Marra Creek Waterponding Program – rehabilitating and restoring scalded rangelands
Summary A four year program to restore scalded and bare soils in western NSW, Australia, during the 1980s has left a remarkable legacy that has since rehabilitated 30,000 hectares of severely degraded land for environmental and production outcomes. The Central West Catchment Management Authority (CMA) monitoring program demonstrates that native grass and forb diversity will increase three-fold on a typical waterponding site within a few years of construction. Vegetation soon replaces scalded bare earth and can once again provide shelter and food for insects, birds and animals. This widespread increase in groundcover means erosion is limited and water quality is improved. While in much of these rangeland areas the sites have been rehabilitated to native pasture, in some areas the condition can be considered highly similar to pre-existing Saltbush (Atriplex)-dominated shrublands and shrubland components of a Wilga/ Leopardwood reference community This work has also standardised the waterponding rangeland reclamation technique and allowed it to continue in the district and beyond. The program has also influenced the rehabilitation of scalded country in other areas across the world including Israel, Africa, USA, France and China.
Introduction In the Marra Creek District (western NSW) around 100,000 hectares of land had become bare and scalded due to grazing pressure, drought, and wind and water erosion, particularly during the late 19th century when the areas were first opened up to grazing. These scalded areas have virtually no vegetation and habitat for local fauna. Biodiversity and farm production are heavily impacted. The exposed soil also means that erosion continues. Even with grazing pressure removed, the crusted smooth surface, poor water infiltration and high salt surface levels mean that rehabilitation will not happen naturally for a very long time. Work had been undertaken historically to restore these lands, but the process was failing due to limited equipment, knowledge and resources.
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In 1984, a four year program was established to develop effective management techniques to address these problems. This program was designed to carry out trials to better understand the variables involved and improve the waterponding land rehabilitation technique. Over the four years, 40 demonstration sites were established on properties in the Marra Creek area (north of Nyngan, NSW) with dramatic improvements in groundcover and species diversity. The program gave land managers the techniques, tools and confidence to restore scalded sites on their properties. Through this body of work, the waterponding process was refined and documented. It is now a proven land restoration technique and has become recognised and adopted by others globally.
Before and after: The above photographs show the dramatic improvements in groundcover, biodiversity and production possible through waterponding. These are taken 11 months apart.
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What is waterponding? Waterponding is a land management technique to restore scalded land and return it to either grazing production, its previous native vegetation or, as is often the case, both. It involves grading a series of horseshoe shaped banks to catch and hold rainfall. The water collected in the ponds cannot penetrate the sealed clay surface, but causes it to swell and crack on drying. Over a series of rainfalls, infiltration is improved by this deep cracking and seed is able to lodge and germinate in the roughened surface, where moisture is also held. Increases in infiltration also mean that salt concentrated on the soil surface is spread back through the soil profile and will not limit seedling establishment. Site monitoring shows that within a year groundcover can be increased from 0-10% to up to 80% and more. This is done through a combination of natural regeneration and direct sowing of seed. Native grass and forb diversity is typically increased from four to five species to about 15 species within a few years. This means lower erosion, improved local water quality, improved soil health, increased biodiversity and improved farm productivity.
Waterponding results: An aerial shot of results from waterponding.Previously this site was scalded and barren.
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Geographic location The initial Marra Creek Waterponding trials were conducted over 18 properties and a distance of some 150km. This region lies just north of Nyngan and sits between the Macquarie and Bogan Rivers of New South Wales.
The original Marra Creek waterponding demonstration site.
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Stakeholders & budget The Soil Conservation Service was responsible for initiating and implementing the program in partnership with 18 landholders across the Marra Creek region. Led by Rosemary and Clive Simpson of ‘Kapunda’, these 18 landholders were ahead of their time and later formed the Marra Creek Landcare Group. On the Soil Conservation Service side, Doug Rhodes was the main instigator in establishing the initial program. The Soil Conservation Service sought and secured $271,450 from the NSW Government for the initial four year demonstration project, which includes the project manager position. Ray Thompson (pictured below) was appointed as Field Service Manager during these four years. Since then Ray has taken leadership of the technique. Agency changes have meant that waterponding has been carried out under the work programs of the following departmental parentage: • • • • • Soil Conservation Service of NSW (SCS) Department of Conservation and Land Management (CALM) Department of Sustainable Natural Resources (DSNR) Department of Land and Water Conservation (DLWC) Department of Infrastructure Planning & Natural Resources (DIPNR)
The waterponding program is now carried out through the Central West CMA, having outlived five government agencies!
Waterponding program manager Ray Thompson with the 50,000 waterponding site.
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How are scalds formed? Scalded and bare ‘claypan’ country is common across the Nyngan region and rangeland areas elsewhere, and has a damaging effect on the environment and agricultural production. Originally these sites supported diverse grasses, forbs and shrubs that in-turn provided habitat and food for a range of birds, insects and animals. The duplex nature of these soils however means they are prone to erosion and scalding. The top sandy loam layer is easily lost to wind and rain erosion to leave a crusted, sealed clay surface. The picture on the right illustrates this point well. The top 30cm of sandy loam has been eroded away, leaving a barren claypan. Once scalding has occurred, the effects are long-lasting. The crusted surface means water infiltration is poor, and vegetation establishment is severely reduced. Over the course of time, grazing pressure, drought and erosion removes this layer and exposes the heavy clay beneath. This leaves a smooth impenetrable crust. There is no roughness for windblown seeds to take hold and any rainfall cannot penetrate beyond a few centimetres, leaving virtually no vegetation on these sites. Any vegetation that does establish is sand blasted and stunted. The impacts are easily observed: 1. Native vegetation is reduced to often less than one percent, and even then consists of a handful of species. 2. The lack of shrub and groundcover means that habitat range is severely reduced and the site offers little food, shelter and protection to local native fauna. 3. The lack of groundcover and surface roughness means wind erosion continues. Any rainfall on these sites cannot infiltrate, leading to high energy run-off, erosion and sediment in waterways. 4. Farm productivity is severely reduced, and places higher pressure on nonscalded sites.
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Native and reference communities The native vegetation typical of scalded country is likely to have included a range of communities including some Saltbush (Atriplex)-dominated shrublands as well as Leopardwood (Flindersia maculata)-dominated open woodlands. Much of the affected communities were those located on old terraces and raised floodplains of western NSW streams, particularly the Macquarie/Bogan system, and the northern tributaries of the Barwon, the Lachlan, and the Riverine Plain. Restoration goals and planning The aim of the Marra Creek Waterponding Program was to rehabilitate the extensive areas of scalded country in the district to support healthy ecosystems and improve farm productivity. While some components of the waterponding process were proven to work prior to 1988, many others were failing and the overall process was largely ineffective. Through the 40 trial sites, the various techniques would be tested with the goal of perfecting the process and achieving widespread adoption of the technique. Leading up to 1984, erosion was a key environmental issue and scalding was identified locally as a priority to be managed. The overriding concept behind the program was to understand how rainwater could best be held on this sealed surface to create an environment supportive of vegetation growth. Through establishing ground and shrub cover, erosion would be stopped, species diversity would improve and production increase. Initially a mapping project was undertaken to understand the extent of the scalding problem and identify priority areas. This information was used to secure funding and plan the Marra Creek program. The community was a driving force in this process, with the original 18 landholders involved working with the Soil Conservation Service to source funding and initiate the program. Throughout the four year program, this community was involved in the planning process and was a valuable program partner. Also the scientific and academic communities were involved in assessing the process and recording the results and concepts involved.
Reclaiming degraded land piece by piece. The above satellite imagery shows waterponding along Marra Creek, with the waterpond ‘leopard spots’ roughly the half the size of a rugby field.
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Project implementation The four years of the initial program were spent trialing and correcting waterponding design and construction in collaboration with landholders in the Marra Creek district. Through trial and error, astute record keeping and building on successes, a reliable standard waterponding technique was developed and documented. Once the design and construction elements were finalised, Mal Hayes and others from the Soil Conservation Service undertook to develop best practice on seeding banks with native shrub species such as Old Man Salt Bush. This work has also been widely implemented to effectively restore shrub layers on previously barren scald sites. Because more rapid revegetation can speed up the reclamation process and improved ecological outcomes, the method in the last 20 years has included broadcasting seed of some of the more important perennial species of healthy native chenopod grasslands. These are Oldman Saltbush (Atriplex nummularia), Bladder Saltbush (Atriplex vesicaria) and Mitchell Grass (Astrebla lappacea). Tireless extension work has been undertaken through the program manager Ray Thompson and others involved. Field days were held extensively and demonstration sites were established in high traffic areas to showcase the results. To ensure high standards of on-ground works, the process has been thoroughly documented. Contractors are also subject to minimum standards to ensure quality remains high. Guidelines have been set for the short-and long-term management of the waterponding sites and these are well explained to the land manager.
Constructing waterpond banks
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Progress to date Uptake and social benefits Of the original 100,000 hectares of scalded country mapped in the district, 30,000 hectares have been rehabilitated through waterponding. Since 1984, around 2000 ponds have been created each year. Locally, the successes of the original 18 landholders saw many others in the area adopt the technique and even take loans to carry out work. This is largely due to the socio-economic benefits including increased wool cut, lambing percentages and farm productivity. But there are other indirect benefits of strengthened communities and a sense that land managers can pass their properties onto future generations in a better condition than it was when they received it. The process has been adopted as a mainstream land management technique and its implementation supported financially through NSW government. Waterponding is also now implemented in partnership with a number of other Central West CMA programs to encourage sustainable grazing management and erosion control, hence limiting the causes of scalding and the need for restoration. The technique has also spread to other states in Australia (Northern Territory, Queensland and Victoria), and as far as the United States of America, Israel and China globally. Most recently, the waterponding process was explained to delegates at the 2008 China International Rangeland Congress. Ecological results Through waterponding, scalded sites around Marra Creek have been transformed into healthy ecosystems in which species diversity and ground cover is dramatically increased. Scalded country often supports only a few rangeland plants such as Streaked Poverty bush, Goat Head Burr and Five Minute Grass. But within 12 months the species diversity in waterponded areas reliably increases and within two years as many as 15 native grass and forb species can be expected, including a mix of perennial and annual species. Species such as Curly Mitchell Grass and Neverfail will also regenerate or can be successfully sown – an indication that soil health is improving and becoming a healthy and productive ‘heavy cracking clay’. While in most cases full ecological restoration is not achieved due to the need for ongoing grazing, saltbush seeding is achieving the reinstatement of Saltbush (Atriplex)-dominated shrublands in many areas. In others, the shrub layer of the wilga/ leopardwood reference community is being reestablished. This rehabilitation also provides more diversity of habitat which supports a wider range of native fauna than did the degraded state. For example, landholders in the Marra Creek district observe a range of fauna frequently on and between the ponds, including Western Grey Kangaroos (Macropus fuliginosus), Red Kangaroos (Macropus rufus), Emus (Dromaius novaehollandiae), pairs of Brolgas (Grus rubicunda) and the Eastern Bluetongue Lizard (Tiliqua scincoides). Monitors (Varanus sp.) also sometimes traverse the waterponds. Formal monitoring of smaller reptile and invertebrate use of waterponded sites is yet to occur. 9 of 13
The effects of this are long-lasting, with the banks becoming redundant after 20 years or so. By then improvements in soil health, groundcover, shrub cover and seed bank will be self-sustaining and the sealed surface is unlikely to return. Technical developments The results coming from the program have exceeded expectation. The process itself was made robust. There is now low bank failure and sites need little maintenance. The program also redesigned the use of vehicle mounted laser technology in designing banks. This increased the accuracy and efficiency of bank design – previously done through laser, staff, walking and blisters!
Vehicle-mounted laser gear on a site ready for action.
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Monitoring and research links When the four year program was initiated, the science of waterponding was not documented. Some things were roughly understood, but more rigor was needed for the process to be fully explained and effective. Throughout and after the initial demonstration program, scientific and academic research has been closely integrated to better understand the processes in place and improve the technique. The Australian National University in particular has had a close association with the waterponding program. There have been doctorate studies on the technique. D. W. Rhodes (District Soil Conservationist, Nyngan) and A. J. Ringrose-Voase did an indepth examination of changes in soil properties during scald reclamation by waterponding. At least 40 ANU students also travel to Nyngan each year to inspect waterponding sites as part of a rangeland studies subject. Each waterponding site is monitored each year to record results. Photographs, vegetation, species diversity, season and other variables are recorded by the landholder along a consistent transect line. This information is relayed to the program manager for planning and improvement. Waterponding results are also well highlighted by the Landscape Function Analysis tool developed by David Tongway whilst at the CSIRO. This is a rangeland monitoring tool to assess how the landscape responds to management interventions.
Project monitoring: The above site photographs demonstrate the benefits of a formal monitoring program.
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Lessons learned The take home message from the waterponding program is that persistence and long-term commitment are needed to make a difference to the quality of our natural resource assets. This long-term commitment allowed us to see how the waterponding technique stands against the cycles of nature (eg drought and flood) and has meant that techniques could be developed that are robust in all conditions. This commitment applies to staffing also, as having someone in place committed to the program from day-one was an asset to the program. Appropriate staffing on the ground is essential for the success of work such as this. Another lesson relates to the importance of community engagement. The widespread adoption of the waterponding technique highlights the benefit of working with people on the ground for practical and useful outputs. But to achieve adoption by landholders, we found that results must be demonstrated to the community. Field days, media and high traffic demo sites were all used to prove that the science works. Knowledge management is essential also in a program such as this. The technique is now well documented and available to land managers, construction contractors, etc. Getting others to teach it [ie through the state’s Technical and Further Education (TAFE) system] is also a great way to spread information. Meeting future challenges The original mapping of scalded country estimates that 70,000 hectares remain to be rehabilitated in the region. With strong public acceptance and support, the program is well placed to meet this challenge. Demand for waterponding is still strong, and is a key element in the Central West CMA’s work program – so we anticipate that the expanded program will continue indefinitely. The results from this work have been documented in detail to ensure the knowledge is freely available and is spread widely. It has been the subject of a number of professional papers and recorded in Soil Conservation Service Journal. Most recently the process has been documentation and will be taught through the state’s TAFE system. The greatest need for volunteers in the Waterponding Program relates to further development of rehabilitation best practice. While the construction and shrub establishment processes are well developed, there are a number of knowledge gaps relating to establishing perennial grasses after construction. Further research and studies into this area are encouraged.
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Further reading Cunningham G. M. (1987) Reclamation of scalded land in western New South Wales – A Review. Journal of Soil Conservation NSW, 43:2, 52-61. Ditchfield R. (1996). The effects of waterponding on the reclamation of degraded scalds in the semi-arid rangelands of NSW. Australian National University. Hayes M.L. (1995) Direct seeding of saltbush species in conjunction with waterponding on scalds. Soil Conservation Service of NSW. Rhodes, D.W. (1987a) Waterponding Banks – Design, Layout and Construction. Journal of Soil Conservation, NSW, 43:2, pp 80-90s. Rhodes, D.W. 1987b, Vegetation Response and Productivity Improvements Under Waterponding, Journal of Soil Conservation, NSW, 43:2, 62-67. Shelly D. (2000) Flora and Fauna of the Coolabah District. Department of Land and Water Conservation and the Coolabah Landcare Group, Dubbo. Thompson R.F (2008). Scalded? Try This! Waterponding. XX1 International Grassland Congress & V111 International Rangeland Congress, Hohhot, China. Paper/Poster. Thompson R.F (2008). Waterponding: Reclamation technique for scalded duplex soils in western NSW rangelands. Ecological Management & Restoration Vol 9 No 3 pages 170-181. Thompson R.F. (1991) Earth Movers Training Course Unit 20 Special Earthworks, Waterponding. Soil Conservation Service of NSW.
Contact information For further information, contact: Ray Thompson Catchment Officer (Bogan) Central West Catchment Management Authority Phone: 02 6832 1303 Email: ray.thompson@cma.nsw.gov.au
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