Now let’s assume that by the end of May, the snowpack is much less than normal. After five months of a flowing river, the reservoir managers decide to stop the releases. The total releases (January through May) would amount to 379 acre-feet. Replenishing this amount from our groundwater wells would require an increase in pumping of 7.6% over 2007 pumping levels (figured on an annual basis). However, let’s say that heavy rainfall in June and July suddenly fills the reservoir. Now that 379 acre-feet that was “lost” to the river is suddenly replaced by nature. If we had not released that 379 acre feet to the river, it would be “lost” anyway through reservoir spills.

We can imagine many scenarios and possibilities. At the end of April, after four months of flow and without much snowpack, the reservoir managers might decide to reduce the May flow rather than stop it altogether. The scheduled releases are a guide and not a hard and fast rule. Indeed, we know so little about the flow behavior of our river that any plan would need to be closely monitored and adjusted. With careful management, the river’s flow could be reduced in response to dry conditions, and increased when conditions relax. This would minimize the risk of “losing” water from the City supply, which would then have to be made-up with groundwater.

Using groundwater as the safety net for the risk of a flowing river makes sense because the aquifer is the main beneficiary of the river flow. A study commissioned by the Santa Fe Watershed Association estimates that for low volumes of flow (within the range we are suggesting, of 0.5 to 2.5 cubic feet per second), most of that water will infiltrate into the City aquifer recharge zone. Within that zone, the infiltrating water is stored in the groundwater supply where it can accumulate and provide a buffer for the inevitable drought years.

In a wet year, releasing water on a regular basis will free up reservoir space that will be filled by rain and melting snow, effectively increasing the surface storage capacity of the City without any new construction. In a dry year, releases of water into the river could be curtailed or even stopped. Our consolation would be that the water that was released and infiltrated has provided valuable services, both to the aquifer, and to the river corridor ecosystem: the trees and shrubs and the wildlife inhabiting or passing through (migrating) and using the river as a wildlife B&B. Given the arid context of the Santa Fe River, the greenery that the river supports is an invaluable lifeline for creatures trying to move between the Sangre de Cristo Mountains and the Rio Grande, and it also provides a park-like environment for us humans to enjoy.

Allowing the Santa Fe River to keep some of its water is not only a favor to the river; it is a recognition that a living river is more useful to us water-starved humans than a dry river. It takes a relatively small amount of water to bring our river back to life, and that same water that saves the river does double and triple duty by providing a park-like environment above while recharging our aquifers below. The risks are very small, and can be monitored month by month. In the worst-case scenario, we would need to increase groundwater pumping by a few percent. In a better-case scenario, we would actually harvest more water in total because we would put some water into the aquifer and then be able to collect that much more water in the reservoirs.

The biggest benefit of all, however, will be the experience of a living, flowing river, and the satisfaction that we are living more responsibly and sustainably. The river, the wildlife, and the children of Santa Fe will all be the beneficiaries.

David Groenfeldt, an anthropologist by training, has worked on water policies in many developing countries. He has been Executive Director of the Santa Fe
Watershed Association since 2006. www.santafwatershed.org