Importance/Issues

In the Sonoran Desert, groundwater is the source of most surface water bodies, including seeps and springs, streams, and tinajas. Availability of groundwater, expressed as depth to free water, also has critical consequences for plant community structure and productivity; nutrient, water, and energy flows; and the fauna that depend upon them. In many parts of the American Southwest, long-term drought and human development have led to significant declines in groundwater levels at local and regional scales.

Parks Monitored

Chiricahua NM, Coronado NMem, Fort Bowie NHS, Gila Cliff Dwellings NM, Montezuma Castle NM, Organ Pipe Cactus NM, Saguaro NP, Tonto NM, Tumacácori NHP

Monitoring Objectives

Monitor water table elevations to detect long-term changes in groundwater levels.

Provide data to support interpretation of surface monitoring results.

Provide data needed to extend regional groundwater data and regional groundwater trends to immediate park locales.

Provide data contributing to an understanding of water balance dynamics at parks, including relationships between groundwater and surface water resources, biota and climate.

Provide data to support larger scale water balance efforts by other agencies.

Obtain data for assessing site suitability for riparian habitat.

Document water level elevations to support legal protection of the resource.

Potential Measures

Depth to groundwater, as measured by sounding tape or pressure transducer.  Water-level elevation will also be reported.

Management Applications

Many parks are located in areas where routine groundwater monitoring by other agencies does not occur. Groundwater declines often occur gradually, in response to the combined effects of “distributed point sources,” such as wells and springs, and “nonpoint sources,” such as climate and streams. Documenting the status and trends of groundwater levels will support conceptual models needed to work with regional partners to conserve resources. 

Locally, impacts to groundwater resources associated with reductions in infiltration and storage, often related to soil loss and changes in surface characteristics, can be directly addressed by management actions aimed at soil conservation and recharge enhancement. Potential groundwater capture related to stream entrenchment can be prevented if identified in the early stages, and groundwater monitoring will allow managers to better understand actual or potential local impacts of park groundwater pumping, where it occurs.

Protocol Development Status

Protocol developed in 2007-2008; quarterly monitoring implemented in Winter 2008. Initial annual status reports were generated for FY2008.

Status & Trends

Determination of groundwater status is ongoing using current and archived data.

Project Leads

Colleen Filippone, Regional Hydrologist