General Information
Lake Powell Pipeline Project
Frequently Asked Questions
  1. What is the purpose of the Lake Powell Pipeline Project (Project) and when is it needed?


  2. The Project is to meet the future water needs of rapidly growing Southwestern Utah. Based on the water supply currently available and what could be developed in the future for the area, as well as projected population numbers provided by the Governors Office of Management and Budget, we believe it is time to start work on the preliminary environmental and technical studies for the Project. It now appears an additional source of new water, possible from Lake Powell, will be needed in the area by 2025.

  3. Isn’t the Colorado River over used already?

  4. Not in the Upper Colorado River Division States. In 1922 when the Colorado River Compact (Compact) was negotiated, the negotiators had only 20 years of water supply records on the river. At the time the Colorado River had an average annual flow of about 18 million acre-feet (maf). The Compact divided the Colorado River basin into two basins, with the dividing point at Lee Ferry about 15 miles below Glen Canyon Dam. The Upper Colorado River Division (UD) states are Colorado, New Mexico, Utah and Wyoming and the Lower Colorado River Division (LD) states consist of Arizona, California, and Nevada. The water was divided evenly with each basin receiving 7.5 maf. The UD states also agreed to deliver 75 maf (7.5 maf per year) over a ten-year running average to the LD states. The compact negotiators felt the states would meet again in 50 years to divide up the rest of the water. We now know the river was flowing at an all time high between 1900 - 1920. With an additional 80 years of water supply records, we now know the average annual flow of the river is about 15 maf. In addition a treaty was signed with Mexico in 1944 giving it the right to 1.5 maf annually. This leaves about 13.5 maf to divide between the UD and LD states. Since the UD states guaranteed, the LD states would get their 7.5 maf of water first we now believe the UD states will only be able to develop about 6.0 maf annually not the 7.5 maf listed in the compact. The UD states are currently using about 4.2 maf of their annual supply leaving about 1.8 maf of water to be developed in the Upper Colorado River Division States.

  5. If the Lake Powell Pipeline Project is constructed won’t someone in the Lower Colorado River Basin lose part of their water supply?

  6. No. The Lower Division states have developed and are currently using their entire Colorado River allocation. At times when surplus water has been available such as the 1980's when the flow of the river exceeded 20 maf annually for several years, the LD states received more than their compact allocation of 7.5 maf. But since the beginning of the drought in 2000 the LD states have received only their Compact allocation of 7.5 maf each year from the Upper Division.

  7. Does Utah still have water in the Colorado River it can develop and put to use?

  8. Yes. Utah received 23% of the UD states allocation estimated to be about 6.0 maf, leaving Utah about 1.37 maf. Utah is currently depleting about 940,000 acre feet (af) leaving approximately 400,000 af of water to put to use. The Lake Powell Pipeline Project will deliver about 86,000 acre-feet (af) or 1/5 of Utah’s remaining allocation of Colorado River water to Southwestern Utah.

  9. What are the water quality issues of the Lake Powell Pipeline project?


  10. As part of the EIS process the water quality impacts of diverting 100,000 af of water annually from Lake Powell will be reviewed. One potential impact could be the increase in salinity caused by the depletion of water by the project. The Colorado River Basin States have already developed the mitigation for any increase in salinity in the river water delivered to the LD States and Mexico, with the passage and funding of the Colorado River Basin Salinity Control Act in 1974 by Congress. All seven basin states continue to participate in the salinity control program with the US Departments of Interior and Agriculture with the objective of allowing continued water development by the UD states while at the same time reducing the salt load in the river. Since its inception, the salinity control program has prevented more than 1.0 million tons of salt annually from entering the Colorado River.

  11. What is the present per-capita water use in Southwestern Utah?


  12. Based on reports recently published by the Utah Division of Water Resources on its web page entitled, “Municipal and Industrial Water Supply and uses in the Kanab Creek/Virgin River Basin” the per-capita water use for 2010 is shown in the following table.



  13. How will global warming affect the project?


  14. It is impossible at this time to determine what if any impact’s global warming will have on this or other projects in the Colorado River basin. Since global warming impacts will occur slowly, the Department of Interior and Colorado River Basin States will have the time to modify the operation of the reservoir system to compensate for the impacts of global warming.

  15. Will this project affect the amount of power generated at Glen Canyon Dam?


  16. The construction of the Lake Powell Pipeline Project or any project by the Upper Division States does not impact the amount of water being released annually from the Upper Basin to the Lower Basin and Mexico which is 8.23 maf. In most years this entire supply goes through the Glen Canyon Dam turbines. As the UD States continue to develop their Colorado River Compact allocation the water level at Glen Canyon dam will be lower reducing the head on the turbines. The amount of power generated from time to time from the unused water allocation of the UD States is expected to decrease as the UD states continue to develop their compact apportionments. Such changes were envisioned and authorized in the Colorado River Storage Project Act. At full development, it is estimated the Lake Powell Pipeline would lower the water level in Lake Powell by less than a foot in any given year

  17. Is Lake Powell a reliable source of water?


  18. The facts are the Lake Powell Pipeline Project (LPPP) will likely have one of the best water supplies and water rights in the Upper Colorado River system because the project will divert directly from Lake Powell at the bottom of the Upper Colorado River Basin. There are very few diversions in Utah directly from the Colorado River. The majority of Utah’s use of its compact allocation is diverted from tributaries to the Colorado and Green Rivers. For example most of the uses in the Uinta Basin as well as the diversion by the Central Utah Project come from the diversion of tributaries to the Green River such as the Uinta and Duchesne Rivers. In the Price/San Rafael, San Juan, Escalante, Fremont and Mill Creek River Basins almost all of the diversions come from tributaries to the Green and Colorado Rivers. When we have a drought in Utah those using the tributaries are the first to feel the impacts of the drought as the streams begin to dry up and they start to experience shortages. If the UD is ever required to reduce its water uses so it can meet its compact allocation to the Lower Basin it is likely Utah water users will have already made most of the cuts they may be required to make, because of the shortages they will already be experiencing on the tributaries. The State Engineer has said, he believes with the LPPP water rights and point of diversion being from Lake Powell makes it one of the most firm water supplies in Utah’s part of the Upper Colorado River Basin.