Federal water managers have proposed a new plan aimed at protecting native fish species in the Grand Canyon, but some conservation groups argue it does not go far enough.
The Colorado River runs 277 miles through Grand Canyon National Park. This iconic stretch of river is home to several native fish species, including the humpback chub, which is found nowhere on earth besides the Colorado River system. The humpback chub was previously listed as an endangered species but was downlisted to threatened status in 2021, meaning it still receives protections under the Endangered Species Act although its population has somewhat rebounded.
Upstream from the Grand Canyon lies Lake Powell, the nation’s second largest reservoir, held back by Glen Canyon Dam, completed in 1963. Lake Powell began filling with water in the 1960s and was stocked with non-native fish such as smallmouth bass in 1982 to create recreational fishing opportunities.
Water levels in Lake Powell have been falling to historic lows in recent years as the region struggles to curb demand amid dry conditions fueled by climate change. As the reservoir’s surface drops, these non-native bass are able to swim deep enough to enter tubes inside Glen Canyon Dam, allowing them to pass from Lake Powell into the Colorado River below, where they compete with and prey on native fish.
Details of Draft Plan
On February 9, 2024, the Bureau of Reclamation, the federal agency managing western dams, released a draft plan detailing proposals for how best to manage water flows from Glen Canyon Dam. The goal is adapting water releases in a way that keeps native species thriving in Grand Canyon waters belowLake Powell.
The draft plan puts forth five new options for managing dam releases. Four of these options focus on making the water cooler at certain times, in order to disrupt spawning of non-native fish. The fifth proposes that no change be made to current operations.
Issues Raised by Conservation Groups
While intended to aid native species conservation, the draft plan has drawn criticism from some environmental organizations. Taylor McKinnon, Southwest Director for the Center for Biological Diversity, takes issue with two key aspects.
First, McKinnon argues the Bureau should consider tangible physical changes to Glen Canyon Dam’s intake structures themselves, like adding screens to block non-native fish passage. He states the agency has skilled engineers who should have developed such solutions already if they prioritized this issue.
Secondly, McKinnon claims the plan does too little to evaluate the long-term viability of Lake Powell as the region’s climate becomes hotter and drier. He advocates agencies take a more proactive approach of assessing forecasts for future Colorado River flows and acknowledges the potential for Lake Powell to face what is known as “deadpool” – when waters drop so low they cannot pass through Glen Canyon Dam. Some groups argue this inevitability means the dam and reservoir should be decommissioned.
Public Comment Period and Path Forward
The Bureau of Reclamation’s draft plan is now in a 45-day public comment period running from February 9th to March 26th, 2024. Stakeholders and citizens have the opportunity to weigh in on proposals before the Bureau determines next steps for finalizing a strategy to protect the Grand Canyon’s threatened native fish.
Cover photo courtesy of: Utah Division of Wildlife Resources