Cochiti Dam is one of the largest earthen dams in the country. The Rio Grande was transformed after the U.S. Army Corps of Engineers finished building it in the 1970s.
Some communities downstream experienced serious negative impacts, and the river's ecosystem suffered.
But a lawsuit may have federal water managers shifting the way they manipulate water flows out of the dam to support wildlife.
On a blustery day Steve Harris, who has been boating rivers for almost half a century, blew up an inflatable blue raft and rowed out onto the Rio Grande, downstream from Cochiti Dam.
“The riverbanks are probably 12 feet overhead right here,” Harris pointed out, “and even at the highest flows the river really doesn’t connect to its floodplain, so it stays within its banks, and that’s kind of by design.”
Harris said before the dam was built, the river was shallow and wide, with graceful meandering curves. But nowadays the channel is deep and narrow, and ecosystems have crashed in some places.
“My question is just how many insults can a river take before it stops functioning?” Harris asks. “We live on this incredibly dynamic planet and we share it with all kinds of creatures. It makes life worth living.”
We have a responsibility to protect those creatures, Harris said, like the endangered silvery minnow, the southwestern willow flycatcher, and the riparian habitat they need to survive.
“And we’re mandated to because of the Endangered Species [Act]!” he exclaimed.
The river gets wider when it crosses onto Santa Ana Pueblo where the tribe has been restoring wetlands. Invasive plants have been cleared along the banks and replaced with native willow and cottonwood. There are side channels that form marshes.
The boat scrapes against some rocks that were placed in the river to slow the flow and prevent erosion.
“This is a restoration project,” Harris said. “This stack of rocks that’s extending out from the banks, that’s using natural materials to deflect the river current.”
Harris said a lot of groups and agencies are working together to mimic historical flows in the river, but it’s tough when you run up against the flood control objectives.
“Cochiti Dam was authorized primarily for flood control, and operated exclusively for flood control,” explained Ryan Gronewold, the Chief of Reservoir Control in Albuquerque for the U.S. Army Corps of Engineers.
Gronewold said they built Cochiti Dam to protect Albuquerque from flooding, and that’s all they’re allowed to do. “It’s very narrowly defined,” Gronewold said. “Congress told us exactly how we were to operate.”
The Flood Control Act of 1960 says that the dam is also for sediment control, and later recreation and wildlife habitat were included.
Then the Endangered Species Act was passed in the mid-1970s, which requires federal agencies like the Corps to assess how their actions could affect vulnerable species.
But Gronewald said that didn’t change the mission of Cochiti Dam, where floodwater is captured then released over time.
“The Endangered Species Act didn’t say you’re going to operate all of your dams differently,” Gronewald said. “There are negative effects to the riparian habitat, but that’s not really our concern.”
The environmental group WildEarth Guardians said endangered species like the silvery minnow and southwestern willow flycatcher have taken a hit.
The group has sued federal water managers, including the Corps, multiple times under the Endangered Species Act.
As recently as 2010 the Corps deviated from their normal operations and released water out of Cochiti for the benefit of the endangered species.
“When they did that it created this large pulse in the river that would have happened historically, and really helped the species,” said Jen Pelz, who is with WildEarth Guardians.
“We’re trying to hold the Corps accountable to step up and have the river have a seat at the table,” Pelz explained, “so while we are allocating water to different uses, we’re being mindful of the fact that the river also has a water requirement that needs to be met in order to keep the environment healthy.”
Pelz said it’s odd that the Corps has now made a 180, and is saying they don’t have the discretion to modify their operations.
The judge hearing the latest suit against the Corps has said it can advance. Pelz said that is a huge step.
Back on the banks of the river, Nathan Schroeder points out improvements they’ve made in the riparian zone. He runs the Bosque Restoration Division at Santa Ana Pueblo.
“Everybody is looking for a silver bullet, and there isn’t one,” Schroeder said. “So when people say we just need to do that one thing and we need to do it a lot, that’s never the case.”
Here they’ve changed the grade of the river in a few different spots, and re-sculpted the banks.
“We ended up creating a floodplain in a spot where there was a sheer 15 foot drop off,” Schroeder said. “All the trees have survived, all the grasses have just exploded, and this is a real win for us!”
Santa Ana Pueblo partnered with the Corps on some of these projects for over a decade and Schroeder said these ‘wins’ wouldn’t have been possible without their support.