171 D6. The Multidisciplinary Faces of Cave and Karst Science (Posters)

Monday, 23 October 2017
9:00 AM - 6:30 PM
Halls 4EF

SPATIAL DISTRIBUTION AND MORPHOMETRIC ANALYSIS OF DOLINES OVER TIME IN A WASTEWATER SPRAY IRRIGATED LANDSCAPE

Paper number: 171-5
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

Abstract

The geomorphological effects of agricultural irrigation on karst geology have not been thoroughly studied in the past. Since karst features in the Ridge-Valley region of Central Pennsylvania can be extensive and interlinked, it is important to track any significant changes to the surface morphology that could have larger implications for the subsurface features. Wastewater spray irrigation is a technology that has existed for decades but has only recently become a more widespread trend, particularly in the Middle-East and the Western United States. Pennsylvania State University has been operating a wastewater irrigation site known as the “Living Filter” continuously since 1962, making it one of the oldest wastewater irrigation sites in operation with an unparalleled wealth of data accumulated over decades. The geology of central Pennsylvania, specifically the Nittany Valley, is comprised of carbonate-derived geologic formations with regionally orientated fracture traces in a SW-NE trend. The presence of fracture traces can produce concentrated areas of high permeability which can result in dolines in areas of easily dissolved rocks such as carbonates. The addition of roughly 1.5 MGD of secondary treated wastewater over cropped and forested lands has resulted in the formation of several suspected subsidence dolines in the area with the same general lineation as the fracture traces. Digital Elevation Models (DEMs) over the past decade indicate a rate of change for the growth of the depressions over time ranging from several inches to more than a foot. Repeated elevation data over time of the irrigated site can be compared to that of the non-irrigated control sites adjacent to the Living Filter in order to determine a rate of subsidence induced by continuous wastewater irrigation. By tracking the dolines over time we can determine whether or not irrigation using secondary treated wastewater has a significant impact on the regression of dolines.

Geological Society of America Abstracts with Programs. Vol. 49, No. 6

doi: 10.1130/abs/2017AM-300222

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