Burnett Water Pty Ltd Eidsvold Weir EIS ALTERNATIVES TO

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					                                                                      Burnett Water Pty Ltd
                                                                         Eidsvold Weir EIS




4.     ALTERNATIVES TO AND NEED FOR THE
       PROPOSAL
The Central Burnett Region (comprising Biggenden, Gayndah, Mundubbera and Eidsvold
Shires) is heavily dependent on the primary industries sector for economic prosperity and
growth, with over 42% of the workforce employed in Agriculture, Forestry and Fishing
(BIEDO, 1998). Irrigated horticultural and agricultural enterprises make a very important
contribution to the sector, particularly in the Mundubbera and Gayndah Shires. Some 64% of
the value of agricultural production in the Central Burnett is derived from irrigated land so that
the region is dependent on good quality water supplies.

The higher reliability of production and local employment associated with irrigation enterprises
as compared with rainfed enterprises is an important factor in maintaining investor confidence
in rural communities. Moreover, increased economic stability and growth prospects will also
have favourable social implications; e.g. through better retention of young people in the
community, reduced unemployment and availability of services in the town.

An appreciable proportion of the horticultural production, particularly citrus, is exported so
existing irrigation developments contribute to national export earnings as well as to the
Queensland economy.

In addition, urban and industrial developments are dependent on the availability of water
supplies. The three Shires of Eidsvold, Mundubbera and Gayndah have a total allocation for
urban use of 1,670 ML and 1,577 ML were delivered against this allocation in 1998-99 (State
Water Projects, 1999). This utilisation level of over 94% effectively leaves very little margin
(i.e. ~6%) available for future urban or industrial growth.

All water available from existing storages in the Burnett is committed already. Water
allocations, including those for urban centres, in the area served by the Upper Burnett Water
Supply Scheme total 27,954 ML and deliveries totalled 26,865 ML or over 96% of allocations
in 1998-99 (State Water Projects, 1999) again illustrating the lack of available supplies to
support further economic growth and underpin prosperity.

DNRM (2001) Report contains the results of a 1993 survey by the Steering Committee of the
Central Burnett 2005 Study to assess estimated future demands from existing and potential
water users. The total quantity of water requested in the section from Wuruma Dam to Degilbo
Creek over a ten-year period was 15,700 ML with 10,500 ML being a priority requirement
within five years. Because of failure of supplies from Wuruma Dam in 1995/96 and from the
start of 1999/2000 to the present, and restricted supplies over other periods since 1993, it is
highly likely that demands have increased substantially since the survey.

DNRM (2001) have estimated the potential demand for irrigation water based on full
development of irrigable soils. Estimates for the area within 5 km of the Burnett River between
the Nogo River and Degilbo Creek are given in Table 4.




Status – Final Draft                            31                                       September 2001
Project Number – 831/000259                                              Our Ref − draftreport-vers04.doc
                                                                             Burnett Water Pty Ltd
                                                                                Eidsvold Weir EIS


Table 4. Potential demand for irrigation water based on full utilisation of available soils with
an average water use of 5.8 ML/ha

          River reach           Total area of        Regulated        Additional area          Additional
                                irrigable soils    licensed area            for                  water
                                     (ha)               (ha)           development            requirement
                                                                           (ha)                  (ML)
Nogo River to Mundubbera                 7,850              2,220               5,630                32,650

Mundubbera to Gayndah                    8,070              1,120                 6,950                40,310

Gayndah to Degilbo Creek                10,240                770                 9,470                54,930

Total                                   26,160              4,110                22,050               127,890

Source: DNRM (2001)

The 1993 survey of potential water users indicates that there is appreciable demand for the
water that will become available for irrigation as a result of the project and Table 4 shows that
there are more than adequate reserves of suitable land to use the water.

In addition, Mundubbera Shire Council has indicated that they have an urgent requirement for
an additional 200 ML of high priority water to remove the need for repeated annual negotiations
with Gayndah Shire Council for temporary transfers of allocation. Further supplies are likely to
be sought to support future urban developments.

Eidsvold Shire has a water allocation of 350 ML and water use is currently around 290 ML or
83% of the allocation. Thus it is anticipated that an increase in allocation or some reserve of
high priority water to be set aside as a result of the project will be sought. However, the matter
has not been considered by Council so that no estimate of volume is available at present.
Council will be seeking an allocation to support an integrated aquaculture/cabinet timber
production project as well. This project is anticipated to underpin a more permanent
employment base for the town in future. The majority of the town’s workforce is currently
employed seasonally in the fruit industry.

Alternatives to the project may be considered in terms of alternative sources of water and
alternative water storage options. The likely feasibility of a number of alternative sources of
water are summarised in Table 5. More detail on some issues may be found in DNRM (2001).
Available alternatives only yield small volumes of water in comparison with those from the
proposed project and/or provide water at a high cost.

Table 5. Feasibility of alternative sources of water

              Source                                    Notes on feasibility

Demand management                §   Water shortages in recent years have forced irrigators to improve
                                     efficiency of water use through practices such as trickle or
                                     microspray irrigation of tree and vine crops so potential gains are
                                     small
                                 §   Urban water use in the catchment is a small proportion of total water
                                     use – DNRM state that a 20% reduction in urban demand across the
                                     whole catchment would reduce water use by only 3,600 ML

Rainwater tanks                  §   DNRM (2001) indicate that rainwater tanks could supply only 9% of
                                     total urban demand at a capital cost of $56,000 /ML of yield
                                     ($56 /KL)
                                 §   Quality of rainwater from tanks may be poor and first flush and



Status – Final Draft                              32                                            September 2001
Project Number – 831/000259                                                     Our Ref − draftreport-vers04.doc
                                                                           Burnett Water Pty Ltd
                                                                              Eidsvold Weir EIS


              Source                                  Notes on feasibility

                                   disinfection systems may be required for potable use
                               §   Rainwater tanks are already used on almost all rural properties and
                                   in some towns such as Mundubbera where aesthetic qualities of
                                   reticulated water have been poor from time to time

Greywater reuse                §   DNRM (2001) indicate that greywater requires treatment before use
                                   and that the capital cost of systems would be $23,000 to
                                   $69,000 /ML of yield – 7,450 ML/a could be saved by full
                                   implementation across the catchment by 2025

Wastewater reuse               §   Mundubbera wastewater is used for golf course irrigation already
                               §   Reuse of 90% of wastewater for irrigation would yield about
                                   6,000 ML/a at present at a capital cost of between $4,600 and
                                   $13,800 /ML (DNRM 2001)

Urban stormwater harvesting    §   Reliable estimates of cost are not available
                               §   Applicability in the Eidsvold to Gayndah area is limited because of
                                   small urban centres

On-farm storages               §   Capital cost of ring tanks (1,454 ML capacity) is estimated at
                                   $963 /ML of yield (DNRM, 2001)
                               §   Additional capital costs are incurred for high-capacity pumping
                                   systems to fill storages
                               §   Additional operating costs are associated with the double handling of
                                   water on-farm (filling then irrigating as a separate operation)


Alternative storage sites in the Central Burnett were examined by Hyder (1998). Their study
looked at the following proposals:

    §    dam on the Auburn River at AMTD 14.4 km, 18.8 km or 22.5 km;
    §    weir on the Auburn River at AMTD 4.64 km;
    §    weir on the Burnett River between AMTD 290 km and 312 km; and
    §    dam on the Burnett River between AMTD 317 km and 366.6 km.

Dam sites at AMTD 18.8 km and 22.5 km on the Auburn River were eliminated because any
dam with appreciable storage capacity at these sites would have a significant impact on
conservation values within the Auburn River National Park. A dam at AMTD 14.4 km would
be constrained by impacts on the National Park but could still increase system yield at Jones
Weir by an estimated 23,700 ML/annum at an estimated cost of $2,776 /ML.

It was found that a weir on the Auburn River at AMTD 4.64 km could yield 5,600 ML/annum at
low reliability of supply and an estimated cost of $1,100 /ML. However, it was concluded that
closer economic study was required.

Seven storage options along the Burnett River were examined by Hyder (1998) and the
outcomes of their evaluations are summarised in Table 6. Where more than one full supply
level was considered at any site, that with the lowest cost per megalitre of yield of high
reliability water is considered. The Consultant put the AMTD 300.4 km site forward as the
preferred weir option on the basis of similar performance and environmental impacts to the
AMTD 296.8 km site and lower cost. It was noted that further geotechnical investigations
should be undertaken before adoption of the site as a final choice.




Status – Final Draft                           33                                             September 2001
Project Number – 831/000259                                                   Our Ref − draftreport-vers04.doc
                                                                             Burnett Water Pty Ltd
                                                                                Eidsvold Weir EIS


Table 6. Summary of the evaluation of alternative storages in the Central Burnett

           Site / Issue                                          Evaluation

Dam at AMTD 366.6 KM
     Engineering                   §   Rock about 10 m under alluvium
                                   §   Saddle dam required on left bank
     Yield and cost                §   19,400 ML at $3,206 /ML
     Terrestrial flora and fauna   §   No extensive tracts of remnant native vegetation
                                   §   Narrow and fractured riparian zone
                                   §   Similar to weir sites near Eidsvold
     Aquatic flora and fauna       §   Flood plain and a number of off-stream pools associated would provide
                                       a wide diversity of high quality habitats
                                   §   Natural flows downstream would be reduced appreciably
     Cultural heritage             §   No sites of significance identified by study
                                   §   Community consultation and an archaeological field survey would be
                                       required
     Socio-economic                §   Some 11,000 ha of land suitable for irrigation downstream
                                   §   Appreciable resumption costs

Dam at AMTD 317.0 km
     Engineering                   §   Weathered rock outcrops on both abutments
                                   §   Suitable for an RCC gravity dam
     Yield and cost                §   74,000 ML at $1,277 /ML
     Terrestrial flora and fauna   §   No extensive tracts of remnant native vegetation
                                   §   Narrow and fractured riparian zone
                                   §   Similar to weir sites near Eidsvold
     Aquatic flora and fauna       §   A number of off-stream water bodies (small tributaries) along the
                                       waterway
                                   §   Stream partly covered by riparian vegetation
                                   §   Impoundment will result in loss of a number of high quality habitats
     Cultural heritage             §   Impoundment would drown Ceratodus railway station
                                   §   Community consultation and an archaeological field survey would be
                                       required
     Socio-economic                §   Severe impacts include inundation of current rail and road routes
                                       requiring substantial diversions
                                   §   Appreciable land resumption costs and loss of land already irrigated

Dam at AMTD 293.4 km
     Socio-economic                §   Eidsvold to Theodore road would require diversion
                                   §   Flooding of Eidsvold to Monto road and rail routes would limit storage
                                       capacity
                                   §   Site not investigated further

Weir at AMTD 295.3 km
     Engineering                   §   Up to 6 m of sand and gravel over decomposed or moderately
                                       weathered rock
                                   §   Right abutment would require extensive erosion protection works
                                   §   River within Quaternary alluvium
     Socio-economic                §   Road bridge would have to the carried over the weir with associated
                                       costs
                                   §   Site not investigated further

Weir / Dam at AMTD 296.8 km
     Engineering                   §   Site would be suitable for RCC weir
                                   §   Site would be suitable for RCC dam with saddle dams up to 70 m long
                                       and 21 m high
                                   §   Longest saddle dam is 700 m
                                   §   Up to 10 m of to hard rock in the streambed
     Yield and cost                §   Dam 40,000 ML at $1,338 /ML
                                   §   Weir 28,000 ML at $475 /ML or
     Terrestrial flora and fauna   §   Tolderodden Conservation Park is downstream and unlikely to be
                                       affected



Status – Final Draft                              34                                             September 2001
Project Number – 831/000259                                                      Our Ref − draftreport-vers04.doc
                                                                             Burnett Water Pty Ltd
                                                                                Eidsvold Weir EIS


           Site / Issue                                          Evaluation

                                   §   Much of the impoundment area for the dam has been cleared or partly
                                       cleared
                                   §   Narrow strips of riparian vegetation remain
     Aquatic flora and fauna       §   A number of off-stream pools associate with tributaries
                                   §   Dam would result in loss of high quality off-stream pool habitats
                                       reducing habitat diversity
                                   §   Weir impacts would be confined to in-stream and riparian habitats
     Cultural heritage             §   Close to Eidsvold Station homestead
                                   §   Local waterhole believed to have cultural significance for Aboriginal
                                       people
                                   §   Community consultation and an archaeological field survey would be
                                       required
     Socio-economic                §   Weir would be within bed and banks without impacting on
                                       neighbouring properties
                                   §   Better dam sites are available

Weir at AMTD 300.4 km
     Engineering                   §   Materials are similar to those at the 296.8 km site with an alluvial
                                       terrace extending about 400 m from the river on the right bank
                                   §   Interpretation of seismic data indicated a dense layer, apparently
                                       moderately weathered to fresh rock under the right bank alluvium
                                   §   Further geotechnical investigations required
                                   §   Site is suitable for a mass concrete or RCC weir
     Yield and cost                §   28,000 ML at $418 /ML
     Terrestrial flora and fauna   §   Very similar to a weir at the 296.8 km site
     Aquatic flora and fauna       §   Very similar to a weir at the 296.8 km site
     Cultural heritage             §   Generally similar to a weir at the 296.8 km site
                                   §   Site may be more acceptable to Aboriginal people than the 296.8 km
                                       site
     Socio-economic                §   Very similar to a weir at the 296.8 km site




Status – Final Draft                              35                                             September 2001
Project Number – 831/000259                                                      Our Ref − draftreport-vers04.doc
                                   Burnett Water Pty Ltd
                                      Eidsvold Weir EIS




Status – Final Draft          36                     September 2001
Project Number – 831/000259          Our Ref − draftreport-vers04.doc