Assessment of surface water storage options in the Flinders and Gilbert catchments. A technical report to the Australian Government from the CSIRO Flinders and Gilbert Agricultural Resource Assessment, part of the North Queensland Irrigated Agriculture Strategy

[摘要] OverviewCurrent allocations of water in the Flinders and Gilbert catchments are low, relative to their median annual streamflow (i.e. ≤ 2%). The recent release of water in the two catchments in 2013 was followed by calls for a review of the Gulf Water Resource Plan. However, further incremental releases of water for consumptive use may preclude the development of large water storages in the future. Consequently the primary purpose of this study is to provide a comprehensive overview of the different surface water storage options in the Flinders and Gilbert catchments, to help enable decision makers take a long term view of water resource development and to help inform future allocation decisions.The construction of large instream dams in the Flinders catchment would be expensive (i.e. greater than $6000/ML of water supplied in 85% of years, excluding water distribution costs and losses) and no locations in the Flinders catchment were considered to be particularly suitable for development. The better large dams in the Flinders catchment have an equivalent annual unit cost per ML of water supply in 85% of years of more than $430, excluding operation and maintenance costs, water distribution costs and losses. This is nearly twice the equivalent annual unit cost per ML of effective offstream storage (i.e. after accounting for evaporation and seepage losses from the offstream storage), storing water for 12 months of the year. Consequently offstream storages are the most promising water storage option in the Flinders catchment.The construction of the more promising large instream dams in the Gilbert catchment is estimated to cost between $1500/ML and $2000/ML of water supplied in 85% of years. These dams have an equivalent annual unit cost per ML of water supplied in 85% of years of between $100 and $140, which is considerably less than the equivalent annual unit cost per ML of effective offstream storage (i.e. after accounting for evaporation and seepage losses from the offstream storage) of at least $140 and $240, storing water for 4 and 12 months of the year respectively. Furthermore the Gilbert River does not have many locations suitable for offstream storages due to its highly permeable soils and substrata. In select locations the soils adjacent to the Einasleigh River may be suitable for offstream storages.The investigation of a potential dam site generally involves an iterative process of increasingly detailed studies over a period of years, occasionally over as few as 2 or 3 years but often over 10 or more years. For any of the options listed in this report to advance to construction, far more comprehensive studies would be needed. Studies at that detail are beyond the scope of this regional scale resource assessment.Instream water storagesThis report documents the results of an assessment of 22 potential dam locations, 15 in the Flinders catchment and 7 in the Gilbert catchment. One of the potential dam locations in the Gilbert catchment had not previously been investigated (i.e. Dagworth). The remaining 21 potential dam locations had been investigated and documented in some form prior to the Assessment. The extent of prior investigations ranged from vague and isolated references to potential locations (e.g. Mount Alder and Mount Noble) to detailed hydrological and geotechnical investigations (e.g. Cave Hill and Glendower). A difficultly in comparing the outcomes of these studies was that they were undertaken by a wide range of organisations, at different times, using different methods and with varying degrees of rigour. Furthermore, many of the reports were never officially published or only exist as hardcopy documents in the Queensland State Government or SunWater archives.As part of the Assessment, all available published and unpublished literature on the previously identified potential dam locations were accessed from the Queensland State Government and SunWater archives. These studies were reviewed and a...

[发布日期] 2013-12-19 [发布机构] CSIRO

[效力级别] Sedimentology [学科分类] 地球科学(综合)