to study how urban areas influence regional climates, the water cycle and flood risk. He is also studying the interrelationship between water system services and energy demand.