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San Juan-Chama Water Supply Project - The Wow Factor

on October 5, 2012 - 10:17am

Staff Report

At the Tuesday, Oct. 3 County Council meeting, Deputy Utilities Manager - Engineering, James Alarid of the Los Alamos County-Department of Public Utilities (LAC-DPU), led a presentation providing the details of a preliminary engineering report regarding access to Los Alamos County’s contracted 1,200 Acre-Feet-Per-Year (AFY) of water from the San Juan-Chama Water Project. 

Council took no action on the information presented.

The LAC-DPU has chosen a preferred alternative for developing the County’s share of San Juan-Chama project water. (Five alternatives were evaluated. See the links at the bottom of this story for more details.)

Alarid explained that older wells are becoming less productive and will need to be replaced.  Alarid also said that water rights can be questioned if not used, although he noted that there are no eminent challenges to the Los Alamos San Juan-Chama water rights at the current time. 

The county is using 75 percent of its 5,541.3 AFY groundwater water right, but has used more than 90 percent in the past. Alarid went on to explain that LANL expects to use more water for its next supercomputer installation expected as soon as 2016. Alarid also noted that there is the potential for household growth in Los Alamos that must be planned for.

The preferred LAC-DPU alternative is to develop wells at the edge of White Rock Canyon at the rim before the canyon drops steeply to the river level below. 

The wells would be 1,200 feet deep, which would create wells that surface at the top ridge of White Rock Canyon and go straight down to a depth just below the surface level depth of the Rio Grande. 

The wells are designed to capture water that would otherwise travel into the Rio Grande River if not intercepted by the wells.

Water from these new wells would be piped to existing Pajarito Booster Station No. 1 for use throughout Los Alamos County.

The San Juan-Chama Project.  Courtesy/LAC-DPU

Water Allocations of the San Juan-Chama Project. Courtesy/Bureau of Reclamation

Los Alamos Water Project Alternatives Map. Courtesy/LAC-DPU

The County has rights to 1,200 AFY of San Juan-Chama project water.  The San Juan-Chama water currently flows through the Rio Grande and is stored in the Abiquiu Reservoir until it is currently leased to the Bureau of Reclamation for release to downstream users.

The State Engineer’s Office must confirm that the proposed groundwater wells are collecting water that would have flowed into the Rio Grande.

If this preferred alternative is built, the County will intercept water destined for the river and release an equal amount of water from the county’s 1,200 AFY allotment and thereby breaking even, so to speak.

The water Los Alamos “uses” from our San Juan-Chama allotment stored at Abiquiu Reservoir will not be leased back to the Bureau of Reclamation, but it will be released to downstream users as before.  What will not reach the river as before will be the water Los Alamos County captures in the new wells.

Los Alamos has the legal right to 1,200 AFY of San Juan-Chama water and by taking water destined for the Rio Grande and releasing our stored San Juan Chama water, the County is in effect “using” the County’s San Juan-Chama water allotment instead of leasing it back to the Bureau of Reclamation.

It is unknown at this time if a single well will provide the county with the 1,200 AFY that is legally available to Los Alamos County.  In the case that one well does not produce enough water, two more well sites have been selected, if tests prove one or both of these additional groundwater wells are needed to reach 1,200 AFY capacity.

Proposed White Rock Canyon Rim Groundwater Well Sites #1, 2 and 3. Courtesy/LAC-DPU

The southern most well, site #3 (seen at the bottom of the above map) will be the first well dug in order to determine its potential. Well site #3 will be considered a “test” well, but if productive, is scheduled to be put into full production after the test is completed.

Well sites #2 (middle site) and #1 (top right site) could be added, if necessary, to reach the goal of a 1,200 AFY draw down of the San Juan-Chama water rights.

The LAC-DPU engineers and engineers/geologists from the consulting firm CDM Smith were clearly excited about another alternative plan that involved drilling a slant tunnel from the White Rock town elevation down to the river elevation.

In this alternative, water would be pumped up to an existing White Rock Booster Station from a collection tunnel dug below the river bottom.

Alarid described the tunnel alternative as having a big “wow” factor among engineers, but the problem with this alternative is that it also carried a “wow” price tag for the cool engineering challenges.

The tunnel alternative had a price tag of approximately $59 million and was not selected as the recommended alternative.

The recommended alternative of using groundwater wells on the White Rock Canyon Rim has a price tag of approximately $27 million, if all three wells are required. A savings of just under $10 million is possible for each well that is not required.

Using the rim groundwater wells alternative also saves money as no water treatment facilities are necessary for this type of water source. The LAC-DPU would treat the groundwater wells with chlorine to make the water potable. Alternatives that use water directly from the river require an expensive surface water treatment plant in order to make the water potable.

Proposed White Rock Well Site #3 (Red Circle.) Terrain Map Data (c) 2012 Google. Click Here to view full Google terrain map of area.

A “test” well at site #3 will be drilled beginning in the next couple of months, if all goes as planned.

If all three wells are required, the entire project is expected to be completed by June 2017. If two wells are required the project will be completed by January 2017. If a single well is able to provide the 1,200 AFY necessary, the project can be completed by June 2016, according to current project estimates.

The Los Alamos Daily Post will provide continuing coverage of further developments regarding the San Juan-Chama Water Supply Project. 

To view the full LAC-DPU slide presentation provided to the Los Alamos County Council, click HERE. This link provides larger images of the alternatives and well site maps found above.

To read background on the Chama River Project from the Bureau of Reclamation, click HERE.

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