Southwest Hydrology: The Resource of Semi-Arid Hydrology Volume 4 Number 2

• Description: Southwest Hydrology: The Resource of Semi-Arid Hydrology Volume 4 Number 2
• State: CO
• Date: 3/1/2005
• Title: Southwest Hydrology: The Resource of Semi-Arid Hydrology Volume 4 Number 2
• Water Supply Pro - Doc Type: Publication

SSD, contined from page 25
decade are comparatively greater as a
consequence of lower levels in Lake
Mead. It is noteworthy that observed water
levels at Lake Mead are lower than those
obtained in the SSD study, even though
substantially more water has been released
from Lake Powell in the current situation.
Is an SSD in Our Future?
There is no way to know the fate of
the current drought. Tarbotten (1995)
estimated that the SSD drought had a
return period of between 2,000 and 10,000
years. On this basis, and assuming that the
climate has not changed, it is very unlikely
that the current drought will reach both the
duration and severity of the SSD drought.
On the other hand, we find ourselves in
the current drought with almost 20 maf
less water in the principal reservoirs
than at a corresponding point in the SSD
analysis, a situation worthy of attention.
The system is now susceptible to shorter
dry spells, which occur considerably
more frequently than severe droughts.
This susceptibility will increase rapidly if
withdrawals are not reduced.
Contact Ben Harding at blh @hydrosphere.com. The
entire contents of the special edition of the Water
Resources Bulletin on the Severe and Sustained
Drought Project are available at www hydrosphere.
com/publications/ssd/ssd. htm.
References
Piechota,T., J. Timilsena, J. G. Tootle, and H.
Hidalgo, 2004. The western U.S. drought: How
had is it ?, Eos, 85(32): 301, 304. meteora.ucsd
edu /cap /docs/hugo_eos_aug2004. pdf
Tarboton, D. G., Hydrologic scenarios for severe
sustained drought in the southwestern United
States, 1995. WaterResour. Bull., 31(5): 803-
814. wwwhydrosphere .com/publications/ssd/
HydrologicScenariosSevereSustainedDrought.
pdf
Webb, R.H., G.J. McCabe, R. Hereford, and C.
Wilkowske, June 2004, rev. Aug. 2004. Climatic
fluctuations, drought, tout flow in the Colorado
River Basin, USGS Fact Sheet 2004 -3062, ver.
2, U.S. Dept. of the Interior, U.S. Geological
Survey. warer..usgs.gov /pubs /fs/2004/3062/
38 • March /April 2005 • Southwest Hydrology
Lower Basin, contined from page 23
reduced as early as 2006. As the lowest
priority user in the Lower Basin,
Arizona's water deliveries through the
Central Arizona Project are likely to be
reduced, by an amount that remains to be
agreed upon.
No More Business as Usual
Although the current drought will
eventually subside, we cannot afford to
return to business as usual. Increased
demand has eliminated historic unused
supplies in the Lower Basin, resulting in
less water to replenish the reservoirs and
a reduced cushion against drought in the
future. From now on, cooperation and
prudent water use will be the hallmarks
of successful water management in the
Colorado River Basin.
Contact Rita Maguire at rpmaguire @thinkaz.org.
hydroGEOPHYSICS, Inc,
www. hydrogeophysics.com
Non - Intrusive Hydrogeologic Characterization
,/Alluvial Basin Definition
✓ Recharge Site Monitoring
✓ Plume Mapping
✓Fracture and Fissure Mapping
Arizona registered geophysical engineer • over 30 years experience
2302 N. FORBES BLVD. • TUCSON, ARIZONA 85745
TELEPHONE [phone] • FAX [phone]