Publication Date
April 2018
Abstract
Infrequent and episodic turbidity events within the karst spring at the Albert Powell Trout Hatchery in Maryland's eastern Great Valley threatened late winter fry populations. Turbidity events in early winter 2016-2017 prompted detailed geologic, dye tracing, and resistivity studies. The hatchery spring lies at the juncture of a northeast trending thrust fault and a northwest trending cross strike fault. Dye tracing study along these structures produced mixed results. Fluorescein tracing, injected 1,500 m north, and upstream of the spring was used to test the conductivity along the Beaver Creek fault and Beaver Creek. This dye was not conclusively identified at any of the surrounding recovery sites. Rhodamine WT injected more than a kilometer northwest of the spring, and along the trend of the cross fault, was detected at both the hatchery spring and surrounding recovery sites after about one week. 2D resistivity studies attempting to identify subsurface voids along the cross-fault trend show a high resistivity anomaly possibly indicating an air-filled void and warrant further investigation. The study suggests that while faulting plays a role in direction of ground water movement, turbidity events appear to be most prone during periods of lowered flow.
DOI
https://doi.org/10.5038/9780991000982.1045
Factors Affecting Karst Spring Turbidity in Eastern Washington County, Maryland
Infrequent and episodic turbidity events within the karst spring at the Albert Powell Trout Hatchery in Maryland's eastern Great Valley threatened late winter fry populations. Turbidity events in early winter 2016-2017 prompted detailed geologic, dye tracing, and resistivity studies. The hatchery spring lies at the juncture of a northeast trending thrust fault and a northwest trending cross strike fault. Dye tracing study along these structures produced mixed results. Fluorescein tracing, injected 1,500 m north, and upstream of the spring was used to test the conductivity along the Beaver Creek fault and Beaver Creek. This dye was not conclusively identified at any of the surrounding recovery sites. Rhodamine WT injected more than a kilometer northwest of the spring, and along the trend of the cross fault, was detected at both the hatchery spring and surrounding recovery sites after about one week. 2D resistivity studies attempting to identify subsurface voids along the cross-fault trend show a high resistivity anomaly possibly indicating an air-filled void and warrant further investigation. The study suggests that while faulting plays a role in direction of ground water movement, turbidity events appear to be most prone during periods of lowered flow.
