A new effort is underway to develop guidelines to help communities make stormwater systems safer.
In September 2014, several vehicles were swept into a retention pond when they got caught in a flash flood in El Paso, Texas. The drivers, who all escaped unharmed, were in the wrong place at the wrong time. The street is designed as a channel to guide flash flood water to the retention pond to protect lives and property downstream.
In DeSoto, Texas, in May 2015, a 14-year-old boy and his dog died in a storm drain after heavy rains. The same day in Oklahoma, a firefighter leading a flash flood rescue drowned when he stepped in front of a submerged culvert and was pulled into a drainpipe. Another man trying to rescue him was swept all the way through the 200-yard pipe but survived. In 2013 in Oklahoma City, nine Guatemalan immigrants were killed in one storm, including four children and an adult from one family caught by a surge of water that swept them into a stormwater tunnel.
While most of the country is dealing with EPA regulations aimed at keeping urban runoff out of water bodies, stormwater has been an important issue in the Southwest for years. Due to unique weather patterns and an arid climate with soil that doesn’t readily absorb rainfall, heavy rains can quickly cause deadly and damaging flash floods.
El Paso is both arid and has the Franklin Mountains running through the center of the city. “The water that comes down from the mountain slopes becomes very energized with a lot of velocity and momentum,” says El Paso Stormwater Engineering Manager Gonzalo Cedillos. “You could be in a park and it might be raining up on the mountain. Fifteen minutes later you have this flood of water coming at you.”
Cedillos says the city has installed a fence to prevent cars from being swept into the retention pond where the 2014 incident happened. But the community has more than 360 stormwater ponds along with nearly 40 dams and basins, about 20 pump stations, around 6,000 drop inlets, more than 145 miles of storm drain conduits, 74 miles of stormwater channels, and 43 miles of agricultural drains.
Seeking safer solutions
“We, the engineers of America, have the smartest people in the country available to work on this,” says Ken MacKenzie, the master planning program manager for the Urban Drainage and Flood Control District in Denver and the Stormwater Committee chair for the National Association of Flood & Stormwater Management Agencies (NAFSMA).
His community also lost a firefighter in 2000 when he was sucked into a drainage pipe during a swift-water rescue. “That pipe should have had a safety grate. It would have saved his life. You hear a lot that we don’t want to put a grate over an inlet because it might cause flooding. When we put our heads together, we can come up with a standard design for inlet grates that will minimize clogging and will save lives.”
MacKenzie thinks safety grates could prevent some flash flood deaths that occur every year. “I realized that really what this nation is lacking is a national safety guidance document to help communities decide whether to put a safety grate on an inlet. Historically, local governments have been on their own to design what they think might work.”
The issue is, of course, that grates can collect debris and make flooding worse. If a grate is too small, it can increase danger to people because they could be pinned to the grate and drown. “Do we put on a safety grate and maybe save a life, or do we leave it off and save a neighborhood? It is possible to engineer a safety grate that will minimize clogging and maximize safety.”
MacKenzie has formed a group to look at such engineering guidelines. It includes representatives of the Environment and Water Resources Institute of the American Society of Civil Engineers, and the American Public Works Association. “There are some basic criteria to help,” he says.
His Urban Drainage and Flood Control District in Denver covers grates in its storm drainage criteria manual. It says a safety grate may not be needed only if:
- You can “see daylight from one end of the culvert to the other”;
- The culvert is 42 inches or larger in height; and
- Conditions in the culvert (bends, obstructions, vertical drops) or at the outlet are not likely to trap or injure a person.
It adds that inlets don’t typically require grates if stormwater won’t be more than 12 inches deep.
The second goal of the ad hoc group is to create a national public safety awareness campaign such as the National Weather Service’s “Turn Around Don’t Drown” program. MacKenzie hopes to build upon efforts of Mark and Lisa Blake of Cedar Rapids, Iowa. Their son, Logan, died in 2014 when he was swept into a drainpipe.
The Blakes have formed Project Storm Drain Safety (www.projectstormdrainsafety.org). “Our group is committed to helping Mark and Lisa, and moving their mission forward,” MacKenzie says. He has pledged $100,000 in matching funds for any branch of the federal government that will sponsor the national guidance document and a national public safety awareness campaign.
Several agencies have been approached but nothing formal has been arranged.
Safety and flood prevention
El Paso has been improving its stormwater infrastructure since citywide flooding struck in 2006 when the city received a year’s worth of rain, about 8 inches, in two days. Flooding caused more than $200 million in damage to homes and businesses and another $115 million in damage to the stormwater system.
A stormwater utility was formed in 2008 to help fund improvements based on a master plan developed by El Paso Water Utilities and a citizen advisory committee. “Year after year, to keep taxes down, maintenance was deferred,” Cedillos says. “Then we were given a dedicated fee so we had money and resources to go out there, clean it up, and put it back to its intended function.”
Then the real work began — a list of 100 large projects and another 200 smaller projects to reduce flooding. The original $650 million price tag has grown to about $800 million.
With phase one almost complete, the flood risk has been reduced by about 50 percent with more ponds, expanded street inlets, expanded water reservoirs, additional storm drains, the lining of earthen channels, and by enlarging culverts and road underpasses. “We’ve been ticking off the to-do list for the seven years I’ve been here, and I probably won’t see the end of the list,” Cedillos says. “When we started, we were in a reactive mode. Over the last seven years we’ve stepped into the proactive mode.”
The monthly fee was increased last year to help accomplish more of the projects on the master plan, but it’s still only about $4 a month for an average homeowner. For nonresidential property, the rate is $3.27 per 2,000 square feet of impervious area.
The city now does more to prepare for flooding and has even contracted with a meteorologist to help predict storm patterns as weather systems form over the oceans. As work continues, Cedillos wonders what future weather will mean to the plan: Last September, the city received 6 inches of rain in one day, while 4 inches rates as its 100-year storm. “We’ve been getting a very awkward change in intensity of rain,” he says. “I’ve been with the city for 37 years and never heard of a 6-inch rain; that’s a 500-year storm. Is that the new 100-year storm?”
Challenges of educating people about flash flooding
While the stormwater utility in El Paso, Texas, has become more widely accepted as people learn about how it protects the community from flash flooding, there are still those who don’t fully understand the details of how the protections work.
“We still have challenges of the community not understanding that some streets function as a channel to carry water,” says Christina Montoya, the communications manager for El Paso Water Utilities. “We’re trying to educate them that that is the way it was designed.”
Since flash flooding is a rare event, only once or twice a year in El Paso, it’s more difficult to get people to realize how all the infrastructure works and what they can do to stay safe. So the community began using the “Turn Around Don’t Drown” educational campaign from the National Weather Service in July 2015 to help increase knowledge of the general public.
EPWU partnered with the El Paso County Water Improvement District, which manages many irrigation channels in the region, and the city’s Office of Resilience and Sustainability. With three agencies providing funding, they were able to do a larger advertising and promotional campaign.
It included print and digital billboards across the city. “They not only featured ‘Turn Around Don’t Drown,’ but other taglines and photos,” says Montoya. “One said, ‘Storm drains can be deadly,’ with a picture of a man being rescued. Another said, ‘Flash floods can kill in a flash,’ that featured a photo of an SUV trapped in flood water.” There was also a 30-second public service announcement in English and Spanish that ran on radio and was posted on YouTube.
The effort began with a kickoff news conference at the location where several vehicles were swept into a stormwater retention pond after being caught in floodwater. “All the media turned out for the news conference and did stories,” says Montoya. It was followed by live appearances on various radio and TV programs.
“We also work with the media and TV meteorologists and ask them to give reminders when a storm is coming in,” adds Montoya. Social media is used prior to storms reminding people about “Turn Around Don’t Drown” and providing other safety tips. “The media is very cooperative and continues to use a lot of our information. If you look at last year compared to this year, the presence of the message is definitely amplified.”