Effects of timber harvest on streamflow and water quality in small watersheds in the Piedmont of North Carolina

North Carolina Forest Service; North Carolina State University; Weyerhaeuser

SUMMARY: In the United States, the best quality water comes from forested watersheds, even when forests are managed primarily for timber production. However, forestry activities such as access and logging roads, stream crossings, skid trails, and other potential sources of disturbance to the forest floor can cause soil erosion and contribute sediment and nutrients to streams and other water bodies.

This study seeks to quantify how additional water, sediment, and nutrients will be added to a stream after a clearcut in forests in the Piedmont of North Carolina. Researchers hypothesize that any changes in water quality and increases in streamflow due to the clearcut will not negatively affect aquatic species that live in the streams.

EFETAC'S ROLE: From 2007 to 2010, this project was funded by an EPA 319 grant and the Eastern Threat Center where cost share was 50/50. Now, the Eastern Threat Center provides full project fiscal support and NC Forest Service and other partners provide field, data, and outreach support.

STATUS: Completed

PROGRESS: The six-year study has resulted in important findings in forest hydrology, nutrient losses to streams, and vegetated riparian buffer functions in Piedmont watersheds. Among similar studies in the region, this paired watershed study provides a complete assessment of streamflow and water quality responses to timber harvesting.

Researchers conclude that a clearcut plays a more significant role in affecting how much water and nutrients flow into a stream in the Piedmont region than in the mountains and coastal plains. However, overall stream water quality in the Piedmont was not negatively affected by increases in streamflow, nutrients, and stream edge tree blow down.

The knowledge gained from this project will be useful to land managers. It will provide a better understanding of how Piedmont watersheds store and release water and nutrients across growing and dormant seasons, how riparian buffers function, and how to apply the most appropriate timber harvest management practices for water resources across regions.

Boggs, J., G. Sun, and S. McNulty. 2016. Effects of timber harvest on water quantity and quality in small watersheds in the Piedmont of North Carolina. Journal of Forestry 114(1):27-40. (PDF)

Boggs, J., G. Sun, J.-C. Domec, S.G. McNulty, and E. Treasure. 2015. Clearcutting upland forest alters transpiration of residual trees in the riparian buffer zone. Hydrological Processes 29:497-499. (PDF)

Boggs, J.L., Jones, D., Sun, G., McNulty, S.G., and Swartley, B. 2010. BMP Effectiveness Monitoring Study – Phase II. Grant Final Report. US-EPA Non-Point Source (NPS) Pollution Control Grant through Section 319h of the Clean Water Act N.C. Department of Environment and Natural Resources Division of Water Quality. NC- DENR Contract EW 1683. (PDF)

Boggs, J.L., G. Sun, S.G. McNulty, W. Swartley, E. Treasure, and W. Summer. 2009. Temporal and spatial variability in North Carolina piedmont stream temperature. In: Proceedings of 2009 American Water Resources Association Spring Speciality Conference. May 4-6, 2009. Anchorage, AK. (PDF)

Boggs, J.L., G. Sun, W. Summer, S.G. McNulty, W. Swartley, E. Treasure. 2008. Effectiveness of streamside management zones on water quality: pretreatment measurements. In: Proceedings of 2008 American Water Resources Association Summer Specialty Conference on Riparian Ecosystem and Buffers: Working at the Water’s Edge. June 30-July 2, 2008. Virginia Beach, VA. (PDF)

Slideshow: Effectiveness of Forestry Best Management Practices for Water Quality Protection in Headwater Catchments in the Falls Lake Watershed (PDF)


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CONTACT: Johnny Boggs, Eastern Threat Center Biological Scientist, johnny.boggs@usda.gov or 919-549-4060

Updated June 2016

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