Investigating correlations between upland forest management practices and
the economic consequences of stream turbidity in municipal supply watersheds
 
This project prepares and applies a framework for estimating the downstream
costs from increased sedimentation and determining the extent to which
sediment stems from land and reservoir management activities. It focuses on
estimating the sediment costs incurred by the City of Salem, Oregon  and its
water users from such activities in the Santiam watershed, and works with
stakeholders and other interest groups to identify and evaluate policy
alternatives for managing these costs. The opportunity for this project
emerged from flooding in 1996 at levels unseen in the Pacific Northwest for
three decades. High sediment loads during and following the February flood
overwhelmed the City’s filtration capacity and caused it to cease water
deliveries. The City has incurred extraordinary costs and major water
customers have incurred costs to alter their operations or obtain backup
supplies. The Santiam watershed contains predominantly forest land uses in
the uplands and there is now focused debate as to the extent that logging
and related activities in the watershed underlie the extraordinary sediment
loads.

The floods heightened awareness in Oregon of urban areas’ exposure to
sedimentation risks and of the potential for protection of forest ecosystems
to mitigate these risks. Landowners, the U.S. General Accounting Office, the
U. S. D. A. Forest Service and its research arm the PNW Forest and Range
Experiment Station, the Oregon Department of Forestry, and others are
investigating the factors that determine the increased sediment delivery
>from land management activities. Despite extensive, recent assessments of
activities affecting forest ecosystems in the region, there exists no
analysis of their full downstream economic consequences. Past efforts have
focused on the impacts on fisheries and some recreational activities, but
have not incorporated effects, such as increased sedimentation, or placed
them in an economic context. The Salem-Santiam case study offers a unique
opportunity to examine the risks, if any,  to metropolitan economies from
upland land and water management and other activities that affect forest
ecosystems. These risks will intensify as the impacts on sediment and
flooding of past activities persist and urbanization increases in downstream
areas.
 We will work with stakeholders in the Salem-Santiam case study and other
interested parties. Stakeholders have formed the North Santiam Forum, and we
will work with it and the City of Salem. We similarly will work with other
interested parties, including the governor’s office, key legislators, and
participants in the Willamette Valley Livability Forum, a state-sponsored
group co-chaired by the governor, formed to address alternative policies for
accommodating anticipated population growth. Through aerial and ground-based
identification and mapping of sediment sources within the North Santiam
watershed, we will identify  the location of episodic and chronic sediment
inputs to the stream  network.  These data will be used to develop spatially
distributed predictions of sediment delivery through time to the main river
systems, by major tributary, and under various land and water  use
scenarios. We anticipate that the project will increase understanding of the
external costs of land and water management, stimulate consideration of
alternatives for internalizing these costs, and increase understanding of
the economic basis for protecting the integrity of forest ecosystems.
 It is the intent of this effort to test a methodology which will ultimately
be refined and applied to a larger effort comparing and contrasting the
effects of upland land and water management on municipal water supply
watersheds in the Willamette River Basin. Collaborators include Dr. Gordon
Grant (USFS), Dr. Ed Whitelaw (UO) and others.