Loddon–Avoca

Typical of many rivers of the southern Murray–Darling Basin, the Loddon and Avoca rivers rise in the Great Dividing Range in south-central Victoria. From wooded hilly terrain. the rivers descend northward through undulating foothills and emerge onto the plains of northern Victoria.

Flows from the Loddon and Avoca do not contribute much water to the River Murray, however they are a significant water source for important wetlands in northern Victoria, such as Boort District Wetlands and the Kerang Lakes.

The catchment is home to about 7% of the population of the Basin, which includes Victoria’s fourth largest city, Bendigo. The main land use is dryland cropping and grazing, but there is extensive irrigation in the north of the catchment, with dairying being the largest industry. About 75% of the water used in the catchment is transferred in from other catchments, with urban water for Bendigo supplied from the Campaspe River catchment, and irrigation areas in the north supplied mainly by the Goulburn and Murray catchments.

Snapshot

Catchment area	2.3% of the Murray–Darling Basin
Contribution to Basin water	1.7%
Annual stream flow	Loddon River: 201 GL (Laanecoorie Weir) Avoca River: 84 GL (Coonooer Bridge)
River length	Loddon River: 310 km Avoca River: 270 km
Tributaries	Bet Bet and Tullaroop creeks
Distributaries	Gunbower, Reedy, Pyramid and Barr creeks in the northern plains, Bullock and Bendigo creeks in the central catchment, Piccaninny and Mt Hope creeks in the east.
Towns include	Bendigo, Maryborough, Castlemaine, Kerang Avoca, St Arnaud, Charlton, Sea Lake
Water storages	Loddon River: Cairn Curran Reservoir (147 GL), Tullaroop Reservoir (73 GL), Laanecoorie Reservoir (8 GL) Avoca River: none
Water users	2.3% of the Murray–Darling Basin

The landscape and its water

The Loddon River has its headwaters in the Central Highlands of Victoria, between Daylesford and Woodend, and only 1 kilometre from the start of the Coliban River. It is the second longest river in Victoria and has many tributaries. Water from the Loddon is important for many wetlands on the lower Loddon River floodplain. Beyond the wetlands, the Loddon joins the Little Murray River (an offshoot of the main River Murray) north of Kerang, which in turn, meets the River Murray at Swan Hill. Within its catchment the Bendigo and Bet Bet creeks also flow from the ranges to wetlands on the northern floodplains.

The Avoca River runs west of the Loddon River. Rising south of the Pyrenees Ranges, the Avoca flows 270 km north to terminate at Lake Bael Bael between Kerang and Swan Hill. In times of high flow, the waters of the Avoca River will flow into the Kerang Wetlands and reach the River Murray. The Avoca River splits into several channels. Its pattern of flow is the most variable of all Victorian rivers in the Basin.

The rivers rise at elevations up to 600 m within the Great Dividing Range, where waterways have cut deep ravines in rich volcanic plateaus. These parts of the region may have an average annual rainfall of up to 1,200 mm. North of the volcanic country are rolling foothills of granitic soils and low rocky ranges that were mined for gold in the 1800s. The hills give way to wide riverine plains in the north, which are much warmer and drier than the southern regions, with annual rainfall in the north-west being about 350 mm.

Groundwater in the catchment exists mainly in fractured rock aquifers (including basalts) of the Central Highlands in the upper catchment, and in sedimentary deposits of the Basin in the lower catchment under the northern plains.

People, industry and water use

Most of the Loddon catchment and the Avoca catchment is the traditional land of the Dja Dja Wurrung Aboriginal nation. On the floodplains, around Kerang and Kow Swamp, is the traditional land of the Barapa Barapa nation.

In the 1830s, settlers followed the expedition trails of Major Thomas Mitchell and took up land along the rivers, primarily for grazing. In the 1850s and 1860s, gold was discovered throughout the central part of the catchment, in what became one of the richest alluvial goldfields of the world. Many towns were established to service the gold rush, some of which remain important regional centres, such as Bendigo, Castlemaine and Maryborough. Land on the northern plains was taken up as large pastoral holdings from the 1840s. Much smaller holdings of land were offered in the 1900s, as railways were constructed, irrigation schemes were developed and soldier settlement schemes were implemented.

The Loddon–Avoca catchment has about 7% of the population of the Basin. Victoria’s fourth largest population centre, the city of Bendigo, has a population of around 95,000 people (ABS 2016). It is a major service centre for in central and northern Victoria, providing health, education and financial services to the region, as well as employment through many and varied industries. Other large population centres in the catchments include Castlemaine (7,000) and Maryborough (7,000). Smaller centres such as Boort and Kerang service rural communities. In the southern part of the catchment, some people commute to Melbourne for work.

Non-urban industry in the central part of the catchment, around Bendigo, involves dryland agriculture, viticulture and some pome fruit production. Agriculture is the key industry in the northern part of the catchment with dairying, broadacre crops, livestock grazing, intensive animal industry (pigs, poultry and eggs), and horticulture (stone fruit, grapes and vegetables). Irrigation underpins the productivity in the northern parts of the catchments.

Tourism is an important industry throughout the catchment, with national parks and historic gold-mining towns drawing visitors to the southern catchment, and the waterways attracting fishermen, hunters and water-sports enthusiasts to the central and northern parts of the catchments.

The latest Commonwealth Scientific and Industrial Research Organisation (CSIRO) report found that 32% of available surface water was diverted for use in irrigated agriculture, stock and domestic, and urban water supply. Irrigation water in the northern part of the catchment is also sourced from the Goulburn, Campaspe and Murray river systems. Groundwater within the Loddon–Avoca region is used for urban, stock and domestic and irrigation purposes. Groundwater accounts for about 9% of total water use in the region.

Regulation of water in the catchment

The course and condition of the Loddon River was changed substantially as European settlers took up landholdings in the southern areas of the catchment through the 1830s and 1840s. The land was cleared, stream banks grazed and the waterways de-snagged. In the 1850s, the gold rush in the region resulted in irreversible sedimentation and erosion of the waterways.

The growing towns required reliable water and a reservoir was built on the Coliban River to supply water to residents of both the Campaspe and Loddon river catchments. An additional 2 reservoirs were built on the Coliban in 1903 and 1941, and Lake Eppalock was built on the Campaspe River in 1963. In the 21st century, the Coliban and Campaspe system supply water for much of the Loddon catchment, especially Bendigo. In drought years, Bendigo urban supplies are also sourced by transfers of water, through Lake Eppalock, from the Goulburn system.

The potential of irrigated agriculture on the riverine plains around Kerang and Boort was recognised and the construction of Laanecoorie Reservoir on the Loddon River began in 1889. Irrigation water was also supplied into the region from the Torrumbarry Weir (on the River Murray), which was constructed in 1919. The Cairn Curran and Tullaroop reservoirs were built on the Loddon in the 1950s to meet expanding production. The irrigation areas of northern Victoria are also supplied with water from the Goulburn River (through the Waranga Basin and channel).

With regulation, stream flows in the catchment have been reversed (high in summer and low in winter), which has had a significant effect on native species in the river and wetland environments. High salinity and algal blooms are major water quality issues as a result of historic mining and modern land use.

The Avoca River is one of the Basin’s least regulated rivers, as there are no water storages along its channel, however there are 12 small weirs along its length. There are some small storages on tributaries of the Avoca, to supply small towns with water. Water is extracted from the river throughout the year for stock and domestic use, and a small amount of irrigation. Water supply in the catchment is supplemented with water transferred from the Murray and Goulburn catchments, and the Grampians region.

Environmental importance

The Loddon and Avoca catchments support a range of environmental features, significant ecosystems and a diverse range of endangered plants and animals. Environmental flows are used to improve the condition of the river channels.

The Boort District Wetlands at the northern end of the Loddon provide a range of important habitats in a heavily modified catchment, including the deep water marsh Woolshed Swamp.

The Kerang Wetlands, where 23 of the 100 wetlands in the system are Ramsar listed, receive water from the Loddon and Avoca rivers.

The Sustainable Rivers Audit reported the overall ecosystem health of the Loddon River as very poor. Flow regulation had seriously affected species abundance and diversity for fish, but not so much for macroinvertebrates. Riverine vegetation was rated in extremely poor condition in all zones of the Loddon. The physical form of the river was rated as moderate condition, despite elevated sediment loads. Flow seasonality and variability was rated poor in the lowland zone of the Loddon and good in the slopes zone.

The overall ecosystem health of the Avoca River was rated as poor. The numbers and diversity of native fish was rated very poor, with alien species dominating. The macroinvertebrate community was rated in moderate condition. Riverine vegetation was rated in poor condition. The physical form was rated in moderate condition with elevated levels of sediment. Flow seasonality and variability was rated in good condition.

Water recovery

The Basin Plan sets Sustainable Diversion Limits, which is how much water can be used in the Murray–Darling Basin, while leaving enough water for the environment. A Sustainable Diversion Limit (SDL) was established for each catchment (or group of catchments) and the reduction in diversions required to achieve the SDL was identified.

The use of environmental water in a specific catchment or region will vary from year-to-year. The Murray–Darling Basin Authority (MDBA) has a Basin-wide environmental watering strategy to guide the use of environmental water across the Murray–Darling Basin to help achieve the best possible results over the long term. Environmental water managers make the day-to-day decisions on what to water and when, in line with the strategy and taking into account seasonal conditions, priorities and the availability of environmental water. Watering decisions are made in consultation with various waterway managers and local landholders.

Catchment or regionally-specific details about environmental water use in the catchment including watering actions, portfolio details and planning, and monitoring of environmental watering, can be found through the Commonwealth Environmental Water Holder or the state government environmental water manager.

More information

Water management

The management of water resources is the responsibility of local, regional, state and Australian governments.

Delivery to households, industry and farms is managed by local councils or regional water authorities.

State government departments ensure the network of authorities manage water responsibly and fairly, that catchment and waterway health is maintained or improved through catchment management authorities, and that water saving, re-use and flood management projects are implemented. State governments must manage their state's water resources according to state and commonwealth water legislation.

In addition to directing operations of the regulated River Murray system, the MDBA implements a number of plans and programs to ensure the waters of the Basin, which flow through 4 states and 1 territory, are managed cohesively and in the best interests of all water users of the Basin.

Rural water authority