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The Coorong, A BETTER CHANCE FOR NATIVE FISH LAMPREYS MULLOWAY Lower Lakes & Barrages Many of native fish species frequent the estuary and Lower Lakes. A few are BARRAGES AT A GLANCE profiled below to highlight the benefits of fishways and improved barrage Mulloway Grow to 200 cm long, Goolwa, Mundoo, Boundary Creek, Ewe Island and operation. Scientists are still learning about native fish; the installation of but are commonly Tauwitchere barrages separate fresh and salt water monitoring traps at the fishways will provide opportunities to study the caught from beaches environments of the Lower Lakes and the Coorong. The breeding and migration patterns of many species. Lampreys at sizes between 75 barrages are operated by SA Water on behalf of the Murray- Grow to 60 cm long. and 150 cm. Darling Basin Commission. © Gunther Schmida © Rudie H Kuiter Two trial fishways operate at Goolwa Barrage and Tauwitchere COMMON GALAXIAS CONGOLLI The bizarre life cycle of pouched lamprey Mulloway (Argyrosomus japonicus) is an Barrage. More fishway installations are expected following the edited environmental management system. The paper used is 50% recycled fibre (15% post consumer and 35% pre-consumer waste) trial phase. (Geotria australis) and short-headed lamprey important fish for the local commercial fishing (Mordacia mordax) marks them as one of the industry and a prized catch for recreational Barrage Length Bays Gates curiosities of the fish world. anglers. Goolwa* 632 m 128 123 stop-log Mundoo 792 m 26 26 stop-log† Common galaxias Congolli Larval lampreys are spawned in fresh water and Adult mulloway in spawning condition Grow to 25 cm long, Grow to 36 cm long, THE RIVER MURRAY Boundary Creek 244 m 6 6 stop-log but are commonly but are commonly burrow into fine silt where they feed on small gather in the surf zone adjacent to the Murray Ewe Island 2270 m 111 50 stop-log, 61 radial° between 6 and 9 cm. between 10 to 15 cm. algae. In the spring of their fourth year, juvenile Mouth between October and December each © Gunther Schmida © Gunther Schmida Tauwitchere* 3658 m 322 130 stop-log, 192 radial° individuals migrate from freshwater spawning year. Based on overseas studies, mulloway are * Barrage features lock and fishways. Common galaxias (Galaxias maculatus) reside in Congolli (Pseudaphritis urvillii) reside in grounds to the sea. Whilst living in the sea, thought to spawn in this zone around this BARRAGES & FISHWAYS † A vertical axis spindle gate is being trialled as the first of several the lower reaches of many coastal rivers. They the Lower Lakes and estuarine section of lampreys attach themselves to other fish using period. Soon after spawning, juvenile mulloway which will replace some of the stop-logs. This will dramatically simplify and speed up barrage operation. can usually be found in waterways with plenty of the Coorong just inside the Murray Mouth. their modified mouth and feed on the host’s are believed to move into the Coorong and use ° 10 of the radial gates at Tauwitchere Barrage are remotely aquatic and fringing vegetation. Congolli are diadromous. This means they move body tissues. this and the adjacent near-shore environment operated and there are plans for 10 more at this location. A further between fresh and salt water environments. as nursery habitat for the next two to five years. 10 automated gates will be installed at Ewe Island Barrage. Although they can complete their life cycle After several years, lampreys return to fresh wholly in fresh water, common galaxias normally Small numbers of congolli are believed to still water as young premature adults, climbing small Freshwater flows establish estuarine conditions MAP LEGEND migrate between the fresh water and estuary to move between the freshwater lakes and estuary obstacles using their mouth as a sucker. Once in the Coorong. This provides juvenile

Salt water environments (ocean and estuary) spawn. Juveniles spend their early months in to spawn via small channels on Mundoo and they have developed into sexually mature adults, mulloway with their preferred habitat. The the estuary before moving back into the Lower Hindmarsh islands. lampreys stop feeding, spawn in fresh water and decline in local annual catches of mulloway Fresh water (watercourses and lakes) die soon afterwards. following the construction of the barrages Lakes. The fishways will significantly improve prospects National parks and reserves is thought to be the result of a reduction in Fishways, especially the rock ramp at for congolli and other fish that previously had The long journey of the lamprey between fresh 2005 Aboriginal lands (Ngarrindjeri) estuarine conditions. Tauwitchere, now make this process much easier. difficulty moving between the salt and fresh and saltwater environments—and back again— Barrages waters of the Coorong and Lower Lakes. will be easier with the fish passage improvements Operation of the fishways and establishment The return of environmental flows to the River Murray, more flexible Watercourses of the Sea to Hume Dam project (see below). of an environmental flow to the Coorong may Townships improve mulloway stocks in this area. operation of the barrages and the installation of fishways will improve

ecological health for the Coorong and the Lower Lakes. For the latest information on the fishways project, visit www.sardi.sa.gov.au and search for ‘barrages’ from the home page. Project partners FIND OUT MORE THE NATIVE FISH STRATEGY Several organisations have worked together to The goal of the Murray-Darling Basin migration, including the barrages and locks and ensure the best environmental outcomes of barrage Murray-Darling Basin Commission (MDBC) The Living Murray initiative Department of Water, Land and SA Water Commission’s Native Fish Strategy is to weirs along the Murray’s length. In recognition operation and the use of fishways. www.mdbc.gov.au Tel (02) 6279 0100 www.thelivingmurray.mdbc.gov.au Biodiversity Conservation (DWLBC) www.sawater.com.au rehabilitate native fish communities after of this, the $25 million Sea to Hume Dam project The Murray-Darling Basin Commission has funded www.dwlbc.sa.gov.au 50 years of implementation. is under way. This project, the largest of its kind the fishways and barrage improvements Visit for in-depth information on the Native Fish The Living Murray website explores what constitutes Visit to learn more about water conservation, SA Water operates and maintains the barrages Flow regulation, including the construction in the world, will provide fish passage for 2275 Strategy, fishways, environmental flows and a broad a healthy working river and what is needed to The River Murray section of this website provides water quality, water levels at monitoring kilometres upstream from the Murray Mouth. the Department of Water, Land & Biodiversity range of other issues related to the health and achieve it. Visit to learn more about the initiative further detail and data on river operations, salinity, points (including the barrages) and for of dams and weirs, is noted in the Native Fish Conservation (SA) coordinates environmental productivity of the Murray-Darling Basin. and its progress. water quality, and environmental flows. historical information on the River Murray. Strategy as one of the key threats to native fish Part of this program includes construction and The Native Fish monitoring and adaptive management across the Murray-Darling Basin. Recent surveys monitoring of barrage fishways. Strategy is available fishways are monitored by multi-state team have identified around 5000 barriers to fish for download from involving SARDI (SA), Department of Primary The Murray-Darling Basin Commission thanks the following people and organisations for their contributions to this publication: Jason Higham (PIRSA); Russell Seaman and David Thompson (DEH); Peter Lewis (SA Water); Qifeng Ye (SARDI); Jacqui Symonds and Brenton Erdman (DWLBC). www.mdbc.gov.au Industries (NSW) and Arthur Rylah Institute (Vic). © Environmental Information, DEH SA © Russell Seaman, DEH © Thomas Brown, Ecocreative © Ross Carter, SA Water © Ross Foster, SA Water © State Library of South Australia © M Wright-Simon, Ecocreative

Murray Mouth congestion is the result of reduced flows The Coorong and Lower Lakes Estuaries provide protected nursery There has been very little flow The vertical slot and Denil fishways of the Goolwa Preliminary plans for barrages were The remote operation of gates at from the river to the sea. Closure of the mouth would are important to the continued areas for fish species. Environmental through the barrages since Barrage are just beyond the lock and navigable pass for prepared as early as the 1890s. Work Tauwitchere Barrage enables more result in damage to the Coorong ecosystem. survival of many waders and flows are vital to maintaining fish December 2001. Without adequate boats (clearly visible in the centre of the barrage). began around 40 years later when flexible management of available other wetland birds. populations and the viability of the flows, dredging maintains the link increasing salinity threatened irrigated flows. local fishing industry. to the sea. areas as far upstream as Mannum. THE COORONG & The Coorong and the Lower Lakes are listed as THE RIVER What the barrages do Lake operation for ecological benefits a Wetland of International Importance under Prevent sea water entering the lakes and river. The Lower Lakes management strategy will THE LOWER LAKES the Ramsar Convention, a treaty that obligates MURRAY BARRAGES Maintain the lake height above sea level. This consider more varied water levels and releases governments to protect and manage the area raises river levels by up to half a metre all the of water for longer periods. This allows for The Coorong and the Lower Lakes (Lake wisely. The region is also subject to migratory In the pre-barrage era, some Low flows and the Murray Mouth Sand dredging commenced at the Murray Historically the barrages have helped way to Lock 1 at Blanchetown (274 river Maintaining these water levels has always environmental flows to the Coorong and the The added operational flexibility aims to maintain reliable water supplies for Alexandrina and Lake Albert) provide bird agreements with China and Japan. estuarine fish were found as far up Over the past century, river regulation and Mouth in October 2002 in order to prevent the kilometres upstream). required careful consideration of local factors operation of fishways. improve ecological outcomes from the available human use. They are now also operated diverse wetland habitats for many native The Coorong and the Lower Lakes are of great river as Murray Bridge. water diversion have severely reduced flows in closure of the Mouth and the resultant impacts Retain a secure supply of water for domestic, such as tidal variation and the effect of strong water, while still providing water for domestic, plants and animals. to improve environmental outcomes. spiritual and cultural significance to the region’s the River Murray. Now only about 27% of the on the fishing industry, tourism, recreation and industrial and irrigation use, including winds. Southerly winds can blow large volumes Greater operational flexibility industrial and irrigation use. Future studies will The early settlers in the Lower Murray region metropolitan Adelaide. The wetlands and lagoons provide feeding indigenous people, the Ngarrindjeri. These areas are no longer tidal and contain only natural flows reach the Murray Mouth. the overall ecology of the Coorong. of water far upstream and wind can vary levels aims to improve ecological aim to enhance these benefits. fresh water. This is a big change from the pre- soon discovered that water supplies for domestic across the lake by as much as 0.4 metres. It is territory and a drought refuge for large numbers In the last century, the natural flows of the Large volumes of sand are carried in through Dredging helps maintain the connection Traditional lake operation outcomes and water supply. These improvements to the barrages and of waders and other waterbirds, with 33 barrage era when estuarine fish were once found the Mouth by incoming tides. Under natural between the sea and the Coorong, allowing the use and farming were unreliable; they fluctuated As with other parts of the river system, the for this reason that lake levels are measured as the installation of fishways is funded by the River Murray have changed dramatically. This is as far up river as Murray Bridge. in level and were subject to the ‘intrusion’ of sea the average of heights at six different monitoring migratory species listed under international especially evident in the Lower Murray. conditions, this sand would be carried out entry of cool, fresh oxygenated water through Lower Lakes have traditionally been managed Australian, NSW, Victorian and South Australian treaties. The area is also home to dozens of Due to the presence of the barrages, the change again by river flows. However, the reduction in tidal movements and therefore a healthier water into the river and estuary lakes. These long, reinforced concrete structures were to ensure a water supply for human uses rather points. These measurements are then considered Changed gate function at Tauwitchere includes governments through the Murray-Darling species of native fish. The Murray Mouth allows The environmental features of the region, The impact of the barrages from fresh to saltwater environments is abrupt river flows from large-scale water consumption ecosystem. However, dredging is only a part of Construction: a huge undertaking built in the channels between Lake Alexandrina than for ecological outcomes. Typically, barrage in decisions on barrage gate operation. hydraulic radial gates (including those in the Basin Commission. SA Water is responsible for water to flow into and out of the Coorong including the Coorong National Park, are Before the construction of the barrages in the and the tidal range of the estuary is reduced. upstream, combined with the effects of drought, the long-term solution. The answer lies in the In 1931, after decades of pressure from and the Murray Mouth in a massive engineering gates are opened and closed to maintain a level The high water levels of the Lower Lakes have fishway bays) to be remotely operated from the design, operation and maintenance, while the estuary, a narrow lagoon system that follows a major tourist attraction. A wide range of late 1930s the estuarine area was much larger This is believed to be one of the major factors has led to the accumulation of large volumes provision of adequate flows in combination with landholders, riverboat traders and others in and construction project that took more than of 0.75 metres above sea level. Near the end of an impact on the environment. Lake edge Goolwa office by computer. Department of Water, Land and Biodiversity the coast for about 100 kilometres. This is an recreational activities, including fishing, boating, than it is today. The estuary once included that has generally degraded habitats and caused of sand and therefore the constriction of the dredging during periods of low flow. favour of flow regulation, the River Murray five years. Together with the islands of the river spring, this level is increased to 0.85 metres to habitat is frequently under water and lakeshore Gates automatically close to prevent saline Conservation coordinates planning, monitoring important nursery area for many fish species of bird watching, bushwalking and camping are areas of Lake Alexandrina and the channels declines in native plant, bird, fish and animal Murray Mouth. Commission decided that five barrages be built delta, the barrages form a continuous barrier allow for evaporation and irrigation over the erosion is increased, adding sediment and inflows when sensors indicate that sea levels may and adaptive management. significant environmental and commercial value. dependent on a healthy wetland ecosystem. immediately upstream of the barrages. populations throughout the system. with gates that would allow for flow regulation. between fresh and saltwater environments. summer. nutrients to the water. rise above that of the lake.

VERTICAL SLOT FISHWAY GOOLWA BARRAGE DENIL FISHWAY TAUWITCHERE BARRAGE ROCK RAMP FISHWAY Studies at Tauwitchere have indicated that e THE FISHWAYS more than 30 species will use the fishways. The vertical slot fishways installed at Goolwa and FISHWAY LOCATIONS The Denil fishway installed at Goolwa Barrage FISHWAY LOCATIONS The rock ramp fishway installed at Tauwitchere Tauwitchere barrages are used by a range of fish is well suited to larger-bodied fish, including Barrage is very good for small and medium-sized All fishways (also known as ‘fish ladders’) It is expected that between 800,000 and 1.6 f sizes and species such as lamprey and mulloway. perch and bream. The adjustable height and fish, including common galaxias and congolli. are designed to allow fish to pass both ways million fish will use the fishways in a year. This To depict barrage operation, the fishway is angle of these fishways suits varied water levels Wide variation in water flow patterns is provided e through or around a barrier. At the River will include fish that are classified as freshwater, d e shown alongside an open Goolwa barrage gate. either side of the barrage. Fresh water by the arrangement of rocks. Murray Barrages, water flows so swiftly estuarine and diadromous (move between fresh g Lake Alexandrina (upstream side) through open gates that the barrages and salt water). The fishways will also allow the f Remote d a Water flow attracts fish to the entrance. a Water flow attracts fish to the entrance. Vertical a Water flow attracts fish to the entrance. present a physical barrier to upstream fish freshwater fish that are ‘flushed’ through open slot fishway receiver unit Calmer water in chambers provides resting The angled baffles of the fishway reduce The varied rock sizes and positions provide a migration. barrage gates to return to the Lower Lakes. b Sea water b c b pools for fish between slots. (downstream side) water speed for fish. range of velocities for fish to move through the Water flowing through the barrage fishways Future plans Various enhancements are being fishway. c c attracts fish to the entrance. Once inside, fish of considered for the fishways. These include fish Water flowing through the barrage gates is too Vertical slot The screw jacks allow for the Denil support various sizes move through the fishway with the monitoring traps, walkways for workers, trash fast for fish passage. This presents a barrier to fishway frame to be manually lowered and raised to c The weight of the radial gates creates a seal entry from the estuary side. suit lake levels. b Sea water against the sea bed to close the barrage bay c help of slowed water velocity, eddies and resting racks and screens to minimise birds snaring Denil (downstream side) fishway d and prevent sea water entering the lake. pools. Fish then exit on the other side of the migrating fish. Carp separation cages are being d The crane moves along the barrage rails to d Concrete stop-logs of various heights are barrage. trialled at fishways upstream and may also be b remove or replace stop-logs. stacked to close the barrage bay. They are d Hydraulic arms are automated via remote installed here. slotted into the central cavity of the barrage signals from the Goolwa SA Water office or c e Concrete stop-logs of various heights are The benefits Before the installation of or removed to regulate flow. triggered by rising tides or sea conditions. fishways, the barrages presented a barrier to stacked to close the barrage bay. They are Rock ramp Lock and a fishway Fresh water b slotted into the central cavity of the barrage or navigable pass e The gate allows for closure of the fishway e Fish exit on the other side of the barrage.* fish movement between salt and freshwater Lake Alexandrina environments. This made survival difficult for removed to regulate flow. (upstream side) when not in use. Monitoring devices can be fitted at this location to prevent salt water many species that require these environments f The vertical slots are angled to slow moving a a entering the lake. to complete their life cycle. Refer to the illustrations for more detail on how water. This enables fish passage. The fishways are located in adjacent bays of the The rock ramp is located at the Pelican Point end *The fishways assist fish to migrate in both directions the vertical slot, Denil and rock ramp fishways barrage on the Hindmarsh Island side of the lock f Fish exit on the other side of the barrage.* of the barrage. The vertical slot fishway is located (from one side of the barrage to the other). g Fish exit on the other side of the barrage.* * operate at Goolwa and Tauwitchere barrages. and navigable pass (beyond the public walkway). in a bay near the middle of the barrage.