Baltimore Ecosystem Study Cary Institute of Ecosystem Studies

2012 BES Annual Meeting Presentation and Poster Abstracts

Assessing Hydrologic Function in Urban Landscapes
Cullen, Kathleen
Co-Authors: Kathleen Cullen, Brennan Smith, Stu Schwartz

Abstract: Understanding the saturated hydraulic conductivity of soils is essential for characterizing the hydrologic function of a landscape. The infiltration capacity of a site is important for a variety of reasons including plant health, runoff and stormwater management. The inherent heterogeneity of soil requires multiple infiltration measurements to reliably characterize any site. This is especially true in the disturbed soils of the Baltimore Ecosystem Study’s urban landscapes. Many methods are available for measuring infiltration, including double ring constant head, single ring falling head (SRFH) and modified Philip-Dunne infiltrometers, each with its own benefits and drawbacks. SRFH tests are fast, inexpensive, and relatively easy, offering an appealing alternative for rapid characterization of the heterogeneity and hydrologic function of urban landscapes. Like all infiltration tests, accurate estimates of saturated conductivity with SRFH tests require corrections to nominal infiltration rates, to account for test condition geometry, capillarity, radial flow, antecedent soil moisture content, and pressure head. This poster describes field research at CUERE using SRFH infiltration tests and soil analysis to characterize site specific hydrologic function found in Baltimore’s urban landscapes. Site-specific soil texture and bulk density complement infiltration testing and extend the functional inferences that can be drawn from heterogeneous landscapes. We will also consider some of the corrections involved with SRFH tests, as well as the underlying assumptions of these corrections and the lessons learned over two summers of sampling. Preliminary findings and lessons learned about the inherent heterogeneity of urban soils are highlighted using results from field assessments at Cylburn Arboretum and sites in the Baltimore metropolitan area.