Category Archives: Environmental watering

Waterponding the Marra Creek, NSW rangelands – UPDATE of EMR feature

Ray Thompson and Central West Local Land Services

[Update of EMR feature – Thompson, Ray F (2008) Waterponding: Reclamation technique for scalded duplex soils in western New South Wales rangelands. Ecological Management & Restoration 9:3, 170-181. https://onlinelibrary.wiley.com/doi/10.1111/j.1442-8903.2008.00415.x]

Figure 1.  Scalded country with 30cm of sandy loam topsoil swept away by wind after extensive overgrazing. (Photos NSW SCS)

Introduction. Overgrazing of native pastures in the second half of the 19th Century stripped vegetation and led to the wind erosion of sandy topsoil during inevitable dry periods.  By the 1960s, tens of thousands of square kilometres of rangeland sites in western NSW had a legacy of moderate or severely bare or ‘scalded’ lands. This left bare and relatively impermeable clay subsoil which prevents water penetration and is very difficult for plants to colonize (Fig 1.)

Waterponding is the holding of water on the scald in surveyed horseshoe-shaped banks, each covering 0.4 ha. The ponds retain up to 10 cm of water after rain which leaches the soluble salts from the scalded surface. This improves the remaining soil structure, inducing surface cracking, better water penetration and entrapment of wind-blown seed. Consequently, niches are formed for the germination of this seed and recovery of a range of (typically around 15 out of a total of about 30) locally native chenopod (saltbush) grassland species on the sites.

The original 2008 EMR feature described how barren scalds at a range of properties in Marra Creek, near Nyngan in semi-arid NSW were transformed during the 1980s and 1990s into biodiverse native pastures through a technique called ‘waterponding’ developed after five decades of work by consecutive soil conservation officers exploring a range of prototype treatments.  Over time, a wide range of machines have been used to construct waterponding banks including standard road graders (ridged frame and articulated) or similar. Pre-1985 road graders were generally too small to construct banks of sufficient size, which resulted in too many breached banks. Over a 4-year period, the Marra Creek Waterponding Demonstration Program, backed by committed landowners, researched different horsepower road graders, constructing different size banks, winning the dirt from different locations, and evaluating the economics of construction methods. The results showed that the higher-powered articulated road graders exceeding 200 HP proved to be the most economical and efficient for waterpond construction. This type of machine has the power to  form the bank with one pass on the inside of the bank and two passes on the outside, achieving a bank with well over 2 m base width and over 60 cm in height (Fig. 2).

Figure 2. The process of of waterponding including (a) ute-mounted laser levelling to design the waterpond for a particular site, (b) bulldozing the pond walls to the designed levels, (c) rainfall filling the pond to allow deep watering and cracking of the clay subsoil and (d) resulting revegetation within the walls of the pond. (Photos NSW SCS)

Update and the broader program.  Photos and pasture measurements undertaken on ‘Billabong’ Marra Creek NSW, till 2014 show that the waterponding site had increased ground cover (predominantly native species) from 1% in 2005 to 84 % in 2014. After five to seven rainfall years a typical treatment can result in recovery of up to 15 native species from a range of up to 31 species (Table 1). The method in the last 20 years has also included broadcasting seed of some of the more important perennial species of healthy native chenopod grasslands including  Oldman  Saltbush  (Atriplex nummularia), Bladder Saltbush (Atriplex vesicaria) and Mitchell Grass (Astrebla   lappacea) (Fig 3).  Landholders in the Marra Creek district observe a range of fauna frequently on and between the ponds, including Western Grey Kangaroo (Macropus fuliginosus), Red Kangaroo (Macropus rufus), Emu (Dromaius novaehollandiae), Brolga (Grus rubicunda) and the Eastern Bluetongue Lizard (Tiliqua scincoides). A species of Monitor (Varanus sp.) also sometimes traverses the waterponds. Formal monitoring of smaller reptile and invertebrate use of waterponded sites is yet to occur.

Figure 3. Curly Mitchell Grass (Astrebla lappacea) sown on pond banks. (Photo NSW SCS)

Marra Creek was not the first series of waterponding programs in the Nyngan area – nor the last. The outputs of the entire program by 2019 included over 80,000 waterponds laid out and constructed, resulting in 40,000 hectares returned to local native vegetation. A total of 164 properties in the rangelands area are now using waterponding, the majority of landholders in the Marra Creek district and representing an increase from 17 landholders back in 1984 when we first ran the waterponding.

Figure 4. Landholders themselves are teaching the Waterponding technique to other landholders. (Photos NSW SCS)

Economic model of waterponding. The primary driver for land reclamation was not biodiversity conservation but returning the natural capital of rangelands. As such the program has returned a clear profit to the landholders in terms of increased native pastures that can be grazed, improving ecologically sustainable income sources for farming families.

With the reinstatement of vegetation, there have be increases in total stock feed, resulting in an increase in lambing percentages and wool cuts, as well as the ability to carry stock further into prolonged dry periods with overhead cost per head remaining static. Once rehabilitation has been completed, stocking  rates have been raised from zero to one sheep to 1.5 ha. This iseffectively the long-term grazing average for  saltbush pastures in the Nyngan district.

A treatment involving the full design and survey, pond construction and revegetation cost the landholder about $144.00 per hectare. (This includes approximately $25 a hectare for seed.) If the landholder does all the work the cost is reduced to $72/ha. The type of land involved was calculated in 2008 to normally  have  a  resale  value  of  about $365.00 per hectare In its unproductive state.  Scalded land does not contribute to the farm income yet still incurs rates. Investment in rehabilitation, in contrast, improves carrying capacity thus reducing hand-feeding costs, improving lambing percentages and avoiding forced stock sales. This allows landholders to pass the property to the next generation in a far better condition than it has been previously.

Research has found that the scalds store approximately 18.7 t/h of soil organic carbon to a depth of 30 cm. Once the landscape has been restored by waterponding and revegetation, we have found there is a rapid increase in soil organic carbon up to 25 t/ha within five years. The results are indicating that land in the rangelands that has been rehabilitated using waterponds does sequester carbon. This could lead on to waterponding being eligible for a carbon abatement activity and hopefully lead to Carbon Farming Initiative activity for carbon credits.

Figure 5. Australian National University students attending ‘21 years of participation in Rangelands Waterponding’. (Photos NSW SCS)

Potential for further application. After decades of field days and uptake of the methodologies by local graziers (Fig. 4), waterponding now forms part of standard district farming methodologies and landholders are now passing on knowledge to new generations, including through universities (Fig. 5). The methodologies have also been applied at one national park and one Trust For Nature site in Victoria, and are being applied in the Kimberley, with potential for far greater application in desert conservation reserves throughout Australia and the rest of the world (See Fig. 6 and https://justdiggit.org/approach-2/#).

Contact. Kyra Roach, Central West Local Land Services, Nyngan, 2825 Australia. Email: kyra.roach@lls.nsw.gov.au

Figure 6. A total of 79 trainees from 26 Africa countries (including Ghana, Tunisia, Rwanda, Burundi and Djibouti) over a three year period were sponsored by AusAid to study waterponding in Nyngan. Resullting work in African countries is making a big difference to degraded lands particularly in North Sudan and Kenya (Photo NSW SCS)

Table 1. Species found in waterponds after standard revegetation treatments and five to seven rainfall years. The species found by Rhodes (1987b) are still commonly found, with additional species (marked with a diamond +) observed by Ray Thompson. (Plant names are consistent with the New South Wales Herbarium database PlantNet, http://plantnet.rbgsyd.nsw.gov.au/ and  growth forms are consistent with Cunningham et al. (1981) (Exotics are marked with an asterisk)

Scientific name Common name Growth form
Alternanthera denticulata Lesser Joyweed Annual forb
Astrebla lappacea+ Curly Mitchell Grass Perennial grass
Atriplex leptocarpa Slender-fruited Saltbush Perennial subshrub
Atriplex lindleyi+ Eastern Flat Top Saltbush Annual subshrub
Atriplex nummularia+ Oldman Saltbush Perennial shrub
Atriplex pseudocampanulata Mealy Saltbush Annual subshrub
Atriplex semibaccata+ Creeping Saltbush Perennial subshrub
Atriplex spongiosa Pop Saltbush Annual forb
Atriplex vesicaria Bladder Saltbush Perennial subshrub
Centipeda thespidioides Desert Sneezeweed Perennial forb
Chamaesyce drummondii Caustic Weed Annual or short-lived perennial forb
Chloris truncata Windmill Grass Annual or perennial grass
Diplachne fusca Brown Beetle Grass Perennial grass
Eragrostis parviflora Weeping Lovegrass Annual or short-lived perennial grass
Eragrostis setifolia Neverfail Perennial grass
Hordeum leporinum* Barley Grass Annual grass
Hordeum marinum* Sea Barley Annual grass
Maireana pentagona Hairy Bluebush Perennial subshrub
Malacocera tricornis Soft Horns Perennial subshrub
Marsilea drummondii Common Nardoo Perennial forb
Medicago minima* Woolly Bur Medic Annual forb
Medicago polymorpha* Burr Medic Annual forb
Osteocarpum acropterum+ Water Weed Perennial subshrub
Phalaris paradoxa* Paradoxa Grass Annual grass
Pimelea simplex Desert Rice-flower Annual forb
Portulaca oleracea Common Pigweed Annual forb
Salsola kali var. kali Buckbush Annual or biennial forb
Sclerolaena brachyptera Short-winged Copperburr Short-lived perennia
Sclerolaena calcarata+ Red Copperburr Perennial subshrub
Sclerolaena divaricata+ Pale Poverty Bush Perennial subshrub
Sclerolaena muricata Black Roly-poly Short-lived perennial
Sclerolaena trycuspis Streaked Poverty Bush Perennial subshrub
Sporobolus actinocladus Katoora Grass Perennial grass
Sporobolus caroli Fairy Grass Perennial grass
Tragus australianus Small Burr Grass Annual grass
Tripogon loliiformis+ Five Minute Grass Perennial grass

 

 

 

 

 

 

 

 

 

 

 

 

 

Still repairing wetlands of the Lower Murray: continuing the learning – UPDATE of EMR feature

Anne Jensen

[Update to EMR feature – Jensen, Anne (2002) Repairing wetlands of the Lower Murray: Learning from restoration practice. Ecological Management & Restoration, 3:1, 5-14. https://onlinelibrary.wiley.com/doi/10.1046/j.1442-8903.2002.00092.x]

Key words:         Environmental water requirements, regeneration, wetlands, black box seedlings, Lower Murray Valley

Figure 1. Location of the Lower Murray Valley in South Australia (Map A. Jensen)

Introduction. As highlighted in the original EMR feature this summary is updating, in the Lower Murray Valley 1100 wetlands have been identified in 250 hydrologically-linked complexes (Fig. 1). They have undergone major changes to their water regime over the last 100 years, altering the timing, frequency and duration of floods. Wetlands at lower elevations have become permanently flooded by stable river levels and wetlands at higher elevations are ‘droughted’ by much reduced flooding. All would benefit from environmental watering, to fill gaps in breeding and regeneration cycles.

Our 2002 feature showed that, from 1998 to 2002, the not-for-profit conservation company Wetland Care Australia coordinated on-ground projects to repair priority wetlands in the Lower Murray. The Gurra Gurra project was the largest of these projects, with engineering works at 17 sites to restore multiple flowpaths through the 3000 ha floodplain complex.

Key funding from the National Heritage Trust terminated in 2002 and Wetland Care Australia relocated in 2003 to northern New South Wales, where project funding for wetland projects was still available. However, individuals involved with the Wetland Care Australia projects remained in the Lower Murray Valley in other jobs, so the intellectual property was retained and wetland conservation activities continued.

In 2002, the extent and severity of drought conditions in the Murray River Valley were just being recognised. By 2004, a survey estimated that >75% of the two main tree dominants in floodplain woodlands –  River Red Gum (Eucalyptus camaldulensis) and Black Box (E. largiflorens)  – were dead, dying or extremely stressed along 700 km of the Murray River Valley . The Millenium Drought (2000-2010) caused extreme stress to both ecological and human communities. Government agencies commenced emergency environmental watering from 2004 through the Living Murray program to limit catastrophic damage at eight iconic sites but millions of mature eucalypts were lost from floodplain woodlands along river valleys.

The Millenium Drought changed the governance context radically, with the Water Act 2007 establishing a new Murray-Darling Basin Authority and the Basin Plan. The Commonwealth Environmental Water Holder (CEWH) was able to purchase water for environmental use.

Nature delivered life-saving floods in 2010-12, which broke the drought and sent flows through the Gurra Gurra complex flowpaths, so the works completed back in 2000 finally fulfilled their function (Fig. 2). Water flowed through the pipes at Tortoise Crossing for 170 days in 2010-11 and again for 71 days in 2012.

Figure 2. The sign at the key Tortoise Crossing flow path explains that replacing three pipes with 160 pipes back in 2000 now allows 50 times more flow when the river floods, as seen at the flood peak in December 2016 (Photos A. Jensen)

The sequence of floods led to mass germination of Black Box at medium floodplain elevations, with mass River Red Gum seedlings at lower elevations. A range of studies show that the survival of these seedlings is critical to fill age gaps and replace the losses from the Millenium Drought, as survival rates from germination events in the 1970s and 1990s were very poor and the last successful mass recruitment of Black Box in the Lower Murray Valley was from the 1955-56 floods.

Following the floods in 2010-2012, conditions were dry in 2013-15 and the fields of mass seedlings began to dry out and die. A further short flood in 2016 watered the surviving fields of Black Box seedlings for at least two weeks, adding to prospects of survival and flowing through the Tortoise Crossing pipes for 75 days. However, conditions in 2018-19 and into summer 2019-20 are once again extremely dry, with stress appearing in mature trees and saplings dying off. The Lower Murray Valley is still recovering from the Millenium Drought, thus needing more frequent watering over a sequence of years to bring mature trees back to health and full seed production, so this is a significant setback.

Further works and activities since 2002. Since 2008, the environmental charity Nature Foundation SA (NFSA) has been undertaking environmental watering projects on smaller, privately-owned sites in the Lower Murray, many from the original Wetland Care Australia list. In the Lower Murray Valley, water needs to be lifted up to 3 m from the river channel to reach wetlands on the floodplain, requiring costly energy. This is done using irrigation techniques, including pumps, pipes and sprinklers. These smaller projects complement government agency projects using major infrastructure to deliver environmental water to much larger wetland complexes.

In 2008-09, the primary purpose was to acquire water and use it to limit extreme environmental damage in the drought. In 2009 NFSA provided supplementary water for Little Duck Lagoon, one of the sites from the Wetland Care Australia Gurra Gurra project.

From 2012-19, NFSA has held a contract partnered with the Commonwealth Environmental Water Holder (CEWH) to deliver up to 10 GL/y of environmental water to selected sites. A priority for the NFSA Water for Nature program has been to sustain the mass germination triggered by the 2010-12 floods, watering fields of seedlings and saplings so they can fill the very large gap in age structure of Black Box populations. Stressed mature Black Box trees are being watered to improve their condition and volumes of seed produced. While delivering water to a defined wetland is relatively simple, with water pumped to an inlet point and allowed to pool in the wetland, watering scattered fields of seedlings and saplings on relatively flat floodplain land is a challenge, especially when they are in gaps between mature trees. The solution has been to use high-throw sprinklers (simulating rainfall) and operating them at night, to allow soakage into clay soils and to avoid evaporative loss during the day.

Since 2008, NFSA has delivered almost 13 GL of water to 97 watering sites in 20 wetland complexes, covering 27 different ecological targets across 12 habitat types. A total of 4.9 GL was delivered to 15 sites in 2017-18 and 1.55 GL was delivered in 2018-19 to 25 sites covering 126 ha. Rolling 5-year watering plans have been developed for each site, able to respond to annual water availability, Basin-wide priorities, environmental water requirements, climatic conditions, site watering history and feasibility of delivery.

One of the NFSA sites is Lyrup Lagoon in the Gurra Gurra complex, being watered to reduce accumulated salinity from groundwater inflows. Importantly, the infrastructure of the Central Irrigation Trust was used to deliver water to the lagoon. Thus, local irrigators are partners in delivery of water for regional environmental benefits and river health.

Figure 3. Watering guidelines developed by the Water For Nature program for stressed and healthy woodlands, for (a) River Red Gum and (b) Black Box (Water for Nature).

Further Results. The initial watering guidelines reported in the original EMR feature have been expanded through research and monitoring of responses to watering events, developing guidelines for timing and frequency of wetting and drying cycles to promote recovery in mature trees and support germination and survival of seedlings. These have been applied for each site in the rolling 5-year watering plans, which then determine the annual list of sites due for watering (see NFSA 5 year strategy and Fig. 3).

Watering by NFSA 2013-2019 has sustained Black Box seedlings and saplings through four dry summers, with watered plants 2-3 times taller than non-watered plants (Fig. 4). The Water For Nature monitoring report shows that, at NFSA sites, mature Black Box trees that have received periodic environmental water as determined by their 5-year watering plan during 2015-2019 were 21-46% (average 36%) better in health than adjacent non-watered sites, with denser, more vigorous canopies and the relative improvement was greatest during hotter and drier periods. The watering events thus provided water between natural floods to sustain growth in saplings and crop cycles in mature trees. Watering at other NFSA sites has provided vital habitat for vulnerable and endangered fauna including the Murray Hardyhead (Craterocephalus fluviatilis), Southern Bell Frog (Litoria raniformis), Regent Parrot (Polytelis anthopeplus) and Latham’s Snipe (Gallinago hardwickii).

Figure 4. Watered River Red Gum saplings at Thiele Flat, Loxton; November 2013 (top) and March 2018 (bottom). Note 2016 flood level mark on foreground trees (Photos A. Jensen)Lessons learned and future directions.

The significant benefits of environmental water have been demonstrated at NFSA’s Water For Nature sites, for floodplain vegetation communities and in temporary wetlands. Evolving research indicates that watering in late spring-early summer mimics peak flows in the natural water regime, coinciding with highest chances of breeding and germination events and thus ecologically ideal timing (See bibliography). Benefits are increased if seasonally filled wetlands are topped up in early summer, to ensure sufficient duration to sustain frog and waterbird breeding.

As well as ideal timing, studies have shown that watering at any time of the year can be beneficial, including enhancing soil moisture storage in the unsaturated zone and sustaining volume in bud and fruit crops. A key finding has been that watering in late autumn-early winter sustains soil moisture, priming sites to give an enhanced response to watering in the following spring-summer.

However, dry climatic conditions and political pressures to minimise water recovery volumes are combining to reduce availability of environmental water, with only very highest priority sites likely to receive water in the 2019-20 water year. Environmental water cannot create floods, it can only provide water to selected priority sites during dry times and enhance the benefits of any natural floods. Current volumes can only meet the requirements of a limited number of sites, leaving many sites without the water needed to sustain them through dry times or to recover from the severe impact of the Millenium drought.

Bureaucratic processes for approvals also hinder effective delivery of environmental water. With the water year coinciding with the financial year from July to June, water delivery stops in June to allow water accounts to be finalised. Approval to water in the following year can take 2-3 months, meaning no water can be delivered during the winter months for priming, missing the advantage of low evaporation rates and higher chances of piggy-backing on rainfall events.

Funding for environmental projects tends to be short term, leading to job insecurity for project managers, loss of continuity and project knowledge, and inability to complete watering sequences. Very significant volunteer resources are required to make these watering projects happen, including inputs from landholders who have donated electricity connections to the floodplain, transported diesel to re-fuel pumps, loaned pumps, tractors and irrigation equipment, plus use of irrigation and local government infrastructure to deliver water, and physical assistance and maintenance from local volunteer groups.

Practical on-ground watering knowledge is maturing well; what is needed now is sufficient water and ongoing consistent funding to support projects to deliver minimum environmental water requirements for the wetlands of the Lower Murray Valley. The pipes at Tortoise Crossing, installed in 2000 and only flooded twice, are more than ready for the next high flows to pour through!

Stakeholders and Funding bodies. The monitoring project was supported as part of the project Ecological Responses to Environmental Watering in the South Australian River Murray Valley, assessing the benefits of salinity interception schemes on floodplain vegetation, coordinated by Australian Water Environments for SA Water from March 2015 to June 2017. Continuing funding for monitoring in 2017-2019 was provided in a grant from the Ian Potter Foundation to Nature Foundation SA, as well as funding from the Commonwealth Environmental Water Holder (2018-19). Water for the environmental watering projects studied here was provided through annual allocations of water from the Commonwealth Environmental Water Office to Nature Foundation SA.  Water delivery was managed by the NFSA Water For Nature program through Program Manager Natalie Stalenberg. Practical support and site access was provided by Steve Clark, landholder and committee member for Water for Nature program, and landholders John and Bronwyn Burford.

Contact. Dr Anne Jensen, Environmental Consultant; Volunteer member, Water for Nature Committee, Nature Foundation SA; part-time consultant Wetland Ecologist for Water for Nature Program of Nature Foundation SA (7 Ford Street, Maylands SA 5069, Australia; Tel: +61 407 170 706; Email: ajensen@internode.on.net