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Title: VARIATION OF INFILTRATION WITH LANDSCAPE POSITION IN AN OZARK WATERSHED: IMPLICATIONS FOR WATERSHED MANAGEMENT

Author
item Sauer, Thomas
item Logsdon, Sally

Submitted to: North America Forest Soils Conference
Publication Type: Abstract Only
Publication Acceptance Date: 7/24/2003
Publication Date: 7/24/2003
Citation: Sauer, T.J., Logsdon, S.D. 2003. Variation of Infiltration With Landscape Position in an Ozark Watershed: Implications for Watershed Management [abstract]. North America Forest Soils Conference. p. 14.

Interpretive Summary:

Technical Abstract: Variation of infiltration rates with landscape position influences the amount, distribution, and routing of overland flow. Knowledge of runoff patterns gives land managers the opportunity to affect changes that optimize water use efficiency and reduce the risk of water quality impacts. The objective of this study was to assess the effect of landscape position and associated soil properties (rock fragment content and soil texture) on infiltration and related physical properties in a small forest/pasture watershed in the Ozark Highlands. Single-ring and tension infiltrometer measurements at three pressure heads (h = -0.03, -0.06, and -0.12 m) were completed at 42 sites along 3 transects across the 147-ha watershed. Upland and side slope soils had significantly less rock fragments and lower infiltration rates (i) at and near saturation compared to the valley bottom soil. Average infiltration rate at h = -0.03 m for all soils was only 9% of the ponded value suggesting that pores > 1 mm-diameter dominated water flow under saturated conditions. At saturation, infiltration tended to increase with rock fragment content while, at h = -0.12, the opposite was true. It is proposed that source of rock fragments and contact with the surrounding fine earth fraction affect water flow by influencing hydraulic continuity near fragment surfaces. Results indicate that forest/pasture management in the Ozark Highlands should consider variation in runoff potential as an opportunity to improve productivity while reducing the risk of nonpoint source pollution.