 |
| Titel |
Modelling acidification, recovery and target loads for headwater catchments in Nova Scotia, Canada |
| VerfasserIn |
C. J. Whitfield, J. Aherne, P. J. Dillon, S. A. Watmough |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1027-5606
|
| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 11, no. 2 ; Nr. 11, no. 2 (2007-03-02), S.951-963 |
| Datensatznummer |
250009226
|
| Publikation (Nr.) |
 copernicus.org/hess-11-951-2007.pdf |
|
|
|
|
|
| Zusammenfassung |
| The response of twenty acid-sensitive headwater catchments in Nova Scotia to
acidic deposition was investigated for the period 1850–2100 using a dynamic
hydrochemical model (MAGIC: Model of Acidification of Groundwater in
Catchments). To ensure robust model simulation, MAGIC was calibrated to the
long-term chemical trend in annual lake observations (13–20 years). Model
simulations indicated that the surface waters of all twenty catchments
acidified to the 1970s but showed subsequent recovery (increases in acid
neutralising capacity (ANC) and pH) as sulphate deposition decreased.
However, under proposed future emissions reductions (approximately 50% of
current deposition) simulated ANC and pH will not return to estimated
pre-industrial levels by 2100. An ANC of 20 μmolc L−1 and pH
of 5.4 were defined as acceptable chemical thresholds (or critical chemical
limits) for aquatic organisms in the current study. Under the proposed
emissions reductions only one catchment is predicted to remain below the
critical limit for ANC by 2100; three additional catchments are predicted to
remain below the critical limit for pH. Dynamic models may be used to
estimate target loads, i.e., the required deposition reductions to achieve
recovery within a given time. Setting target loads at approximately 30%
of current depositions would allow three of the four lakes to reach the
chemical criteria by 2030. In contrast to the generally good prognosis for
surface waters, soils lost an average of 32% of estimated initial base
saturation and recovery is estimated to be very slow, averaging 23% lower
than pre-acidification levels in 2100. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|