Skip to Main Content
Soil moisture gradients and controls on a southern Appalachian hillslope from drought through rechargeAuthor(s): J.A. Yeakley; W.T. Swank; L.W. Swift; G.M. Hornberger; H.H. Shugart
Source: Hydrology and Earth System Sciences. 2(1): 41-49.
Publication Series: Miscellaneous Publication
PDF: View PDF (324 KB)
DescriptionSoil moisture gradients along hillslopes in humid watersheds, although indicated by vegetation gradients and by studies using models, have been difficult to confirm empirically. While soil properties and topographic features are the two general physiographic factors controlling soil moisture on hillslopes, studies have shown conflicting results regarding which factor is more important. The relative importance of topographic and soil property controls was examined in an upland forested watershed at the Coweeta Hydrologic Laboratory in the Southern Appalachian mountains. Soil moisture was measured along a hillslope transect with a mesic-to-xeric forest vegetation gradient over a period spanning precipitation extremes. The hillslope transect was instrumented with a time domain reflectometry (TDR) network at two depths. Soil moisture was measured during a severe autumn drought and subsequent winter precipitation recharge. In the upper soil depth (0-30 cm), moisture gradients persisted throughout the measurement period, and topography exerted dominant control. For the entire root zone (0-90 cm), soil moisture gradients were found only during drought. Control on soil moisture was due to both topography and storage before drought. During and after recharge, variations in soil texture and horizon distribution exerted dominant control on soil moisture content in the root zone (0-90 cm). These results indicate that topographic factors assert more control over hillslope soil moisture during drier periods as drainage progresses, while variations in soil water storage properties are more important during wetter periods. Hillslope soil moisture gradients in Southern Appalachian watersheds appear to be restricted to upper soil layers, with deeper hillslope soil moisture gradients occurring only with sufficient drought.
- You may send email to firstname.lastname@example.org to request a hard copy of this publication.
- (Please specify exactly which publication you are requesting and your mailing address.)
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationYeakley, J.A.; Swank, W.T.; Swift, L.W.; Hornberger, G.M.; Shugart, H.H. 1998. Soil moisture gradients and controls on a southern Appalachian hillslope from drought through recharge. Hydrology and Earth System Sciences. 2(1): 41-49.
- Topography may mitigate drought effects on vegetation along a hillslope gradient
- Variability in soil CO2 production and surface CO2 efflux across riparian-hillslope transitions
- Seedling establishment and physiological responses to temporal and spatial soil moisture changes
XML: View XML