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Aerial view of Rillito Wash in the Tucson Basin. The Rillito has been identified as an important site of current groundwater recharge in the Tucson basin based on isotopic analysis of groundwater samples.
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The
major goal of Thrust Area 2 is to understand the dynamics
of water and solute balances in semiaridregions at large
spatial and temporal scales (i.e. the river basin scale
and decadal and longer time scales).
The research in TA2 is divided into
two groups: 1) Vegetation and vadose zone process of
the basin floor; and 2) Basin-scale hydrologic systems.
These two groups are both placed under TA2 because of
their common interest in water and solute balances at
large spatial and long temporal scales.
2.1 Vegetation
and Vadose Zone Process of the Basin Floor
The desire to better manage
groundwater resources in arid and semiarid regions results
in a need to better quantify all components of water
and solute budgets of a basin. Basin floor environments
have been given little attention until recently even
though they represent a large proportion of the land
area in the Southwest (e.g. ~50% of the Rio Grande drainage
in CO and NM). Basin floor vadose zones are significant
sites of salt storage and - over decadal to century
time scales - perhaps water flux. Researchers in this
group seek to understand the role of vegetation and
soil structure in controlling the water and solute balances
of the basin floor. Perturbations to water and solute
balances caused by vegetation change (resulting from
human land use practices or climate change) are of critical
importance.
Individual research efforts include:
2.2 Basin-Scale Hydrologic Systems
Groundwater stored in alluvial
aquifers is by far the largest reservoir of water in
semiarid basins. In addition to providing a ready source
of water, groundwater also sustains the baseflow of
many rivers for most of the year. Understanding the
dynamics of this system is of critical importance for
balancing sustainable water use and maintaining the
remaining riparian areas. The objective of the Basin-Scale
Hydrologic System group is to develop tools for determining
recharge areas, flowpaths of groundwater, and residence
times along those flowpaths at the scale of a basin
aquifer, using a combination of emerging and routine
environmental tracers.
Individual research
efforts include:
Additional TA2 Information
Integration
of TA2
Additional activities
SAHRA
Annual Recharge Workshop
March 22-23, 2001, New
Mexico Tech, Socorro, NM.
Organizers: Fred Phillips, James Hogan.
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