Harvey dumped 51.6 inches of rain in a few days, leaving 300,000 still homeless in January 2018, 36 fatalities, and billions in personal property and infrastructure damage. The sheer land mass of Houston, 669 square miles, creates a beastly management problem. Thirty-nine wastewater treatment plants, 382 lift stations, and 6,200 miles of sewer lines support the city. Of these, seven wastewater treatment plants flooded. Five returned online within four days; two wastewater treatment plants were inaccessible for more than two weeks due to controlled flooding by the Army Corps of Engineers. Now, the City of Houston seeks up to $5 billion to improve the third-largest water infrastructure in the United States. With priorities on both municipal optimization and mitigating the effect of extreme weather events, is it possible to adapt the existing system to new demands, or is a full redesign in order? Houston Water looks to leverage both new and old systems in defining and designing resilience.
At a base level, it’s a problem by design: Wastewater treatment plants require adjacency to the floodway along bayous, not just the flood plain, for efficient discharge. This makes them particularly vulnerable to storm events. Myriad issues have delayed their restart since Harvey, including an energy provider not giving Houston Water priority, flooding at fueling locations, and protocols requiring police escorts to bring additional chemicals to treatment plants.
Houston Water Operations Manager Sydney Bomer announced that capital projects, with an annual $375 million budget, are being placed on hold. With multiple floods in the past few years, the useful life of damaged equipment will be re-evaluated through life-cycle comparisons after an intensive assessment process. Based on these findings, Houston looks to consolidate from 39 to 27 regional wastewater treatment plants within seven years.
To mitigate the impact of future storm events, Houston Water and AccelerateH20, a public-private partnership, created the Houston Water Innovation Hub. The hub is not a physical building; rather, it utilizes Houston Water’s existing facilities to test new technologies for real, full-scale results. The process expedites findings and deployment, simplifying the process of extrapolating pilot results to real-time problems. In January, at Verde Exchange in Los Angeles, Bomer shared the goal of incorporating five to seven innovation projects annually, while speaking about resiliency. Current innovation projects include pop-up treatment plants to service populations trying to get back to business post-disaster; bio-solid filtration; and independent pressure monitoring of stormwater covers to provide predictive analytics in storm events.
“With increasing droughts, floods, population growth, and advanced manufacturing, Texas will only have more water challenges in the future,” says AccelerateH20’s Richard Seline. Altogether, Texas has 4,600 public water utilities, 5,000 medium or larger corporate campuses, and thousands of ranches that rely on the $9 billion Texas water market. “Because of the highly regulated scenarios for public health in the drinking-water sector,” Seline says, “the oversight and review of water used in the energy and manufacturing arenas, and the requirement for engineered solutions that are evaluated before introduction and deployment into existing or new facilities, the pathway for commercialization can be challenging, at best.”
Houston Water Innovation Hub will be the first large-scale water technology demonstration hub in the U.S. “The launch of the Houston Water Innovation Hub in collaboration with AccelerateH20 promises our customers access to the most innovative water and wastewater technology in the nation,” says Yvonne Forrest, deputy director of Houston Water. “As Houston continues to grow, this innovative program invites global ideas and solutions to be evaluated, tested and showcased for our region and the world.” Key partners include NASA, Rice University, the University of Houston, Texas State University, the National Advisory Board, National Renewable Energy Lab, and various worldwide and regional water agencies.
NASA is an ideal partner for the water tech hub: The agency has recycled water for space travelers since manned space flight began. The question becomes more complicated when applying these technologies to industrial, commercial, and residential facilities across the range of densities and climatic conditions that compose Texas. Production and cost efficiencies vary by scale, demand, and the availability of groundwater.
Currently, AccelerateH20 supports four demonstration hubs across Texas: brackish desalination and advanced treatment in El Paso, one-water and drought resilience in West Texas, smart data and instrument integration utilizing the internet of things in Central Texas, and municipal optimization and water resiliency in Houston. These implementations are modeled from the best in water management across scales, use, and climate varieties from around the world.
For example, Lingang, China — a “sponge city” — demands flood control through policy provisions. By 2020, the government wants 20 percent of the built area of each pilot district to have sponge-city functions, meaning that at least 70 percent of stormwater runoff should be captured, reused, or absorbed by the ground. By 2030, 80 percent of the city should meet this requirement.
In Rotterdam, flooding is expected to be an annual event, and home design is adapting to prevent loss of life. New codes in flood-prone districts require wiring to be moved from basements to upper floors and wood floors to be replaced with water-resistant floor coverings. Green roofs are incentivized through subsidies, with a 50 percent install discount and a tax reduction, as well, yielding 140,000 square meters of green roofs since 2008. “We’ve also built water storage facilities — for example, an underground parking garage with a basin the size of four Olympic swimming pools,” says Alexandra van Huffelen, Rotterdam’s vice mayor in charge of sustainability. “And we’ve introduced more green areas, including green roofs and green facades, that will be able to absorb water as well.”
Israel is a champion producer of clean water, processing three million cubic meters of potable water daily through desalination, water recycling, and sustainable conservation policies. The largest desalination plant was built for $500 million and provides water for 20 percent of the country’s consumption needs. Worldwide, over 700 million people do not have access to clean water, and in many places, such as in coastal and South Texas, pulling fresh water from the ocean might be the best option to increase the supply to meet rising water demands.
As an accessible first step, architects can combat drought impacts through a range of certification and benchmarking systems to curb supply-demand ratios. The Better Buildings Challenge, created by the U.S. Department of Energy, is a particularly strong champion of curbing water demand: Its low cost and relative ease of use promote both energy and water conservation across asset classes, ownership types, and scale for both new construction and retrofits. These systems have the added benefit of ascertaining a building’s relative performance savings for owners and investors. Participants in the program have curbed water demand reductions at a minimum of 20 percent, but some have achieved water savings as high as 30 to 50 percent. As municipal building codes integrate graywater and rainwater reuse, approachable demand reductions greater than 50 percent are on the horizon.
Beyond curbing water consumption, additional individual building responses can include sponge design principals and siting for flood events. Currently, Houston’s building code prohibits construction in the 100-year flood plain. For new structures and substantial renovations of 30 percent floor area increase or more, city officials may increase the restriction to two feet above the 500-year flood plain with zero net fill. The invitation to increase pervious habitation and density simultaneously could lead to a new architectural design identity for Houston.
“Resiliency is defined by everyone differently,” Forrest says. “Houston’s definition is still being written, and we are not making knee-jerk reactions. We are considering life-cycle costing, consolidation versus plant size, and proximity to need. In the past five years, we’ve had Harvey and drought between two major hurricanes. We must be prepared for both extremes.”
Houston Water and AccelerateH20 invite active participation in their pursuit of water resilience. Recently, they launched a series of cross-disciplinary idea competitions, with the goal of elevating water tech and resilience to the forefront of Texas designers’ prerogatives. Winning ideas may receive fast-track review for implementation in the innovation hub and potential adoption. Current open calls include grit and settled solids management, sludge and biosolids management, pressure monitoring, repressurization, and smart data integration for flood alerts. Architects, grab your sketchbooks: We have some work to do.
Jen Weaver, AIA, is an architect and developer active in Austin and Los Angeles.