2011

C.G. Ochoa, A.G. Fernald, S.J. Guldan

http://www.zonanosaturada.com/zns11/publications/p337.pdf

ABSTRACT. In arid areas, an important source of water supply comes from shallow aquifers. In agricultural valleys of northern New Mexico, the use of traditional irrigation systems contributes to the recharge of the shallow aquifer. The objective of this study was to characterize the hydrological interactions occurring in an agricultural valley of New Mexico. Field data (2003-2010) were used to characterize the hydrological interactions between the unsaturated zone and the shallow aquifer. Different climate variables, river and acequia flows, and irrigation levels were used to calculate the water budget at the field and valley scale. Piezometric levels were used for characterizing the water table fluctuations and for estimating aquifer recharge rates. Water balance calculations at the valley scale showed that 33% (12% acequia seepage and 21% deep percolation from irrigation) of the total water distributed in this agricultural valley contribute to potential aquifer recharge. Piezometric levels obtained from multiple wells in the valley showed a seasonal pattern in response to acequia and irrigation percolation. A piezometric level rise of up to 0.8 m was observed in 3 to 5 weeks after the onset of the irrigation season in 2008, which after temporary storage, receded gradually towards the end of the irrigation season. The influence of piezometric-level temporary rise was observed in wells located in irrigation areas, but also in wells located outside of the irrigated areas. Results from this study contribute towards a better understanding of the hydrological interactions of the unsaturated zone and the shallow aquifer in a semi-arid agricultural valley in the southwestern United States.