New Alcoa Dike Floodgate To Help Protect Corona Community

The Los Angeles District completed the installation of a 19-ton floodgate March 10 on the Alcoa Dike alongside the Temescal Wash in Corona, California.

The new floodgate bisects Auburndale Street about two and a half miles northeast of the Prado Dam and Spillway and is designed to help keep water within the flood basin and prevent flooding of the street and nearby structures — all while accommodating through traffic during normal conditions.

The gate and adjoining concrete floodwall will be integrated into the three-quarter-mile-long Alcoa Dike, which runs parallel to Temescal Wash — a tributary of the Santa Ana River. Auburndale Street is one of three street crossings on the dike embankment, and the floodgate is the only one in use in the system.

“There are different options of how you navigate those crossings: You either need to create a new road to go around, you need to have a road that would go over top of the dike or you would have to have a floodgate that would allow cars or water to pass through the dike if you’re going to keep the same roads open for infrastructure,” said Capt. Sean Hutchison, project engineer for the Alcoa Dike Phase 2 project and deputy project manager for Prado Spillway.

“As part of this project, we actually are doing all three,” he said.

For the other two dike crossings, Hutchison said the Corps rerouted part of Rincon Street to go up and over the top of the embankment for the second crossing and, for the third, built a new thoroughfare called Butterfield Connector Road to go around the dike.

Throughout the project, Hutchison said, the LA District has been in close coordination with community partners like the City of Corona, including attending city council meetings to provide quarterly updates about project progress and how the work is anticipated to affect community members’ daily lives, as well as distributing informational fliers to residents and local businesses.

“We focus on partnership here in the Corps,” Hutchison added. “There’s always challenges, and there are people who live in the community and use this road to get to work. This road over here, Rincon, is very popular, driven from people coming from Norco, East Vail or Chino to get over here to this neck of the woods.”

The floodwall, into which the contractor placed the floodgate, will complete the connection between the floodgate and embankment on both sides once the overall dike project is complete. Four different utility lines run beneath the project site, something Hutchison said required both significant technical work from the contractor and extensive collaboration with community partners, such as the City of Corona, Orange County and Southern California Edison.

“It looks as if you just see a concrete wall, but it’s actually a lot more than that,” Hutchison said. “Underneath this was an existing, regular road that went through here. Our contractor had to tear it up, put in a new line, a bypass for a sewer system, a domestic water line for the city, and then they had to build up a significant foundation.”

The gate itself swings 180 degrees to open and close and includes a push/pull bar to facilitate manual operation, if needed. Hutchison said it’s only the second floodgate of its kind in the Los Angeles District.

“It’s extremely heavy — it’s 19 feet high, 36 feet wide and about 2-and-a-quarter-feet thick — so it’s quite the feat to put that thing in there,” he said.

“It’s been a fantastic morning to get to witness our contractors, our partners, install this gate safely and very professionally,” said Col. Julie Balten, LA District commander, who was at the site to watch the gate installation. “We’re here to be able to help protect businesses and communities from potential flood risk. We take pride in the safety of our communities, and we can’t do this alone. It requires the partnership with our contractors to deliver these great projects that we have here in Southern California.”

“Our contractors are great,” Hutchison said. “They’ve been extremely flexible, and they work really hard. They prioritize safety. They prioritize quality. And, there are all the people on the USACE team: We have a great safety team, and we have people working hard for us in engineering, along with the project management team and the construction folks on the ground to make all of this happen.

“I love working for the Corps,” Hutchison added. “It’s an awesome organization. It’s so cool being able to come out here and see the actual changes that we’re making. We’ve had a very wet winter — a lot of water. We’ve seen a lot of these roads flood out, and there’s a lot of water behind the dam, so, it really brings meaning and purpose to everything we’re doing and working hard for on a regular basis.”

Travis Tutka, acting Dam and Levee Branch chief for the Corps’ headquarters in Washington D.C., who was in town to speak at the Society of American Military Engineers gathering about the Corps’ dam safety and resilience efforts, joined Balten, Hutchison and other LA District leaders, engineers and safety specialists to witness the floodgate emplacement.

“I timed it beautifully to come out here and see this wonderful floodgate get put up today, and it was an impressive sight to see,” Tutka said.

“When it comes to flood risk management, there’s a lot of choices for our communities to figure out how best to deal with what Mother Nature is going to throw at us,” he added. “It takes years of study to look at the options and look at what the hazards are, and one of those options is this wonderful structure and infrastructure like this that can help protect the communities from what comes down the rivers at us.”