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1075' - Shortage on the Colorado River Ep. 4 - CAGRD (Dennis Rule) | CLIMAS


1075' - Shortage on the Colorado River Ep. 4 - CAGRD (Dennis Rule)

Tuesday, August 5, 2014

Lake Mead from the Hoover Dam - Source: Wikipedia Commons

1075’ – Shortage on the Colorado River is a CLIMAS podcast series that explores what the first ever shortage declaration on the Colorado River would mean to those living in the Southwest. 

1075 refers to the elevation of Lake Mead – in feet above sea level – that serves as the trigger for shared shortage restrictions[1]. While this has never happened before[2], after years of drought and ever-increasing demands on the river, the latest projections from the Bureau of Reclamation suggest the lake could drop below 1075[3] as soon as early 2015.

In this series, we attempt to demystify the rules and regulations that govern water use on the Colorado River and discuss what it means to the people and sectors across Arizona when a shortage occurs. This series will explore the opportunities and consequences of a shortage to construct a nuanced view of a complex issue.

  • Episode 4: The Central Arizona Groundwater Replenishment District (Dennis Rule) - In this episode, CLIMAS climate scientist Zack Guido talks to Dennis Rule, manager of the Central Arizona Groundwater Replenishment District (CAGRD), about the importance of CAGRD in the management of Arizona groundwater and potential impacts on the system from continued drought in the Colorado River Basin.


Dennis Rule is the Manager of the Central Arizona Groundwater Replenishment District (CAGRD).  In 1993, the legislature created a groundwater replenishment authority to be operated by the Central Arizona Water Conservation District ("CAWCD") throughout its three-county service area. This replenishment authority of CAWCD is commonly referred to as the Central Arizona Groundwater Replenishment District ("CAGRD"). In 1999, the legislature expanded CAWCD's replenishment authorities and responsibilities by passing the Water Sufficiency and Availability Act. The purpose of the CAGRD is to provide a mechanism for landowners and water providers to demonstrate an assured water supply under the new Assured Water Supply Rules ("AWS Rules") which became effective in 1995. Every ten years, the CAGRD is required by law to submit a Plan of Operation to the Director of ADWR. The Plan describes the activities that CAGRD proposes to undertake in the Phoenix, Pinal and Tucson Active Management Areas ("AMAs") over the next one-hundred years based on continued membership enrollment through 2015.

[1] Note: Mead elevation falling below 1075' in a given month does not automatically trigger shortage restrictions. The January 1st forecast from the August 24-month study is the Mead elevation value that determines if a Tier 1 Lower Basin shortage will occur. The 24-month study is a monthly report produced by the Bureau of Reclamation to keep track of Colorado River system reservoirs. So even if Lake Mead is forecasted to drop below 1075' in mid-2015, shortage is not declared unless the 2014 August 24-month study forecasts a January 1st Mead elevation at or below 1075'.

[2] Any shortage before 2026 would be the first declared shortage under the 2007 Interim Guidelines. However, there was a shortage declared in 1963/1964 when Lake Powell was filling up. Drought caused low inflows into Lake Mead and deliveries to the Lower Basin were subsequently cut.

[3] The Applied Climate Science Group in the School of Natural Resources at the University of Nebraska-Lincoln has compiled an impressive array of photos and data relating to the drop in Lake Mead levels - be sure to check it out!

Many thanks to Dr. Mohammed Mahmoud (of the Colorado River Programs / Central Arizona Project) for providing the clarifications in footnotes [1] and [2].