Precipitation and Aquifers

posted Feb 25, 2012, 10:33 AM by Water Project
Precipitation and aquifers are two natural resources of fresh water. Precipitation is any form of moisture accumulating on the land, such as snow or rain. An aquifer is a “geologic formation that stores water and releases it to a well or a natural point of discharge, like a spring or stream.” With less than average precipitation and decreased flow through aquifers, the natural water supply is strained supporting the City of Santa Fe1.

The southwest United States has a semiarid climate, characterized by low precipitation.  The image above shows the daily rainfall in the Sangre de Cristo Mountains, where the Santa Fe River begins. The Santa Fe area experiences heavy storms in the summer, rainfall comes in quick, strong storms that often flood the river. The sharp peaks in the graph illustrate the rapid rainfall durig the summer months.  The average precipitation is below 10 inches in the river valley but averages above 20 inches in the mountains.  Precipitation in the mountains is collected in the city’s dams and distributed to the city residents . Some of the water collected is allowed to flow down the river, where it leaches into the ground and replenishes the aquifer2

 The Santa Fe River has reaches of the river that are “gaining” and “losing.” The gaining regions are where water flows through the river, like immediately after the dams and where the water treatment plant flushes its water. Losing regions are where the water in the river seeps into the ground to replenish the aquifer, where very little water, if any, is apparent in the river bed. The figure at the right illustrates how precipitation is able to replenished the aquifer. Rainfall infiltrates the soil and percolates through sand and soil into the ground water supply. The higher the elevation, the more the aquifer gets recharged.

In Santa Fe, because of the less than national average amount of rainfall and an increasing population, water is being pulled from the aquifers before it can be replenished by precipitation. This results in a river with less water flow and lower ground water level. A detailed report  about the recharging of the Santa Fe River aquifer published by the Santa Fe Watershed Association can be found here.

Look again next week for another team update!

1Grant, Paige, and Neil Williams. 2009. Aquifer recharge from the santa fe river: Santa fe watershed association white paper. New Mexico: Santa Fe Watershed Association
2 Gutzler, D. S. Climate in new mexico. Earth Matters 4 (2).