Here’s how one Houston area utility dealt with the storm when it hit, and what is happening now in the aftermath
When Hurricane Harvey hit South Texas Aug. 25, the city of Pearland’s Department of Public Works was put to the test. It passed, but not without teaching moments for the department’s director, Eric Wilson, and his staff.
“A lot of the staff of Pearland had not been through a major event, so it was a learning experience for a sizeable number of city employees,” Wilson says. “Having been through something like this now — the landfall and three or four days of rain that followed — will be helpful going forward.”
A Target for Gulf Storms
Pearland is former prairie land about 30 miles south of Houston. Two hundred years ago, the prairie soil was turned and farms began to grow figs, cantaloupes and pears. Because the fruitful land is only about 50 feet higher than sea level, it is infiltrated by bayous and vulnerable to the vagaries of seasonal storms coming off the Gulf waters.
Wilson knows the territory. A resident of the region since he was 6 years old and a graduate of the University of Houston, he became the department director four years ago after, among other positions, serving as assistant city manager of Galveston. He was in Galveston in 2008 when Hurricane Ike devastated the coastal city.
“When I left Galveston, I traveled 30 miles inland thinking I didn’t have to worry about hurricanes anymore,” he says.
He actually had experienced three hurricanes before Hurricane Harvey arrived in Pearland, so Wilson knew the drill, which he says more or less consists of “battening down the hatches.”
The Storm Strikes
Harvey’s landfall Friday, Aug. 25, was mostly uneventful for Pearland.
“We mobilized at 6 a.m. Saturday looking for wind debris,” he says. “Rain had not arrived as predicted and I made a mistake: I released staff to go home that day about 3 p.m. When I called for all hands on deck at 10 p.m., about 50 or 60 percent of our staff (the department has 120 employees) could not get back because flooding had begun.”
Besides overseeing water and sewer systems, Wilson is also responsible for Pearland’s streets, so the shortage of employees as floodwaters rose handicapped early efforts to do such things as barricade subdivision streets. The idea is to prevent citizens from “hurting themselves” by willfully plunging into deep water they somehow believe their cars can cross.
“And later, when home rescues began, we might have been able to field a larger rescue operation had more staff been available,” he says.
In the end, though, Pearland recorded no storm-related deaths.
The Effect on Water and Sewer Infrastructure
As the water rose, so did anxiety about its impact on the city’s water and sewer systems. Pearland has five wastewater treatment plants, 78 lift stations, and 478 miles of sanitary sewer lines. The water system includes 620 miles of pipe, nine wells and two repump stations where purchased water from Houston is introduced. The underground collections and distribution systems range from 6-inch to 60-inch pipe, most of it 6 or 8 inches in diameter.
Pearland is fairly flat. Its nearly 50 square miles is spread across three counties but elevation in the city varies just 10 feet, with the lower areas on the east side nearest Galveston Bay. Planning and engineering of structures in the city is based on a 100-year flood event, with a foot of freeboard added. Unfortunately, based on bayou stream gauges, Harvey turned out to be a 500-to-1,000-year event.
The city’s flat topography was an asset in one respect: Despite being inundated by Harvey, the city experienced no interruption in water service. While floodwater did enter a couple of pumping stations, it did not reach electrical systems. However, had they failed, Wilson says, the remaining pumps could have maintained water pressure because within the city there is so little pushing of water uphill.
The sewer system did not fare as well. Two of the city’s five wastewater treatment plants were temporarily lost, with 4 to 5 feet of water in one facility and about 3 feet in the other. The two plants are located on the east side of the city where more than 46 inches of rain fell, twice the amount recorded on the western edge of Pearland. Self-priming pumps in the plants were inundated and the motors had to be replaced after water receded.
Pearland is a commuter community of 120,000, with many residents driving away each morning to work at places like NASA’s Lyndon B. Johnson Space Center in Houston. More than 80 percent of land area is zoned residential. That means Pearland has more individual water and sewer connections than communities with a broader mix of industrial and retail properties — 37,500 water-only connections in total and about 34,000 sewer connections. For the most part, these all withstood Harvey’s floodwaters, Wilson says. He attributes this to Pearland being one of the fastest-growing cities in the nation — its population was just 38,000 in the 2000 census — with relatively new infrastructure to match.
“The majority of our infrastructure is 25 years old or younger,” he says. “With the design technologies that goes along with that, the performance of the infrastructure under stress was much better than it might have been under different circumstances.”
Clay sanitary sewer pipe in the older section of Pearland on the city’s east side was the most vulnerable to storm stress. In recent months, the city has begun to replace the 74 miles of clay pipe through what Wilson calls a “fairly aggressive inflow and infiltration program” that involves bursting and replacing old pipe. The goal is to annually replace several miles of old pipe in the area, which features porous soil that induces infiltration and blockage. Preliminary indications are that the I&I work already completed was not damaged by Harvey.
The hurricane’s flooding was horrific in Pearland, principally to homes and private properties, but infrastructure damage was minimal. No washouts of pipelines or streets occurred, and no treatment plants were permanently ruined and left inoperable. Insidious damage, on the other hand, has yet to show itself, Wilson says.
“We still have very preliminary estimates of damage,” he says. “We are bringing in some consultants to look at buildings and take a more in-depth look at systems. For example, some water reached some of our electrical panels, which means they are now contaminated. They will fail. It is a matter of when, not if.”
Other yet-to-be-determined assessments include the impact of flooding on pre-existing I&I problem areas and on the 35 percent of city streets that are asphalt-paved, mostly in the older sections of town. Those streets were inundated for several days and testing of the base and subbase will determine the extent they were compromised by all that water. Furthermore, while floodwaters flowed deepest along traffic arteries just as city engineers intended, irrigation systems in highway medians were hit hard.
“Another thing we haven’t wrapped our arms around is our meter reading system,” Wilson says. "It is a drive-by system with thin wiring connecting a transmitter to the meter box. I don’t know how many of those we’ve lost. We’re getting ready to start reading meters again and that’s when we’ll find out.”
Equipment losses were minimal and outside assistance was barely needed. A dewatering pump that had been running continuously for four days failed and the department rented one. When the department’s street barricades all were deployed, the Department of Emergency Management was called and provided some more.
The Next Steps
The storm may hasten some upgrading of Pearland’s sanitary sewer system, according to Wilson.
“Depending on funding out of Washington, D.C., we want to harden our treatment facilities and make them more resilient. We had planned to regionalize the system and go to four treatment facilities from five, expanding one plant and mothballing the other. We may be able to expedite that process as a result of Harvey.”
Water usage from the city system is temporarily down, as is the amount of wastewater returning to treatment plants, because so many residents have not yet returned to live in their homes.
“Folks have started mucking out their houses and rebuilding their lives,” Wilson says.
An immediate consequence is that the city must remove an estimated 50,000 cubic yards of debris.
“That’s a lot for Pearland,” Wilson says.
Two weeks after Hurricane Harvey hit, Pearland’s public works department is moving on, a little wiser for the experience. When the next storm strikes, staff members won’t be sent home as early and some communication glitches will have been corrected. For now, Wilson says, operations are back to normal.
“All in all, Pearland was very, very fortunate. The whole city operation — public works, fire, police — we all worked together and anyone who knows municipal government knows that is pretty much a rarity and impressive to see. I have some staff who lost everything but didn’t miss a beat in helping other people. They can really be proud of how they reacted.”
In the end, eventual recovery from Harvey will be a regional story, Wilson says.
“After the rain stopped over the Labor Day weekend, we sent a team to Lake Jackson to help them down there. The whole Houston metro region has done a great job of coming together.”