RCMAP - Lake Fork of the Gunnison near Lake City, Colorado

Science Center Objects

The U.S. Geological Survey was engaged in a program to monitor and assess the long-term geomorphic behavior of selected river and stream reaches that previously had undergone some physical modification.  These modifications included natural channel adjustments to floods as well as intentional channel reconfigurations to alter the function or appearance of a river reach.

In cooperation with the Colorado Water Conservation Board and Colorado River Water Conservation District, the USGS began a study in 2010 to quantify existing hydraulic and habitat conditions for a reach of the Lake Fork of the Gunnison River in Lake City, Colorado. The purpose of the study was to quantify existing Lake Fork channel conditions to establish a baseline against which post-rehabilitation conditions can be compared.

The Lake Fork of the Gunnison River has been an area of active channel modification since the 1950s (Lake Fork Valley Conservancy, 2010).  In the 1950s, increased rates of land use change within Lake City have resulted in the straightening and channelization of the Lake Fork to promote channel stability and development of riverfront properties. Sediment-retention structure failures (cribbing piles) on Henson Creek in the 1960s and 1970s have contributed large volumes of sediment into the fluvial system. In the late 1980s and early 1990s, the Colorado Department of Transportation (CDOT) built temporary berm structures along the river on the north side of town to protect the highway from channel migration until permanent structures could be completed. Areas downstream of the 8 ½ street bridge were also straightened by CDOT and U.S. Army Corps of Engineers in the 1980s.

Lake Fork of the Gunnison near Lake City, CO. XS1, looking upstream, from left hand bank, April 10, 2012. Discharge: 175 cfs

Lake Fork of the Gunnison near Lake City, CO.  Channel Reconfiguration. Cross Section 1, looking upstream, from left hand bank, April 10, 2012. Discharge: 175 cfs

Topographical surveying was used to map water-surface elevations, and stream channel elevations for a 1,100 meter reach at Lake Fork at Lake City. The majority of the surveying occurred between August 2-6, 2010, with additional flood-plain surveying on May 24, 2011 and April 11, 2012. Topographical surveying of water-surface elevations includes conditions present during each day of surveying as well as preserved high-flow conditions (high-water marks) from Spring 2010 and 2011 that were identified from sediment deposition and debris lines. Eight monumented cross sections were established in the study reach for long-term channel monitoring.

Location:

The Lake Fork of the Gunnison River study area is located in Lake City in Hinsdale county, Colorado. Streamflow gaging station 09124500 Lake Fork at Gateview, Colorado, is located 22 river miles downstream and has recorded streamflow in the Lake Fork since October 1, 1937.

The study area consists of two actively monitored reaches, both of which have been modified and straightened to accommodate land use changes.

Reach 1 begins at the 5th street pedestrian bridge flowing northeast 0.28 miles downstream to the 8 1/2 street bridge. Reach 2 begins downstream of the 8 1/2 street bridge flowing northeast 0.26 miles.

Streamflow Data:

Current streamflow: 09124500 Lake Fork at Gateview

View peak streamflow: 09124500 Lake Fork at Gateview, CO

Photographic History:

Photographic monuments at Lake Fork of the Gunnison near Lake City, Colorado

Map of photographic monuments at Lake Fork of the Gunnison near Lake City, Colorado.

Sediment Surveys

See Sediment Distribution Charts for Lake Fork of the Gunnison near Lake City, Colorado

Channel Surveys

See Cross Section Data for sites on Lake Fork of the Gunnison near Lake City, Colorado