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Appendix A – 100k Drainage Network

Appendix A – 100k Drainage Network

Owned by Cathie Campbell
Last updated: 23, Dec, 2024
3 min read

The 100k drainage network displays the way or course through which surface water flows from time-to-time and comprises both natural and constructed features covering the State of Queensland.  The network is segmented, concatenated and flow directed to assist with hydrological representation.

The Topographic 100k drainage network:

  • The 100k drainage network will form a connected (concatenated and segmented) network where possible.

  • The drainage network is in 2D.

  • The drainage network will flow downstream.

  • Watercourses are identified, determined, and captured in orthorectified imagery at best scale.

  • The drainage network is a fit for purpose at 1:100 000 (100k) scale of drainage features in Queensland for use in Vegetation Management, Land Administration, Emergency Management, monitoring of Climate Change, hydrological representation, and Topographic mapping.

  • Stream ordering values are assigned at specification scale 1:100 000 to identified watercourses lines. See Appendix B for further information.

NOTE: The Strahler stream order values attributed as part of the Statewide 100k drainage network and WatercourseLines dataset are not consistent with the definition of a watercourse in the Water Act 2000. The Water Act 2000 does not use stream order to determine WIM regulated watercourses and drainage features.

The Topographic 100k drainage network features will agree with the following specifications:

  • All watercourses, including dry watercourses and areas where water can be ponded, are captured and an attribute for perenniality is included in the attribute table. The feature is attributed as either Ephemeral, Intermittent, Perennial or Near Perennial in the Perenniality column.

  • In cases where a linear water feature dissipates, the water feature is linked, if possible, to the same downstream linear water feature by the route of most likely flow using an Underground Connector feature.

  • In cases where a linear water feature disappears beneath the landscape or a significant urban development through pipes or tunnels and the same linear water feature reappears downstream, the features are linked by a DEM Connector feature along the route of most likely flow. If the route of most likely flow cannot be determined, a straight line joining the two ends is to be used.

  • In cases where a linear water feature travels under a railway or major road through pipes and or the structure is of significant construction, clearly visible in imagery, then the linear water feature is linked to the same downstream feature by a Culvert feature in the direction of flow.

  • Drainage patterns are made up of both linear (narrow streams) and polygon features (such as watercourse areas, lakes, and swamps) and consequently do not constitute a rigorous linear network. To allow linear analysis of drainage networks an artificial feature called a "Connector" has been added to the data.

  • This Connector feature is used to connect linear watercourse features where they are separated by water areas such as lakes, swamps and watercourses depicted as area features. The Connector will only be used if there is flow across a waterbody polygon feature. If there is only inflow to a lake and no outflow the Connector feature will not be used.

  • If more than one Watercourse flows into a waterbody feature, then each watercourse is continued by a Connector to join with other Connectors inside the waterbody area to form a continuous drainage network.

  • Isolated farm dams and waterholes or lakes can be the exception to the continuous network when these features are not directly on a watercourse.

  • The full supply level or as best that can be determined is shown for waterbody areas. For major features such as large dams where the full supply level is documented, this value is included in the attribute table of the data.

  • All waterbodies that can be determined in the imagery are captured.

  • Generally, lakes less than 625 m² captured at 1:25 000 specifications or less than 1,200 m² for data captured at 1:100 000 specifications are displayed as points and greater than 625 m² for data captured at 1:25 000 specifications or greater than 1,200 m² for data captured at 1:100 000 specifications are displayed as polygons and at the full supply level (FSL) or the closest to FSL that can be determined.

  • Connectors are used to join watercourses through Lakes and Watercourse Areas. For Areas Subject to Inundation, a Watercourse feature is shown. For Swamps, where the watercourse flowing through the swamp is not visible, a Connector feature is used to join through the swamp. Where the course of the watercourse is clearly visible, a Watercourse feature is used.

  • Features to be progressively updated throughout Queensland.

 

 

The 100K drainage network consists of linear features e.g. canals, channels, connectors, culverts, DEM connectors, drains, watercourse, and connectors underground.

The drainage pattern consists of all linear, and polygon water features encompassing the drainage network and waterbody areas, e.g. Lakes, flats, etc. 

 

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