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  • C S I R O L A N D a nd WAT E R

    Water erosion in the Murray-Darling Basin:Learning from the past

    By Anthony Scott

    CSIRO Land and Water, Canberra

    Technical Report 43/01, November 2001

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    Water erosion in the Murray-Darling Basin:Learning from the past

    By Anthony ScottCSIRO Land & Water, CRC for Catchment Hydrology

    CSIRO Land & Water Technical Report No 43/01(ISBN 0 643 06098 7)

    November 2001

    AcknowledgementsThis report was funded by the Murray-Darling Basin Commission and the Cooperative Research Centrefor Catchment Hydrology. The author would also like to thank the following people and organizationsfor kindly providing information, reviewing the draft report or contributing photos;

    • Jon Olley, Ian Prosser, Chris Moran, Jacqui Olley (CSIRO Land & Water),• Carolyn Young, Greg Bowman (Department of Land & Water Conservation, NSW),• Pat Feehan (Goulburn-Murray Water, Victoria),• Geoff Titmarsh, Bernie Powell, Bruce Carey (Department of Natural Resources and Mines,

    QLD),• Lisa Robins (Robins Consulting),• Tony Jakeman, Lachlan Newham, Barry Croke (CRES, Australian National University),• Klaus Koop (Environment Protection Agency, NSW),• Nicki Taws (Taws Botanical Research),• Peter Russell,• Mitchell Library - State Library of NSW,• National Library of Australia,• State Library of Victoria,• Museum Victoria.

    Copyright: © 2001 CSIRO Land and Water.To the extent permitted by law, all rights are reserved and no part of this publication covered bycopyright may be reproduced or copied in any form or by any means except with the written permissionof CSIRO Land and Water.

    CSIRO Disclaimer: To the extent permitted by law, CSIRO Land and Water (including its employeesand consultants) excludes all liability to any person for any consequences, including but not limited to alllosses, damages, costs, expenses and any other compensation, arising directly or indirectly from usingthis publication (in part or in whole) and any information or material contained in it.

    MDBC disclaimer: The contents of this publication do not purport to represent the position of theMurray-Darling Basin Commission. They are presented solely to stimulate discussion for improvedmanagement of the Basin's natural resources.

    Front cover photo; Gully erosion along a tributary of Merrill Creek, near Gunning, NSW(photo; Nicki Taws)

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    Table of Contents

    SUMMARY ................................................................................................................................... 41. INTRODUCTION TO EROSION PROCESSES .............................................................................. 52. THE LANDSCAPE AT THE TIME OF EUROPEAN SETTLEMENT ................................................. 8

    2.1 Previous episodes of gully erosion ............................................................................. 82.2 Impacts of Aboriginal land use .................................................................................. 82.3 The shape and size of streams and drainage lines ..................................................... 92.4 Chains of ponds in Southern Tablelands of NSW..................................................... 122.5 River turbidity prior to European settlement ........................................................... 15

    3. EXPLORATION FOLLOWED BY PASTORAL EXPANSION; 1813 TO 1850S .............................. 173.1 Explorers and settlers move into the Murray-Darling Basin................................... 173.2 Early forms of pastoralism ....................................................................................... 203.3 Early attempts at cropping ....................................................................................... 213.4 The first signs of landscape change ......................................................................... 22

    4 THE GOLD RUSH ERA ......................................................................................................... 244.1 Discovery of gold...................................................................................................... 244.2 Environmental impact on rivers and streams........................................................... 264.3 Loss of forests in gold mining districts..................................................................... 304.4 Growing concern about the sludge problem ............................................................ 33

    5. 1860S – 1920S; CLOSER SETTLEMENT AND ACCELERATED LAND DEGRADATION .............. 375.1 The Free Selection Acts and closer settlement ......................................................... 375.2 Expanding frontiers .................................................................................................. 385.3 Accelerated erosion from overgrazing and land clearing........................................ 395.4 Further notes on land clearing................................................................................. 485.5 Eroded gullies initiated by animal tracks, roads and drains ................................... 525.6 The introduction of rabbits....................................................................................... 565.7 Expansion of cropping.............................................................................................. 585.8 The effects of droughts and floods............................................................................ 635.9 Land degradation on the Western Plains ................................................................. 66

    6. THE CAMPAIGN FOR SOIL CONSERVATION ......................................................................... 716.1 Setting up Agricultural Colleges and Departments ................................................. 716.2 NSW sets up Soil Conservation Service ................................................................... 716.3 Soil Conservation Board established in Victoria ..................................................... 746.4 Soil Conservation Act of South Australia................................................................. 786.5 Growing awareness of soil conservation in Queensland ......................................... 796.6 Erosion problems in the high country ...................................................................... 81

    7. IMPROVED MANAGEMENT FROM 1945 ONWARDS .............................................................. 857.1 Overview of improvements ....................................................................................... 857.2 Rates of erosion declining in most regions .............................................................. 927.3 Improved pastures and fertilizer use ........................................................................ 987.4 Erosion associated with increased cropping.......................................................... 1007.5 Farm dams and water storages reduce sediment yield .......................................... 102

    8. INVESTIGATING THE SOURCES AND YIELDS OF SEDIMENT. ............................................... 1058.1 Sediment yields for different land uses................................................................... 1058.2 Effects of logging and plantation forests on stream sediment concentrations....... 1068.3 Streambank erosion – another source of sediment in rivers .................................. 1078.4 Sediment surveys of reservoirs ............................................................................... 1088.5 Erosion studies using small plots or paddocks ...................................................... 109

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    8.6 Studying the impact of single storm events .............................................................1108.7 Recent surveys of erosion in NSW and Victoria .....................................................1118.8 Sediment budgets ....................................................................................................113

    9. LOOKING TO THE FUTURE ................................................................................................118REFERENCES ............................................................................................................................123

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    SummaryWhen travelling across the Murray-Darling Basin, it becomes clear that many regions sufferfrom extensive soil erosion. What isn’t so clear is that much of this erosion commenced over150 years ago when European settlers started farming (and later mining) the land. Tounderstand the current condition of the landscape it is essential that we have a knowledge ofwhat has happened in the past.

    In the first half of the 19th century, European farmers and pastoralists took possession of landthroughout the Murray-Darling Basin. The large numbers of sheep and cattle that they broughtwith them, grazed the perennial grasses and reduced the ground cover that protects the soil. Thehard hooves of the stock also disturbed the soil surface, particularly along streamlines andaround waterholes. Disturbance to the land accelerated in the second half of the 19th century assettlement and associated land clearing intensified and this was exacerbated by the huge plaguesof rabbits which ate any remaining vegetation.

    In some regions, particularly along the western slopes of New South Wales and Victoria,alluvial gold was discovered in the 1850s, and this led to long stretches of creeks andsurrounding floodplains being completely dug up and processed through primitive ‘puddlingmachines’.

    All of these disturbances resulted in a massive increase in soil erosion, which probably reached apeak during the second half of the 19th century and the first half of the 20th century. By theearly to mid 20th century there was a growing awareness of the problems associated with soilerosion and this eventually led to the establishment of soil conservation agencies in each state.From the 1940s onwards there has been a concerted effort to repair the damage caused by soilerosion. Today, the landscape appears to be gradually adjusting towards a new ‘equilibrium’ andthe rates of erosion are slowly declining from their peaks. However, these new rates of erosionare still many times higher than those of pre-European times, and the legacy of the past 180years continues to have a significant impact on both the environment and agriculturalproductivity.

    This report documents these major events, and the changes to land use since Europeansettlement, that led to the increase in soil erosion throughout the Murray-Darling Basin. A betterknowledge of the history of soil erosion not only helps to understand the processes that lead toaccelerated erosion, but should also assist with the prediction of future trends. It also provides along term perspective (over a timeframe of 150-200 years) which can complement morequantitative but shorter term studies (of 5 to 10 years) that might be undertaken in a specificcatchment or paddock. Most importantly, by learning about the mistakes made in the past, wemight be able avoid them in the future.

    “We could not have made a bigger mess of the soil of the country if its destruction had beencarried out under supervision.”

    (Henry Bolte, Premier of Victoria, introducing legislation in 1949 which replaced the original SoilConservation Board with the new Victorian Soil Conservation Authority.)

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    1. Introduction to erosion processes

    Erosion, by water or wind, is a natural process. While volcanic and tectonic processes build upland surfaces, erosive processes wear them away. However, the effect of European settlement inthe Murray-Darling Basin (and elsewhere in Australia) has been to drastically increase the rateof erosion, and this has resulted in significant land degradation (Woods 1983). There are twomain forms of erosion in the Murray-Darling Basin, wind erosion and water erosion. This reportexamines the history of water erosion.

    Increased water erosion has been caused by a number of factors, the most important being;- land clearance and the loss of the protective vegetation cover due to grazing,- increased runoff from cleared areas and,- increased erodibility of disturbed soils (eg. cropping land).

    The potential soil loss increases sharply when ground cover falls below 70% (Lang andMcCaffery 1984), and bare, tilled soil is particularly prone to high rates of erosion.

    Soil erosion by water is a complex process being dependent on many factors, such as climate,soil, topography, plant cover and land use. Initial detachment of soil occurs when the erosiveforces of raindrop impact, or of flowing water, exceed the soil’s resistance to erosion. Detachedparticles are then transported downslope by surface runoff, the quantity and size of particlestransported being dependent on the velocity and turbulence of the water flow.

    There are four main types of water erosion, and these are;

    • Sheet erosion is the removal of a fairly uniform layer of soil from the land surface byraindrop splash or surface runoff. It is often less visible than rill or gully erosion. Sheeterosion often occurs on cropping land where the soil is loosened by tillage. In someregions, sheet erosion is also associated with the presence of salt scalds (van Dijk 1969,Graham et al 1989, Bullock and Neil 1990, Neil and Richardson 1990).

    • Rill erosion is the formation of small eroded channels that could be obliterated by normaltillage. A depth of less than 30 cm is normally used as a criterion to distinguish rillsfrom gullies. Rill erosion occurs when soil is detached by concentrated runoff. Rillscommonly develop along tillage lines and on the edges of roads and tracks where the soilhas been disturbed and runoff is concentrated. (Sheet and rill erosion are sometimescombined under the more general term of ‘hillslope erosion’.)

    • Gully erosion is the removal of soil by flowing water, resulting in the formation ofchannels sufficiently large that they disrupt normal farming operations and are too largeto be filled during normal cultivation. Incision of gullies tends to occur when thevegetation along drainage lines is disturbed or when changes in land use within thecatchment causes an increase in surface runoff. Once gullies have started to form, theyare difficult to control.

    • Streambank erosion refers to the undermining and collapse of banks along rivers andstreams. This is a natural process but has been accelerated by the removal of riparian

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    vegetation, trampling of river banks by stock, and increases in bankfull discharges inregulated rivers. (Gully and streambank erosion are sometimes combined under themore general term of ‘channel erosion’.)

    The direct or ‘on-site’ consequences of accelerated soil erosion are;

    • loss of nutrients required for plants to grow,• a loss of organic matter which plays a vital role in sustaining the desirable physical and

    chemical characteristics of soil,• decrease in soil depth which reduces water storage capacity, and• damage to infra-structure such as fences, roads and buildings.

    The Soil Conservation Service of NSW has found that, on the black soils of the Namoi Valley ina season following bad erosion, a fall of up to 30% in wheat yields is possible (Seymour 1993).Fertilisers can be added to the soil to compensate for the loss of nutrients associated with soilerosion, but the reduction in water holding capacity (caused by a decrease in soil depth) is moredifficult to address.

    Accelerated soil erosion can also cause ‘off-site’ impacts, in particular the increased turbidity inrivers and streams, and the sedimentation of reservoirs, lakes and estuaries. In some estuaries,increased quantities of sediment has led to the smothering of valuable seagrass beds. Increasedsediment loads have also changed the nature of streams and wetland habitats by filling deepwaterholes that used to be drought refuges for plants and animals. The sediment also transportsnitrogen and phosphorus into streams, which can lead to increased growth of algae. Increasedwater turbidity can also interfere with aquatic organisms, for instance the reduced visibility canaffect the foraging habits of many fish species.

    High sediment loads also reduce the storage capacity of reservoirs, and the increase in turbiditycan add substantially to the cost of water treatment. In summary, accelerated soil erosion has asubstantial economic, ecological and social cost to society.

    Why study the history of erosion in the Murray-Darling Basin?Studying the history of erosion over the last 150-200 years, helps develop a better understandingof the causes and processes that led to accelerated erosion rates. To understand the currentcondition of the landscape it is essential that we have a knowledge of what has happened in thepast. A better knowledge of the past also assists with the prediction of future trends. It providesa much longer term perspective of the issue which can complement more quantitative studieswhich might only investigate a shorter time scale of 5 to 10 years, or even just one storm event.

    A Basin-wide study provides a useful overview of general trends and major events that affectedthe entire region and can this complement more detailed studies of a specific catchment orpaddock. Most importantly, by learning about the mistakes made in the past, we might be ableavoid them in the future.

    The following chapters describe the landscape at the time of European settlement, and then tracethe activities and events that led to the disturbance of the land, and hence accelerated erosionrates. This includes details of;

    • The initial pastoral expansion across the Murray-Darling Basin and the grazing ofpastures by large numbers of hard hoofed stock.

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    • The gold rush eras and the massive disturbance to gullies in the gold mining districts.• Accelerated clearing and intensification of settlement after the Land Acts of the 1860s.• Overgrazing and degradation of the western plains in the late 19th century.• Increasing areas of cropping land and the impacts of the bare-fallow rotation.• Growing awareness of land degradation followed by the establishment of Soil

    Conservation Agencies in the mid 20th century.• Introduction of restoration works to repair badly eroded land and attempts at better land

    management practices in the second half of the 20th century.

    Finally, a discussion of current land management activities and research is presented, along witha brief look at future issues and trends.

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    Figure 1. Murray-Darling Basin.

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    2. The landscape at the time of Europeansettlement

    2.1 Previous episodes of gully erosion

    Today, many valleys in the Murray-Darling Basin contain eroded gullies, some up to 10 metresdeep. At the time of European settlement, most of these gullies did not exist. Clearly, there hasbeen a major change in geomorphic processes over the last 200 years, causing considerableproblems with soil loss from paddocks and reduced water quality in rivers.

    Studies of the landscape indicate that earlier episodes of gully erosion have also occurredthroughout many regions of eastern Australia (Erskine 1986, Wasson 1979, Coventry andWalker 1977, Prosser 1991). In the Southern Tablelands of NSW, past gullies were of a similarsize to those of today but were not as widespread across the region (Prosser et al 1994, Prosser1996). These episodes of erosion were followed by 1,000 to 4,000 years of relatively stableconditions, with continuous sedimentation and the gradual formation of swampy meadows alongthe drainage lines. In some other regions there is little or no evidence of previous phases ofgully erosion, and the current phase of gullying may be unique in terms of landscape history(Fanning 1999).

    The present episode of gully erosion in eastern Australia is the result of major environmentalchange caused by European settlement, and this has had a greater effect on erosion processesthan any other environmental change over the last 10,000 to 20,000 years.

    2.2 Impacts of Aboriginal land use

    Evidence uncovered at Lake Mungo in south-western NSW suggests that Aborigines have beenpresent in the Basin for at least 40,000 years (Powell 1993). This is equivalent to over 1000generations of Aborigines who have successfully lived within the Murray-Darling Basin. Theirtotal population was relatively small and sparsely settled, and as subsistence hunter-gatherers,their overall impact on the environment was minimal.

    Their biggest impact was the change in the fire regime. This changed from one of rare, highintensity natural fires to one of more frequent low intensity fires. These fires were used to flushout animals while hunting and also to encourage a new growth of grass, which would attractkangaroos and other grazing animals. The frequent, low intensity fires allowed a quick recoveryof vegetative cover.

    Studies of some archaeological sites indicate that there was an increase in sedimentaccumulation which coincided with the initial occupation of these camp sites (Hughes andSullivan 1986). However, any increase in erosion associated with disturbance of vegetationaround these sites would have been localised in extent, and unlikely to have had an impact on aregional scale.

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    A detailed stratigraphic study of Wangrah Creek in the Southern Tablelands of NSW wasundertaken by Prosser (1988, 1990) to investigate the effects of Aboriginal settlement and theiruse of ‘fire stick farming’. An increase in fire frequency was detected, beginning at 3,000 to4,000 yrs BP, but this did not change the rates of erosion or cause widespread alluviation in thevalleys.

    Figure 2. Prior to European settlement, the western slopes of the Murray-Darling Basin contained largeareas of grassy woodland. Today, only small remnants remain, such as this reserve near Tarcutta, NSW.(photo; Nicki Taws)

    2.3 The shape and size of streams and drainage lines

    The initial period of settlement in the Murray-Darling Basin, between 1813 and 1850, isrecorded in the journals and diaries of explorers and early settlers, and also in the reports andmaps of government surveyors. One of the most important issues they reported on was theavailability and permanence of water, and their records provide descriptions of the rivers andstreams. These descriptions provide evidence of what these drainage lines looked like prior tothe introduction of the pastoral and agricultural activities of the first settlers.

    The early reports indicate that the broad valleys in upland regions often contained swampymeadows and ‘chains of ponds’ (Eyles 1977b, Page and Carden 1998). In drier areas along thewestern slopes, valleys often contained ephemeral channels which linked deeper water holes(Davis and Finlayson 2000, Randell 1980). Some larger streams had well defined channels anda semi-permanent flow of water during wetter periods. In the drier semi-arid regions throughoutthe western half of the Murray-Darling Basin, flow is highly ephemeral, and drainage linesconsisted of shallow meandering sandy streams bordered by trees (Williams et al. 1991).

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    Most importantly, however, detailed studies of historical evidence (for example Beavis et al.1999; Davis and Finlayson 2000, Starr et al. 1999) indicate that the continuous networks ofdeeply eroded gullies now found in many catchments of the Basin, were not present prior toEuropean settlement.

    ‘Chains of ponds’ described by explorers and settlers of VictoriaMajor Thomas Mitchell was the first European to explore central and western Victoria duringhis expedition of 1836. On returning to Sydney he described this region as follows;

    “The land is, in short, open and available in its present state, for the purposes of civilized man.We traversed it in two directions with heavy carts, meeting no other obstruction than thesoftness of the rich soil; and in returning over flowery plains and green hills, fanned by breezesof early spring, I named this region Australia Felix, the better to distinguish it from the parcheddeserts of the interior country, where we had wandered so unprofitably, and so long.” (Mitchell1839)

    Mitchell made no mention of encountering networks of deeply incised gullies, whichpresumably would have posed a major obstacle to his carts. He did however describe crossingnumerous ‘chains of ponds’ as well as some running streams. It is not exactly clear whatMitchell meant by the term ‘chain of ponds’. He may have been referring to ephemeral channelswith large pools in which water remained, or he may have been describing the true ‘chain ofponds’ form still evident along a few of the less disturbed creeks in Victoria (Davis andFinlayson 2000).

    Mitchell’s expedition and his report of ‘Australia Felix’ prompted many people to move fromSydney along ‘The Major’s Line’ and settle in the newly discovered land in the Port Phillipdistrict. One of these overlanders was Alexander Mollison who travelled south in 1837. In hisdiary he describes the creeks near Euroa;

    “I observe that those creeks and chains of ponds which have large water ponds and a broad,shallow water course, are now full and running, while those which have deep channels, steepbanks cut into the earth and ponds small in proportion to their channels, are now quite dry, withthe exception of a few ponds in some of them in which there may be found a little muddy water”(Randell 1980)

    Mollison’s description indicates that some streams consisted of ‘chains of ponds’ along broadshallow streamlines, but some others did in fact have steep earth banks.

    Early descriptions of Tarcutta Creek, NSWThe earliest descriptions of Tarcutta Creek were made by the first explorers in the 1820s and30s. The channel then consisted of a connected chain of ponds and swamps. Remnants of theswamps persist in the upper catchment at Courabyra (10km north of Tumbarumba) and upstreamof Tarcutta township. Evidence of their former existence is found in exposures of dark organicsoil in present cut banks at Parsons, Borambola and elsewhere. (Page and Carden, 1998)

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    Chains of ponds in the Darling DownsIn 1827, Allan Cunningham, the distinguished and intrepid explorer and botanist, set out fromSegenhoe (near the present town of Scone in the Hunter Valley, NSW) and travelled north overthe Liverpool Plains. After crossing the Namoi and Gwydir Rivers, the arid drought strickencountry forced him to swing east, and crossed the Dumaresq River near Beebo. Soon after, heentered the Darling Downs, which he named in honour of Governor Darling. A few hours later,he camped on the bank of the Condamine near Toolburra. The explorer actually gave the name‘Darling Downs’ only to the narrow valley along Glengallan Creek, about 29 km long, and 2.5to 5 km wide. The Downs were defined, he wrote, by “their lightly wooded ridge, and on theiropposite margin by a level forest of box and white gum. A chain of deep ponds passes along thecentral lower flats”.

    Cunningham spent the next week traveling through the Darling Downs and discovered some ofthe finest pasturage he had ever seen in the colony of New South Wales. On his return toSegenhoe, he passed through the Canning Downs (near the township of Warwick) and continuedsouth through heavily timbered forest of box and casuarinas, and camped at a “chain of smallponds”. (From Allen and Skerman 1986)

    Figure 3. An undisturbed drainage line in Roseburg State Forest near Cowra, NSW.(photo; Anthony Scott)

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    Figure 4. Undisturbed drainage line in a Travelling Stock Reserve near Yass, NSW.(photo; Nicki Taws)

    2.4 Chains of ponds in Southern Tablelands of NSW

    On the Southern Tablelands of NSW, explorers and pioneer settlers made frequent reference to“chains of ponds” (Eyles 1977a, b, c; Starr et al 1999). While it is clear that some of thesefeatures were pools within river channels, other ponds were described as being sunk in grassyalluvial flats with no connecting channels. The ponds were generally long (10-100 metres) andnarrow and separated by bars of fine sediment vegetated with species such as Juncus, Typha,Phragmites and Poa. Except during wet weather, there was little or no flow between the ponds.Maps produced by the early surveyors also show ‘chains of ponds’ along many of the drainagelines in the broad, flat valleys typical of the Southern Tablelands.

    Most valleys which previously contained these ‘chains of ponds’ now contain continuous gulliesincised to bedrock, and up to 10 m deep. However, there are some valleys which remainunaffected by channel incision and still contain ‘swampy meadows’ interspersed with ‘chains ofponds’. Here, alluvial flats have a dense cover of tussock grass and sedge up to 1m high and theflows of water twist between the vegetation (Prosser et al 1994). Larger meadows, those withcatchment areas of greater than 10 km2, often contain drainage ways of concentrated flow asmuch as 0.5 m deep and 1-10 metres wide but with no discernible banks. Within drainage ways,sedge is more prevalent than tussock grass, and 3-40 cm high aquatic plants predominate at sitesof standing water (Costin 1954).

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    Figure 5. This pond on Murrumbateman Ck, north of Canberra, shows little sign of incision andcontains a variety of aquatic plants. In pre-European times, many streams in the Southern Tablelandscontained ‘chains of ponds’ similar to this. (photo; Ian Prosser)

    Chains of ponds on the ‘Yas’ Plains“…. There is a small and new species of lobster, which is also procured in large quantities fromthe muddy ponds on the Yas Plains; they are delicious eating, and taken readily by placing apiece of raw meat on a bent pin…… The ponds in which the lobsters are taken are always fullof water being supplied by springs; one of them is about 50 yards in length by 20 in breadth, butof no great depth at any part. They form a chain along the plains during the dry season of theyear; but during heavy rains they unite into a running stream which empties itself into the YasRiver. It is only at the season when there is merely a chain of ponds or swamps, with but littlewater, that the lobsters can be caught with facility.” (Bennett 1834)

    Chains of Ponds – near Lake George in the 1830s“The first part of our day’s journey lay through a bush, between McFarlane’s and the ranges, ofan ordinary character, and along a chain of ponds, called Cavan River. We then entered a gapwhich led through the ranges, and in due time descended on the other side; there emerging fromthe bush, we suddenly came upon the plain of Lake George....” (Walker 1838)

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    Early description of ‘chain of ponds’In 1834, the naturalist Dr John Lhotsky gave the following account;

    It was at the Pack Inn, and afterwards at Lockyer's Farm, that I first observed those highlycharacteristic chain of ponds, which would deserve a geological examination of months, as theyare a phenomenon not to be found, to my knowledge, in any other part of the world. They arecommonly round or oval basins, of from 20 to 200 feet in diameter, or length, excavated or sunkin the superficies of an alluvial soil, which is commonly of a rich kind, fed by subterraneoussprings; often indeed generally very deep, and not at all to be confounded with water holesowing their origin to the accumulation of atmospheric water.

    The Pack Inn and Lockyers Farm are in the catchment of the Lachlan River to the immediatenorth of the Murrumbidgee, but similar chains-of-ponds were observed in the UpperMurrumbidgee Catchment. The ponds not only existed in chains, but also as single features. Inthe lower reaches of Ingelara Creek, which flows into the Murrumbidgee south of Michelago,Lhotsky ‘found finally one of those circular deep waterholes, I characterised in page 25.’(Andrews 1979, Starr et al 1999)

    ‘Chains of Ponds’ and ‘Swampy Meadows’ in Wangrah CreekWangrah Creek is a headwater catchment of the Murrumbidgee River, on the SouthernTablelands of NSW, covering an area of 50 km2. An 1842 map produced by the Governmentsurveyor WK Wright, shows that a sequence of pools preceded the present gully in the lowerreaches of Wangrah Creek. The original form of the valleys is preserved locally at sites thathave escaped gully erosion in historical times, including a section of Limekiln Creek and theheadwaters of Wangrah Creek, and sections of other creeks in the region. Floors of all thesevalleys are covered to their full widths by swamp ground with a rough surface of tall sedge andtussock grass up to 80 cm high, and flows spread through the vegetation, often in severalpreferred pathways which may include shallow scour pools. These wet valleys withoutcontinuous channels are termed ‘swamp meadows’. (Prosser et al 1994)

    Early records of Jerrabomberra Creek and Molonglo RiverThe lower reaches of Jerrabomberra Creek were described in a surveyors letter as a swamp flatthat contained chains-of-ponds (Eyles 1977b). This term was also used by Lhotsky who wrote“After 7 miles we reached Giribombery, which lies on the banks of a distant creek, or chain ofponds.” In 1822 Kearns described the Molonglo River where it flowed across the MolongloPlain as “a chain of connected ponds running from the south end of the plains.” Along differentreaches, Allan Cunningham (1824) described the Molonglo River as a “reedy creek”, a “largecreek” and a “fine brook” flowing over a plain that was “low and swampy”.(From Starr et al 1999)

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    Burra Creek – once a chain of ponds now deeply incisedAlong almost its entire course Burra Creek is today incised to bedrock leaving its former alluvialflood plain as a prominent terrace which averages 2.8 metres in height above the presentchannel. In the earliest survey plans of the catchment (eg Hoddle 1836, cited by Eyles 1977c)Burra Creek is represented as a chain of ponds. It seems likely that Burra Creek, in the first fewdecades of settlement, may have had steep 1 to 2 metre high banks and a channel consisting ofponds separated by ‘bars’ of fine sediment stabilized by various species of native reeds. Thiswould explain the considerable difficulties bullock trains experienced in crossing the creekduring the early years of settlement. (Eyles 1977c)

    Figure 6. A swampy meadow along the upper reaches of Merrill Creek, near Gunning, NSW.(photo; Nicki Taws)

    2.5 River turbidity prior to European settlement

    In the early 19th century, when the first explorers headed westward from Sydney to discover newlands beyond the Great Dividing Range, they often followed the large inland rivers, either onhorseback or in small boats. In their journals, Charles Sturt, John Oxley and Thomas Mitchell,for instance, all provided quite detailed descriptions of these rivers, and in some instances alsomentioned the clarity of the water. Also, some of early settlers, and a few natural scientists whoexplored the region, also provided descriptions of the rivers. Many of these reports describecobble and gravel bedded rivers with clear flowing water, and this indicates that in many of therivers the supply of fine suspended sediment was limited, and sediment transport exceeded thesupply of sand and mud (Olley and Scott, in press). Sturt, for instance (in 1829), described thewaters of the Murrumbidgee at Jugiong as “hard and transparent” and for the Murray at the

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    Murrumbidgee confluence, he reported that, “its transparent waters were running over a sandybed.”

    The Lachlan River, however, is one river which appears to have always been more turbid thanmost, and Oxley (in 1818) refers to this when he describes the Macquarie River as being, “inevery respect different from the Lachlan; its waters are pure and transparent.” The DarlingRiver was also often described as turbid as illustrated by Sturt’s (in 1829) comparison of theMurray and Darling Rivers at their confluence;

    “there was as distinct a line between their respective waters, to a considerable distance belowthe junction, as if a thin board alone separated them. The one half of the channel contained theturbid waters of the northern stream, the other still preserved their original transparency.”

    Although many of the reports by early explorers and settlers indicate that the rivers of theMurray-Darling Basin were less turbid than in present times, heavy rainfall could quicklychange their appearance, as Oxley discovered when camping on the banks of the Castlereaghriver in 1818;

    “The river during the night had risen upwards of eight feet; and still continued rising withsurprising rapidity, running at the rate of from five to six miles per hour, bringing down with itgreat quantities of driftwood and other wreck. …. The water was so extremely turbid, that wecould not use it; but were forced to send back to the marshes for what we wanted. …… Now thequantity of matter is astonishing, and such as must take some years to remove.”

    In summary, there is historical evidence which indicates that prior to European settlement, manyof the rivers within the Murray-Darling contained less turbid water, due to the lower supply offine sediment from the upper catchments.

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    3. Exploration followed by pastoral expansion;1813 to 1850s

    3.1 Explorers and settlers move into the Murray-Darling Basin.

    Although the First Fleet arrived at Port Jackson (Sydney) in 1788, it was not until 1813 thatBlaxland, Lawson and Wentworth crossed the Blue Mountains and established a gateway to theinterior of New South Wales. Governor Macquarie then commissioned the surveyor GW Evansto undertake further exploration in 1813 and 1815. This resulted in the discovery of the upperreaches of the Macquarie and Lachlan Rivers. Then, in 1817, Surveyor-General John Oxleyfollowed the Lachlan River westward, almost as far as its junction with the Murrumbidgee. Thefollowing year Oxley followed the Macquarie River down to the Macquarie Marshes.

    Initially, settlers were slow to follow in the footsteps of the explorers, and in 1819, there wereonly about 8 settlers in the Bathurst district, along with 24 flocks of sheep and about 1,400 headof cattle. Ten of the flocks belonged to William Cox and the remainder to 7 other individuals(King 1957). By the 1820s, however, explorers such as Hume and Hovell, Allan Cunninghamand Charles Sturt were discovering new lands to the south, west and north of Port Jackson (seeTable 1), and settlers were following soon after. The pastoral expansion of the colony hadcommenced. This phase of exploration and settlement expanded rapidly in the 1830s, withThomas Mitchell conducting expeditions into the north-west of NSW in 1831 and 1832, andthen in 1836 travelling through south-west NSW and into western Victoria. Within months ofMitchell’s return, squatters with large herds of cattle and flocks of sheep followed his tracks tothe new pastoral lands.

    Initially, the Government had tried to restrict settlement to the official ‘Nineteen Counties’which only extended inland as far as Yass, Bathurst and the southern edge of the LiverpoolPlains. However, squatters were occupying large tracts of pastoral land well beyond theseofficial limits. In 1836 the first attempt to regulate squatting beyond these boundaries wasmade, when by ‘Act of Council’, it was decided to admit the right of the squatters to graze theirstock, but imposed annual licence fees of 10 pounds each (King 1957). Nine squatting districtswere proclaimed, and Commissioners of Crown Lands were appointed to safeguard governmentinterests in each. Squatting had been officially recognized by the government. Since squattersdid not own their runs, they hesitated to develop their holdings and they usually remaineduncleared and unfenced.

    By 1840, settlers had established themselves in a continuous belt from Port Phillip in the south,sweeping up between the Lachlan River and the coast, to the Darling Downs in the north. Thenext ten years was an era of consolidation within this region as well as further expansion west.After considerable political pressure, the famous ‘Order in Council’ of 1847 provided furthersecurity of tenure to squatters outside the ‘settled districts’ in the form of 8 and 14 year leases.In 1848 the Government Gazette listed the successful applicants for leases. In the Monarodistrict on the Southern Tablelands of NSW for instance, there were 42 runs, many of whichwere close to 50 sq miles (13,000 ha) and at least one, Michelago, which was closer to 150 sqmiles (38,800 ha). There was no restriction on the number of runs a person could lease sosquatters could control vast properties if they could afford the rent (Hancock 1972).

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    In 1821 NSW only had 139,000 sheep, essentially producing meat for a restricted local market(WRC 1984). In the 1830s, improved shipping and increased British investment allowed woolgrowing to establish itself as the main pursuit of the pastoral industry, and by 1850 there weremore than 12 million sheep grazing the whole of south-eastern Australia. This expansionrequired little capital apart from livestock itself. Land cost either nothing or a nominal amountfor a lease, shepherds were employed instead of building fences, and accommodation wasprimitive.

    Table 1. Exploration and settlement of the Murray-Darling BasinDate Event1788 First Fleet arrived at Port Jackson.1813 Blue Mountains crossed by Blaxland, Lawson and Wentworth, and they were the

    first Europeans to enter the Murray-Darling Basin.1815 George Evans explored from Bathurst, south to Abercrombie River, reached the

    Lachlan River and returned to Bathurst.1817 Oxley expedition. From Bathurst to the lower reaches of the Lachlan River.1818 Oxley travels from Bathurst to Macquarie Marshes, then eastwards through the

    Liverpool Plains to Port Macquarie on the coast.1820 Throsby explores Lake George and Canberra region in the Southern Tablelands of

    NSW, and by 1825 herds and flocks were being depastured in the region.1824 Hume and Hovell expedition starting from Yass, first to cross the Murray River and

    then down to Port Phillip Bay.1827 Alan Cunningham discovers the Darling Downs in southern Queensland.1829 Governor Darling issued Government order defining the 19 Counties, the limit of

    permissible settlement until 1840. Yass, Bathurst, Wellington and the southern endof the Liverpool Plains were within this boundary.

    1829-30 Sturt travels down the Murrumbidgee and Murray, reaching the sea at LakeAlexandrina.

    1831-2 Liverpool Plains and north-west NSW explored by Thomas Mitchell. Settlers arrivein Liverpool Plains soon after.

    1835 Mitchell follows the Bogan River down the Darling, erects a stockade at ‘FortBurke’ and travels down the Darling to Menindee.

    1836 First squatting Act to help control the ‘squatting’ boom. Licence fee set at £10 perannum.

    1836 Mitchell travels down Lachlan, Murrumbidgee, Murray and back through Victoria.This opens up most of Victoria, and squatters follow in his footsteps.

    1836 Colony of South Australia proclaimed. The Colony’s first land sale is held atWellington, on the Murray River, in 1837.

    1838 Horton and Bonney are the first to move cattle overland from NSW, down theMurray River, to South Australia. Within a few years, hundreds of thousands ofsheep and cattle had followed the same route.

    1840s Settlement of the Western Division of NSW begins, initially along the major rivers.1840s By the early 1840s, squatters had established more than 20 stations in the Darling

    Downs in QLD.1845-46 Thomas Mitchell explores westward, discovers Maranoa River, which flows into the

    Darling.1847 The 1847 ‘Order in Council’ improved security of tenure for squatters outside the

    settled districts by establishing 8 and 14 year leases.1847 Stewart – explored the back country between the Lachlan and Murrumbidgee in

    search of grazing territory.1851 The goldrush era begins when Edward Hargreaves discovers gold near Bathurst.

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    Gwydir R

    Namoi R.

    MacIntyre R

    Macquarie

    R.

    Lachlan R

    Culgo

    a R.

    Murrumbidgee R

    War

    rego

    R.

    Par

    ooR

    .

    Goulburn R.

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    g R

    Cam

    pasp

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    Edward R

    Murray R

    Lodd

    onR

    Avo

    caR

    Mur

    ray

    RSettlement of the Murray-Darling Basin

    1830

    1840

    1850

    1860

    Figure 7. Settlement of the Murray-Darling Basin from 1830 to 1860.

    Murrumbidgee valley already settled – 1837“The whole of the Murrumbidgee has long since been fully stocked (every four or five miles wecome to a head station), at all events as far down as seventy or eighty mile below this, afterwhich the country becomes dead level, and in wet seasons almost an entire swamp and unfit forpasturage.”

    From the journal of Thomas Walker, one of a party of gentlemen who travelled from Sydney toPort Phillip in 1837. The observation was made while camping downstream of the present siteof Gundagai, NSW. (Walker 1838)

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    3.2 Early forms of pastoralism

    The rural industry in the Murray-Darling Basin began when outstations for the more establishedproperties near Sydney were set up in the 1820s near Bathurst in the west and Yass in the south-west. Pastoral methods were simple, and for those who were squatting or leasing the land,investment was kept to a minimum. There was little incentive to fence paddocks or to outlaycapital on extensive clearing.

    Cattle roamed at will, usually forming their own camps near water, and were mustered whenneeded. Sheep were shepherded. They were held in flocks ranging from 400 to 1000 sheep withseveral flocks folded each night in the care of a night watchman (Gallagher 1989). They werecounted out to the shepherds in the morning, taken to fresh pastures to graze and returned to thefold again at night. For shearing, flocks were taken in rotation to a home station, to be washedand shorn (Fitzhardinge 1941). Home stations were established near rivers or creeks so thewashing could be carried out.

    Quite large areas of land were allowed for each head of stock, three and half acres (1.4 hectares)frequently being allowed for one sheep. The leasehold regulations of 1847 allowed four acres(1.6 hectares) per sheep and 34 acres (14 hectares) per head of cattle (Jeans 1972). Initiallythere was ample land for all and the runs must have been understocked. However, stock numbersincreased rapidly. In the first nine years the stock on the Duntroon property near Canberra,multiplied 35 times (Moore 1977) and by 1838 Campbell of Duntroon had 60 or 70 shepherdsworking for him (Fitzhardinge 1941).

    The pastoral system meant that up to 2,000 sheep were folded each night on an area rarelyexceeding a hectare, for several nights at a time. The two or more flocks folded at a station weretaken out in opposite directions soon after sunrise, kept slowly moving all day and returned eachnight. Because of the shortage of labour the flocks were generally larger than the optimum sizeand the larger the flock the more trampled the vegetation became and the further the sheep hadto be taken each day (Roberts 1935). Due to the belief that yarding in one spot led to foot rot(Roberts 1935) the whole station was moved every few days. The grazing system would havecreated severely trampled and denuded areas of one or two hectares in extent. These bare anddisturbed areas were left to recover, or erode, as the station moved to repeat the process(Gallagher 1989).

    Fewer cattle were run per hectare than sheep as they require more feed per head. The cattlewere not held in closely bunched herds, and therefore generally spread out more than sheep(Roberts 1935, Jeans 1972, Hancock 1972). While one head of cattle might consume as much asten sheep, the ten sheep could trample more vegetation and disturb more soil (Gallagher 1989).However, the cattle tended to feed along the moister valley floors where disturbance to sensitivevegetation in swampy meadows and along streamlines was greatest.

    The movement patterns and grazing habits of herds of cattle were different from thoseof sheep. The Rev. Henry William Haygarth (1848) noted that:

    “The usual feeding times [of cattle] are in the morning and evening, and during the first part ofthe night; at mid-day they congregate on the low grounds in the vicinity of water... Here theybask for hours, lying closely grouped together until the heat begins to abate, when they draw offtowards the forest in all directions, moving leisurely, and grazing as they go.”

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    The cattle congregated to rest on the valley floors. Haygarth wrote about the impact of thiscongregation:

    “A spot on which cattle are thus in the habit of assembling and basking during the day is calleda 'rendezvous' and is easily known, for, from the constant pressure of innumerable vast bodies,the surface of the ground becomes smooth and hard, resembling a blighted ring in the midst ofverdure; these marks still remain on stations from which the cattle have long been removed andbeing seen from a considerable distance, are frequently used as a means of direction for thelonely traveler.”

    The impact of grazing of sheep and cattle was soon being noticed by astute writers. AlfredMcFarland’s (1872) words on seasonal variations and drought in the area south of Michelago onthe Monaro, are cautionary to those using stocking rates based on seasons of plenty;

    “But there are other sides to the picture which should also be given; for it must not be supposedthat Manaro is always green. On the contrary, in mid-winter the withered grass converts into ahalf-white and half-brown appearance; and then, when the sun is shining strongly on a hill sideor plain, it sometimes looks as if it were covered with snow. During a drought the face of theland is changed still more; there is scarcely a blade of grass to be seen, the hills are glisteningwith red iron stone, the creeks are dry, most of the rivers are shriveled up, and the sheep andcattle half dead from starvation, or away on the mountains.”

    And…

    “The tall waving grass of the plains bending before the wind, and reflecting the passing clouds,is one of the commonest and not the least beautiful of the sights in Manaro; and in the paddocksat Bibbenluke, as well as other places, I have seen acres of grass up to my horses shoulders –though in times of drought, the whole country is bare enough – as bare as bare can be.”

    3.3 Early attempts at cropping

    The first crops planted in the Murray-Darling Basin were small gardens of vegetables for localconsumption. In the early 1830s Lhotsky noted one such garden on an outstation that containedcabbages and watermelons (Andrews 1979). He also noted that it had been planted in the richhumus soil that was associated with many of the drainage lines.

    Planting of cereal crops followed. The method of cultivation was primitive. The first wheatcrop in Wagga Wagga was planted in 1846 and demonstrated some of the methods used at thistime (Irvin 1962). The plough was homemade using wood and a bolted-on iron blade. Teamsfor ploughing consisted of up to eight bullocks which could turn over four acres (1.6 hectares) aweek. Roots and stumps left in the roughly cleared land often wrecked the plough, delayingplanting. Hand-made wooden harrows could be used for cultivation, which was completed byusing a mallet to break up any soil clods left. The seed was broadcast and rolled in with a log. Ifit was a cereal crop it was cut by hand using a sickle, then bound and stacked. Threshing wasdone using a simple flail of two saplings bound together at two ends with a piece of greenhide.A bushel of grain could be threshed in an hour. The grain was then winnowed by tossing it inthe air with a shovel.

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    Even with convict labour these labour intensive methods must have restricted the area of landcultivated. For instance in 1832 the County of Murray (578,000 ha covering Yass and theCanberra region on the Southern Tablelands) had only 200 hectares under cultivation (NSWColonial Secretary 1832). Wheat, maize, barley, oats, potatoes and tobacco were the main cropsgrown.

    Through the 1840s and 1850s the area of land cultivated for crops steadily increased, butpastoralism remained the dominant land use. Although the area cultivated was small, almost allthe cropping occurred along the river flats, and on the rich humus soils of the swampy meadowsof valley floors. Drainage of these was necessary and was carried out as a deliberate operation.These drains often developed into deeply eroded gullies over the following decades.

    3.4 The first signs of landscape change

    Even the simple early forms of agriculture and pastoralism carried out in the 1820s and 30s werea radical change from what had gone before. Stocking rates were often set in ignorance of theextremes of the climate and the complex interactions of a long established ecosystem. The stockwere different to the indigenous grazing animals. They had hard hooves and they grazed indifferent ways. Animal movements became more confined and more directed. The pastoralistswere dealing with an environment vastly different to that in Europe with which they werefamiliar and their methods did not always successfully transfer from one environment toanother.

    Early erosion in the Upper Murrumbidgee catchmentThe first evidence of accelerated erosion in the catchment of the Upper Murrumbidgee Riverappeared soon after settlement. The 1848 diary of John William Buckle Bunn contains a sketchtitled ‘The well in the deep creek’. This shows a four to five metre deep gully with exposedroots of a large tree, indicating recent incision.

    In 1851, Rev. WB Clarke (1860) witnessed a major storm when he was camped near the‘Berudba’ (Bredbo) River. Of the effects of that storm Clarke wrote;

    “…. the masses of rock and earth that had been washed down to the Berudba, and also a mile ortwo to the southward, especially about Mr Cosgrove’s, where the torrent had sought a way tothe Murrumbidgee, were perfectly astonishing.”

    (Starr et al 1999)

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    First signs of degradation in the ‘Wannon’ country of Victoria – 1850sIn 1840, John Robertson settled on 11,000 acres (4400 hectares) in the Portland District ofwestern Victoria (which is to the south of the Murray-Darling Basin). In 1853 he wrote a letterto Governor Latrobe which described his experiences over the previous 13 years as he set up asheep grazing farm. This included a description of his concerns about the loss of perennialgrasses, the commencement of gully erosion and the appearance of salt water springs in lowlying areas. The land degradation, now widespread across much of eastern Australia, hadcommenced on his farm only a decade after it was first settled.

    “….the long deep-rooted grasses that held our strong clay hill together have died out; theground is now exposed to the sun, and it has cracked in all directions, and the clay hills areslipping in all directions; also the sides of precipitous creeks - long slips, taking trees and allwith them. When I first came here, I knew of but two landslips, both of which I went to see; nowthere are hundreds found within the last three years. A rather strange thing is going on now.One day all the creeks and little watercourses were covered with a large tussocky grass, withother grasses and plants, to the middle of every watercourse but the Glenelg and Wannon, andin many places of these rivers; now that the only soil is getting trodden hard with stock, springsof salt water are bursting out in every hollow or watercourse, and as it trickles down thewatercourse in summer, the strong tussocky grasses die before it, with all others. The clay is leftperfectly bare in summer. The strong clay cracks; the winter rain washes out the clay; nowmostly every little gully has a deep rut; when rain falls it runs off the hard ground, rushes downthese ruts, runs into larger creeks, and is carrying earth, trees, and all before it. Over Wannoncountry is now as difficult a ride as if it were fenced. Ruts, seven, eight and ten feet deep, and aswide, are found for miles, where two years ago it was covered with tussocky grass like a landmarsh.” (From Bride 1983)

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    4. The gold rush era

    4.1 Discovery of gold

    In 1851, Edward Hargreaves discovered gold in a creek at Ophir, not far from Bathurst. Thiswas the first publicly recognized gold discovery in Australia, and signified the start of the goldrush era. Over the next few years, gold was discovered at numerous sites in the uplands andslopes of NSW and Victoria (see Figure 8), and tens of thousands of people flocked to thesegoldfields, taking away labourers from the fledgling pastoral industries.

    AvocaStawell

    Maryborough

    MoliagulDunolly

    Wedderburn

    St Arnaud

    Creswick

    ClunesTalbot

    Maldon

    Inglewood

    Castlemaine

    Daylesford

    Bendigo

    Rushworth

    Alexandra

    Melbourne

    Chiltern

    Eldorado

    GulgongMurray-Darling Basin

    Bright

    Junee

    YackandandahBeechworth

    Forbes

    Parkes

    Harden

    Young

    Adelong

    Tumbarumba

    Hill EndSofala

    Lucknow

    Ophir

    Junction Reefs

    Grenfell

    Sydney

    Nundle

    Bingara

    Uralla

    Figure 8. Major goldfields discovered in the 19th century within the Murray-Darling Basin

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    Figure 9. Goldfields of central Victoria in the 19th century (source; Flett 1970)

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    Figure 10. Part of the great complex of gold workings of the Castlemaine –Mt Alexander field. (The map covers and area of 8.5km by 12.5km. Source; Flett 1970)

    4.2 Environmental impact on rivers and streams

    The land degradation during the gold rush period differed from that of pastoralism in that theeffects were very dramatic but localized in extent. The mining activities and associatedsettlements quickly degraded the streams and surrounding countryside. The initial phase ofmining involved surface digging and washing from shallow alluvial deposits by individuals orsmall parties. This required a great deal of water to sort the gold from the washdirt using smallwooden puddling tubs, cradles and pans.

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    Later, the horse driven puddling machine was introduced wherever a sufficient water supply wasavailable. In the peak year of puddling in 1858 over 5,000 puddling machines were used inVictoria and, at Bendigo alone, some 10,000 men and 5,000 horses worked 2,000 machines(Powell 1976). The creek beds themselves were often so ravaged that the evidence persiststoday. In some instances the entire stream was diverted so that the alluvium in the stream bedand banks could be processed more easily. Beautiful valleys were stripped bare of soil,processed in the puddlers and then flushed downstream. Vast quantities of sludge moved downthe valleys, frequently blocking the natural watercourses and depositing on the lower floodplains(Brough Smyth, 1869).

    With advances in technology during the latter half of the 19th century, a second phase of alluvialmining occurred. ‘Hydraulic mining’, including a variety of sluicing operations, was introducedinto Victoria’s north-eastern fields by Californian miners. The method depended upon reliablewater supplies of good volume and was not widely employed elsewhere. Its most devastatingprocedure involved the undercutting of hillsides and steep stream banks down to bedrock, usingpowerful jets fed by water races which stretched for between three and twenty miles across thecountryside. Depending on the nature of the material involved, hydraulic sluicing enabled asingle worker to shift between 50 and 100 cubic yards daily, twice the amount obtained by othersluicing methods (Powell 1976).

    Where the source of gold was traced to underlying rocks, companies were formed to sink deepshafts. The underground mining industry produced huge quantities of tailings and sludge whichflowed into nearby streams.

    Figure 11. A miner sluicing for gold along a creek in the Castlemaine district in 1894.(Reproduced courtesy of Museum Victoria)

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    Impact of gold mining commenced in 1851Only two months after the discovery of gold at Ophir, near Bathurst, the magnitude ofenvironmental disturbance was noted by John Erskine, a naval officer who visited the diggings.“The whole of the sides of the creek, here 80 to 90 yards wide… were dug and turned up to adepth of five and six feet, like a stone quarry, the slate rock lying about in heaps.” (Keesing1967)

    Whole valley torn up in 1851-52“The whole valley had been torn up by the diggers: in the bed of the creek, and on the risingground on either side, and up the lesser valleys which led into it, holes and pits were dug, fromone to twenty feet deep.” Written by two travellers, Samuel Mossman and Thomas Banister(reprinted 1974), as they visited the goldfields along Forest Creek, part of the Mt Alexanderdiggings in Central Victoria, in 1851-52.

    Spring Creek, Ovens Diggings in Victoria“On reaching the brow of a hill, we see a broad valley lying below us, and white tents scatteredalong it for a mile or more. The tents, right and left, glance out of the woods on all sides. In theopen valley they stand thick, and there is a long stretch up the center of the valley, where all theground has been turned up, and looks like a desert of pale clay. … We go on, - huts, dustyground, all trodden, trees felled and withering up in the sun, with all their foliage; here andthere a round hole like a well, a few feet deep, where they have been trying for gold, and havenot found it. Down we go, - more tents, more dust, more stores, heaps of trees felled and lyingabout; lean horses grazing about on a sward that a goose could not lay hold of; hole after holewhere gold has been dug for, and now abandoned; washes hanging out; horrid stenches frombutchers’ shops, and holes into which they have flung their garbage. …. all the ground isperforated with holes, round or square, some deeper, some shallower, some dry, some full ofwater, but in few of which work now seems going on…. All between the holes, the hard clay-coloured sand lies in ridges; and you must thread your way carefully amongst them. … There isthe creek or little stream, - Spring Creek, - no longer translucent as it comes from the hills, but athick clay puddle, with rows of puddling-tubs standing by it, and men busy working their earthin tins and cradles.” (written by William Howitt, 25th Dec. 1852)

    Digging for gold at Spring Creek“…. We have wandered about amongst the diggings. No language can describe the scene ofchaos where they principally are. The creek that is a considerable brook is diverted from itscourse; and all the bed of the old course is dug up. Then each side of the creek is dug up, andholes sunk as close to each other as they can possibly be, so as to leave room for the earth thatis thrown out….. The course of the creek is lined with other diggers washing out their gold.There are whole rows, almost miles, of puddling-tubs and cradles at work. The earth containingthe gold is thrown into the puddling-tubs – half hogsheads – and stirred about with the water, todissolve the hard lumps, then it is put through the cradle, and the gold deposited in the slide ofthe cradle, then washed out in tin dishes.” (Written by William Howitt, 25th Dec. 1852)

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    Destroying Yackandandah Creek“We have begun to destroy the beauty of this creek. It will no longer run clear between itsbanks, covered with wattles and tea-trees, and amongst its shallow parts overgrown withforeign-looking shrubs, flags and cypress-grass. A little while, and its whole course will exhibitnothing but nakedness, and heaps of gravel and mud. We diggers are horribly destructive of thepicturesque.” (Discovering gold at ‘Upper Yackandanda’, written by William Howitt on 28th

    February, 1853)

    Degradation of Bendigo Creek“Little more than a year ago, the whole of this valley on the Bendigo Creek, seven miles long byone and a half wide, was an unbroken wood! It is now perfectly bare of trees, and the whole ofit riddled with holes of from ten to eighty feet deep – all one huge chaos of clay, gravel, stonesand pipeclay, thrown up out of the bowels of the earth! So much has been done on this oneforest in one year; and not only so much but a dozen other valleys as large… It is thus that afew months sees the most wonderful metamorphosis of the country where gold is. It is thus thatone of those tremendous rushes which takes place whenever there is the least rumour of successanywhere, brings tens and tens of thousands speedily together, like a flight of locusts, who tearup and leave the earth desert in a few weeks.” (Written by William Howitt, 30th October 1853)

    Digging up the hill sides“We observed, with astonishment, as we went on, how the diggers had followed the traces ofgold up the very hill sides, over the hills; sometimes cutting deep openings, which must havecost enormous labour, and following them down again into the open valley, where all was dugand thrown up in the wildest manner. Hill after hill, and gully after gully, we passed over,everywhere the trees felled, the ground turned topsy-turvy, deep pits and huge openworkdelvings, as if they had been making reservoirs, with strange, rude machinery and dams forwashing out gold. Everywhere, amongst the ravaged and desolated woods, tents andnondescript huts, and people leading a rude, wild sort of life, which no one can realise tohimself without seeing it.” (William Howitt describing the Bendigo gold fields in November1853)

    The creek has been dug and sluiced“For many miles the woods between this creek and Spring Creek have been felled, and theground dug up for gold. Where we used to travel through unbroken forest with the compass nowextend the tents and the delvings of the digger race. Nuggety Gully, New Rush, Europa Gully,and a whole succession of gullies are dug up, and all their woodland scenery desolated. NineMile Creek has been dug out again and again, and has been sluiced three times. This creek,which has acquired the cognomen of Back Creek, and Snake Valley has also been amazinglyworked. Whole miles of its banks that a year ago were wild and desolate, shrouded in densethicket of tea-trees and wattles and lightwood, and thick with sedge and jungle, are now butheaps of clay; the trees prostrate, the whole scene laid bare; the stream deviated from itscourse; and the bed of the creek has been dug and sluiced, and it’s banks themselves cut downand put through the sluice.” (Upper Yackandanda, as described by William Howitt, December1853)

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    Effect of gold mining on the Avoca RiverAvoca River is located in north-western Victoria and is a terminal, anabranching river systemwith highly variable stream flow from a large catchment covering 12,340 km2. The first settlersmoved into the Avoca catchment in the 1840s. In the early 1850s gold mining commenced andtens of thousands of miners began working the creeks of the catchment, particularly atAmpitheatre, Avoca and St Arnaud. Most of the mining was not actually in the stream lines asin other parts of Victoria, but the mining would have released large amounts of sediment into thestreams. The gold was almost exhausted by the 1890s, but from 1953 to 1956 large scaledredging was used to re-work alluvial deposits just north of Ampitheatre. (Rutherfurd andSmith 1992)

    Figure 12. ‘Australian Gold Diggings’, in about 1855. A painting by Edwin Stocqueler, from the RexNan Kivell Collection. (By permission of the National Library of Australia)

    4.3 Loss of forests in gold mining districts

    Gold mining created a huge appetite for timber, and the surrounding forests rapidly disappeared.Initially timber was used for firewood and for building shelters, but when reef and deep leadmining commenced in the 1860s, timber was also needed as boiler feed and as props inmineshafts. Throughout the gold mining districts, and in particular Central Victoria, hundreds

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    of square kilometres of forest disappeared, leaving the fragile soils prone to sheet and gullyerosion.

    Tree felling at goldfields“The diggers seem to have two especial propensities, those of firing guns, and felling trees. It isamazing what a number of trees they fell. No sooner have they done their day’s work, than theycommence felling trees, which you hear falling continually with a crash, on one side of you orthe other… you see numbers of stringy bark trees standing with the bark stripped off for six oreight feet high, and others felled and completely stripped…” (Howitt 1855)

    Reckless destruction of forest“Wherever the miners have pursued their labors the trees have been cut down; and we see acresof bare short stumps where a few years ago there was a stately growth of eucalypti. There hasbeen so much waste, and so much almost wanton destruction, that no time should be lost inrepairing the damage, if indeed there is yet time to repair it with any hope of the new growthbeing available before some of the mines are abandoned. The general interests of the minershave been sacrificed to the greed or caprice of those who, until lately, ravaged the beautifulforests, as if the loftiest tree were the growth of a single night, and was placed there merely to beirreparably damaged or destroyed as soon as found. A giant of the forest has been killed inorder to furnish a sheet of bark, and the smaller kinds have been burnt for the purpose of boilinga kettle.” (From ‘Gold Fields and Mineral Districts of Victoria’, 1869, written by Victoria’sSecretary for Mines, Robert Brough Smyth)

    Figure 13. ‘Mt Alexander gold diggings, 1853’, a painting by William Bentley. (By permission of theNational Library of Australia)

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    Figure 14. Gold was first discovered at Chewton, Victoria in 1851. 150 years later, the area has slowlyrevegetated and many of the eroded gullies have stabilized. Chewton was part of the ‘Mount AlexanderDiggings’ which covered a large area around the township of Castlemaine. (photo; Anthony Scott)

    Figure 15. Deep erosion gullies at Sailor’s Diggings near Daylesford, Victoria, which formed during thegold rush era in the late 19th century. (photo; Anthony Scott)

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    4.4 Growing concern about the sludge problem

    About 1885, public concern had been aroused about the siltation of some Victorian streamscaused by the alluvial mining operations then in full swing. Alluvial mining was active alongtributary streams and gullies in the catchments of the Avoca, Loddon, Campaspe, Goulburn andOvens Rivers. In 1887 an official Board was appointed by the State Government to enquire intothe sludge question and a report was produced. In this report the following comments weremade about the siltation of rivers (Thompson 1979);

    “The injuries already inflicted and which, unfortunately, in many cases cannot be cured, consistof the filling up of the large clear watercourses in the creeks and river, the silting up of the riverbeds causing sludge to overflow on the adjacent lands, to the destruction of vegetation and fruittrees; the liability of horses and cattle going to water in the creeks being bogged in the sludgeand perishing there, or contracting disease by drinking the muddy and often mineralizedwater…. these, and the destruction of roads and bridges, are some of the evils arising from theabsence of foresight on the part of the legislature in years gone by, and the want of care on thepart of the miners.”

    No immediate legislation for the control of these operations resulted from this report but some ofthe larger mining companies, which were working deep alluvials and operating crushingbatteries, were persuaded to, and in fact did, construct a series of sludge dams which werereasonably effective.

    However, severe floods in the 1890s accentuated erosion of the banks of many Victorian riversand streams.

    It was not until 1904 that the Mines Act was amended to provide for some control over thequantity of sludge, from mining operations, that would be permitted to enter any naturalwatercourse. The Sludge Abatement Board was established in 1905, under the provisions of thislegislation. The appointment of this Board was the first positive action taken in Victoriatowards the control of soil loss caused by erosion.

    However, Victoria’s ‘sludge problem’ continued into the twentieth century, with the operationof hydraulic mining and dredging. Hydraulic mining used pressurized water jets to displacealluvial deposits for the purposes of sluicing (Shakespear et al 1887). This technique could onlybe used where there was a reliable water supply and consequently was not widely practised.However, in areas where it was used, such as the Upper Loddon catchment, the damage to theriverbanks and floodplains was severe (Davis 1996). After gold extraction, the muddy effluentwould often drain into the nearby creeks and rivers, and large quantities of sediment wouldmove downstream.

    Giant dredges were also being used to rework enormous quantities of sediment both in the riverbeds and on the floodplains, and once again, large quantities of fine sediment would bedischarged into the river system. The peak period for hydraulic mining and dredging was from1907-1909 and Table 2 indicates the scale and location of this mining during 1907.

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    Table 2. Dredge Mining and Hydraulic Mining, operating in Victoria, December 1907District

    Bucket dredge Hydraulic pumpsluice

    Jet elevator Total

    Ararat & Stawell 0 4 0 4Ballarat 1 20 0 21Beechworth 37 11 2 50Bendigo 0 4 0 4Castlemaine 2 28 2 32Gippsland 5 3 0 8Maryborough 0 14 0 14(From a report issued by the Victorian Sludge Abatement Board in 1908 and cited by Davis 1996)

    The large quantities of sediment originating from alluvial mining, hydraulic mining anddredging, contributed towards the siltation of Laanecoorie Reservoir on the Loddon River.Constructed in 1891, the initial capacity of 17,000 ML was reduced by over half during its first41 years of operation (see section 7.5 for more details).

    In relation to instream mining, the Beechworth District, in northern Victoria, was probably theworst case, with 50 dredging and sluicing operation operating in the district in 1907 (see Table2). An Inquiry in 1913 by the Sludge Abatement Board reported many instances of seriousstream and floodplain siltation throughout the Beechworth area (Davis 1996). One example wasSandy Creek, a tributary to the Mitta Mitta River with a catchment area of approximately 155km2, where there were extensive dredge mining operations. It was reported that from theconfluence of Sandy Creek with the Mitta Mitta River, to a point 5 km upstream, a deposit ofmining sediment had been laid down. The total size of the deposit was 1.2 km wide, 5km longand 1.2 m deep, or 7.2 million m3 (Sludge Abatement Board 1915, cited by Davis 1996).Another example was the Reids Creek catchment where it was reported that much of thesediment had moved downstream into the Ovens River and had deposited onto the floodplains inthe Wangaratta and Tarrawingee districts, all the way down to the Murray River (Davis 1996).

    Dredges were still operating in the Avoca River as late as the 1950s (Rutherfurd and Smith1992), while an abandoned dredge on the outskirts of Maldon was operating until 1984 (seeFigure 16).

    Fish in creeks choked with ‘gold dust’ - 1852“There used to be fish in the creeks, but our washings must have choked them all with golddust.” (James Bonwick describing the impact of alluvial gold mining on a creek near Bendigoin 1852. Extract from Keesing, 1967)

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    Figure 16. This abandoned dredge is located on the outskirts of Maldon, Victoria. It processed thesurrounding alluvial soils in the 1970s and was finally abandoned in 1984. (photo; Anthony Scott)

    Figure 17. Between the 1930s and 1954, high pressure water jets were used to cut into the embankmentof alluvial soils at Red Hill in the Forest Creek diggings near Castlemaine, Victoria. The resulting slurrywas collected and passed through a series of traps to separate the gold. The roar from the jet could beheard 3-4 kilometres away. (photo; Anthony Scott)

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    Figure 18. The goldfields of the 19th century, such as this valley at Chewton, Victoria, have slowlyrevegetated, often with weeds such as blackberry and gorse bushes. However, many of the steep sidedbanks continue to be active sources of sediment. (photo; Anthony Scott)

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    5. 1860s – 1920s; Closer settlement andaccelerated land degradation

    5.1 The Free Selection Acts and closer settlement

    In NSW the Crown Lands Alienation Act and the Crown Lands Occupation Act (commonlyreferred to as the Robertson Land Acts or Free Selection Acts) were passed in 1861. Theoutcome of these Acts was that any person could select a holding of between 40 and 320 acres(16 to 130 ha) on any vacant Crown Land, even land that had previously been under pastorallease. Existing leases had to expire before the land was available for selection. Ascompensation, the pastoralists were able to buy the land on which their buildings, tanks, damsand stockyards stood. These Acts were introduced as a response to the very large pastoralholdings that were held by a small number of people. They were intended to assist ruraldevelopment by encouraging more people onto the land.

    Up until the introduction of the Free Selection Acts, many large landholders had done little toimprove the land or to increase its productivity, except for the small cleared and fencedcultivation paddocks close to the homestead, simply because they had so much land and alsobecause they did not own it. However, the new farmers soon realised that to make a living onthese smaller sized farms required more intensive farming practices, including higher stockingrates and the clearing of trees to encourage pasture growth. This led to an accelerated rate ofland clearing and a higher potential for land degradation.

    The Commissioner of Crown Lands in Monaro described this problem in 1879;

    “There is a very great number of stock now kept on the same area of land than formerly,throughout the whole of the Monaro, on those parts where selection has been going on rapidly,as the lessees of the runs have not decreased their stock in the same proportion that large areasof their runs have been taken from them by conditional purchasers, and as most of the selectorshave got sheep the land has been made to carry twice the number it formerly did, and whichoverstocking is, and has done, an immense harm to the grazing capabilities of the country..”(NSW Department of Mines 1879 and cited by Gallagher 1989).

    In Victoria, Queensland and South Australia, similar Land Acts slowly came into force duringthe 1860s and 70s, and this led to the gradual replacement of the large squatting runs held underleasehold, with a greater number of new settlers who had purchased smaller blocks of land(Roberts 1968). In Victoria, a series of Land Acts were progressively introduced in the 1860s,but the system was initially abused by squatters who submitted a series of ‘dummy’ names toselect all of their original land. In 1869 fresh legislation was introduced, and in the followingtwo years, thousands of new settlers had been placed on the land. By June 1872, there had been19,420 selections for 1,916,860 acres (766,700 ha) and this resulted in increased pressure ontimber resources for domestic fuel, fencing and building materials, as well as widespreadclearing for cultivation and grazing paddocks (Powell 1976).

    From the 1870s onwards, pastoralists started to use ringbarking as a quick and cheap method ofclearing the land. William Farrer was one who, in 1873, promoted ringbarking as the cheapestand easiest method of improving pasture growth by the removal of competition of trees for soil,

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    water and sunlight (Hancock 1972). In a number of districts gangs of travelling Chinese, nolonger able to make a living from gold mining, offered their services as cheap and hard-workingcontractors for ringbarking.

    With the continuing belief in the virtue of closer settlement, renewed efforts were made to createsmall farms by soldier settlement after World War I. The size of farms were set on the basis ofwhat was considered to be sufficient to maintain a family, an area calculated on the optimisticbasis of temporarily high prices. Falling prices during the Depression inevitably led to heavylosses.

    Closer settlement and ‘land improvement’ encouraged by Government - 1869“Let a man take his 320 acres, at a shilling a year if you like, but let him remain on the land;make him cultivate it, because, if he does not cultivate it, it may be very reasonably assumed thathe does not want it.” (Victorian Parliamentary Debates 1869: 956, cited by Powell 1976)

    5.2 Expanding frontiers

    By the 1850s nearly all the suitable grazing land on the highlands and slopes in the eastern halfof the Basin had been occupied. Most of the river frontages in the drier, western half of theBasin were also occupied, but the ‘back blocks’ (those with no border along a river) were onlyutilized during wet seasons. The introduction of well sinking, construction of earth dams anderection of galvanized tanks in the late 1860s enabled these ‘back blocks’ to be stocked on amore permanent basis. The most spectacular developments were achieved following thediscovery of the Great Artesian Basin in 1879, which had the effect of opening up the north-westof NSW and the south-west of QLD. Much of this land however, was marginal and sensitive todrought.

    In the 1860s the railway system started to rapidly expand from Melbourne, Sydney andBrisbane, and by the 1890s most large towns in the Murray-Darling Basin were connected via anetwork of railway lines (Jeans 1972). With better transport and prices, wool production alsobecame an increasingly popular rural enterprise, outstripping beef and sheep meat production,which had been stimulated by demand from the gold fields. Sheep numbers in NSW rose from8.5 million in 1855 to almost 62 million in 1891 (Jeffcoat 1988).

    The development of riverboat services also assisted with the pastoral occupation along theDarling and Murray Rivers. In 1853 there were two steamboats on the Murray, and by 1861there were 30 (Jeans 1972). The trade created new towns along the rivers, boosted agricultureby providing better access to markets and thus allowed more land to be opened up for farming.

    Due to the high costs of transport, in the first half of the 19th century crops were mostly grownalong the coastal valleys, close to the larger towns. However, the introduction of railwaysopened up the western slopes and plains to cropping. Further developments such as thestumpjump plough (1876) and HV McKay’s combine harvester (1885) reinforced the move tothe west. In NSW, 91% of wheat was grown on the coast and tablelands in 1860. By 1890,71% was grown on the western slopes and plains (Dunsdorfs 1956, Jeans 1972, Robinson 1976).However, clear trends of declining crop yields soon emerged and by 1902 wheat yields in south-eastern Australia had plummeted to about one third (ie 0.5 t/ha/hr) of yields obtained a few

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    decades earlier. The practice of frequent cropping without adequate fallowing encouraged soilborne diseases, and the lack of fertilizers or rotation with legumes reduced the supply ofavailable nutrients.

    From its high point in 1891 the wool industry also started to slump. Overgrazing and the arrivalof rabbits in the mid-1880s caused problems, but it was the drought in the second half of the1890s that triggered the collapse, halving the number of sheep shorn between 1895 and 1900(WRC 1984). Many graziers went broke and their pastoral leases were passed on to the banksor larger pastoral companies.

    Agricultural development in Australia in the late 19th century“In central Queensland and the dry interior of New South Wales and South Australia thediscovery and exploitation of extensive artesian basins further increased the potential forgreater intensification, and in higher rainfall regions such as Victoria’s Western District, thewell established grazing freeholds consolidated their reputations for stud-breeding by confidentinvestments in water storages, elaborate subdivisioning and management research. Thecumulative benefits of all these efforts were obvious enough: the sheep population of Australiaincreased from 42 million in 1872 to about 106 million in 1892. What the industry lacked,however, was the ability to adjust to drought, and the concurrence in the ‘nineties of dryseasons, rabbit plagues and the economic depression proved that far too many holdings,especially in the outback, had become over-financed and over-grazed.” (Powell 1976)

    5.3 Accelerated erosion from overgrazing and land clearing

    The exact timing of accelerated erosion after European settlement is difficult to determine butanecdotal evidence and archival records indicate that in many places it coincided with the periodof rapid agricultural expansion of the late 19th century (Bird 1985, Prosser 1991, Williams et al1991, Wasson et al 1998, Starr et al 1999, Beavis et al 1999). Many erosion gullies thatformed during this period, continued to expand during the early 20th century.

    Under natural conditions, prior to European settlement, most of the hills and valleys werecovered by forest or woodland. The trees, and perennial grasses (such as Kangaroo and Wallabygrass) had extensive, deep rooted systems. The roots had two main effects – they bound the soiltogether, and used up most of the moisture in the ground. Because the soil was kept fairly dry,most of the rain was soaked up, and runoff occurred only during heavy storms.

    By 1900 many of the forests and woodlands throughout the Murray-Darling Basin, particularlyin the highlands and western slopes, had been ring-barked or cleared to improve productivity forgrazing. The deep rooted perennial grasses also slowly disappeared under the heavy grazingpressure, and were replaced by faster growing annual grasses which have a shallower rootsystem. From the 1870s onwards, the impact of grazing was exacerbated by the increasingpresence of rabbits, which rapidly spread throughout eastern Australia.

    The reduction in soil moisture being taken up by the vegetation led to increased surface runoff.Many soils also suffered a reduction in permeability because of compaction by stock, and thediminished ground cover during summer (when the annual grasses died off) allowed surfacewater to flow away rapidly, before it could soak in.

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    The overall effects of clearing and grazing were to increase the amount and speed of surfacerunoff, and to remove most of the