Land Use and Soils of Deer Creek Watershed
Land use and soil types are key features of a landscape that determine the water flow and quality of a stream. What we do on the land ultimately affects the quality of the water. Certain soil types can make the land especially sensitive to actions on the land.
Past and Present Land Uses
As with the larger Nemadji River Basin, vegetation of the Deer Creek Watershed has been dramatically altered from its natural state due to a history of logging, fires, and a conversion to agriculture. The loss of native coniferous species took place during the logging era of the late 1800s. Subsequent fires in 1894 and 1918 were followed by conversion of land use to agriculture in the early 1900s. Today the watershed is composed of a mix of land use, with a small percentage of coniferous forest remaining. Deer Creek land cover is approximately 18% coniferous, 50% deciduous, and 32% non-forested with a small percentage of that being open water/wetland (Wold, Queen, and Brooks, 1994). Previous study of the Nemadji River and tributaries including Deer Creek concluded that the loss of water storage and moderation once provided by the large coniferous population has resulted in higher water yields. The influx of water has increased rates of downcutting and incision producing more sediment loading to the system (Riedel, Verry and Brooks, 2002).
Connecting the Stream to the Land
The shape and formation of a stream is the result of deposition and erosion that occurs during high flow events where the stream is just about to flood out of the banks (at bankfull). During these higher flows, the stream has enough energy to carry and deposit sediment for channel shaping and formation. A storm event that produces enough rain to cause the stream to reach this point happens approximately every 1.5 years. Yet, when a landscape is dramatically altered, the high flows can happen more frequently, altering the natural erosion and depositional process.
Soil of Deer Creek Watershed
Slightly over one half of Deer Creek watershed is comprised of glacial till and glacial lake laid clay soils that are highly prone to erosion and mass wasting. Additionally, these clay soils have a high runoff potential. Historical changes in land use that resulted in less water storage in addition to the high sensitivity of clay soils can result in high amounts of runoff. The compounding factors of clay soils and historical changes in land use have led to efforts to reduce the amount of open lands in Deer Creek and the greater Nemadji River Basin. The Open Lands Inventory map was completed in 2002 to aid as a planning tool for forest management in the Nemadji River Basin, including Deer Creek.
Clay Soils and Open Lands in Deer Creek Watershed: An Open Lands Inventory 2002
A Landsat Based Open Land Inventory was completed in 2002 to aid as a planning tool for forest management in the Nemadji River Basin. The GIS project was completed during the Nemadji River Basin Project where the goal was to positively affect the hydrology on a subwatershed scale. The project recognized the effects of historical land use changes on hydrology and aimed at reducing peak flows. The recommendation of the project was a maximum of 40% open space per subwatershed.
The open lands invetory GIS project divided the 11 subwatersheds of the Nemadji River Basin (one of which is Deer Creek) into sub-subwatersheds. Young forest (0-15 year age class) and open lands (agriculture and field) were identified using Landsat Imagery from 1983-1999. The maps and percentages were produced to assist in prioritizing subwatersheds of high erosion potential for reforestation and other conservation practices. The map includes clay soils boundaries (dotted yellow) to help identify the sensitive clay soils in relation to the open lands.
Hydrograph Comparison of Two Streams
These hydrograph comparisons of Deer Creek and Otter Creek during the same storm event illustrate the hydrological effects of two distinctly differing landscapes, yet similar scale watersheds (the sites of flow data collection for each creek represent similar size watersheds). The Deer Creek hydrograph displays a sharp increase in flow during the rain events due to the predominance of high runoff potential clay soils, sloping topography, and lack of water storage such as large wetland areas. The Otter Creek hydrograph displays a more gradual increase in flow and peaks at a much lower flow in comparison to the Deer Creek. The upper portion of Otter Creek watershed is dominated my lower runoff potential soils and flatter topography with more water storage.
Note the scale difference for the two graphs! Deer Creek peaked at nearly 225 cfs while Otter Creek peaked at only 44 cfs during the same storm event!
Links to documents on land use change:
“Soil Mass Movement in the Nemadji River Watershed” by Wayne Wold (1994)…Study concluded that # slumps increased in watershed as percentage of non-forested area increased
“Land Use Impacts on Stream Channel Processes in the Nemadji Watershed” by Mark Riedel (1998)…. Results of project provided strong correlations between land use and bankfull discharge and between bankfull discharge and slump occurrence
“Land Use Impacts on Fluvial Processes in the Nemadji River Watershed” by Mark Reidel, Sandy Verry, and Kenneth Brooks (2002)… Dendrochronology, land use change research, and channel survey was used in a study which revealed the forest fires, timber harvest, and agricultural land use conversion resulted in increased episodes of channel incision.
“Stream Bank Stability Assessment in Grazed Riparian Areas”by Mark Reidel, Kenneth Brooks, and Elon Verry (2006)… Grazed riparian stretches were investigated along Deer Creek under a variety of cattle traffic scenarios over a three-year period. Study concluded that stream bank stability was significantly reduced in grazed riparian areas.
“Historical Land Use Change in the Great Lakes Basin” by Kenneth Cole, Margaret Davis, Forest Stearns, Karen Walker, and Glenn Glutenspergen….General Land Office surveys and fossil pollen deposits are incorporated into landscape-scale analysis and presented through Geographic Information Systems (GIS) . The study concluded that over the past 150 year, the landscape has changes more dramatically than the past 1000 years. There has been a 40% decline in forest cover and much of the remaining forest cover has been coverted to early successional forest cover.