Conference Presentation Abstract
Journal Article: Rains, Mark Cable
and Mount, Jeffery F. 2002. Origin of Shallow Ground Water
an Alluvial Aquifer as Determined by Isotopic and Chemical Procedures: Ground
Water, Vol. 40, No. 5, p. 552-563.
Abstract written by Brian M. Snelten
This study was completed where the Little Stony Creek flows into the East Park Reservoir on the east front of the Coast Range, in northern California. Identity of the origin of shallow ground water, which supports unique plant and animal habitats, is important to ensure that local ground water withdraws do not harm or endanger these habitats. Sampling of Little Stony Creek water, Hyphus Creek water, Franciscan Complex regional ground water, Great Valley Group regional ground water, and shallow ground water for deuterium, oxygen-18, temperature, pH, redox potential, conductivity, and major cation and anion concentrations was completed during the dry and wet seasons. In the wet season Little Stony Creek water is the dominant source of shallow ground water and decreases with distance from the banks of the creek. In the dry season, Little Stony Creek recharges the upper part of the alluvial valley and drops off midway through the valley where Franciscan Complex ground water becomes the predominant source of local shallow ground water as the ratio of Little Stony Creek water to Franciscan Complex water decreases down the valley. Local shallow flow turn over is high, indicating shallow ground water is dependent of recent recharge. Since the local shallow ground water flow is generally recharged by the Franciscan Complex and the Little Stony Creek waters, any increased withdrawal from the Franciscan Complex could result in lower recharge to the local shallow ground water, especially in the dry season, reducing the water availability and quality thus possibly endangering the unique plant and wildlife habitats found near the East Park Reservoir.
Last updated December 2, 2002