Stormwater plan presented to Rio Communities Council

RIO COMMUNITIES—As the monsoons continue to wet the Middle Rio Grande Valley, Rio Communities’ leadership is planning on how to maneuver the rainfall through and around the city.

HDR Engineering presented its stormwater plan to the city council last month, saying the last master drainage plan was completed in 2021.

Dan Pfeifer, the transportation hydraulics regional manager for HDR, told the council the company began its study by taking an inventory of existing drainage issues in the city, and also talked with the city’s maintenance department employees as well as both residential and commercial property owners about their concerns.

“This included a whole lot of incised and unstable ditches and channels,” Pfeifer said of the drainage deficiencies in the city. “Erosion is deteriorating roadways and we’ve seen busted pipes throughout the community as well.”

Pfeifer also said they discovered a lot of exposed and damaged utility infrastructure, much of which is on N.M. 47. He explained there are a lot of drainage issues along the state highway.

In studying the hydrological analysis, HDR determined a large volume of water and the discharge rate results in a large water shed into the region.

“This helps formulate a plan — an action plan to evaluate the discharge rates in the community,” Pfeifer said.

The HDR manager said they came up with a list of eight projects as a starting plan to deal with the stormwater drainage issues in Rio Communities.

“These are living documents and are typically updated every five years,” Pfeifer said. “As you go into the next five years, you can say what projects are done and what needs to be done in the future.”

One of the first areas looked at was on Manzano Expressway, where they found several culverts in a perched position, sitting up in the air. Pfeifer said water is dropping from the perched pipe and it’s continuing to dig in the ground, making it unstable.

“The one on N.M. 47 is one of the major outfalls in the community,” Pfeifer said. “Almost everything is going there. Everything leads to it, and there’s quite a bit of instability in there.”

Pfeifer told the council there are drop structures that are failing, and every concrete culvert is undermined at every intersection off N.M. 47.

“You have a large amount of sediment as well,” he said. “With improvements, we can stabilize that channel. It’s a (New Mexico Department of Transportation) channel, and this provides an opportunity to work together to improve conditions not only for them but for yourselves.”

Pfeifer said the city has addressed some stormwater drainage issues on Damon Street, where Pfeifer said there was “quite a bit of flow.” He told the council the improvements have been observed with water flow being captured into the N.M. 47 ditch.

Other improvements include a completed spillway on Chamartin Avenue that had completely failed.

“We did an emergency repair because the pavement around it had also failed,” Pfeifer explained. “We talked to the neighbors about the flooding, and we did a complete redesign of that and looked at a downstream pond. This was, I’m happy to report, completed.”

Pfeifer said drainage planning will include how much infrastructure the city is preparing for and potential future land use .

“Again, everything leads to Highway 47, and if it stays in the present condition, it only has a limited capacity,” he said. “We can’t over tax it at this point. If it stays in the present condition, it can’t handle more development.”

He advised the council the city needs more ponding areas and regional channels to handle the stormwater drainage issues. He said examples of channels can be anything from parks and soccer fields that could potentially catch the water flow.

While the city can continue to invest in completing what Pfeifer called spot repairs, he recommended city leaders plan for the future by stabilizing the outfalls, especially on N.M. 47.

“This drainage master plan is a guiding document — a living document,” Pfeifer said. “It’s a proactive approach to say the community wants to develop further out and also improve the life for the residents living here.”

Pfeifer recommends the city work with NMDOT so they can regulate and control the stormwater drainage into the channel.

“There is no plan right now, and NMDOT is just as nervous as you are,” he said, explaining that he’s been in conversations with the state agency. “They know it needs support and repair and it also really needs a redesign.”

Pfeifer also showed the council topographic information regarding the flow rate of water into the city, including the velocity and erosion conditions. He noted there are some uncontrolled channels streaming into Rio Communities.