I attended an interesting meeting last night, concerning Silver City’s 40-year water plan. I say interesting, but I should say fascinating. Hydrology is an incredibly complex field of study. Yet, in two hours time, I had a basic grasp of several aspects of the aquifer system that supplies water for Silver City.
You can find a draft report of the plan here (pdf, acrobat reader required).
Summary: conservation in Silver City is something that we need to worry about in the future, but, that said, it looks like the Gila Group Aquifer can supply plenty of water for the town in the long term, if mining use drops. While some resources indicate mining will be “reduced to nil by 2035,” the draft report anticipates a steady increase for the next 60 years or so, just to be on the safe side.
I wish I had my story, or had some way of posting it online. I’ll try and get that tomorrow. Nonetheless, I did want to stress the potential political impacts of the report (which you should read to follow along).
Staff members of the Gila Conservation Coalition are already arguing that it will be more economically feasible to drill additional wells in the Silver City well fields to maintain yields and meet growth estimates. The other option, construction of a diversion project to get surface water from the Gila River, would likely cost a whole lot of money ($200+ million).
Nonetheless, the sustainable levels of pumping outlined in the draft report (the levels based on a decline in mining) would have problems for water users downstream of Silver City. Under the report, the sustainable level of pumping is only accomplished by pumping water that would otherwise be discharged from the aquifer into the Gila and Mimbres river systems. For the Mimbres, we’re talking about almost 5,000 acre-feet per year. The Gila would see a decrease of 600 AFY.
These downstream figures, factored in with the possibility of using surface water from the Gila to supplement Silver City’s wells, present an interesting political question. With so much discussion of surface water (during this time of drought), what happens when groundwater issues begin to affect rivers and streams as well?