EAWSD: Eldorado sits atop a century’s worth of water

Assuming the district drills enough wells, says study

“The answer is yes,” geohydrology modeler Megan Hodgins said. The question was whether Eldorado has enough water to last 100 years.

Water customers can expect reliable groundwater supplies for 100 years if the Eldorado Area Water and Sanitation District drills six new wells, according to a study completed in July.

With 19 new wells, the district might be able to supply 1,160 acre-feet a year, which is nearly twice as much water as customers currently use, Jay Lazarus, president of Glorieta Geoscience Inc., told the water board.

“We have a really high confidence the water is there,” Glorieta Geoscience hydrologist Mustafa Chudnoff told the water board and community members who gathered to learn the results of the $40,000 water-availability study.

The more important question, Chudnoff said, is whether available water can be economically pumped from the ground and delivered to customers. With no new wells, in 10 years the district will not be able to pump enough water to supply existing customers, the Glorieta Geoscience study concludes.

The water-district board ordered the study as part of long-range planning after taking over the water system fromEl Dorado Utilities Inc. in December 2004 in a court-approved condemnation. The board is also awaiting the results of another study that surveys the condition of the district’s water storage and distribution system.

A third study under way will assess the availability of water according to the formula Santa Fe County land-use officials use to assure new developments have a century’s worth of water available.

Hydrology experts believe there is plenty of water under Eldorado available to be pumped, but they aren’t sure exactly how much. The Glorieta Geoscience hydrologists said they have no evidence that Eldorado has used half of its share of water in the area’s aquifers.

The hydrology study that senior Glorieta Geoscience analysts presented to the water board July 24 didn’t calculate how much water was in aquifers under Eldorado. Instead, the study considered whether the stored water could be economically pumped to water-district customers.

Although there might be water in the ground, existing wells will eventually be unable to pump it, Hodgins said. Wells wear out as continued pumping reduces local water levels and clogs aquifers with clay from surrounding areas. The district can expect four of its 11 wells to become unproductive in the next 100 years, Hodgins said.

“We need to look at the water-level decline in wells, which ... we know from (historical) data has been going on for the past approximately35 years,” she said.

Without new wells, the district will have no reserve pumping capacity during dry years when two wells near the Galisteo Creek are out of service. Those wells rely on mountain runoff, unlike wells closer to Eldorado that rely on stored groundwater. Hodgins recommended the district maintain a reserve pumping capacity of 200 acre-feet a year from its groundwater wells to allow for droughts and low runoff, when the Galisteo Creek wells can’t be used.

To continue supplying the peak demand of 600 acre-feet a year, the district will need to drill or acquire most of the six new wells it needs within the next 20 years, Hodgins said. To double current water delivery, the district would need up to 19 wells within 20 years, she said.

“One well per year, that gets to be very expensive,” Hodgins said.

The district’s effort to drill its first new well has been plagued by delays and higher-than-expected costs. That well, which the water district had hoped to have in service by this summer, is completed but might not be available for pumping until next summer.

District efforts to acquire wells from private developers in exchange for access to the district water system have been thwarted by Santa Fe County decisions to prohibit new developments from hooking up to the water district. The district has challenged the prohibition in court, and a hearing is scheduled for later this month.

To study Eldorado groundwater and pumping capacity, Glorieta Geoscience experts created a computer model that divided the area into a grid in which each block represented an area between 400 and 4,000 feet wide. Using well data from 1972 through 2006, the model approximated water to a depth of 7,000 feet in 10 layers.

Hodgins said deeper wells in the area might not be feasible because deeper groundwater flows more slowly into wells and is often too salty to be useful for drinking-water supplies.

With the exception of Galisteo Creek wells, all groundwater used to supply Eldorado will be mined from aquifers that can’t refill nearly as quickly as they are pumped, the experts said. Hodgins said 100-year forecasts are typically used in water-availability planning. The study offered no outlook for local water availability beyond 2106.

District directors in 2005 discussed eventually piping water from the Rio Grande through a pipeline originating at the planned Buckman diversion, but the board has not taken steps to develop such a pipeline.

District vice president and acting president Jerry Cooper said the district prepared the study for its own planning purposes and not to satisfy Santa Fe County land-use concerns that have led to an 11-year development moratorium.

County water resources division director Steve Wust attended the July 24 presentation but did not comment on how the latest information might affect the county’s view of development in the area. Wust earlier said through a county spokesperson that his department would review results of a study still under way that analyzes water availability in Eldorado using a formula detailed in the county land-use code.

Board members John Mattis and George Haddad are also corresponding with county staff in hopes of improving the exchange of information between the district and the county, Mattis said.

Contact David Collins at 995-3893 or dcollins@sfnewmexican.com.