Sustainability of Groundwater Resources and its Indicators (Proceedings of symposium S3 held during the Seventh IAHS Scientific Assembly at Foz do Iguaçu, Brazil, April 2005). IAHS Publ. 302, 2006, 59-66.

 

Groundwater flow model of the Lower San Pedro River basin for the sustainability of riparian habitats

 

Jonathan Whittier1,2 & Thomas Maddock, III1

1       Department of Hydrology and Water Resources, 1133 E. North Campus Drive, Harshbarger Building,
PO Box 210011, University of Arizona, Tucson, Arizona 85721, USA

jwhittier@hargis.com

2       Hargis & Associates, Inc., 1820 E. River Road, Suite 220, Tucson, Arizona 85718, USA

 

Abstract Water issues in the Lower San Pedro River (SPR) basin are becom­ing increasingly contentious as human activity competes with sustainability of the riparian habitat. The SPR flows north from Sonora, Mexico to its confluence with the Gila River in Arizona, USA. In order to better understand the water demands in this basin, a new groundwater flow model was created simulating conditions prior to 1940 and changes from 1940 to 2000. The model results project potential impacts to the sustainability of groundwater within the basin. Natural indicators show downward trends involving declines in water table levels near the river due to pumping, underflow to the Gila River basin, water available for sustaining riparian vegetation, water available in storage, and flow from the aquifer to the river. In the future, the model will be used as an administrative tool to assess alternative land management scenarios and their abilities to sustain or improve the riparian habitat.

 

Key words  Arizona; GIS; GMS; MODFLOW; natural indicators; phreatophyte, riparian habitat; San Pedro River; sustainability