Upper Mississippi River System Weighted Wind Fetch Analysis (1989, 2000, 2010/2011)

Science Center Objects

Wind fetch is defined as the unobstructed distance that wind can travel over water in a constant direction. Fetch is an important characteristic of open water because longer fetch can result in larger wind-generated waves. The larger waves, in turn, can increase shoreline erosion and sediment re-suspension. Wind fetches were calculated using the wind fetch model available from (http://www.umesc.usgs.gov/management/dss/wind_fetch_wave_models_2012upda...) for aquatic areas within the Upper Mississippi River System. 

This toolbox calculates effective wind fetch using the recommended procedure of the Shore Protection Manual (USACE 1984). A baseline conditions assessment of wind fetch was conducted to assist the Upper Mississippi River Restoration program's Long Term Resource Monitoring element (LTRM) in identifying areas within the river system where excessive wind fetch could be a problem. This was accomplished using three separate years of land cover/land use data developed by the LTRM (1989, 2000, and 2010/2011). Wind fetch from 36 directions (10 degree increments) was developed and then a weighted wind fetch output was developed. Additionally, separate outputs were developed calculating the difference of weighted wind fetch between 1989 and 2000, and the difference between 2000 and 2010/2011.

 

Depiction of weighted wind fetch results for lower pool 8, Upper Mississippi River System using land cover data from 2010.

Depiction of weighted wind fetch results for lower pool 8, Upper Mississippi River System using land cover data from 2010.  Radar graph in upper left corner shows the graphical breakdown of wind direction frequencies from the La Crosse Municipal Airport Local Climatological Data station.

(Credit: Jason Rohweder, USGS - UMESC. Public domain.)

Information generated by this project will advance our understanding of the distribution of large open water areas within the Upper Mississippi River System where wind generated waves may be problematic and aid in the habitat rehabilitation and enhancement project design and selection process.

 

Link to USGS contract report - https://umesc.usgs.gov/documents/reports/2020/umrr_ltrm_weighted_wind_fetch_101620.pdf

 

Link to weighted wind fetch output data sets -  https://doi.org/10.5066/P99OVGZB