Water Runoff & Erosion

Water Runoff and Erosion

We are evaluating the relationships between changes in the plant community and ground cover and water runoff and erosion processes. Emphasis is placed on determining if critical thresholds exist in vegetation and ground cover that significantly influence runoff and erosion and how land management treatments may influence such thresholds. This work is focused on the pinyon-juniper zone due to limited understanding of hydrologic processes and the hydrologic effects of tree removal treatments in this cover type. Data are being collected at three of the SageSTEP study sites: Onaqui, Marking Corral, and Castlehead.

Water runoff and erosion research objectives are as follows:

• Identify thresholds for increased runoff and erosion as tree overstory increases and understory plants decrease.
• Measure the impact of prescribed fire on water infiltration capacity, overland flow and soil erodibility as tree overstory increases and understory plants decrease.
• Determine the impact of cross-felled and masticated trees on hillslope surface runoff and rill erosion dynamics.
• Improve our basic understanding of the hydrologic connectivity between areas of a hillslope under tree canopies and in areas between tree canopies.
• Provide data sets to expand applicability of the Erosion Risk Management Tool to cover woodland management scenarios studied in this project.

Measuring runoff in a small plot interspace

Measuring rill depth during a rill flow experiment

Data are being collected from small- (0.5 m²) and large-plot (13m²) artificial rainfall simulations and concentrated flow experiments. Pre-treatment data were collected in the summer of 2006 at the Onaqui and Marking Corral sites, and prescribed burning and mechanical treatments were implemented in the fall of 2006. Post-treatment data were collected from 2007-2009. Post-treatment data were collected on control, cut tree, and burn plots at the Castlehead site in 2008 ans 2009. Pre-treatment data collection at Castlehead became unattainable due to a wildfire that passed through the site.

Publications and poster presentations resulting from the water runoff and erosion research can be found on our SageSTEP Publications page.

A related study, Soil and hydrologic response to mastication of juniper woodlands, was conducted in collaboration with SageSTEP hydrologists. Click here to view more information on this collaborative study.