Complementary use of tracer and pumping tests to characterize a heterogeneous channelized aquifer system in New Zealand
The combined use of pumping and tracer test data enabled the derivation of equivalent average hydraulic conductivities (K avg) for each test in a heterogeneous channelized alluvial aquifer, whereas K values of the preferential flow paths were two orders of magnitude higher. Greater and earlier drawd...
Gespeichert in:
Veröffentlicht in: | Hydrogeology journal 2008-09, Vol.16 (6), p.1177-1191 |
---|---|
Hauptverfasser: | , , , , |
Format: | Artikel |
Sprache: | eng |
Schlagworte: | |
Online-Zugang: | Volltext |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
Zusammenfassung: | The combined use of pumping and tracer test data enabled the derivation of equivalent average hydraulic conductivities (K avg) for each test in a heterogeneous channelized alluvial aquifer, whereas K values of the preferential flow paths were two orders of magnitude higher. Greater and earlier drawdown was generally observed along preferential flow lines in a pumping test, within an array of 21 wells. The study aim was to characterize hydraulic properties of a channelized aquifer system in New Zealand by combining tracer and pumping test data. Estimates were able to be made of the percentage of highly permeable channels within the profile (~1.2%), effective porosity that reflected the maximum fraction of highly permeable channels within the aquifer ([Greek Phi symbol] eff ₋pc ~0.0038), and flows through highly permeable channels (~98%) and the sandy gravel matrix material (~2%). Using [Greek Phi symbol] eff ₋pc, a tracer test K avg value (~93 m/day) was estimated that was equivalent to pumping test values (~100 m/day), but two orders of magnitude smaller than K calculated solely from transport through permeable channels (K pc ~8,400 m/day). Derived K values of permeable and matrix material were similar to values derived from grain size distribution using the Kozeny-Carman equation. |
---|---|
ISSN: | 1431-2174 1435-0157 |
DOI: | 10.1007/s10040-008-0291-4 |