Sources of data and definitions

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Wetlands condition data have been provided by the Australian Centre for Tropical Freshwater Research (ACTFR) and form part of a Wetlands Condition report for the Burdekin Dry Tropics region

Wetland condition data have been summarised in a table and a map produced for each of the 52 sub-catchments. (Wetland condition maps are found in the Map section of each sub-catchment).

Sources of data

Data for the summary tables and wetland condition maps have been sourced from the following Queensland Government Departments:

  • Environmental Protection Agency (EPA). Data were sourced from the “Queensland Wetlands Programme Statewide Mapping Project – Release 1, 8th November 2006”. This project mapped wetlands using satellite imagery from 6 different years (5 dry season scenes and 1 wet season scene); regional ecosystem vegetation mapping; and existing topographic maps. The categories used in this inventory exercise, were: wetland type, using a classification based Blackman et al. (1992); and water regime.

  • Department of Primary Industries and Fisheries (DPI&F). Inundation data was sourced from spatial data that has been created by identifying inundated waterbodies from 20 years of satellite imagery of dry season scenes (1986-2005) and a percentage showing how many of those years a particular water body was inundated. A stream network from Geoscience Australia (GA) (1:250 000 Geodata version 2) was added to some of the maps where wetland connectivity was unclear.

The Wetland maps found on this site were created by ACTFR and show EPAs wetland type, EPAs water regime, DPIFs inundation frequency, EPAs floodplain data, GA named waterbodies and 1:100,000 topo maps.

Section Definitions

1. Names for inventory units were taken from GA 250K geodata or GA 100K topomaps where available (eg, for large individual wetlands). Where suitable names were not available (eg, for river reaches), we have supplied nominal names to identify the inventory units being discussed.

2. Inventory unit type was taken directly from Queensland EPA statewide mapping.

3. Permanence of inundation refers to the likelihood of water being present somewhere within the inventory unit. The regime is applied to the most permanent part of the inventory unit. Thus, even if there is only one permanent waterhole within an entire, otherwise dry reach, the inventory unit is considered to have permanent inundation. Its contribution to the overall unit can be judged by the number and percentage of waterbodies given in those classes below. For example, two large river reaches may contain 1 and 10 permanent waterbodies respectively but both are considered to have permanent inundation (because there is always some water present within the reach). However, the second reach will have a greater number of waterbodies present and a greater proportion of the surface area covered by water.

For permanence of inundation, the following definitions apply:

  • Permanent = water present all year in most (>50%) years

  • Semi-permanent = water is present well past the wet season (eg, to middle of dry season) in most years and all year in high rainfall years.

  • Seasonal = water is present whenever an average or better than average wet season occurs, and remains until at least the end of the wet season

  • Intermittent = water is present after rain but seldom present for an entire season

  • Ephemeral = presence of water is rare

4. Flushing frequency/flow refers to the likelihood of surface flow being present and the following definitions apply:

  • Permanent = surface flow is present all year in most (>50%) years

  • Semi-permanent = surface flow is present well past the wet season (eg, to middle of dry season) in most years and all year in high rainfall years.

  • Seasonal = surface flow occurs whenever an average or better than average wet season occurs, and remains until at least the end of the wet season

  • Intermittent = surface flow is present after rain but seldom present for an entire season

  • Ephemeral = surface flow is rare

5. Number of permanent waterbodies is an approximation, based on expert judgement of the number of waterbodies meeting the above definition of permanent.

6. Proportion of permanent waterbodies is the proportion of surface area of the inventory unit that is permanently covered by water. Judgement was based on relative differences between inventory units. This varied between riverine and lacustrine/palustrine units. For example, 5% surface area covered by permanent water is quite high for a riverine inventory unit but low for a lacustrine/palustrine inventory unit. It can be seen from this that only inventory units that are classed as having permanent inundation can have any rating within the number and proportion of waterbody categories (ie, inventory units that are not classified as having permanent inundation cannot by definition, have any permanent waterbodies present).

7. Description. RAMSAR wetlands, wetlands listed in the Directory of Important Wetlands in Australia, and National Parks and reserves have been displayed in the maps and identified in a short description, showing the level of protection of (part of) the inventory units.

8 -11. Water quality and aquatic habitat were rated by the authors of the report for their departure from natural pre-European condition and their functionality. This difference is based on the knowledge that not all departures from natural condition result in loss of functionality. For example, where the hydrology of a wetland has changed from semi-permanent to permanent as a result of irrigation, that represents a change from natural, but the wetland may still be performing most of its natural functions (eg, as fish and bird habitat). Alternatively, wetlands that have retained their natural pre-European hydrology but are afflicted by aquatic weeds may have more significant loss of functionality.

12. The values of each inventory unit were determined from expert judgement based on the perceived overall ecological values of the inventory unit. A value of 5 does not necessarily imply any degradation or that the inventory unit has no ecological value, it only implies that its ecological values are relatively less than other inventory units.

13. Degree of confidence represents the confidence the authors have in their ability to judge the overall criteria. The degree of confidence varies for each descriptor but only a single ranking is provided, this being the overall average. For instance, confidence in the hydrology regime may be high but confidence in the functionality low. These have not been rated separately but averaged. Confidence levels of ‘1’ represent inventory units the authors are familiar with and have visited and studied. Confidence levels of ‘5’ have not been visited by any of the authors. Confidence levels in between these may include sites the authors have visited briefly or have obtained separate information from other sources.

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