{"id":424,"date":"2013-12-31T22:10:29","date_gmt":"2014-01-01T03:10:29","guid":{"rendered":"https:\/\/sites.temple.edu\/geophysics\/?p=424"},"modified":"2013-12-31T22:14:48","modified_gmt":"2014-01-01T03:14:48","slug":"presentation-at-2013-annual-gsa-meeting","status":"publish","type":"post","link":"https:\/\/sites.temple.edu\/geophysics\/2013\/12\/31\/presentation-at-2013-annual-gsa-meeting\/","title":{"rendered":"Presentation at 2013 Annual GSA Meeting"},"content":{"rendered":"

Monday, 28 October 2013: 8:00 AM-12:00 PM
\nColorado Convention Center Room 207<\/p>\n

Paper No. 102-5
\nPresentation Time: 9:10 AM<\/p>\n

GEOPHYSICALLY-MONITORED DYE TRACER TEST OF INFILTRATION IN THE<\/p>\n

UNSATURATED ZONE AT THE SHALE HILLS CZO<\/p>\n

NYQUIST, Jonathan1, PITMAN, Lacey1, TORAN, Laura1\u00a0and LIN, Henry2<\/p>\n

<\/em>\u00a0(1) Earth and\u00a0<\/em><\/em><\/em><\/em><\/em><\/em><\/em>Environmental Science, Temple University, Philadelphia, PA 19122, lacey.pitman@temple.edu,<\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/p>\n

<\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em>(2) Crop and Soil Sciences, Penn State University, University Park, PA 16802<\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/p>\n

<\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em>We conducted a dye tracer test of artificial infiltration and monitored the hydrologic process using ground\u00a0<\/em>penetrating radar (GPR) on a hillslope at the Shale Hills CZO. After the geophysical surveys were\u00a0<\/em><\/em>conducted, the site was excavated to photograph the dye pathways. The goal of the project was to\u00a0<\/em><\/em><\/em>improve the understanding of how GPR can be used to interpret infiltration by comparing GPR images\u00a0<\/em><\/em><\/em><\/em>and photographed dye pathways and to evaluate the importance of the soil-bedrock interface and saprolite\u00a0<\/em><\/em><\/em><\/em><\/em>fabric on infiltration pathways. Brilliant blue dye (4 g\/L) was used as the tracer, and 50 L was injected\u00a0<\/em><\/em><\/em><\/em><\/em><\/em>into the unsaturated zone through a 1 m long trench on a hillslope. We performed dye injection at two\u00a0<\/em><\/em><\/em><\/em><\/em><\/em><\/em>sites, one under wet antecedent conditions and one initially dry. A 3D GPR survey with an 800 MHz\u00a0<\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em>antenna was conducted downslope of the trench on a 1 m by 2 m grid at tightly spaced 0.05 m intervals.\u00a0<\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/p>\n

<\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em>While GPR does not directly image the dye, its signals respond to changes in soil moisture content and\u00a0<\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em>changes in radar propagation in saprolite versus bedrock. Mapping the bedrock is important because its\u00a0<\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em>low permeability may control flow paths. The GPR bedrock map shows a highly irregular surface and\u00a0<\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em>shallow bedrock (approximately 0.5 m depth). The dye tracer photographs show preferential flow paths at\u00a0<\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em>both tracer test sites. Dye pathways were anisotropic and strongly influenced by the saprolite fabric\u00a0<\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em>(oriented along strike). Under wet antecedent conditions, dye also followed root traces but under dry\u00a0<\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em>conditions, only structural fabric controls were observed. GPR radargrams showed a fingering pattern\u00a0<\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em>similar to the dye trace photographs, but with less obvious resolution of the structural fabric. The depth of\u00a0<\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em>penetration of the dye (approximately 0.5 m) and lateral migration (about 0.2 m) were also captured by\u00a0<\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em>the radargrams. Although the depth of penetration was controlled by bedrock, the fingering observed in\u00a0<\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em>the dye did not seem to be influenced by undulations in the bedrock but was set by the fabric encountered\u00a0<\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em>in the saprolite. The GPR provided a rapid method for mapping bedrock, which was an important control\u00a0<\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em>on depth of infiltration. GPR also suggested fingering occurs, but detailed pathways were difficult to\u00a0<\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em>resolve without dye tracing and excavation.<\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

Monday, 28 October 2013: 8:00 AM-12:00 PM Colorado Convention Center Room 207 Paper No. 102-5 Presentation Time: 9:10 AM GEOPHYSICALLY-MONITORED DYE TRACER TEST OF INFILTRATION IN THE UNSATURATED ZONE AT THE SHALE HILLS CZO NYQUIST, Jonathan1, PITMAN, Lacey1, TORAN, Laura1\u00a0and … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":606,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-424","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/sites.temple.edu\/geophysics\/wp-json\/wp\/v2\/posts\/424","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sites.temple.edu\/geophysics\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/sites.temple.edu\/geophysics\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/sites.temple.edu\/geophysics\/wp-json\/wp\/v2\/users\/606"}],"replies":[{"embeddable":true,"href":"https:\/\/sites.temple.edu\/geophysics\/wp-json\/wp\/v2\/comments?post=424"}],"version-history":[{"count":0,"href":"https:\/\/sites.temple.edu\/geophysics\/wp-json\/wp\/v2\/posts\/424\/revisions"}],"wp:attachment":[{"href":"https:\/\/sites.temple.edu\/geophysics\/wp-json\/wp\/v2\/media?parent=424"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/sites.temple.edu\/geophysics\/wp-json\/wp\/v2\/categories?post=424"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/sites.temple.edu\/geophysics\/wp-json\/wp\/v2\/tags?post=424"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}