Conservation Corner: Gross Reservoir and the Colorado River

For this issue of Conservation Corner, it seems appropriate to consider new developments regarding the proposed expansion of Gross Reservoir, and the associated problems affecting the Colorado River. 

The environmental effects of the proposed Gross Reservoir expansion will be huge, if it goes ahead. Over 200,000 trees will be cut; there will be a massive quarrying/blasting operation to mine rock for concrete; trucks will travel up and down Coal Creek Canyon for years; and the Upper Colorado River will be further depleted. It will raise the dam by 131 feet and add 77,000 acre-feet of storage to support more urban sprawl in the greater metro area. Denver Water denies that it will support sprawl, but its contracts with various municipalities guarantee that to be the case.

On July 2, the Boulder County Commissioners approved a settlement agreement with Denver Water to conclude a Federal lawsuit, much to the dismay of many citizens and local conservation and environmental groups.

The Settlement Agreement

As background, when Denver Water completed the Federal reviews by the Army Corps of Engineers and the Federal Energy Regulatory Commission (FERC), it indicated it would begin construction on the biggest project ever undertaken in Boulder County. Boulder County asserted its authority to review and regulate the project under state law, known as 1041 authority. Denver Water challenged this authority in state court, but Boulder County prevailed. Then, in July of this year, Denver Water sued in Federal Court, asserting that Federal law superseded any state or local regulations, and that it did not have to submit to county review. It is that suit that resulted in the settlement agreement just reached.

Unfortunately, both the County Attorney’s office and the Commissioners discovered that all the Federal court precedents held that the FERC review would almost certainly be deemed to have precluded county regulation of the project, despite the fact that the environmental impacts and impacts on Boulder County and its residents were not addressed.  (I’ll skip the legal details of the precedents. They are horrible and make no sense, but there is little doubt that the Commissioners were right.) As a result, it was apparent that whatever could be negotiated in advance was going to be the best that could be achieved. County officials thus did the best they could in negotiations and then agreed to settle.

The settlement agreed to calls for Denver Water to pay Boulder County $12.5 million for a number of mitigation purposes—$5 million compensation to residents who will be directly affected, such as those residing near the reservoir, and a number of areas of environmental mitigation. In addition, 70 acres of land owned by Denver Water will be transferred to Boulder County and added to the Walker Ranch Open Space. Denver Water also agreed to limit the hours of truck traffic and to take various measures to reduce noise and production of dust.

Other Legal Action

The lawsuit by The Environmental Group (TEG), Save the Colorado, and several other environmental organizations is still active and has not been settled.

On the Colorado River

At the same time, while Denver Water plans to divert even more water from the Colorado River headwaters, the state of the river is ever more dire. Both Lake Powell and Lake Mead, the two main storage reservoirs at either end of the Grand Canyon, are both at their lowest levels since they were first filled. If we have one more winter as dry as the last one, the system will be in severe crisis. Lake Powell is close to losing the ability to generate power, and there are other significant problems.

The natural-color images above were acquired in March 1999, April 2005, May 2011, and April 2021 by the Landsat 5, 7, and 8 satellites. The images capture years with the two highest and lowest levels over the past 22 years. Image from NASA Earth Observatory.

A number of important matters governing management of the river are coming up for renegotiation, as well as a long list of long-festering issues. The current operating rules that were negotiated among the states who are party to the agreements on the use of the river expire in 2026, so a new set of rules is now being negotiated, at the same time that the current drought continues to manifest itself, with climate change exacerbating the problems.

The “Law of the River” has its roots in the Colorado River Compact of 1922. That compact has many problems, some of which are only now becoming apparent, but the root problem has been known for a long time. The states participating in the Compact are divided into the Upper Basin (Colorado, New Mexico, Utah, and Wyoming) and the Lower Basin (Arizona, California, and Nevada). Mexico also is on the river and has rights to water, one of the facts that was bungled in the Compact, along with ignoring the water rights of the various tribes along the river.  

The Compact intention is to allow the same amount of water to the Upper and Lower Basin States, but the way it was actually written guarantees major problems. It calls for the Lower Basin states to be delivered a fixed amount, amounting to one-half the average that had been measured during the 25 years preceding the agreement to the Compact. This measure is 7,500,000 acre-feet, measured at Lee’s Ferry, just below Lake Powell. Of course, that means that the Lower Basin states are supposed to always get that amount. Mexico’s portion was carefully allocated from the nonexistent surplus, and we now know from tree-ring studies that the period the Compact authors averaged was the wettest period in 400 years. In other words, the authors not only ignored the rights of indigenous tribes along the river, but they also divided up much more water than they actually had. Additionally, they specified that the Lower Basin would receive a fixed amount, rather than half of what actually came down the river from the snowpack in the Upper Basin states. Mexico’s allocation was to come half from the Upper Basin and half from the Lower, but given the premises, that made no sense in the real world.

The rest of the subject of the Colorado River, its management, drought contingency plans, and related topics will be left for another day and another article.