T72 Approaches to Characterizing Groundwater Flow Systems at the Watershed-Scale for Water Management and Regulation (Posters)

Sunday, 25 September 2016
9:00 AM - 5:30 PM
Exhibit Hall E/F

CONTROLS ON GROUNDWATER RESOURCES IN LOESS-COVERED VOLCANICS: CHEMICAL AND ISOTOPIC ANALYSES OF BANKS PENINSULA SPRINGS, NEW ZEALAND

Paper number: T72-8
Program: Technical Sessions
Time: 9:00 AM – 5:30 PM

Authors

Abstract

This study uses chemical and isotopic analyses to determine the source waters and define resources for individual springs on Banks Peninsula, Canterbury, New Zealand. Three types of springs are found across the peninsula: loess, volcanic, and fault-controlled thermal springs. ẟ18O and ẟ2H are used to identify the origins of spring water, and tritium is used to calculate residence time in the rock. ẟ18O and ẟ2H values reveal that loess and volcanic springs originate due to infiltration of local meteoric water at low to moderate elevations (ẟ18O: -8.00 to -6.81 ‰ V-SMOW; ẟ2H: -52.40 to -44.53 ‰ V-SMOW), while thermal springs contain fluids sourced from higher-elevation Southern Alps precipitation and transported via faults (ẟ18O: -9.46 to -8.09 ‰ V-SMOW; ẟ2H: -64.19 to -60.15 ‰ V-SMOW). Chemical analyses indicate most water from these springs is suitable for human consumption if springs are maintained, i.e. not accessible by stock. New data have been supplemented by data from older, previously unpublished research. This data is presently being used to update hydrogeological models of Banks Peninsula and its springs. Using this information to better constrain source and catchment areas for springs is crucial to the development of appropriate resource management plans. This ensures the springs’ long-term utility for municipal and agricultural applications across Banks Peninsula.

Geological Society of America Abstracts with Programs. Vol. 48, No. 7

doi: 10.1130/abs/2016AM-283897

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