By Terrance Fulp and Jane Harkins, Proceedings of ASCE World Water &
Environmental Resource Congress, Orlando, Florida, May 2001
During calendar year 2000, the Secretary of the Department of the Interior
(Secretary), acting through the Bureau of Reclamation (Reclamation), considered
the adoption of specific interim surplus criteria under which surplus water
would be declared in the lower Colorado River Basin during an interim period
that would extend through 2016. An Environmental Impact Statement was prepared
to discuss the specific alternatives under consideration and to identify
the potential environmental effects of implementing such criteria.
Potential hydrologic effects of the alternatives compared to baseline
conditions were analyzed using Reclamation’s long-term policy model,
implemented in RiverWare, a general-purpose river and reservoir modeling
framework. Using RiverWare’s rule-based simulation option, each alternative
was represented in a different rule set and used to direct the particular
simulation. Multiple runs were made to quantify the uncertainty with respect
to future inflow hydrology. The results were then used to quantify the
comparative impacts on various resources, including recreation, fisheries,
special-status species, and energy production.
The work culminated in the selection of a preferred alternative and the
Record of Decision, which was signed by the Secretary on January 16, 2001.