North Fish Creek Bluff Stabilization Monitoring
Project Number: 9KO33
Project Chief: Faith Fitzpatrick
Project Topics: Bluff erosion, restoration monitoring, episodic geomorphic change
Cooperators: University of Wisconsin at Madison - Civil and Environmental Engineering Department
Period of Project: 2001-ongoing
Looking downstream at a bluff with a flow deflecting vane, Site 12.2 2004.
Problem
North Fish Creek has accelerated erosion and sedimentation problems that have affected a highly valued fishery resource. Previous USGS studies identified bluff erosion along the upper main stem as the major source of sediment to downstream reaches. Upstream controls on bluff erosion were needed to reduce downstream sediment transport (potential scour effects) and sedimentation (covering of spawning beds), but the bluffs are remote and difficult to access. From 2000-2006, re-directive (flow-deflecting) techniques were installed by hand at three sites by the University of Wisconsin-Madison Civil and Environmental Engineering (CEE) Department. The USGS monitored bluff erosion by conducting repeated channel cross-sections and bluff-top erosion surveys and monitoring stream-flow and stage before, during, and following installation to detect changes in channel morphology and bluff erosion in the context of hydrologic conditions. As part of a geomorphic assessment of Bayfield Peninsula streams, extensive upland ditch networks in abandoned farmland were observed that provided fast concentrated runoff that did not exist naturally.
Objectives
The overall objective of this project is to monitor three sets of rehabilitation projects and determine their effect on the bluff erosion rate and overall volumes. These data help guide the designs of future bluff rehabilitation. An additional objective for 2006 is to identify/describe the upland ditch network in North Fish Creek in terms of land cover and soils to help guide future management decisions on control of runoff from uplands.
Approach
This project will continue to monitor channel morphology and bluff erosion at three sites in North Fish Creek with bluff stabilization techniques. Upland ditch networks will be identified in a GIS (using aerial photographs, soils maps, land ownership records, and on-site inspection). A USGS streamgage will continue operation. Channel cross sections along the main stem of North Fish Creek established in 1995-96 will be resurveyed to describe stream-wide geomorphic responses to 2 extreme floods in 2005 and put changes at the bluff stabilization sites in perspective with stream-wide conditions.
Progress
Two large floods occurred in the summer and fall of 2005 (recurrence intervals of 500+ years). The effects of the large floods on erosion and sediment volume chanages were documented at the three bluff stabilization sites through continued surveys of channel cross sections and bluffs. Data from the streamgage was used to document peak flows, flashiness, and estimated water depths encountered by the flow-redirective techniques at the bluffs. A master’s thesis was published on the effects of the 2005 large floods on channel morphology and sediment movement at the three bluff stabilization sites. Upland ditch networks were be identified. Channel cross sections along the main stem of North Fish Creek were resurveyed in 2008.
Plans
Channel cross sections and bluff erosion will continue to be monitored at the three sites. The USGS will work closely with UW-Madison personnel in these efforts. Streamflow conditions will continue to be monitored at a USGS streamgage. Analysis of the ditch networks and repeated channel cross sections is continuing.
Publications and Reports
Fitzpatrick, F.A., Peppler, M.C., Schwar, H.E., Hoopes, J.A. and Diebel, M.W., 2005, Monitoring Channel Morphology and Bluff Erosion at Two Installations of Flow-Deflecting Vanes, North Fish Creek, WI, 2000–03: USGS Scientific Investigations Report 2004-5272.
Fitzpatrick, F.A., Knox, J.C., and Whitman, H.E., 1999,
Effects of Historical Land-Cover Changes on Flooding and Sedimentation, North Fish Creek, Wisconsin: Water-Resources Investigations Report 99-4083.
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