Final Summary Western Catchment Management Authority ...archive.lls.nsw.gov.au/.../pdf_file/...river-scoping-study-summary.pdf · Western Catchment Management Authority ... This study

Western Catchment Management Authority

Final Summary 2008Final Summary

Warrego River Scoping Study W E S T E R N

Contact Details

Western CMA Offices:

45 Wingewarra StreetDubbo NSW 2830Ph 02 6883 3000

32 Sulphide StreetBroken Hill NSW 2880Ph 08 8082 5200

21 Mitchell StreetBourke NSW 2840Ph 02 6872 2144

62 Marshall StreetCobar NSW 2835Ph 02 6836 1575

89 Wee Waa StreetWalgett NSW 2832Ph 02 6828 0110

Freecall 1800 032 101www.western.cma.nsw.gov.au

WMA Head Office:

Level 2, 160 Clarence StreetSydney NSW 2000 Ph 02 9299 2855Fax 02 9262 6208E [email protected] www.wmawater.com.au

Warrego River Scoping Study – Summary1.

Project Rationale and Objectives1.1. The Queensland portion of the Warrego is managed under the Warrego, Paroo, Bulloo and Nebine Water Resource Plan (WRP) (2003) and the Resource Operation Plan (ROP) (2006). At present, there is no planning instrument in NSW. As such, there was concern in the community that available information be consolidated and assessed for usability for the purposes of supporting development of a plan in NSW and for future reviews of the QLD plan. There was also concern that an assessment be undertaken of current hydrologic impacts due to water resource development and potential future impacts.

As a result, the Western Catchment Management Authority (WCMA) commissioned WMAwater to undertake a scoping study for the Warrego River and its tributaries and effluents. This study was to synthesise and identify gaps in knowledge / data relating to hydrology, flow dependent environmental assets and water planning instruments.

The key objectives of the study include:

Provide an overview of the surface water hydrology of the Warrego River and its tributaries. 1.

Review existing literature on flow dependent environmental features of the region.2.

Summarise available hydrology related data.3.

Evaluate the impacts that water resource development has had, or could have, upon the regional flow regime.4.

Identify gaps in the available data sets, assessment tools and performance indicators and make recommendations to 5. assist future water resource planning and management.

Study Area1.2. This scoping study examines the major distributary systems, in addition to the Warrego itself, as illustrated in Figure 1

Floodout channels of the Warrego system, May 2008.

warrego river scoping study - page 2

Figure 1 - Hydrological Features of the Warrego Hydrologic data availability and an assessment on the impact of development on the flow regime have been presented separately for seven hydrologic regions identified for the purposes of this study. These are:

1. Warrego Basin down to Wyandra

The upper part of the basin drains a large area with numerous creeks and rivers entering the Warrego River upstream of Wyandra.


2. Noorama and Widgeegoara Creeks

These effluents leave the Warrego downstream of Wyandra and head south east, occasionally spilling into the Nebine.

3. Warrego River from Wyandra to NSW Border

Downstream of Wyandra the river changes from a gaining river to a losing river due to the numerous effluents which leave the river.

4. Cuttaburra Creek

The Cuttaburra Creek has it’s main offtake from the Warrego immediately downstream of Cunnamulla weir however other high flow offtakes occur upstream of the weir and some 20-30 km downstream of the weir. Flows from the Cuttaburra occasionally connect with floodwaters from the Paroo/Darling - on average every 15 years (QDNR, 2004).

5. Thurrulgoonia and Tuen Creeks

Numerous effluents leave the Warrego downstream of Cunnamulla heading in a south easterly direction draining into extensive floodplain areas. Two key creeks in the region are the Thurrulgoonia and Tuen.

6. Irrara Creek

The Irrara Creek leaves the Warrego just upstream of the NSW border and re-connects upstream of Fords Bridge. The Irrara also feeds the Kerribree and Green Creeks; the latter may connect back into the Warrego downstream of Fords Bridge.

7. Warrego River from Barringun to Darling

The NSW section of the Warrego is examined separately due to different regulatory arrangements. A special section on cross border flows is included in the report as this is a key performance objective of the QLD ROP and warrants careful consideration and clarification in this study due to stakeholder concerns over this objective.

Methodology1.3.

Literature and Data Review and Gap Analysis

This project was based on a desktop study that collates and reviews information drawn from existing publications, reports and datasets.

Some stakeholder consultation was undertaken from 5th – 7th May 2008, primarily for the purposes of obtaining copies of existing reports and information. Consultation also assisted the authors in obtaining a better appreciation of the region and highlighted a number of landholder concerns regarding water management. Given the scope of the project, extensive consultation was not possible. The consultation conducted was focused on landholders in the Lower Warrego in accordance with the requirements of the project brief.

Impact Assessment

The assessment of flow regime change due to development has been quantified through use of modelling data obtained from the Queensland Department of Natural Resource and Mines (QDNRM). Whilst the QLD model extends into NSW, there is scope for improvement in the representation of flows in the NSW section of the system. Therefore, WMAwater

The consultants gained information by interviewing numerous landholders, including Paul and Debbie Kaluder of Naree Station, located on the

Cuttaburra Channel.


1 The Noorama and Widgeegoara are not included. Estimations for Cuttaburra, Upper and Lower Warrego are based on a sample area of these zones which covers a significant proportion of area inundated but not the entire area.

developed an IQQM model for the NSW portion of the system using information provided from the NSW Department of Water and Energy. The information included licensing access conditions and details of infrastructure and cropping. It is important to note that due to the lack of streamflow data the model has not been verified and many additional improvements are possible.

The two IQQM models were used to assess impacts on low flows, minor and moderate flooding for a number of sites on the Warrego and for major effluent creeks. Impacts on ecological assets were limited to “Directory of Important Wetland” sites, which have been assessed where there was suitable model data and sufficient information regarding the hydrological requirements of the wetlands. The assessment of ecological impacts associated with flow regime changes was limited to very broad comments. More sophisticated assessment tools are required to properly assess these impacts, as is discussed in the full report.

The impact assessments presented in this scoping study assume that the available historic climate records are representative of future climate patterns. This assumption may not be valid, not only due to climate change, but also because the level of climate variability that might have occurred may not be well represented in the relatively short period of climate records available. The impact of climate change on the water resources and ecosystems of the Warrego was examined by CSIRO (2007), however a more detailed analysis of CSIRO’s results is warranted. It has not been possible to undertake this analysis for this report and as such it is recommended for future studies.

Overview of surface water hydrology1.4. Unlike southern basin rivers which generally experience some level of flow throughout the year, the Warrego is an ephemeral river. Flows generally occur in late summer to early autumn although winter flows also occur in some years. In addition to the seasonal basis of flows in the Warrego, wet and dry phases across groups of years can be established from the flow record.

Wyandra is the point at which the Warrego changes from a river that is generally gaining in flow volume to generally losing in flow volume. The flow volume downstream of Wyandra is dramatically reduced due to the distributary nature of the system. For example, the average flow at Wyandra is approximately 550 GL per year whilst it is only 83 GL per year at Fords Bridge.

Widespread flooding occurs periodically in the Lower Warrego, due to the gently sloping terrain, low banks and meandering nature of the drainage profile. These floods, which can occur without local rainfall, are highly desirable for maintaining fertility of the floodplain (Mottell, 1998). Many areas also rely on local runoff in addition to river flows.

The total area inundated in the Warrego has been evaluated by several authors:

Mottell (1998) estimated, through community consultation, that a total of 457,772 ha is inundated in a major flood.o

Kingsford et al. (2002) estimated historic areas of inundation based on analysis of Landsat imagery. The maximum o area inundated was 284,410 ha in 1990 however it is important to note that this study does not represent total area of inundation in the basin1.

CSIRO (2007) reported that the maximum inundation area is approximately 2,066,000ha based on automated analysis o of MODIS satellite imagery over the 2000-2006 period and extrapolation of this to 1990 – 200 period based on flow data.

Overview of Flow Dependent Environmental Features 1.5.

Categories of Assets1.5.1. Flow dependent assets can be both structural and functional aspects of aquatic ecosystems. Structural aspects are generally the different types of physical aquatic habitats, eg rivers, floodplains, lakes, wetlands, etc. Functional aspects are generally the processes that are critical to providing the existence of the biota of aquatic ecosystems such as primary production, organic


carbon dynamics, food web interactions, etc.

The flow dependent environmental assets for the Warrego have included instream waterholes, terminal and floodplain wetlands, and various vegetation communities. These assets support a wide variety of fauna. For the purposes of reporting the flow dependent assets of the Warrego have been grouped into the following structural categories:

Instream (waterholes including fish, water quality)•Riparian (riparian vegetation)•Floodplains, Lakes and wetlands (vegetation types, waterbird populations).•

The following information for these categories was obtained from published reports and records from landholders.

Waterholes1.5.2. Waterholes on the Warrego River system provide a critical refuge for fish and waterbird populations during no flow periods. Refilling events for waterholes sustain fish populations, allows for movement between waterholes and into the river channel and act as a stimulus for some fish species to undertake recruitment events. The shape of waterholes is also important for sustaining different fish populations.

Detailed assessment of waterholes and fish populations has been undertaken for some sites in Queensland by Balcombe et al. (2006). Compared with other rivers in the Murray-Darling Basin, this study found that the Warrego waterholes had higher abundances and more species. There was also a relatively low proportion of alien species. The authors considered the Warrego to be “a model dryland river for the further investigation of ecological processes sustaining fish in variable environments both in the MDB and other similar systems.”

Although waterholes exist in NSW, particularly along the Cuttaburra and lower Warrego, no similar assessment has been undertaken. Preliminary information on waterholes in NSW was collated during this study, through topographic maps and interviews with residents. This information can be found in Appendix A of the main report. While the locations of waterholes in NSW are largely known, important information on their physical characteristics, water persistence, response to different flow events and aquatic biota is not available in a consistent and systematic framework. Consequently, it is recommended a rigorous inventory of waterholes on the Warrego be undertaken, particularly for the NSW portion.

Water Quality1.5.3. Water quality is an important factor for the health of aquatic ecosystems as many naturally occurring chemicals, compounds and conditions (eg temperature and light) in water are needed for a range of functions, but also chemical contaminants can also cause a range of ecosystem dysfunctions. The importance of water quality is recognised in the FARWH approach to assessing ecosystem condition (AWR 2005).

Water quality information has been collected from spot samples at several locations for the Warrego River since the 1960s, the record for most stations is sporadic, either due to the truncated nature of water quality monitoring programs or the intermittency of flow events, or both.

Analysis and reporting of the water quality results is only in very general terms, eg DWR (1990) and DNR (2000). Therefore it is difficult to develop an informed picture of the water quality characteristics of the river and/or changes over time. With the intensification of landuse in the catchment, it is likely water quality characteristics will change. There has been no pesticide sampling undertaken, yet landuse intensification often involves increasing use of these chemicals.

A detailed analysis and reporting of the existing water quality information is required, along with the identification of additional risks and the appropriate level of monitoring and reporting required to inform resource managers.

Brolgas Grus rubicunda live in wetlands and on floodplains.


Riparian assets1.6. Riparian areas are known to provide a range of important ecosystem functions such as flora and fauna habitat, organic matter exchanges, filtering of soils particulates and nutrients with adjacent water ways. The importance of riparian areas is recognised in the FARWH approach to assessing ecosystem condition (AWR 2005).

Hale et al. (2008) have recently completed a report of the riparian vegetation of the Warrego and Cuttaburra catchments in NSW as part of a wider intersecting streams (and lower Bogan River) study. The study involved mapping and riparian zone condition assessment components.

Riparian woodlands likely in the region and subject to mapping and condition assessment were:

River Red Gum open forest and woodland •Black Box woodland •Coolabah – River Cooba– Lignum woodland •Coolabah open woodland with chenopod/grassy ground cove •Yapunyah woodland of Cuttaburra-Paroo River system•Poplar Box-Coolabah floodplain woodland •

The Warrego had 5 sites of medium overall condition and 4 of poor condition. The Cuttaburra had 2 of poor condition and 3 with very poor condition. These results are similar to other rivers which were studied.

Floodplain, Lakes and Wetland Assets1.7. Wetlands and waterbirds are the most studied aquatic assets of the Warrego. The Warrego wetlands are considered to be of critical importance to waterbird populations of the Murray-Darling Basin.

Nationally important wetlands/ lakes/ waterholes have been identified since 1993 (ANCA, 1993). EA (2001) provides the most recent listing of nationally important wetlands (DIWA wetlands) in the Warrego system. The large number of listings attests to the overall significance of the catchment for wetlands. Figure 1 illustrates the location of these sites. The information content for several of the DIWA sites on the Directory database is quite limited. Consolidation of the wetland and waterbird information should be undertaken and the Directory database updated.

Where sufficient information on the water requirements of a DIWA site is available, the impacts of flow regime changes due to development have been evaluated in this study. This assessment has been summarised in Section 1.9.2.1.

Hydrology Data1.8. Figure 2 to Figure 8 summarise the available data for each region including:

Rainfall gauges•Evaporation gauges•Official streamflow gauges•Unofficial stream height gauges•IQQM model data•Water allocations and conditions•Storage infrastructure•

Vegetation thrives along the Cuttaburra Channel.


Hydrologic Data Available:Rainfall gauges: o

30 gauges used in IQQM model (see red raindrops on map)

48 additional BOM gauges not used in IQQM model (see blue raindrops on map)

Evaporation gaugeso : Charleville (1954-1996)

Rated streamflow gauges: o Augathella, opened 1/10/1967 1.

Charleville (closed), 13/09/1926 –31/01/19782.

Ward River @ Binnowee, opened 2/12/19993.

Wyandra, opened 27/02/19674.

BOM flood warning gauges:o 1. Drensmaine @ Nive River, opened 3/07/1991

2. Lochinvar @ Warrego River, opened 3/07/1991

3. Wetlands @ Hoganthulla Creek, opened 3/07/1991

4. BiddenhamTM @ Nive River, opened 1/09/1984

5. Oakpark @ Ward River, opened 19/03/1996

6. 27 Mile Garden @ Warrego R, opened 1/07/1982

7. Warilda @ Langlo River, opened 18/03/1996

8. Charleville @ Warrego River, opened 1/09/1926

9. RaceviewTM @ Bradley Creek, opened 14/01/2000

10. Authoringa @ Angellala Creek, opened 22/05/1984

11. Bakers Bend @ Warrego River, opened 1/09/1978

12. Murweh @ Warrego River, opened 1/09/1956

IQQM modelling data:o Climatic period of model data: 1889 - 2006

Gauged locations calibrated in model:

Augathella - model replicates flow well over full 1. flow regime

Charleville – model replicates flow regime well 2. for flows above 1000 ML/D however below this model overestimates flows.

Wyandra – model replicates flow well over full 3. flow regime except that the model has a slightly longer duration of zero flows

Figure 2 - Warrego River to Wyandra – Hydrologic Data Summary

Unsupplemented water allocations: o 2,170 ML total nominal volume located at:

l 260 ML on the Ward River

l 240 ML on Warrego near Charleville

l 1,670 ML on Warrego downstream of Angellala Creek junction

There are no restrictions on when extractions occur except for one license which has a commence to extract restriction based on flows at Wyandra. This license has a large allocation (600ML) and extractions may occur once:

- The peak has passed Wyandra and the flow rate there exceeds 1,100 ML/Dor- the flow at Wyandra exceeds 13,400 ML/D

A maximum extraction rate is specified for each license. The average maximum extraction rate, calculated by weighting each rate by the size of the allocation, is 9.8 ML/D

Estimated that 980 ML unactivated

Estimated Constructed Storages (non-licensed) as of 1997 o (QDNRM, 2004):

Instream/gully dams: 616 structures, total storage approx 17.4 GL

Other dams: 1,156 structures, total storage approx 8.7 GL

Water Resouce Development:



2 gauges along creeks used in IQQM model (see red raindrops on map). No rainfall runoff modelling performed for the creeks however.


Evaporation gaugeso : Gilruth Place (east of Cunnumulla) (1963-1967)

Rated streamflow gauges: o Creek are ungauged

BOM flood warning gauges:o BOM gauges on creeks

Other known stream-height gauges:o Known gauges on creeks however likely that some landholders have kept records

IQQM modelling data:o Climatic period of model data: 1889-2006

Un-gauged locations estimated in model:

Noorama and Widgeegoara lumped 1. start of system - loss from Warrego to creeks estimated through comparison of simulated and recorded flows at Cunnumulla

Noorama and Widgeegoara lumped at 2. border/inflow to Nebine - Streamloss and routing upstream of border estimated based on Nebine Creek residual inflows.

Figure 3 - Noorama and Widgeegoara Creeks - Hydrologic Data Summary

Unsupplemented water allocations: o Only one license which is located in the Widgeegoara and has a nominal volume of 3,000 ML

Extractions under this license cannot occur until there is 10 ML/D at the point of take

Maximum extraction rate: 87 ML/D

Estimated Constructed Storages:o Limited development however details unknown




2 gauges downstream of Wyandra used in IQQM model (see red raindrops on map)


Evaporation gaugeso : nil

Rated streamflow gauges: o Warrego River @ Wallen, opened 2/11/20051.

Cunnamulla Weir, opened 16/01/19922.

Warrego River at Barringun (closed), 13/02/1968 - 3. 31/01/1981

Warrego at Barringun No. 2, opened 1/01/1993 4.

BOM flood warning gauges:o 1. Cunnamulla Bridge @ Warrego River, opened 1/08/1984

2. Rocky @ Warrego River, opened 4/11/1996

Other known stream-height gauges:o (Dates are as indicated by Mottell, 1998)

1. Goolburra: 1973 - 1990

2. Baroona: 1942 - 1997

3. Glencoe: 1981 - 1997

4. Rocky: 1945 - 1997

5. Coonberry Plains: 1945 - 1995



Cunnamulla - model replicates flow reasonably 1. well over full flow regime. Model slightly underestimates flows around 1000 ML/D and overestimates flows below 100 ML/D

Barringun - poor calibration, model generally 2. overestimates flows and low coefficient of determination/efficiency

Figure 4 - Warrego from Wyandra to NSW Border – Hydrologic Data Summary

Supplemented water allocations: o 2,612 ML total nominal volume

Unsupplemented water allocations: o 32,078 ML total nominal volume

Most allocations have restrictions on when water may be extracted based on minimum flows required at Cunnamulla weir. Each allocation has different minimum flows requirements.

A maximum extraction rate is specified for each license. The average

maximum extraction rate, calculated by weighting each rate by the size of the allocation, is 186 ML/D

Estimated Constructed Storages (non-licensed) as of 1997 o (QDNRM, 2004):

Instream/gully dams: 31 structures, total storage of approx 4.6 GL most of which is attributed to Cunnamulla weir (4.48 GL)

Other dams: 172 structures, total storage approx 1.3GL




7 BOM gauges (see blue raindrops on map)

No gauges used in IQQM model (rainfall runoff was not modelled in area)


Rated streamflow gauges: o Cuttaburra channel at Turra, opened 31/05/1993 1.

Other known stream-height gauges:o 1. Tinneburra, 1902 on (pers comm. Carol Godfrey)

2. Maranoa, 1954 on (pres comm. Chris Sharp)

Dates are as indicated by Mottell, 1998:

3. Mowellan, 1991 - 1994

4. Wancobra, 1978 - 1995

5. Yantabulla, 1968 - 1997 (monthly)



Cuttaburra start of system - estimated through 1. hydrographic measurement during 1986, 1990 and 1994 events which established a relationship between Warrego flows and Cuttaburra flows

Cuttaburra creek at border - limited gauge 2. data at Turra at time of calibration hence losses and routing was estimated. Losses upstream of border estimated through stakeholder consultation. Routing parameters, excluding lag time, was based on Cunnamulla to Barringun reach parameters.

Figure 5 - Cuttaburra Creek – Hydrologic Data Summary

Unsupplemented water allocations: o 2,755 ML total nominal volume

Restrictions on when extractions may occur apply to the three (3) largest allocations. Two allocations require a minimum flow at Cunnamulla weir before extractions may begin and the others refer to minimum flows at the point of take

A maximum extraction rate is specified for each license. The average maximum extraction rate, calculated by weighting each rate by the size of the allocation, is 96 ML/D

Estimated Natural and Constructed Storages:o

22 GL (includes Yantabulla Swamp) (pers comm. NRW)




1 gauge on Thurrulgoonia used in IQQM model (see red raindrop on map)



Rated streamflow gauges: o None on creeks 1.


1. Tuen @ Bluegrass from 1954 (streamflow and rainfall records)

IQQM modelling data:o Creeks are not explicitly modelled

Figure 6 - Thurrulgoonia and Tuen Creeks – Hydrologic Data Summary

Unsupplemented water allocations: o No allocations

Estimated Constructed Storages:o

Unknown




6 BOM gauges in vicinity of creek (see blue raindrops on map)

No gauges on creek used in IQQM model


Rated streamflow gauges: o No gauges on creek

Other known stream-height gauges:o No known gauges



Irrara Creek start of system - estimated by 1. assuming that 30% of the losses between Cuttaburra offtake and Barringun gauge can be attributed to inflows to Irrara Creek

Irrara Creek at border - same as start of system2.

Irrara Creek return to Warrego - routing 3. parameters based on Barringun to Fords Bridge reach. Losses estimated at 50% across the whole flow regime. High flows are then returned to the Warrego however the calibration report does not provide details on this relationship.

Figure 7 - Irrara Creek – Hydrologic Data Summary

Unsupplemented water allocations: o No allocations


Details unknown




3 gauges used in IQQM model (see red raindrops on map)

8 additional BOM gauges (excluding Irrara and Darling regions) not use in IQQM model (see blue raindrops on map)

Evaporation gaugeso : Nearest gauge is Bourke Airport (1994 - 2007)

Rated streamflow gauges: o Warrego River at Barringun (closed), 13/02/1968 - 1. 31/01/1981

Warrego at Barringun No. 2, opened 1/01/19932.

Warrego River at Fords Bridge (Main Channel), 3. opened 1/01/1972

Warrego River at Fords Bridge Bywash, opened 4. 1/12/1921


1. Barringun, 1926 to 1981

2. Belalie, 1949 to 1993 (monthly)

3. Fords Bridge, 1921 to 1992

IQQM modelling data:o Climatic period of model data: 1889 - 2006 but end of system only 1922 - 2006


Barringun - poor calibration, model generally 1. overestimates flows and low coefficient of determination/efficiency

Fords Bridge - good accuracy for flows above 2. 1,000 ML/D, small amount of overestimation for lower flows. The coefficient of determination/efficiency was moderatee (around 0.75)

Warrego End of System - Neither the QLD NRW 3. or the NSW DWE IQQM model represents the passing flow conditions on instream dams. WMA water have updated the DWE model to reflect this.

Figure 8 - Warrego River from Barringun to Darling – Hydrologic Data Summary

Unregulated water access licenses: o 3,462.5 ML total volume allocations direct from Warrego, plus additional 6,009 ML which can be extracted from a floodplain storage which is filled during flooding in the Warrego.

Licenses subject to flow thresholds before pumping can begin or storage of water allowed in instream dams.

A maximum extraction rate is specified for each license. The average maximum extraction rate, calculated by weighting each rate by the size of the allocation, is 785 ML/D (rate restricted through specification of pump size - results based on pump capacity from department’s database)


There are a number of instream dams however the total volume is unknown. For the purposes of modelling the storage volume has been estimated at 35 GL.



Impacts of Water Resource Development 1.9.

Full development versus current development1.9.1. IQQM model results are used to quantify the impacts of development under both pre-development and developed conditions. The pre-development model represents the flow regimes prior to infrastructure and diversions. For the developed scenario, the IQQM model for the Queensland section of the Warrego assumes full utilisation of existing allocations and uptake of additional allocations based on the Resource Operations Plan (Warrego, Paroo, Bullo and Nebine ROP 2006). The IQQM model for the New South Wales section of the Warrego assumes current utilisation of existing licenses.

There is at present no model scenario for the Queensland section of the Warrego which approximates current development. Therefore the impacts of current development on the flow regime have been qualitatively determined by estimating the proportion of allocation volumes which have not been utilised. Current impacts also differ to modelled impacts in that the model assumes that additional unallocated volumes which are allowed in the ROP have been allocated. The potential location and volume of these allocations were taken into account when estimating the difference between current impacts and full ROP development impacts.

Current impacts upstream of Wyandra have been estimated to be around 1/5th of that which would result if full levels of development allowed in the ROP were implemented. Current impacts downstream of Cunnamulla have been estimated to be around half that which would result if full levels of development allowed in the ROP were implemented. The current levels of impact towards the end of system are difficult to quantify given the lack of metering.

Key Hydrological Results1.9.2. Impacts on average daily flows and minor and moderate flood frequency are summarised in Table 1 for key locations on the Warrego River. Table 2 summarises impacts on average flow, zero flows, and minor to moderate flooding at the start of major effluent creeks.

Minor and moderate flood thresholds have been obtained from the Bureau of Meteorology (BOM). These thresholds are not available for the distributary creeks and as such the impact assessment for the creeks could not be site specific. Instead, the flow range of 100ML/D to 1,000 ML/D was used as an approximation of small to medium flooding.

The following points summarise the key results:

There is an increase in the loss of average daily flow, for both the Warrego and the effluent creeks, as you move down the system as a result of cumulative extractions due to water resource development. Assuming full development, average daily flows are reduced by approximately 1.5% at Wyandra, 16% at Fords Bridge

Parts of the Warrego Floodplain are used for agricultural production.

The Warrego River in flood, May 2008


and 44% at the end of system.

There is an increase in the loss of minor flooding days as you move down the system as a result of cumulative extractions due to water resource development. Assuming full development, frequency of minor flooding is reduced by approximately 0.5% at Wyandra, 17% at Fords Bridge and 36% at the end of system.

Excluding Barringun (see below for discussion), there is an increase in the loss of moderate flooding days as you move down the system as a result of cumulative levels of development. Assuming full development, frequency of moderate flooding is not impacted at Wyandra, and is reduced by approximately 14% at Fords Bridge and 35% at the end of system.

The flooding thresholds used for flooding at Barringun, Fords Bridge and end of system may need review.

The number of days which have been classified as minor flooding increases between Barringun and Fords Bridge for the pre-development scenario. The same occurs for moderate flooding. This result does not seem likely given the small amount of inflows in this reach.

The flooding thresholds for end of system were not known and as such Fords Bridge thresholds were adopted.

All statistics are estimates only and should be considered indicative. The impacts for the end of system are particularly difficult to quantify given the lack of gauging of flows and lack of accurate data regarding storage volumes, low flow outlet capacities and natural transmission losses. It has not been possible to verify the end of system results generated for this study.

Note that Tuen and Thurulgoonia creeks are not explicitly modelled in the IQQM. As such, the impact assessment for these creeks has been based on data for Cunnamulla and Barringun. The best estimate of impacts for the creeks was that:

the number of days where the Tuen creek flows is reduced by between 6% and 11% as a result of full upstream •development.

the number of days where the Thurulgoonia creek flows is reduced by 2% to 17% as a result of full upstream •development

The Warrego River in flood, May 2008



Average Daily Flow (ML/D) Number of minor flooding days Number of moderate flooding days

Pre-development

1,248

1,057

226

200

191

110

1889 - 2006 Climatic period

Wyandra

Cunnamulla

Barringun

Fords Bridge


Fords Bridge

End of System

% decrease current

0.3%

2.3%

6.2%

not known

not known

not known

% decrease full

development

1.5%

4.5%

12.3%

16.4%

16.6%

44.3%

Pre-development

209

1,604

722

4,460

3,029

1,204

% decrease current

0.1%

4.2%

0.5%

not known

not known

not known

% decrease full

development

0.5%

8.4%

9.0%

17.0%

18.5%

36.2%

Pre-development

30

307

147

1,807

1,157

826

% decrease current

0.0%

0.5%

11.2%

7.0%

7.3%

not known

% decrease full

development

0.0%

1.0%

22.4%

14.0%

14.5%

34.7%

Table 1 - Warrego River - Summary of Flow Regime Impacts

Average Daily Flow (ML/D) Percentage of time with zero flowsNumber of days with flow between 100

and 1,000 ML/D

Pre-development

276

408

42


Noorama and Widgeegoara

Cuttaburra

Irrara

% decrease current

-0.5%

-2.8%

-6.3%

% decrease full

development

-2.5%

-5.7%

-12.7%

Pre-development

48%

87%

86%

Current development

50%

87%

Full development

56%

88%

88%

Pre-development

7,953

1,235

1,881

% decrease current

1.2%

8.5%

6.5%

% decrease full

development

5.8%

17.0%

13.0%

Table 2 - Effluent Creeks start of system - Summary of Flow Regime Impacts

Environmental Flow Requirements of Significance of Impacts1.9.2.1. Environmental assets are dependent on varying aspects of the flow regime depending on where they are located. A generalised relationship between environmental assets and flow regime features is presented in Table 3. The study assessed impacts on all of these features except for short term variability and seasonality which are only a concern in systems with high river regulation, which is not the case for the Warrego. The study also assessed average flows which while not linked to any ecosystem requirements, virtually all aquatic, riparian and floodplain communities would be affected by significant changes in average flow (Davies et al, 2008).

Table 3 - Critical Flow Dependencies of Environmental Assets1

1 Source: (WMA, 2007))

The minor flood threshold used in the hydrologic impact assessment approximates within channel high flows. The moderate flood threshold approximates the start of overbank high flows. As such, it is possible to establish a general relationship between impacts on flooding and the environmental significance of those impacts. A generalised assessment of impact of flow regime changes on instream habitats is summarised in Table 4.

In the case of DIWA wetlands, site specific information about historic inundation frequency has been available which can be used to create a site specific flow threshold. Table 5 summarises hydrologic impacts under the full development scenario for those sites where impacts were predicted.

The hydrologic impact assessment conducted for this study is limited to considering flow quantity/ frequency characteristics of the region and impacts as a result of water extractions and construction of water storages. Land use in the region may also be impacting riparian and floodplain flora and fauna and water quality.

The impact assessment has also not considered economic issues as this is outside the scope of the brief. Grazing as a result of beneficial flooding has been reported to be an important component of the regional economy however (Mottell, 1998) and these activities may be affected by changes in the flow and inundation.

Floodplains and low lying wetlands

aa

a

Instream

refuge areas

aa

aa

a

riparian zone

a

aa

a

a

Flow regime element

Zero flow

Low flow

Within channel high flows

Overbank high flows

Short term flow variability

Seasonality


Emus Dromaius novaehollandiae are one of the many species found on the Cuttaburra Floodplain.


Table 4 - Generalised Impacts on Instream Assets

Zero flow and Low flows

Increased frequency of zero and low flows downstream of Wyandra may be affecting instream waterholes and associated •flora and fauna. These impacts are likely to be most felt in the more downstream waterholes.

The impacts of development on zero to low flows are moderately small upstream of Fords Bridge. However, below this •point the impact is more severe. At Fords Bridge the maximum period of flows below 100 ML/D is increased from 373 to 596 days (an increase of 60%)

Within channel high flows

The decreased frequency of within channel flooding may be affecting waterhole and riparian habitats.•

The impacts on frequency of minor flooding are reasonably small upstream of the border (8% at Cunnamulla and 9% at •Barringun) but are moderate at Fords Bridge (17% reduction) and large at the end of system (36% reduction in minor flood frequency).

Table 5 - Summary of Impacts on Selected DIWA sites

Wetland Name Hydrological Impacts of Full Water Resource Development

Yantabulla Swamp(Cuttaburra Basin)(NSW019)

Warrego River Distributary System(QLD169)

Full development as allowed in the ROP would result in a reduction of low to medium flood frequency which would result in less frequent replenishment of waterholes. This may also impact on the broader floodplain.

Based on modelled data at Turra the following impacts have been estimated:

The number of days of moderate-high flooding (flows greater than 3,700 ML/D) is reduced •from 874 to 819 days in the modelled period (a decrease of 6%)

The number of days of minor floods (1,000 ML/D to 3,700 ML/D) is reduced from 1284 to •1058 days (a decrease of 18%)

It should be noted that the results presented need to be verified when the IQQM model is calibrated to the gauge at Turra. Also, the impacts on floodplain inundation are difficult to ascertain with hydrologic information alone.

Water resource development as allowed in the ROP would result in a reduction in the frequency with which the effluent systems would flow. It is difficult to quantity these impacts however as the IQQM model does not represent the effluents in the region.

The best estimate of impacts on the Tuen that can be established for the purposes of this report is that:

the number of days where the Tuen creek flows is reduced by between 6% and 11% as a •result of full upstream development.

The best estimate of impacts on the Thurulgoonia that can be established for the purposes of this report is that:

the number of days where the Thurulgoonia creek flows is reduced by 2% to 17% as a result •of full upstream development


Green Creek Swamp(NSW013)

Birdsnest Swamp (NSW163) & Racecourse Swamp (NSW166) & Toms Lake (NSW168)

The flood history for the area suggests that Green Creek would be flooded every 2 - 3 years. With ROP levels of development, there is a 13% reduction in the number of days where the Irrara Creek start of system exceeds 800 ML/D which is approximately a 1 in 2 year flood threshold. Based on this, full development as allowed in the ROP would result in reduced inundation of the swamp.

Based on stakeholder information, the sites are inundated approximately every 10 years. The 1 in 10 year flood threshold for Fords Bridge has been estimated at 5,000 ML/D (based on pre-development data). Full development results in a 13% reduction in the number of days that exceed this threshold (115 days to 100 days). Based on this, full development results in a reduction in the number of days where the swamps/lake commence to be inundated.

Table 6 - Summary of Impacts on Selected DIWA sites

Wetland Name Hydrological Impacts of Full Water Resource Development

The banded lapwing Vanellus tricolor is one of the many bird species of the Warrego system.


H1

H2

H3

H4

Recalibration of the IQQM model should occur to take advantage of additional information on streamflow

Upgrade the IQQM to explicitly Model all Major Distributary Creek Systems

The IQQM model should be upgraded to enable better representation of floodplain flows

Upgrade the IQQM model’s representation of the end of system

Recommendations for Data Collection, Evaluation Tools and Planning Instruments 1.10. The following tables summarise recommendations for data collection, improvement of evaluation tools and improvements or additions to planning performance indicators.

Table 7 - Research Recommendation – Hydrology Data and Tools

No. Research Recommendation Significance of Recommendation

The model was not calibrated at the gauge at Turra due to insufficient data, •however there would now be sufficient data to conduct the calibration.

Some river height data collected by stakeholders might be suitable to refine •the model if a suitable height - discharge relationship can be established.

Once a suitable length of record is obtained at the Wallen gauge this •data should be useful to refine the modelled breakouts to Noorama and Widgeegoara Creeks.

It is recommended that the model be upgraded to explicitly model the Tuen •and Thurrulgoonia creeks as they are major components of the Warrego River Distributary System.

The current range of hydrologic models developed for assessment of water •resource management have primarily focused on changes to the flow regime and impacts on irrigation users. Very little assessment of floodplain losses and impacts of development on beneficial flooding has occured.

Further improvements could be made:

a distributed representation of storages instead of a lumped approach and •improved estimation of storage volumes (ideally based on bathymetric data)

improved evaluation of low flow outlet capacities. The capacity used in this •report is the high end, and actual capacity could be significantly smaller

improved infiltration and evaporation values for dams based on field •monitoring which has recently been conducted (WCMA job number 3892007)

represent the breakout from Boera Dam to Darling•

re-assessment of inflows and losses along reach with re-calibration based on •Darling gauges or gauging of Warrego end of system if implemented.


H5

H6

H7

H8

Pending the availability of suitable sites, additional stream gauging stations should be installed at the:

Metering of usage in NSW should take place as a matter of urgency

Additional River Gaugings to Develop Height - Flow Relationships

Improved Representation of Low Flow Regime

Warrego River end of system at the confluence with the Darling River (NSW) •(Fords Bridge is the gauge furthest downstream, below which are numerous in-stream dams which would significantly alter flows)

Gauging of the following creeks near the border would assist in monitoring the cross border flow objective of the WRP:

Irrara Creek (NSW)•

Widgeegoara Creek (NSW)•

Warrego near Rocky or Coonberry Plains•

A gauge between Cunnamulla and Barringun may be warranted for both •modelling and river management purposes. There are a large number of distributary offtakes between Cunnamulla and Barringun. A gauge mid-way between offtakes may be useful for better establishing distributary losses and would be a more reliable reference gauge for licensing conditions.

There are currently no meters in place and there is a significant volume of licensed allocations. Current use is believed to be significantly lower than licensed allocations but metering is still warranted to ensure compliance and would also assist in model calibration.

Gauging of Tuen Creek @ Bluegrass Bridge is recommended as this site has •a significant historic height record and therefore could be useful in explicitly representing these creeks in the IQQM.

Additional high flow gaugings at Augathella, Charleville and Wyandra may •also be warranted.

The IQQM model was not able to robustly represent the low flow regime at several locations, particularly:

Charleville•

Cunnamulla•

Barringun•

Improvement of the model’s ability to represent low flows will most likely be dependent on the incorporation of data from the gauging stations of Barringun and Turra, additional rainfall data to improve system inflows, better representation of instream weirs, and a more robust representation of instream losses.

Table 8 - Research Recommendation – Hydrology Data and Tools



E1

E2

E3

E4

Recommend a rigorous inventory of waterholes on the Warrego be undertaken, particularly for the NSW portion.

A detailed analysis and reporting of the existing water quality information is required, along with identification of additional risks and the appropriate level of monitoring and reporting required to inform resource managers.

Consolidation of the wetland and waterbird information should be undertaken and the Directory database updated, and, where the data is limited, further data collection should be undertaken.

A flora and fauna survey of the Eastern Warrego floodplain is warranted.

While the locations of waterholes in NSW are largely known, important information on their physical characteristics, water persistence, response to different flow events and aquatic biota is not available in a consistent and systematic framework.

Analysis and reporting of the water quality results is only in very general terms, eg DWR (1990) and DNR (2000).

Therfore it is difficult to develop an informed picture of the water quality characteristics of the river and/or changes over time.

There has been no pesticide sampling undertaken

The information content for several of these sites on the Directory database is quite limited and in some instances inaccurate.

Findings from recent studies have not been added to the database.

While a recent study investigated and reported on riparian vegetation condition for the Warrego and Cuttaburra (Hale et al. 2008), ‘floodout’ systems were not included. Thus, for example, large areas of the eastern Warrego floodplain were not surveyed. Also these areas reportedly are dominated by quite different vegetation communities, ie. Warrego Summer grass and Mitchell grass plains, as well as some treed areas. The wetland studies cited in this Consultancy have also not covered this eastern floodplain. These areas are also susceptible to reduced flooding due to upstream extraction.

Table 9 - Research Recommendation – Ecological Data


P1

P2

P3

P4

Zero flow planning performance indicator should be developed.

Low flow performance indicator could be tied to ecological flow thresholds such as minimum flows required to replenish instream waterholes.

Within channel high flow indicator could be tied to site specific thresholds

Include indicator assessing change in frequency/duration of moderate flooding

No such indicator exists in the WRP and zero flows are a key component of the flow regime.

There is currently an indicator examining flows lower than median, however this part of the regime may not necessarily be classified as a low flow

There is currently an indicator examining 1 in 2 year floods, however this flow frequency may not necessarily correspond to within channel high flows

There is currently an indicator examining the median beneficial flooding flow however the change in duration/frequency is not assessed

Table 10 - Research Recommendation – Planning performance Indicators

No. Recommendation Significance


The prickly gecko Heteronotia binoeiis one of the many reptile species of the Warrego system.

References1.11. ANCA (1993) A Directory of Important Wetlands in Australia. Australian Nature Conservation Agency, Canberra.

Balcombe SR, Arthington AH, Foster ND, Thoms MC, Wilson GG and Bunn SE (2006). Fish assemblages of an Australian dryland river: abundance, assemblage structure and recruitment patterns in the Warrego River, Murray-Darling Basin. Marine and Freshwater Research, 57, 619-633.

CSIRO (2007) Water Availability in the Warrego. A report to the Australian Government from the CSIRO Murray-Darling Basin Sustainable Yields Project. CSIRO. 89 pp.

Davies PE, JH Harris, TJ Hillman and KF Walker (2008). SRA Report 1: A Report on the Ecological Health of Rivers in the Murray–Darling Basin, 2004–2007. Prepared by the Independent Sustainable Rivers Audit Group for the Murray–Darling Basin Ministerial Council.

DNR (2000) Preliminary Risk Assessment of Water Quality in Queensland River Basins. Department of Natural Resources, Queensland. Prepared by McNeil, VH, Churchill RC, Marshall CJ and Choy S. 53 pp.

DWR (1990) Revised program for monitoring water quality in the Intersecting Streams. Report to the Management Committee of the Dumaresq-Barwon Border Rivers Commission. Department of Water Resources New South Wales. TS 91.004. Prepared by Rosie Bate. 42 pp.

Hale J, Roberts J, Page K and Kobryn H (2008) Riparian Zone Management in the Western Catchment Phase 2: Intersecting Streams. A report to the Western Catchment Management Authority

Kingsford R.T., K. Brandis, W.J. Young and S. Fryar (2002). Environmental Flows on the Paroo and Warrego Rivers: Progress Report Year 2. Department of Environment and Heritage, Canberra.

Mottell (1998) Natural Resources of the Lower Warrego River System

QDNR (Queensland Department of Natural Resources) (2003) Water Resource (Warrego, Paroo, Bulloo and Nebine) Plan 2003. Brisbane. 60+ pp.

QDNRM (Queensland Department of Natural Resources and Mines) (2004) Warrego River System Hydrology Volume 1- Calibration of Daily Flow Simulation Model from upstream of Augathella (QLD AMTD 447.4km) to Darling River / Paroo confluence (NSW AMTD 0km). Department of Natural Resources and Mines, Brisbane.

WMA (Webb, McKeown and Associates) (2007) A Preliminary Study Into The Socio-Economic And Environmental Assets And Values In The Darling Catchment, Draft Report prepared for the Murray Darling Basin Commission


Documents

Final Summary Western Catchment Management Authority ...archive.lls.nsw.gov.au/.../pdf_file/...river-scoping-study-summary.pdf · Western Catchment Management Authority ... This study