Hydraulic and Geomorphic Impacts of Dam Removal on the Upper Baraboo River, Wisconsin
Abstract
Over time, human interaction with space and place has led to shifts in cultural dominance and
modes of subsistence. Societies depend on the access to particular natural resources for
subsistence, mainly soil, water and timber. This research examines, 1) a brief history of
human settlement within the Baraboo River watershed and the drivers behind the shifts of
cultural dominance as related to the dependence on soil, water and timber, and, 2) an in-depth
study of how society today adapts to a changing natural resources, namely water through the
removal of small, hydropower dams. Often in human history, societies prosper and fail
depending on their ability to adapt to climate-driven shifts in natural resource availability.
However, with the arrival of modern Native Americans and Euro-Americans, shifts in natural
resource availability results primarily from the exploitation of environmental services. An
illustration of the human-driven alteration of a natural resource is the building and removal of
dams along the Baraboo River. This research studies hydraulic and geomorphic responses to
the 2001 removal of the La Valle dam from the Baraboo River. Examination of longitudinal
profile adjustments and hydraulic response to a 500-year flood using stream surveys from the
Flood Insurance Survey, Martin Doyle, the Sauk County Land Conservation Office, and the
author show significant changes in channel form continued to occur several years after the
removal of the dam. Between 36-39% of stored reservoir sediments were transported
downstream since the 500-year flood, involving incision upstream of the dam site and
aggradation downstream of the dam site. These bed adjustments created a smoother
longitudinal profile; however, a grade control structure at the dam site further appears to
strongly influence stream hydraulics and may result in renewed sediment storage within the
old reservoir. This research reinforces the need for more studies which examine fluvial
response to dam removal at larger spatial and temporal scales. With a better understanding
of fluvial response to dam removal, watershed managers and planners can better protect our
safety and the quality of our natural resources.
Subject
Dam removal
Geomorphology
Hydraulics
Baraboo River
Permanent Link
http://digital.library.wisc.edu/1793/47069Description
Includes figures, maps, photographs, bibliography
Licensed under: