| Title: | Analysing the effects of forest cover and irrigation farm dams on streamflows of water-scarce catchments in South Australia through the SWAT Model |
| Authors: | Nguyen, H.H., F. Recknagel, W. Meyer and J. Frizenschaf |
| Year: | 2017 |
| Journal: | Water |
| Volume (Issue): | 9(1) |
| Pages: | |
| Article ID: | 33 |
| DOI: | 10.3390/w9010033 |
| URL (non-DOI journals): | |
| Model: | SWAT |
| Broad Application Category: | hydrologic only |
| Primary Application Category: | land use change |
| Secondary Application Category: | irrigation impacts or irrigation BMP scenarios |
| Watershed Description: | 296.4 km^2 combined Below Holland Creek, Kersbrook, and Sixth Creek, located in the state of South Australia in southeast Australia. |
| Calibration Summary: | |
| Validation Summary: | |
| General Comments: | |
| Abstract: | To assist water resource managers with future land use planning efforts, the eco-hydrological
model Soil and Water Assessment Tool (SWAT) was applied to three catchments in South Australia
that experience extreme low flow conditions. Particular land uses and management issues of interest
included forest covers, known to affect water yields, and farm dams, known to intercept and change
the hydrological dynamics in a catchment. The study achieved a satisfactory daily calibration when
irrigation farm dams were incorporated in the model. For the catchment dominated by extreme low
flows, a better daily simulation across a range of qualitative and quantitative metrics was gained
using the base-flow static threshold optimization technique. Scenario analysis on effects of forest
cover indicated an increase of surface flow and a reduction of base-flow when native eucalyptus lands
were replaced by pastures and vice versa. A decreasing trend was observed for the overall water
yield of catchments with more forest plantation due to the higher evapotranspiration (ET) rate and
the decline in surface flow. With regards to effects of irrigation farm dams, assessment on a daily time
step suggested that a significant volume of water is stored in these systems with the water loss rate
highest in June and July. On an annual basis, the model indicated that approximately 13.1% to 22.0%
of water has been captured by farm dams for irrigation. However, the scenario analysis revealed that
the purposes of use of farm dams rather than their volumetric capacities in the catchment determined
the magnitude of effects on streamflows. Water extracted from farm dams for irrigation of orchards
and vineyards are more likely to diminish streamflows than other land uses. Outputs from this
study suggest that the water use restrictions from farm dams during recent drought periods were an
effective tool to minimize impacts on streamflows. |
| Language: | English |
| Keywords: | River Torrens; water-scarce catchment; SWAT; irrigation farm dams; eucalyptus; scenario
analysis; drought |