Drop 2 Reservoir Index
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• It is a system efficiency project that will help conserve Colorado River water that would otherwise not be put to beneficial use in the United States. Conserving this water and making it available to users in the United States will reduce the amount of water that must be released from storage at Lake Mead.
• It will consist of an all-gravity, off-stream storage reservoir system located north of the All-American Canal and Interstate 8 near Drop Structure No. 2, about 30 miles east of El Centro, CA, and 25 miles west of Yuma, AZ.
• It is not part of the All-American Canal Lining Project.

What is the project’s purpose?

• The project will support conservation of water by capturing non-storable flows resulting from operational mismatches that occur in the Lower Colorado River Basin, and subsequently make those flows available for users in the United States. (Non-storable flows are defined as those flows that cannot be captured and stored for later use.)
• At times, users downstream of Parker Dam reduce or cancel their water orders when rain events or other circumstances change their water needs. Depending on operational circumstances at the time, the water cannot always be stored for later use.
• Because there is limited storage capacity below Parker Dam, primarily at Senator Wash Reservoir north of Yuma, some or all of the water that is ordered but not taken is non-storable.  These non-storable flows average 70,000 acre-feet per year.  Generally, this water flows into Mexico at Morelos Dam but does not count toward the United States’ annual water delivery requirement to Mexico, pursuant to the 1944 Treaty between the United States and Mexico.
• In 2005, the Bureau of Reclamation, in collaboration with multiple stakeholders, completed a study which identified several potential alternatives to address this issue; the Drop 2 Storage Reservoir Project was the preferred option.
• In December 2006, Section 396 of Public Law 109-432 directed the Secretary of the Interior, “notwithstanding any other provision of law and without delay” to “design and provide for the construction, operation, and maintenance of a regulated water storage facility ... at or near the All-American Canal.”

• Non-storable water from the Colorado River will be diverted into the All-American Canal at Imperial Diversion Dam, then into the Drop 2 Storage Reservoir. The water will then be released back into the All-American Canal for delivery to and use by the Imperial Irrigation District according to an approved operations plan.

• They are: an 8,000 acre-foot capacity reservoir comprised of two 4,000-acre-foot capacity storage cells; a diversion structure from the All-American Canal; a 6-1/2 mile-long inlet canal to carry diverted water to the reservoir; and a 1/4 mile-long canal/siphon system to take the water from the reservoir back to the All-American Canal just downstream of Drop 2.

• The estimated construction cost is $172 million.
• In response to drought conditions in the Lower Colorado River Basin, the Secretary of the Interior has adopted interim guidelines for Lower Basin shortages and coordinated operations of Lake Powell and Lake Mead. These guidelines allow Colorado River water contractors in the lower basin to contribute capital for use in Interior projects designed to create a more efficient water management system by conserving water that would otherwise be lost from the Colorado River mainstream in the United States. The guidelines also allow the Secretary to make available to these contractors an amount of water equal to a portion of the water projected to be conserved over a the life of the project, and to release this water to the contributing contractors on a pre-determined schedule of annual deliveries for a specified period of years.
• The Drop 2 Storage Reservoir Project is a system efficiency project. The Southern Nevada Water Authority (SNWA) has agreed to pay most of the project's cost (including the cost of construction of the confluence structure of the project), as well as its operation and maintenance costs for a specified period of time. In return, SNWA will receive 400,000 acre-feet of water, at a maximum of 40,000 acre-feet a year, until 2036.
• The Central Arizona Water Conservation District (CAWCD) will provide $28.6 million for construction of the project. In return, CAWCD will receive 100,000 acre-feet of water, at maximum of 65,000 acre-feet a year, from 2016 through 2036. (This amount is reduced by the amount of water used by SNWA and/or the Metropolitan Water District of Southern California in any given year.)
• The Metropolitan Water District of Southern California is also participating in the project at the same funding level for the same amount of water as CAWCD.

• The Bureau of Reclamation will issue requests for proposal for the project, and will manage the construction. Construction is scheduled to begin in fall 2008, and be completed in 2010.

• The project will not affect the water allocation of any Colorado River water user, including Mexico.
• All construction contractors will be required to meet applicable local, state and federal requirements for air quality, water quality, cultural resources protection, noise abatement, erosion control and other standards.
• Excavated materials will be used to construct canal and reservoir embankments, so there will be very little, if any, waste material.
• The project will be operated to minimize the amount of time water will be in the reservoir, so there will be no water stagnation.
• Recreation sites currently open to the public will continue to be accessible during and after construction, and a crossing will be constructed to provide access to these sites at the end of an existing county road adjacent to privately-held lands and the inlet canal to the reservoir.
• The inlet canal was aligned to minimize the impact on the Flat Tailed Horned Lizard Management Area, while staying outside the boundaries of privately-held lands in the area.

Will traffic be affected by project construction?

• An approximate 4-mile stretch of Evan Hewes Highway near the old Brock Research Experimental Farm will be closed for the duration of the project. Access to the unaffected portion of the highway will still be possible by exiting Interstate 8 north at Gordon's Well, approximately 4-1/2 miles to the east.
• A one-mile stretch of Interstate 8 will be detoured onto Evan Hewes Highway for approximately 4 months while pipes are installed under the roadway.
• Access to the Imperial Sand Dunes Recreational Area, and the Gordon's Well area will be preserved.
• Areas of the Evan Hewes Highway affected by project construction will be rehabilitated at the conclusion of the project.
• All detours and closures will be coordinated with Imperial County and Caltrans with outreach to all affected parties.

What was the project's environmental review process?

• The Bureau of Reclamation prepared an Environmental Assessment that analyzed potential effects on resources associated with various project alternatives.  The Environmental Assessment also identified several Best Management Practices to avoid, minimize or compensate for potential project effects.
• Through an Environmental Determination, Reclamation selected the Proposed Alternative to implement the project and satisfy its Congressional mandate.  As part of the decision, Reclamation may also implement several Best Management Practices described in the Environmental Assessment.