Significant water events
The wet season of the 2011–12 year had two monsoonal events that caused high rainfall and flooding within the Daly region.
The first event was a result of Tropical Cyclone Grant over the Christmas period (21–29 December 2011). This event caused record rainfalls in the catchments of the Fergusson, Cullen and Edith rivers. Major flooding was experienced in these rivers as well as in some parts of the lower Daly River on 27 December 2011.
The second event occurred between 9–19 March 2012 where heavy rainfall occurred across the lower and middle parts of the Daly region as a result of a tropical low. Minor flood levels were reached in the Cullen River in early March and streamflow in the lower Daly River approached major flood levels near the town of Daly River.
Figures W1 and W2 show streamflow pattern, volumes and variation at two major rivers in the region:
- Daly River at Mount Nancar (8140040)
- Katherine River at the Railway Bridge (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.
Both rivers exhibit typical wet-dry season patterns with very little flow from the months of June to November and higher volumes of flow during December to May (Figures W1 and W2). Tropical Cyclone Grant in December managed to wet the catchment and produce higher volumes of flow in January in the Daly River, and January–February in the Katherine River. The tropical low in March caused large volumes of flow during April in both the Katherine and Daly rivers.
Figure W1 Graph of total monthly flow along the Daly River during the 2011–12 year compared with long-term percentiles
Figure W2 Graph of total monthly flow along the Katherine River during the 2011–12 year compared with long-term percentiles
Major water initiatives
No major water initiatives were reported during the 2011–12 year.