Hydrologist explains water well drilling process

LAS CRUCES - A hydrologist working with the city to build three new wells recently held a short course to explain the drilling process.

"The ideal well is efficient, with very little sand production," explained Roger Peery, CEO and principal hydrologist of John Shomaker and Associates, Inc. JSAI is the consultant helping Las Cruces Utilities design three large water well replacement projects this year.

Peery talked about the complicated components of the well drilling process: personnel needed, materials required and daily documentation.

Then Peery got into the choices and decisions necessary to construct a well: determining what type of well to drill and design considerations, including depth to water, potential well yield, aquifer types and any known biofouling problems.

Designers, engineers, hydrogeologists, field inspectors and contractors are all involved in bringing water to Las Cruces. Funding to pay for it — $2 million for the three wells, provided by the state — had to be in place years in advance.

"When drilling a well," explains Peery, "you create a bore hole, approximately 1,000 feet deep in these three cases, you put stainless steel casing and screen down the hole, and then place a gravel pack around the casing and screen to filter out sand as water is being pumped. There are multiple options and parameters for both the screen and the gravel pack, but in the end, it has to be a very good match for the screen slot size."

If the screen is too small for the chosen filter gravel, the well won't produce a lot of sand. That sounds good, but the well might be inefficient — producing only a little water. If the gravel is too large for the screen, the well may produce a lot of sand, which can accumulate in water lines and tanks and wear out pumps quickly.

City Manager, Robert L. Garza noted several months ago when announcing state funding for these projects, "Our clean and reliable water supply is the most important element to ensuring the health and viability of our community."

Safe drinking water is critical to all of us and drilling for our water requires shooting for perfection.

You can reach Las Cruces Utilities at 575-528-3500 from 8 a.m. to 5 p.m. Monday through Friday. Las Cruces Utilities provides gas, water, wastewater and solid waste services to approximately 100,000 Las Cruces residents.