Sheehey: Facts About Water In Los Alamos

By PETE SHEEHEY
Los Alamos County Councilor

One of the major issues in this town is water: do we have enough to keep this a green community, at an affordable cost? Since I was elected to County Council two years ago, I have been gathering facts about water in Los Alamos. Much of this information is in the “2006 Long Range Water Supply Plan for Los Alamos County”, on the county website here.

If we can agree on the facts and the uncertainties, I think the citizens of Los Alamos are likely to agree on good plans and policy regarding water. Here, I will discuss our water supply and demand, threats to our water supply, possible future water needs, and some ideas on responsible water policy for Los Alamos. I welcome any additional facts and thoughts on the subject.

1. Supply and Demand

Despite continuing drought conditions, Los Alamos County is fortunate to have an ample source for very high quality water: the Santa Fe Group (sometimes called Santa Fe Formation) aquifer that lies beneath the entire county and beyond. Our county has 12 water supply wells that are from 1,500 to 3,100 feet deep. The aquifer tapped by these wells is estimated to be between 1,150 feet and 6,000 feet or more below the plateau.

However, our knowledge of the quantity and quality of water available from this aquifer is limited to depths and locations studied; experts differ in opinions about how thick and extensive the high-water-yielding portions of the aquifer are.  The aquifer’s recharge rate (from precipitation on the Jemez Mountains and adjoining Valles) is estimated to be between 4,300 and 8,600 acre-feet per year (ac-ft/yr). That recharge rate is reflected in the water rights granted by the NM State Engineer to the US DOE for Los Alamos in 1975 of 5,541.3 ac-ft/yr.

These rights were transferred to L.A. County in 2001 when the County Water Utility was established, except for ownership of 1,662.39 ac-ft/yr retained by DOE and leased to the county, to cover potential LANL water requirements (L.A. County supplies water at bulk rates to the Lab, which has its own water distribution system). Los Alamos County also holds an entitlement to 1,200 ac-ft/yr of San Juan-Chama project water, which would have to be pumped up from the Rio Grande or from wells within 1 mile of the river. We presently sell that entitlement each year to the Bureau of Reclamation (at our nominal cost, as required by our ownership arrangement), which uses the water for conservation purposes.

As county population and Lab operations grew, total water use grew to around 5,000 ac-ft/yr during the 1970s and 1980s, with peak use of approximately 5,300 ac-ft/yr in 1976 and 1989. Since then, water use has averaged around 4,200 ac-ft/yr. This has served a population stable near 18,000 since 1980. The average drop in water levels between 1965 and 2006, measured in many supply and research wells, has been less than 1.5 feet per year (ft/yr). Larger water level drops on the order of 20 ft/yr were observed in Guaje Canyon replacement supply wells (G-2A to G-5A) in their first three years of use (1999-2001). I have been told that these levels have stabilized near the G-1/G-1A supply well levels (which drop near the average ~1 ft/yr) since then.

If the apparent near-balance between our water use and recharge of the aquifer continues, a drop in water levels of about 1 ft/yr might lead one to feel confident that we are not significantly depleting an aquifer that is thousands of feet deep. However, some consider any drop in water levels due to pumping to be “mining the aquifer”, meaning depletion of a finite (and not completely understood) resource. The observed drop in water levels of around 50 feet in the last 50 years could be considered more significant if the high-water-yielding portions of the aquifer, from which we presently pump, are only a few hundred feet thick.

Santa Fe has pumped as much as 5,000 ac-ft/yr of water from the Buckman well field across the Rio Grande, and now pumps directly from the Rio Grande in the Buckman Direct Diversion project, completed in 2010. Some models indicate a connection, beneath the Rio Grande, between our aquifer and the one serving Santa Fe; hence they predict that Santa Fe pumping could pull water from the aquifer that feeds our wells. So far, I have seen no data that indicates any increase in our aquifer’s rate of water level decline in recent years.

2. Contamination Threats and Mitigation

Lab operations since the 1940s resulted in a wide array of chemical releases, often in effluent discharged from wastewater treatment facilities. Many millions of dollars have been spent to monitor and remediate the environmental contamination caused.

Reactive contaminants, including plutonium and other radionuclides, tend to adhere to solid surfaces, so they usually have not moved very far in groundwater. In fact, wastewater effluent (now treated to strict standards to prevent further contamination) is used to irrigate vegetation holding soil in place to keep previously deposited surface contamination from spreading.

Non-reactive contaminants, including hexavalent chromium, tritium, nitrate, and explosives components perchlorate and RDX, have traveled farther in our groundwater, in some cases reaching portions of our aquifer. The presence of these contaminants above naturally occurring levels has not been detected in our water supply wells, but unless carefully monitored and properly remediated, they could threaten our water supply.

The main thrust of present mitigation work is to try to remove the contaminants from the aquifer before they reach our supply wells. The most serious threat today is hexavalent chromium (Cr+6), which was discharged for many years in cooling tower water containing potassium dichromate to prevent scale buildup. The use of potassium dichromate was discontinued, and the Lab has made significant investments in contamination-preventing and water-saving technology.  The LANL Sanitary Effluent Reclamation Facility (SERF) purifies wastewater so that it can be used in cooling towers multiple times.

A plume of water containing Cr+6 exists within half a mile of one of our Pajarito supply wells (PM-3), which are the biggest producers in the county’s water system. In a presentation to the State Legislature’s Radioactive and Hazardous Materials Committee (LA-UR-14-25531, July 23, 2014), LANL described plans to begin pumping water from this part of the aquifer and treating it to remove the Cr+6.  In the first year, this could involve pumping as much as 400 ac-ft/yr. If necessary, pumping could go up to as much as 1190 ac-ft/yr within three years. This rate of pumping could continue for years, depending upon the measured Cr+6 removal results.

“Pump and treat” is one approach being pursued to remove Cr+6. A second approach planned is “in-place treatment wells”, in which substances are introduced to contaminated groundwater in the aquifer to reduce Cr+6: chemical reducing conditions, produced by chemical or biological means, can transform Cr+6 to the naturally occurring (and non-health-threatening) Cr+3 form. Wetlands irrigated by clean effluent discharge create conditions in the soil favoring this type of removal of Cr+6 remaining in the surface water. 

3. Present and Future Water Use

The average per capita water use in Los Alamos between 2003 and 2012 was about 151 gpcd (gallons per capita per day; data source: L.A. Department of Public Utilities). This includes residential, educational, municipal, and commercial use and losses, but does not include LANL operations.

Los Alamos’ average of 151 gpcd is in the range reported for neighboring communities. Albuquerque and Rio Rancho brought their water use down from over 200 gpcd to 150 or less in the last 15 to 20 years, by enacting strict water use requirements on new building, and offering generous incentives to customers to reduce their water use (e.g., rebates toward the cost of high-efficiency washing machines, toilets, gray-water use systems, and xeriscaping). Santa Fe now has water use around 100 gpcd, due to incentives, but also due to peak season water rates from 65 percent to more than 200 percent higher than the recently enacted Los Alamos tiered water rates.

LANL water use has come down from a high of 1391 ac-ft/yr in 1999, to around 1,100 ac-ft/yr this year, and is projected to drop to near 1,000 ac-ft/yr by 2017 as the water-saving SERF facility is more utilized. Between FY17 and FY20, increased computing (requiring cooling water) could drive water use back up by about 400 ac-ft/yr, again near 1,400 ac-ft/yr (this data was provided by LANL and can be seen in the County website online agenda packet for the July 8, 2014 County Council meeting, item 5978-14 attachment B, LA-UR-13-29071). This LANL estimate of water use does not include the possible 400 to 1,190 ac-ft/yr that would be pumped for Cr+6 abatement. I hope, and will strongly advocate, that the water pumped for Cr+6 abatement, once treated, will then be re-used for part of the Lab’s yearly needs.

The 2006 Long-Range Water Supply Plan for L.A. County makes future water need projections based upon an assumed population of 25,000 by 2020. The assumptions were that planned DOE land transfers to the county would be fully built-out, populated, and 2,500 additional jobs created. This would require more water than Los Alamos owns, even adding full use of the 1,200 ac-ft/yr San Juan-Chama water to our present 5,541.3 ac-ft/yr. Residential water conservation of 12 percent (a quite achievable goal) could bring use down to the total 6,741.3 ac-ft/yr that we do own.

I believe an increase in population of about 2,000, to a total of 20,000, is possible. If properly managed, such an increase could make this town a more economically viable and pleasant place to live. About 7,000 people commute to jobs here from other counties; if 10 to 15 percent of these commuters relocated here with their families, that would bring us to 20,000. I don’t believe a population higher than 20,000 here is likely, without difficult-to-foresee changes like major job growth at the Lab or other employers. In the next update to the town’s long-range water plan, a range of more realistic population projections will be evaluated.

How much water would a 20,000 population Los Alamos need? Start with the 4,200 ac-ft/yr that we’re presently using, add 300 ac-ft/yr for Lab expanded computing, maybe another 100 ac-ft/yr for snowmaking at the Ski Hill, and add 335 ac-ft/yr for the 2,000 new residents at 150 gpcd, and you get 4,935 ac-ft/yr, still less than consumed in the 1970s and 1980s. This is 600 ac-ft/yr less than our 5,541.3 ac-ft/yr water rights, giving us a good margin to allow for severe drought effects on recharge, or for contamination cleanup pumping (e.g. Cr+6) that cannot be re-used or re-injected. While my 150 gpcd estimate for additional population includes normal commercial and civic uses, new businesses that make significant use of water might also employ some of this 600 ac-ft/yr.

4. Responsible Water Plans and Policy

The 1,200 ac-ft/yr San Juan-Chama (SJ-C) water is an important reserve for us, which we legally retain as “beneficial use” by selling each year to the Bureau of Reclamation. Under severe drought conditions, all users of SJ-C project water may be required to reduce their use, so 1,200 ac-ft may not be available every year. It has been suggested that by using SJ-C water, we could minimize pumping to allow our aquifer to recharge at a better rate. However, it is clear that if we do use that water, the wells and infrastructure required will be considerably more expensive than our existing system.

The county plans for regular replacement of existing wells in our budgets and water rates. Well replacement costs $2-4 million each. If wells have to be built in new locations away from the existing L.A. water system, such as wells to tap the SJ-C water, additional infrastructure will be needed. These wells with infrastructure would cost around $9 million each. In addition, it could take more than one well to obtain the full 1,200 ac-ft/yr. That means that water rates would have to go up by 20 percent to 60 percent, beginning to approach current Santa Fe rates (which they need to amortize the $200 million investment to use their SJ-C water).

We should have plans ready to use that water for unforeseen situations. Based on what we know today, I don’t think it is justified to ask the people of Los Alamos to pay for the large investment to utilize our San Juan-Chama water. If new data shows that the aquifer is being depleted at a significantly higher rate, due to drought or competing water users, then we may need to make this investment. In that case, all county users should share fairly in the cost.

If the Lab or another business presents us with a big new requirement for water that would necessitate use of the SJ-C water, the county should negotiate to have the big new user pay a major share of the increased cost. This also applies if Lab contamination cleanup operations require water use beyond our 5,541.3 ac-ft/yr.

Compared to most communities in the Southwest, Los Alamos is in a very good situation regarding water resources. We have sufficient supplies to continue our present economy, at reasonable water rates. And we have extra capacity that could be drawn upon if needed.

Because drought and contamination present threats to our water supply, conservation measures are prudent. This includes continued investment in our non-potable water system, which supplies 200 ac-ft/yr of recycled water to the golf course, parks, and schools, and could be expanded to save twice that amount of water. We should watch carefully and work to preserve the remaining forest in the Jemez Mountains, the source of recharge for our aquifer. I think the county should offer rebates comparable to neighboring communities, to help residents maintain comfortably green homes while using less water; in the long run, this will save us money spent on peak capacity.

My view is that in regards to water, our glass is more than half-full. With a little care and planning, we can keep it that way.

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