The Rocks Weir Fishway Concept Report - Wiki - NQ Dry Tropics

The Rocks Weir
Fishway Concept
Report
2009
Prepared By:
Tim Marsden
Melinda Ferguson

Published by NQ Dry Tropics Ltd trading as NQ Dry
Tropics
Copyright 2009 NQ Dry Tropics Ltd
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whether new information is available on the particular subject matter.

Table of Contents
Glossary of Terms.................................................................................................................................... 4
Introduction ............................................................................................................................................ 5
Site Information ...................................................................................................................................... 6
Burdekin River System ........................................................................................................................ 6
Rita Island Sand-Dam Fishway ........................................................................................................ 7
Clare Weir Fishlock .......................................................................................................................... 7
Bogie River Fishway ........................................................................................................................ 7
The Rocks Weir ................................................................................................................................... 8
Fish Passage Requirements ................................................................................................................... 10
Fish Species ....................................................................................................................................... 10
Migration Timings ............................................................................................................................. 10
Size Ranges ........................................................................................................................................ 10
Fish Passage Option .............................................................................................................................. 13
Fishway Type ..................................................................................................................................... 13
Rock ramp fishways ...................................................................................................................... 13
Fishway Configuration ...................................................................................................................... 14
Materials ........................................................................................................................................... 14
Foundation and Structural Stability .................................................................................................. 14
Equipment ......................................................................................................................................... 14
Timing................................................................................................................................................ 14
Costing .............................................................................................................................................. 15
Conclusion ............................................................................................................................................. 15
Recommendations ................................................................................................................................ 15
Acknowledgements ............................................................................................................................... 15
References ............................................................................................................................................ 16
Appendix 2: Straight Rock Ramp Concept Fishway Design ................................................................... 18
APPENDIX 2 – Dog-leg rock-ramp concept fishway design ................................................................... 20

Glossary of Terms
Diadromous - Diadromous fishes are truly migratory species whose distinctive characteristics include
that they (i) migrate between freshwaters and the sea; (ii) the movement is usually obligatory; and
(iii) migration takes place at fixed seasons or life stages. There are three distinctions within the
diadromous category, catadromous, amphidromous and anadromous.
• Catadromous - Diadromous fishes which spend most of their lives in fresh water, and migrate to
sea to breed.
• Amphidromous - Diadromous fishes in which migration between freshwater and the sea is not for
the purpose of breeding, but occurs at some other stage of the life cycle.
• Anadromous - Diadromous fishes which spend most of their lives at sea, and migrate to freshwater
to breed.
• Potamodromous - fish species whose migrations occur wholly within freshwater for breeding and
other purposes.

Introduction
In 2007 the Burdekin Dry Tropics Natural Resource Management (BDTNRM) group completed a ‘Fish
Passage Study’ that examined potential fish barriers within the Burdekin Catchment. From this study
the report, ‘Final Report: Burdekin Dry Tropics NRM Region Fish Passage Study’ (November 2007,
Alluvium Consulting) was generated and delivered. This report identified 31 potential barriers to the
migration of Australian native fresh water fish species in the Burdekin Catchment.
Following the delivery of the report, a field assessment was undertaken in March, 2008 involving
several parties: Jason Carter (Alluvium), Jim Tait (Econcern), Ross Kaptitzke (JCU) and Tim Marsden
(DPI&F). Each of these parties brought together extensive expertise in fish ecology and passage,
waterway management and environmental engineering. The field assessment examined the 31
barriers identified in the report, and considered fish passage requirements in relation to the existing
barrier structure and waterway condition. Following this assessment, recommendations and
prioritisations for their remediation were made.
The Department of Primary Industries & Fisheries (DPI&F) have been contracted by BDTNRM to
undertake the production of fishway concept design reports for those fish barriers ranked highest on
the priority list for remediation works. In October 2008, eleven sites were re-visited and ground
surveys undertaken. From these surveys concept plans have been created offering (for some sites)
several options for possible remediation works.
This report contains the concept design and rationale for suggested remediation works to restore
fish passage at The Rocks Weir, Burdekin River.

Site Information
Burdekin River System
Covering an area of approximately 130,000 km2, the Burdekin River catchment is the second largest
coastal catchment in Queensland, stretching almost 600km from the central Queensland township
of Alpha to just inland of Ingham, in North Queensland, (Marsden, 2001). The majority of this
extensive catchment lies inland in the Central Highlands with only a small portion of the catchment
located on the coast where it has formed a substantial flood plain and delta system, (Marsden,
2001).
Commencing west of Ingham in the Great Dividing Range, the Burdekin River meanders south
through Charters Towers and down to Lake Dalrymple (Burdekin Falls Dam). At this reach, water
from the the Belyando-Suttor-Cape catchment, the largest coastal catchment in Queensland, enters
the Burdekin River (Burrows et al., 1999). This water is transported from the south and west by the
Belyando and Suttor Rivers which combine to form the Cape River before spilling into the Burdekin.
From Burdekin Falls Dam, the River changes direction and flows northeast to Ayr entering the Coral
Sea in Upstart Bay, (Marsden, 2001), (see figure 1).
Figure 1. Burdekin River System – Inland of Ingham through Charters Towers, into Lake Dalrymple
and northeast to Ayr.
Existing fishways have been installed in the Burdekin River to restore connectivity for fish migration
(figure 2). These fishways are:
• a rock-ramp/bypass channel at Rita Island in the Burdekin River delta;
• a fish lock system on Clare Weir 19km upstream of The Rocks, and;
• a double rock ramp in the Bogie River 85km upstream of The Rocks.

Figure 2. Fishways completed on the Burdekin River system and the proposed Rocks fishway Rita
Island Sand-Dam Fishway
Rita Island Sand-Dam Fishway
The Rita Island Sand-dam is located within the Burdekin River anabranch, at the salt water interface.
The Rita Island rock ramp/bypass channel was constructed in December, 2009 to permit fish passage
past the sand dam that is constructed following each wet season. The fishway consists of a shallow
channel leading to rock ramp that exits into an overflow channel originating upstream of the sand
dam. It is designed to allow fish passage around the sand dam during both low and medium flows.
Clare Weir Fishlock
Clare Weir is a 7.0m high by 350m wide mass concrete structure located at 50.3km AMTD. A fishlock
was installed on the weir in 2004? to permit year round fish passage. The lock consists of three
distinct sections; the entrance chamber, the lock chamber and the exit channel. The lock is
controlled automatically and fish are attracted to the flow of water (Attraction Flow) leaving the
entrance chamber (approximately 0.6m/s). Results from monitoring studies indicate that the
Fishlock is highly effective, passing large numbers and a wide variety of fish species ranging in size
from 14mm-1000mm.
Bogie River Fishway
The Bogie River flows into the Burdekin River 20km upstream of Clare Weir. The fishway is located
46km from the Burdekin River junction on the Tondara Road crossing, a 140 long by 4m wide sheet
metal and concrete structure. In December, 2008, two 18m partial-width rock ramps running
alongside the roadway were constructed. They are designed to function most effectively during low
to medium flows.
The construction of a fishway at the Rocks Weir will ensure that connectivity throughout the lower
Burdekin River is achieved.

The Rocks Weir
Thirty kilometres upstream of Upstart Bay, the Burdekin River narrows and turns east as it passes
through two hills at a location known as The Rocks. Exiting this pass, the channel splits as flows are
deflected around a mid-stream bedrock and sand island. In the northern channel, a 20m wide by
0.7m high concrete and bedrock weir has been constructed extending from the northern bank to the
bedrock island (figure 3 & 4). Adjacent to the weir is a pumping station used to pump water from the
river for irrigation purposes. To maintain pool levels for the pumps, seasonal sand dams are
constructed across the southern channel following the wet season (figure3).
Figure 3. Aerial view of the Rocks Weir (A) and location of sand dams constructed after the wet
season (B) (image Google Earth).
As the site is on the outside of a large bend, high flows that constantly scour out any sediment buildup.
The river bed immediately around the weir is composed mostly of bedrock (figure 4). Upstream,
and on the inside of the bend, the river bed is composed of river sand which is carried downstream
and deposited as seasonal sand banks and aggradations in low-energy zones. Riparian vegetation
surrounding The Rocks section, is dominated by eucalypts, malaleucas and callistemons many of
which grow on the mid-stream island.

Flow Characteristics at The Rocks Weir
Figure 4. The Rocks Weir, Burdekin River
The Rocks Weir reach of the Burdekin River flows year round and levels can vary depending on wet
season flows and releases from dams upstream. The river experiences extremely high flows during
the wet season from December to April (figure 5). During high flow events, The Rocks Weir is
completely flooded, sand dams are washed away and fish passage I permitted past this site.
However, when water levels fall and the sand dams are constructed in the southern channel, flows
are directed solely over the weir which creates a barrier to fish movement as water plunges over its
0.7m high edge. Fish consequently congregate at the base of weir which has made it a popular
fishing spot for local residents. These conditions can last for several months until wet season flows
return to wash the sand dams away offering fish a migration path upstream.
Figure 5. Annual flow records for the Burdekin River at Clare 1949-2006

Fish Passage Requirements
Fish Species
A number of comprehensive studies have been completed on the fish communities of the Burdekin
River and its tributaries which have identified forty-two species of fish (Table 1) (Macleay 1883,
Midgley 1977, Hogan et al. 1997, Pusey et al. 1998, Marsden 2001). Two of these fish species are
endemic: one species of neosilurid catfish (Neosilurus mollespiculum) (Allen and Feinberg 1998,) and
the small-headed grunter (Scortum parviceps) (Merrick and Schmida 1984, Marsden, 2001). Table 1
outlines the most likely species to be encountered in the Burdekin River at the Rocks Weir
Migration Timings
High flows during the wet season have been identified as important trigger events for fish
movement throughout Australia and it has often been assumed that migrations of native fish only
take place on these flows (Marsden, 2001). However, sampling from fishways along the East Coast of
Australia, indicate that upstream migrations are likely to occur all year round on a variety of flows
(Table 1) (Thorncraft 1995, Mallen-Cooper 1996, Marsden 1997, Stuart and Berghuis 1999, Stuart
1999, Marsden, 2001). Given the highly variable nature of flows in the Burdekin River, fish would be
keyed into moving on any flow events that occur; even relatively small events. The most likely time
for fish movement would be late in the wet season. Some migration would be undertaken on the
high flows, especially spawning migrations of eel-tailed catfish species, but it is on the recession of
these flows that the peak movements occur, especially for juveniles dispersing to refuge habitats.
Fish passage is predominantly affected at The Rocks Weir when sand dams are first put in place in
the southern channel. During these times, water velocities passing and plunging over the weir’s
downstream crest are too powerful for fish to negotiate. It is for these low to medium flows that the
fishway will be designed to function most effectively in.
Size Ranges
Eighteen of the likely species from the Burdekin River are highly migratory fish species (Table 1), and
require free passage at all life stages and size ranges (Renfree & Marsden, 2006). The most likely
small fish to migrate include the olive perchlet, bony bream, long-finned eels, rainbowfish, empire
gudgeons and juvenile barramundi which can be as small as 10mm when they are migrating, but
mostly range from 20-150mm long (Stuart 1999, Marsden, 2001). The most likely large fish to
migrate in the Burdekin River include adults/sub-adults of a number of larger fish species, including
barramundi, fork-tailed catfish, the three eel tailed catfish, sooty grunter and sleepy cod which range
in size from 250mm to 450mm (Renfree & Marsden, 2006, Stuart and Berghuis 1997).

Table 1. Migration patterns of the freshwater fish of the Burdekin River, Queensland, adapted from
Allen 1989, Merrick and Schmida 1984, McDowall 1996, ASFB 1999, Stuart 1999, Marsden 2001 and
ACTFR 2008.

Fish Passage Option
Fishway Type
The most appropriate fishway for the Rocks Weir can be determined by consideration of a number
of factors including:
• flow characteristics – the fishway needs to operate on both low and medium flows when the sand
dams are in place.
• weir structure – unknown structural condition of weir means designs that least affect the structure
are best.
• stream geopmorphology – weir located in high energy environment, therefore small structure can
be better protected.
• funding – limited funding available, so low cost design best.
Based on these characteristics, the most appropriate fishway to install at The Rocks Weir would be a
partial-width rock ramp fishway situated against the northern bank.
Rock ramp fishways
Over the past decade, rock ramp fishways have been constructed and refined to suit Australian
systems and represent a low-cost alternative to more formal fishway designs (Gebler 1988; Pasche
et al 1995; Steiner 1995; Eberstaller et at 1998; Baumgartner and Lay 2002). They are generally
constructed on barriers up to two metres in height and consist of a series of stepped ridges and
pools (Figure 6). Ridges are formed in such a way as to create 100mm falls between rocks that native
fish are able to negotiate in short swimming bursts. Low flow pools formed in between ridges afford
fish a safe place to rest before they tackle the next ridge. Rock ramps cater for fish of many sizes,
particularly small fish and juveniles, functioning most effectively during mid to low flows. They have
successfully been constructed in many parts of Australia and have proven to be highly efficient.
Figure 6. Conceptual layout of a partial-width rock ramp fishway.

Fishway Configuration
The partial-width rock ramp fishway would be tied into the existing bedrock below and along the
northern bank (appendix 1). It would be designed to operate on lower flows up to 300mm above the
weir crest. There are two possible configurations for the fishway, both consisting of a total of 7
ridges and 7 cells placed 1.5m apart. The first configuration (see Appendix 1), is a relatively straight
channel that follows the contour of the northern bank placing the entrance 10.5m downstream of
the weir crest. Option two (appendix 2), is dog-legged rock-ramp that places the entrance
immediately below the weir crest taking advantage of the attraction flows spilling over the weir.
Both options are feasible with the dog-leg version likely to attract the greatest number of fish, while
the straight version is a more simple engineering design. The final option will be determined onsite
with project engineers and equipment operators.
Materials
The rock ramp fishway would consist of 1.0 - 1.2m diameter rocks to build up both the base (where
necessary) and the walls, 0.8m diameter rocks would be used to form the ridges and 0.3m rock to
build up floors of the cells. The whole structure will be bound together with pumped concrete to
seal the pools and the walls to prevent leakage and movement of rocks within the structure.
Concrete may be omitted from the design if not suitable from an engineering standpoint.
Foundation and Structural Stability
The structure would be built immediately downstream of the weir on the northern bank, with no
structural modification to the wall required. Large rock will be used to build up the base, filling any
depressions that may be present in the bedrock substrate. Once a relatively uniform base is
achieved, a reinforced concrete slab will be formed upon which the walls and ridges of the fishway
will be constructed.
Equipment
To construct the rock ramp, a 20t excavator provided by the Water Board will be utilised to prepare
the site and to place rock into position. A concrete pump will be utilised to move concrete (if
required).
Timing
It is estimated that to complete the fishway, 8 days of on-site construction works will be required.

Costing
Conclusion
It is evident that in order to complete the facilitation and restoration of fish passage to important
aquatic habitat on the lower Burdekin River and its tributaries, The Rocks Weir requires remediation
work. It is recommended that this fishway be constructed as soon as possible to ensure that the
coming dry season sees the free migration of fish into the system.
Recommendations
• To improve the impacts of this structure on fish passage a fishway should be constructed to
provide passage past the weir.
• Since it is a very wide crossing, it is recommended that a partial-width rock ramp be constructed.
• The fishway should be built, with its entrance placed in the existing downstream scour pool and
channel to utilise natural attraction flows.
• The fishway should be built to operate during medium to low flows.
• The fishway should be constructed to pass various size ranges – 10mm-450mm.
Acknowledgements
The concept design developed in this report was developed after onsite inspections of the site with
Ross Kapitzke (JCU School of Engineering) and Jason Carter (Alluvium Consulting), their engineering
expertise has contributed to this design and the authors would like to thank them for their
contribution. The authors would also like to thank the North Burdekin Water Board for their ongoing
support and Neil Cunnington for his assistance with the detailed site surveys.

References
Allen, G.R. (1989). Freshwater fishes of Australia. T.F.H. Publications, Inc., Neptune City 240 pp.
Allen, G.R. & Feinberg, M.N. (1998) Descriptions of a new genus and four new species of freshwater
catfishes (Plostidae) from Australia. Aqua. J. I. & Aqua. Biol. 3(1): 9-18
Alluvium 2007, Burdekin Dry Tropics NRM Region Fish Passage Study, report to Burdekin Dry Tropics
NRM, Townsville.
Bureau of Metorology. (2008). “BurdekinRiver”.
http://www.bom.gov.au/hydro/wr/unesco/friend/burdekin/burdekin.shtml
Burrows, D., Faithful, J., Kutt, A., Tait, J. and Blunden, L. (1999). Environmental Study of a Proposed
Dam at Mount Douglas on the Belyando River. Australian Centre for Tropical Freshwater Research,
Townsville.
Donald A. Hancock, David C. Smith and John D. Koehn (editors). (1999). Proceedings of Fish
Movement and Migration, Bendigo 28-29 September. Australian Society for Fish Biology.
Hogan, Alf., Graham, Peter. and Vallance, Terry. (1997) Re-design of the Clare Weir Fishway,
Identification of fish movement. Department of Primary Industries, Internal Report.
Macleay, W. (1883). Notes on a collection of fishes from the Burdekin and Mary rivers, Queensland.
Proceedings of the Linnean Society of New South Wales 8:199-215.
Mallen-Cooper, M.C. (1996). ‘Fishways and freshwater fish migrations in South-eastern Australia.’
Ph.D. Thesis. University of Technology, Sydney. 378pp.
Marsden, T. (2001). Clare Weir Pre-Construction Report. Department of Primary Industries &
Fisheries, Queensland.
Marsden, T. J., Gehrke, P. C. and Harris, J. H. (1997) ‘Tallowa Dam High Fishway Project. Stage 2
Comprehensive report', NSW Fisheries and Cooperative Research Centre for Freshwater Ecology,
Cronulla.
McDowall, R.M. (ed.) (1996). ‘Freshwater fishes of South-eastern Australia’. (2 nd ed.). Reed Books:
Sydney.
Merrick, J.R. and Schmida, G.E. (1984). ‘Australian freshwater fishes: biology and management.’
(Griffin Press: Adelaide).
Midgley, S.H. (1977). Burdekin River Catchment Survey. Queensland Fisheries Service Special Report
No. 10, February 1977.
NRW, QLD. (2007). Bogie River Flow Statistics Report.
http://www.nrw.qld.gov.au/watershed/precomp/120005b/fsr.htm
Pusey, B.J., Arthington, A.H. and Read, M.G. (1998). Freshwater fishes of the Burdekin River,
Australia: biogeography, history and spatial variation in community structure. Environmental Biology
of Fishes 53, 303-318.
Renfree, M. and Marsden, T. ( 2006). Clare Weir Post-Construction Monitoring Report. Department
of Primary Industries & Fisheries, Queensland.

Stuart, I.G. (1999). Assessment of a vertical-slot fishway for non-salmonid fish at a tidal barrier on
the subtropical Fitzroy River, Queensland. MSc Thesis. Central Queensland University, Rockhampton.
208pp.
Stuart, I.G. and Berghuis, A.P. (1997). Assessment of Eden Bann Weir fishlock, Fitzroy River,
Queensland. Department of Primary Industries Internal Report. 49 pp.
Stuart, I.G. and Berghuis, A.P. (1999). Passage of native fish in a modified vertical-slot fishway on the
Burnett River barrage, South-eastern Queensland. Department of Primary Industries Internal Report.
53 pp.,
Thorncraft, G.A. (1995). Preliminary assessment of the Fitzroy Barrage vertical-slot fishway and
comments on future assessment of fishways in the Fitzroy River. Department of Primary Industries
Internal Report. 17 pp.

Appendix 2: Straight Rock Ramp Concept Fishway Design
Partial-width straight rock ramp fishway concept on Rocks Weir.
Partial-width straight rock ramp fishway, Kirknie Creek (photo Jason Carter).

APPENDIX 2 – Dog-leg rock-ramp concept fishway design
Partial-width dog-legged rock ramp fishway Concept on Rocks Weir.
Partial-width dog-legged rock ramp fishway, Reliance Creek, Habana.