Overtopped street signs, escape routes closed-off, inundated highways, and trails of emergency relief workers lining the streets present an ominous picture of Houston underwater. Unfortunately, this is only the beginning.
This type of climatic event has drastic implications for a city’s underground infrastructure– namely its water and sewer systems. While the scale of the challenge is immense, it can also be an opportunity for change. We need to invest in more resilient, smarter water infrastructure.
Houston’s water and sewer system by the numbers. The population of the greater Houston area, encompassing nine counties, is estimated at 6.5 million people, served by 1,404 community drinking water systems and 443 publicly owned wastewater treatment works. The City of Houston’s Water and Wastewater Division, the metropolitan area’s largest utility, provides combined services to 2.2 million people. A fragmented network of smaller community water systems serves the rest of the area population.
In the coming days, municipal officials will struggle to keep water treatment facilities operational (rainfall totals topped 51 inches on 29 August). The City of Houston’s 40 wastewater treatment plants are at the greatest risk of being overwhelmed, flushing untreated wastewater into surface waters and putting the public at risk of disease and infection. In the days and weeks ahead, prolonged power outages will further stress water utilities’ ability to operate, as most prepare only short-term emergency power supplies. Power outages could shut down some of the city’s 380 pump stations already exposed to extreme conditions. No power, no water.
The City of Houston, alone, manages 7,000 and 6,500 miles of drinking water and wastewater networks. Over time, these distribution networks will be compromised and are at risk of displacement due to saturated soils. As a result, an increase in leaks can be expected, and, without mitigation, drinking water supply lines could become contaminated.
In the longer-term, utility engineers will be tasked with zeroing-in on these problem areas, but doing so efficiently– doing more with less– is another matter. As federal and state funds roll into the city in coming years, Houston has the opportunity deploy newer, more advanced solutions, such as digital water solutions and smart sensors, to make the system more efficient going forward.
Nine Counties in the Greater Houston Area and Houston Water by the Numbers
Putting Harvey in perspective. Previous storm events illustrate the potential long-term costs in bringing water and sewer services back online. Following Hurricane Sandy, in January 2013 the federal government passed the Disaster Relief Appropriations Act (DRAA), which allocated an additional US$500 million to the Clean Water State Revolving Funds (CWSRF) and US$100 million to Drinking Water State Revolving Funds (DWSRF), primarily for New York and New Jersey. This financing was meant to address wastewater and water system impacts from the storm and to improve system resiliency in anticipation of the next storm event.
FEMA has already pledged US$13 billion to provide emergency aid to Harvey victims, but more funds will be allocated to address long-term recovery in the aftermath. After Hurricanes Katrina and Rita, FEMA allocated US$2 billion to New Orleans to fix water and sewer infrastructure, despite arguments that repairs for the systems were required largely due to underinvestment in infrastructure maintenance and not due to damage caused by the storms.
Houston has already documented a need for investment– up to US$5 billion– to reduce sanitary sewer overflows during large storm events. The city has been negotiating a consent order with the EPA to mitigate these problems. While Harvey is beyond large, disaster aid could be wrapped up in a more comprehensive strategy to improve these already existing long-term issues with the water and sewer systems.
Federal funds will only begin to meet the investment demands to repair the damage wrought by the storm. This discrepancy highlights the need for Houston to secure other sources of funding for repairs, likely meaning higher water and sewer bills for residents. Houston’s average monthly water and sewer bill has only increased 9.5% since 2013, slower than the average increase of 22% for large utilities across the country. Making matters worse, utility revenues are likely to decline in the aftermath because of population declines and non-paying customers. Following Katrina, more than 100,000 people left New Orleans.
In the most recent round of State Revolving Fund requests, Houston received funds for projects totaling US$108 million in investment to rehabilitate sewer systems experiencing infiltration of storm water and for emergency flood reduction. Texas allocated US$775 to clean water and drinking water projects through state revolving funds in the 2016/2017 fiscal year. Before Hurricane Harvey hit, ten community water systems and five publicly owned sewer systems in the greater Houston area had requested State Revolving Funds.
Additional funds to deal with needed infrastructure repair can come from the state level as well. To address drought related investment needs, the state of Texas allocated US$2.0 billion to the State Water Implementation Fund for Texas (SWIFT) in 2013 from the state’s “Rainy Day” fund. It is likely that hurricane related flooding will prompt a special funding allocation from the state legislature.
Making this storm a harbinger for change, improving resiliency of critical infrastructure. Severe storm events are becoming increasingly common across the United States while urbanization, and the associated loss of permeable ground cover, makes the flooding impacts of heavy precipitation more acute. With the impact of climate change, we expect to see more Harveys in the years to come.
The impact is not limited to southeast Texas. EPA tracking of extreme precipitation events demonstrates that their prevalence has been increasing, with over 20% of the contiguous U.S. experiencing an extreme one-day precipitation event in 2015. Harvey represents the third time in as many years that Houston has experienced a 500-year flood, so it is safe to say that extreme storm events and associated flooding will be increasingly prevalent going forward. Improved resiliency for water infrastructure will likely encompass a number of solutions. Measures to reduce the impact of flooding include increased storm storage facilities, sewer operation optimization including smart controls, and green infrastructure like porous pavement, green roofs, and bio retention basins.
Rise in Prevalence of Extreme Storm Events in Contiguous United States
Earlier this month President Trump signed an executive order to overturn a post-Hurricane Sandy rule, Establishing a Federal Flood Risk Management Standard and a Process for Further Soliciting and Considering Stakeholder Input. This Obama directive aimed to establish flood-risk standards for federally funded infrastructure projects, particularly those in flood zones or in areas of potential sea-level rise. With the repeal of this rule, flood-planning challenge will fall on local officials in the absence of federal guidance.
Even if local measures are the better, more actionable route, whether for flooding or drought, staying the current course nationwide is anything but sustainable. At some point, US$10 billion for a hurricane barrier in Boston Harbor or US$1 billion for desalination and reuse plants in San Diego become affordable when put in the context of the cost to rebuild the city of Houston.