Daly
Water overview
Significant water events
There were no significant water events in the Daly region during the 2013–14 year.
Soil moisture
Figure W1 compares annual average soil moisture volumes for the 2013–14 year with those of the 1970–2014 period, expressed in decile rankings for the Daly region. The soil moisture is based on a simple conceptual representation of soil water storage and transfer processes averaged over a 5 km x 5 km grid cell derived from the Australian Water Resources Assessment system landscape model (AWRA-L) version 3.0. The model produces a soil moisture grid for the region at a daily time step, which is then averaged over the entire year to produce an annual soil moisture grid. The annual grid represents the mean daily volume of soil moisture across the region during the year.
Figure W1 Annual soil moisture deciles for the Daly region during the 2013–14 year
As shown in Figure W1, soil moisture for the majority of the region was generally average with above average soil moisture recorded in the northeast part of the region. The average soil moisture conditions are a result of generally below average rainfall which limited water availability and above average temperatures increasing actual evapotranspiration. The above average rainfall which fell in the northeast of the region contributed to the above average soil moisture in the northeast by increasing water availability. Soil moisture deficiencies in the majority of the region combined with above average evapotranspiration have contributed to below average river flows in the months of March–May, and throughout the dry season as described next in Streamflow.
Streamflow
Figures W2 and W3 show streamflow pattern, volumes and variation at two major rivers in the region:
- Daly River at Mount Nancar (Station 8140040)
- Katherine River at the Railway Bridge (Station 8140001).
The two river locations were selected for the following reasons:
- long-term flow data are available
- flows upstream of both river locations are unregulated and diversions are negligible
- both are major rivers in terms of flow volumes.
Figure P5 shows the location of the gauging stations and can be found under Surface water.
Both rivers exhibit typical wet–dry season patterns with very little flow from the months of June–November and higher volumes of flow during December–May (Figures W1 and W2). The wet season of 2013–14 was characterised by an extended period of early rainfall activity, with some more intense periods during January and February. The rainfall in January and February led to moderate flooding in the Daly River, and higher than average flows in the Katherine River. Both rivers experienced lower than average flows from March–May following the wetter months.
Figure W2 Total monthly flow along the Daly River compared to long-term average and percentiles for the river
Figure W3 Total monthly flow along the Katherine River compared to long-term average and percentiles for the river
Major water initiatives
No major water initiatives occurred in the Day region during the 2013–14 year.