The Tahoe Decision Support System (TDSS) is a tool to help resource managers
use the latest scientific information to make sound management decisions that
maintain environmental and socioeconomic health. The system is being developed
by a team of scientists from the Science Section of the USGS Western Geographic Science Center
in conjunction with the Tahoe Regional Planning Agency (TRPA).
The need for TDSS was identified in the Lake Tahoe Basin Watershed Assessment
conducted by the USDA Forest Service (USFS). The report recommended that regulatory
and management agencies within the Lake Tahoe Basin (Basin) work together using
an adaptive management framework. Adaptive management is an approach that
allows for learning and adjustment to occur while management and restoration
actions are ongoing.
Resource managers are challenged with the difficult task of executing policies
that will optimize environmental and socioeconomic benefits. Decision support
models are tools that better enable decision-makers to understand the factors
driving a particular management decision and then predict the outcome and potential
impacts of that choice. For example, creating more biking trails could improve
recreational experiences, but might reduce the habitat of an endangered native
species. A decision support tool will show the potential positive socioeconomic
impact of adding bike trails while evaluating the effects on the endangered
species population. TDSS will optimize Basin agency's long-term planning by
incorporating environmental and socioeconomic considerations.
TDSS will build upon existing related work, specifically a decision support
tool called the Tahoe Constrained Optimization Model (TCOM). USGS in collaboration
with TRPA, US Environmental Protection Agency (USEPA) and the Desert Research
Institute (DRI) built the model in 2002. TCOM was developed to characterize
the economic and environmental consequences of implementing specific land-use
regulations. Specifically, it focused on the regulation of impervious coverage
by granting or denying building permits in a single watershed (the UpperTruckee River
Basin). TCOM sought to identify the optimal allocation of building permits
that maximized the value of the region's land market while meeting TRPA's environmental
objectives.
TDSS will expand beyond a single watershed and incorporate additional criteria
for decision making in the Basin. It will examine a wider array of socioeconomic
and natural resource management issues. It will also provide tools and methods
for integrating and analyzing models, data and modeling results.
The system will utilize TRPA's updated environmental threshold indicators to
measure a scenario's likely impact. A scenario is comprised of an expected development
footprint, an estimate of future population, a projection of future climate
changes, and a set of management controls. In 1982, TRPA adopted nine threshold
categories including: water quality, air quality, soil conservation, wildlife
habitat, fish habitat, vegetation, noise, recreation, and scenic resources. Each
threshold category contains a number of specific indicators and standards that
are used to track, evaluate, and report the attainment status of each threshold
over time. These are currently being reviewed and updated. TDSS will utilize
the updated indicators to characterize the likely outcomes of alternative scenarios.
The system is being developed in phases over the next several years. The first
phase of the project will focus on a small set of established scenarios including
a "No-project Alternative". Results of this scenario will demonstrate the consequences
of continuing to do business as usual, as described in the current regional
plans and the Environmental Improvement Program Update, a list of projects aimed
at improving the Basin's environmental health. A preliminary report will be
completed in the fall of 2004 and will propose procedures for compiling data,
analyzing impacts and communicating results. Updated and enhanced versions
of TDSS are scheduled for delivery in the fall of 2005 and 2006.
Launch TDSS tool.
For more information about TDSS, please contact the Western Geographic Science Center:
David Halsing dhalsing@usgs.gov
Anne Wein awein@usgs.gov
Mark Hessenflow mhessenflow@usgs.gov
Richard L. Bernknopf rbern@usgs.gov
References
Tahoe Decision Support System Interim Report,.US Geological Survey Western
Geographic Science Center, June 2004
Personal communication, David Halsing, US Geological Survey Western Geographic
Science Center, at (650) 329-4237, dhalsing@usgs.gov
Tahoe Constrained Optimization Model, USGS Geographic Analysis and Monitoring
Program, http://gam.usgs.gov/DSSandCSP/tcom.shtml
