PROGRAM TITLE:	Sensitivity of Water Resources
ACTIVITY STREAMS:	Process, Observations/Data Mgmt., Modeling
SCIENCE ELEMENT:	Climate and Hydrologic Systems


DESCRIPTION:  Water resources managers require improved methods for 
assessing the sensitivity of the systems they manage to seasonal and longer-
term variations in weather and climate.  Equally important is the need for 
methods of evaluating the risk or uncertainty associated with such 
assessments.  Many of the existing predictive tools (climate, watershed, and 
aquatic/ecosystem models) are not sufficiently focused on water and energy 
budgets to provide the necessary answers.  Virtually all techniques of 
hydrologic analysis are based on the assumption of a stationary, or 
unchanging climate.  Climate modeling is limited by physical understanding 
and the speed of existing computers.  Hydrologic models have traditionally 
been more focused on the problem of flood responses and not the overall 
water budget.  The need exists for improved procedures for generating the 
meteorological forcing functions within integrated climate/hydrologic 
models under assumptions of a non-stationary climate.  Comprehensive 
aquatic/ecosystem models are just being developed.

The objective of this program is to develop a capability to predict the 
hydrometeorological and water resources response to climate variability and 
change across the range of environmental conditions existing in the United 
States.  This involves the development and testing of approaches to:  the 
generation of meteorological and climatic inputs, the translation of these 
inputs to streamflow and ground-water recharge, and the integration of these 
effects with ground-water responses to streamflow, recharge, and sea-level 
changes.  It involves the nesting of climate models, and the linking of 
watershed models with water management models so that the 
improvements in predicting hydrometeorological conditions are directly 
translated into improvements in the management of water resources and 
water system operations, and aquatic/ecosystem management.  

STAKEHOLDERS:  The U.S. Geological Survey (USGS) and Bureau of 
Reclamation (BOR) are working together to link watershed models with 
water management models.  This is providing Federal, State, and local water 
resource managers with the tools and techniques to improve management of 
existing water supplies.  The BOR is working with the National Center for 
Atmospheric Research on the nesting of atmospheric models to improve 
prediction of hydrometeorological variables.  The USGS is working under 
cooperative agreements with the governments of Japan and Russia on the 
development of improved watershed models.

SHORT-TERM POLICY PAYOFFS:  This program benefits policy makers and 
water resource users in the short term by developing a water resource 
prediction and user management system consisting of coupled atmospheric, 
watershed, water routing and reservoir management models.  The joint 
USGS/BOR modeling activities have already resulted in one example of 
improved seasonal water management decisions in a small watershed in the 
mountainous western U.S.  It is reasonable to expect that continued 
development of coupled models will improve water and aquatic/ecosystem 
management decisions in western watersheds where the BOR conducts 

				Global Change Research Coordinator
				U.S. Geological Survey
				104 National Center
				Reston, VA  22092
				Phone (703) 648-4450
				Fax   (703)  648-5470