New Mexico’s newest volcano has proven to be environmentally beneficial as well as being a fascinating landmark. The man-made volcano houses a one-of-a-kind flood control system designed to divert and aerate stormwater, thus protecting Albuquerque’s South Valley, as well as improving the quality of the stormwater before it flows into the Rio Grande River. Studies of the river have shown that just after a storm, there can be an area of 0 Dissolved Oxygen (thought to come from the stormwater) that causes fish kills.
During area rain events, stormwater rushing downstream from Nine Mile Hill gravity-feeds along an improved arroyo into a series of increasingly smaller diameter CCFRPM (Centrifugally Cast Fiber Reinforced Polymer Mortar) fiberglass pipes, creating a pressurized water spout that shoots the stormwater 6 to 8 feet above the “crater” to simulate a volcanic eruption. This process aerates, increases the dissolved oxygen, in the stormwater to benefit fish in the Rio Grande River. The water then continues down the channel into the city’s underground stormwater system and eastward toward the river, away from its former southward path where it frequently flooded the city’s South Valley. This controlled flow also facilitates the collection of trash and debris in three settling basins where it can be easily removed before entering the river.
Various decreasing diameters of Hobas CCFRPM pipe were selected to facilitate the volcanic eruption design. In all, the “Stormwater Volcano” contains 700 feet of 48-inch pipe, 15 feet of 30-inch pipe, and 150 feet of 18-inch pipe. Special fittings and a custom-built reducer enabled the pipes to feed into the bottom of the structure.
Designed by Wilson & Company for the Albuquerque Metropolitan Arroyo Flood Control Authority (AMAFCA) as the final phase of their West I-40 Diversion Channel Phase IV Project, engineers from both organizations worked closely with the University of New Mexico Hydraulics Lab to erect a 1:36 scale model to make sure water stayed in the channel. Salls Brothers Construction served as the general contractor.
“At first we didn’t know if the volcano idea was going to work,” admitted Tyler Ashton, PE, PMP, CFM with Wilson & Co. “Placing an obstruction in a high-velocity channel is challenging.” Although it is a gravity system, internal pressures exceeded standard storm drain pipe capacities as the stormwater was pushed through the series of smaller diameter pipes to increase the pressure to 14 psi.
Why a volcano?
This rocky, conic structure perfectly camouflages the pipe system. This area, locally known as El Pedregal (The Stony Place), is located near Albuquerque’s ancient volcanoes west of the city. Although this volcano is formed of concrete, it is covered with rocks and boulders reclaimed from the adjacent area.
By night and on holidays, the volcano presents a light show, thanks to clever LED lighting. To further the illusion of a volcano, the project improved approximately 4,000 feet of unlined arroyo with a shotcrete lining tinted red and black.
The volcano concept also conforms with the FHWA Interstate Corridor Enhancement Plan (ICEPlan) that encourages communities to improve the aesthetics of Interstate highway corridors in their areas by incorporating local geographic, historic or cultural artwork.