 |
| Titel |
The effect of saline groundwater exchange, evaporation and variable river flows and on stable isotopes (18O and 2H) and major ion concentrations along the Darling River, NSW, Australia |
| VerfasserIn |
K. T. Meredith, C. E. Hughes, S. E. Hollins, D. I. Cendón, S. Hankin |
| Konferenz |
EGU General Assembly 2009
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250031561
|
|
|
|
|
|
| Zusammenfassung |
| Australia’s longest river, the Darling River, faces extreme pressure from drought and over
extraction of water from its catchment. The lack of detailed baseline hydrochemical and
isotopic data for the Darling River has prompted research aimed at using hydrological tracers
to assess water gains and losses within the Darling River Drainage Basin.
This study uses temporal hydrochemical and stable isotope data (18O and 2H) that has been
monitored from gauging stations along the Barwon-Darling catchment over a five-year period
from 2002 to 2007 as part of the Global Network for Isotopes in Rivers (GNIR) monitoring
programme. Stream flow data, monthly δ18O and δ2H values and major ion chemistry is
presented.
Individual flow events were found to be isotopically distinct but the LELs that develop after
these events have a very similar slope indicating similar climatic conditions across this
region. During low flow conditions, salt concentrations increase systematically, δ18O and δ2H
become enriched and d-excess becomes more negative indicating significant evaporation.
Flow events input isotopically depleted fresh waters to the system and the d-excess returns
towards the local meteoric water line. The major ions increase in concentration at a greater
rate at Louth than they do at upstream at Bourke or downstream at Wilcannia, despite
similar decreases in flow rates for all three sites. The hydrological response of the
river to drought has had detrimental affects on the surface water system because
it provides a pathway for saline groundwater to discharge into the river system. |
|
|
|
|
|
|