Category Archives: Pollution issues & solutions

Audit of water quality problems arising from land use in the Murray-Darling Basin

Key words: water quality, audit, land use, Murray-Darling Basin, Native Fish Strategy

Aims: This is one of a suite of early projects under the Native Fish Strategy (NFS) that sought to scope the issues and information gaps that the NFS would need to address.  Specifically, this project aimed to: :

  • collate data, identify and map regions , landscapes, land uses and industries that are important causes of water quality (WQ) problems in the Basin (e.g. Fig 1)
  • Determine a meaningful scale/accuracy for reporting based on available data and quantitatively report on land use (distributed and point source) contributions to WQ problems on a third order catchment basis.
Figure 1 - this project sought to collate data on land uses and industries which are important causes of water quality problems. Photo courtesy of Arthur Mostead.

Figure 1 – this project sought to collate data on land uses and industries which are important causes of water quality problems. (Photo courtesy of Arthur Mostead.)

Methods: This project was essentially a desktop review and Geographic Information System data atlas formation exercise that included: developing a classification of land uses/management practices in relation to WQ impacts; identifying existing relevant datasets and projects; evaluating available data for relevance and identify gaps; reporting the findings for a pilot catchment (the Broken River/Creek catchment in Victoria). Mapping was available at a range of scales.

There is a wide range of physical, chemical ecotoxicological and ecological parameters that can be used to provide information on WQ, but no single measure of overall WQ. The WQ parameters selected for the study were considered to have direct effects on native fish as well as direct effects on habitat suitability, food sources as well as fish behaviour and ability to migrate and reproduce. Water quality parameters considered of major importance in the study were temperature (cold water); turbidity, dissolved oxygen, and nitrogen/ammonia. Parameters of moderate importance were salinity, pH, toxicants, and pathogens. Land use has known relationships with the nature of WQ changes that occur as a result of that land use (e.g. mining and acid water drainage), and similarly there are known relationships between point source discharges from particular industries and WQ. A matrix of relationships between land use/point source discharges and the nine WQ parameters informed a spatial model that also included a risk assessment of the likelihood and consequence of a critical WQ impact occurring, including the location of high priority native fish sites (species/habitats/refuges). 

The methodology devised for the project was designed to:

  • Facilitate ease of access and use of a complex array of land use and WQ related datasets
  • Display the data so that it can be used by managers responsible for native fish and their habitat
  • Recognise important WQ parameters for native fish in the Basin
  • Provide insight into areas of the Basin under threat from WQ changes with respect to native fish, and
  • provide a predictive yet easy to understand and utilise spatial model.

Findings: The spatial model when applied to the Broken River catchment with land use mapped at ≤1:100,000 scale clearly identified spatial areas that were at risk of WQ impacts, and the level of the risk involved (low, moderate, high extreme). When compared with land use mapped at the 1:250,000 scale, the coarser scale of mapping led to errors in assessment of risk of WQ impacts. Consequently, the spatial model was not recommended to be used for specific catchment investigations where land use was captured at scales >1:100,000. While the limitations of 1:250,00 scale land use capture are acknowledged, analysis using such data may provide useful information to focus further investigations. Consequently the spatial model was applied across the entire Basin at the 1:250,000 scale and indicated the following catchments had the most land use area with high potential to cause water quality impacts that may affect native fish: Gwydir, Namoi, Murray (Hume Dam to SA Border), Murrumbidgee, Loddon, Broken, Goulburn and Campaspe. 

Lessons learned and future directions: The spatial model provided a useful tool for managers to investigate and visualise areas at risk of WQ impacts to native fish. The ability of the model to discriminate such areas at risk at a specific catchment scale declined above scales of 1:100,000 for land use mapping. The lack of detailed information on fish tolerances to various WQ parameters hampers the precision of the model. Similarly the scarcity of spatial data on WQ and the lack of readily available spatial data for fish distribution was a significant issue.

Stakeholders and Funding bodies:  This project was funded through the Murray-Darling Basin Authority’s Native Fish Strategy.

Contact: Earthtech, +61(7) 3343 3166

Link: http://www.mdba.gov.au/sites/default/files/archived/mdbc-NFS-reports/464_execsum_audit_WQproblems_draft.pdf

Bourkes Gorge Spoil Dump #2 Restoration – Kosciuszko National Park

 Elizabeth MacPhee and Gabriel Wilks

Bourkes Gorge Spoil Dump #2 is one of two large spoil dumps created during construction of the Murray 1 Pressure Tunnel between 1962 and 1966 to carry water from the Geehi Reservoir to the Murray 1 Pipelines.  These pipelines deliver water to the Murray 1 Power Station on the western side of Kosciuszko National Park near the township of Khancoban.  At this site during Scheme construction, approximately 300 000 m3 of unconsolidated rock spoil was removed from the tunnel access point on a rail siding and dumped in the steep valley of a tributary creek flowing to Bogong Creek.

 The site prior to rehabilitation. Bourkes Gorge Spoil Dump #2 was one long unstable rock slope devoid of native vegetation with scrap metal, timber and concrete jutting out along erosion scars. It was too steep to stand on, with a slope height of 60m and an angle of approximately 380. The spoil dump was 150m wide across the valley and extended about 250m upstream, blocking the tributary creek. As a result, an 8m washout scar was left in the southern side of the spoil dump with continual erosion down the creek, eroding particularly during peak flows.

Fauna and vegetation surveys were conducted on and in the surrounding forest. Three fauna species listed as vulnerable under the NSW Threatened Species Conservation Act 1995 (TSC Act) were identified in the surrounding forest – the Yellow-bellied Glider Petaurus australis, Gang-gang Cockatoo Callocephalon fimbriatum and the Eastern False Pipistrelle Falsistrellus tasmaniensis. (Schultz, M unpublished). Habitat requirements for nesting and roosting of these species did not occur within the site.  The Spotted Tree Frog Litoria spenceri is listed as Critically Endangered by the International Union for Conservation of Nature (IUCN) and is also listed in the Federal Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) and the TSC Act. This species was known to occur in the vicinity of site, but surveys had recorded a dramatically declining population (Hunter & Gillespie 1999). It was not recorded on or around the site during the fauna survey in 2008. Weeds such as Blackberry (Rubus sp.) and willow (Salix spp.) occurred at the top edge of the site and minimal vegetation was found on the majority of the spoil.

Objectives of the restoration works :

  • Re-shaping the spoil dump to a more stable slope.
  • Constructing an environment that favoured revegetation and habitation of site-indigenous flora and fauna species.
  • Integrating the site into the surrounding tall montane forest
  • Constructing a channel to enable high water flow events to move across the site without scouring or rendering the site unsafe.
  • Slowing high flow events to limit the scour effects on the downstream environment.
  • Safely managing contamination or general construction waste found at the site

Treatments. Works were undertaken from December 2009 to April 2010. Stabilisation works consisted of reshaping the spoil dump and lining 300m of artificial creek line. The resulting land form was planted with 50,000 tubestock in 2010 – 2011 and had specific management practices applied to minimise potential impact on the Spotted Tree Frog.

Plant species used in the revegetation had to be sourced from plants as cuttings, seed or division from the surrounding environment, capable of being commercially propagated due to the number required, and robust enough to withstand the more extreme conditions found on site than in surrounding forest. One rare species Bertya findalyii was found colonising the edge of the site and so was incorporated into the planting list.

Results.

Erosion Control.  The rehabilitation of the Bourkes Gorge #2 spoil dump resulted in 43,300 m3 of rock soil being re-shaped to reduce slope and direct water flow, reducing the potential for surficial erosion and mass slumping. Slope angles were reduced from around 38ْ to between 26ْ and 30ْ  (URS, 2009). Around 560M3 of concrete reinforced with structural synthetic fibre and on site rock was used to form the water channel. In the three years since rehabilitation, there have been two major flood events in the region – October 2010 and March 2012. The Jagungal weather station in Kosciuszko NP recorded 6, 12 and 24 hour duration rainfall intensities exceeding the 100 year Average Recurrence Interval (ARI) intensity. There was no evidence of erosion or slumping at Bourkes Gorge Site following these events.

Revegetation.  Assessment of the vegetation was done two years after planting by Greening Australia Capital Region using BioMetric (http://www.environment.nsw.gov.au/papers/BioMetricOpManualV3-1.pdf).  This monitoring has shown outstanding survival and growth rates – with 35% cover by 19 native species, with virtually nil weed. (Species are listed in Table 1 ).

Lesson learned: Rock spoil in high altitude, steep conditions with no organic matter in a compacted and unstable condition will not naturally revegetate, even if left for a fifty year period.  Applying site appropriate techniques such as re-shaping for stability, allowing for water flow, moving compacted rock to create air pockets and allow water infiltration, and adding the essential ingredients of organic matter, nutrients and plant material can trigger successful site revegetation. Covering the ground with a layer of organic matter such as rice straw ameliorates temperature extremes on site, allowing young seedlings to survive and flourish.

Acknowledgements. Thanks are extended to the restoration team at Kosciuszko National Park, including the many contractors who participated.  We also thank Nicki Taws and Angela Calliess (Greening Australia Capital Region) who undertook the formal vegetation monitoring.

 

After earthworks, planting niches are filled with compost

After earthworks, planting niches are filled with compost

Main slope at Bourkes Gorge #2 spoil dump

Main slope at Bourkes Gorge #2 spoil dump

Liz MacPhee pictured at Bourkes spoil dump one year after planting

Liz MacPhee pictured at Bourkes spoil dump one year after planting

Table 1. Vegetation data recorded on a 50m transect approximately 2 years after treatment.  (Data from Greening Australia Vegetation Monitoring Former Snowy-Hydro Sites Kosciuszko National Park).

Scientific name

Common name

Tube stock

Direct seeding

Transplants from within site

Trees  

 

 

 

Eucalyptus dalrympleana Mountain Gum

X

   
Eucalyptus delegatensis Alpine Ash

X

X

 
Eucalyptus globulus v bicostata Southern Blue Gum

X

   
Eucalyptus viminalis Manna Gum

X

   
Lomatia fraseri Tree Lomatia

X

   
Shrubs  

 

 

 

Acacia dealbata Silver Wattle

x

   
Acacia melanoxylon Blackwood wattle

X

   
Bedfordia arborescens Blanket leaf

X

   
Bossiaea foliosa Leafy Bossiaea

X

   
Bertya findlayii Alpine Bertya

X

   
Cassinia longifolia Shiny Cassinia

X

   
Coprosma hirtella Rough Coprosma

X

   
Coprosma quadrifida Prickly Currant Bush

X

   
Daviesia mimosoides subsp. laxiflora Mountain bitter pea  

X

 
Helichrysum stirlingii Ovens Everlasting

X

   
Kunzea ericoides Burgan

X

   
Leptospermum grandiflorum Mountain Tea Tree

X

   
Leptospermum obovatum River Tea Tree

X

   
Polyscias sumbucifolia Elderberry Panax

X

   
Pomaderris aspera Hazel Pomaderris

X

   
Prostanthera lasianthos Mint bush

X

   
Forbs  

 

 

 

Derwentia derwentiana Derwents Speedwell

X

   
Dianella tasmanica Mauve Flax lily      
Senecio linearifolius Tall Senecio

X

   
Stellaria pungens Prickly starwort

X

   
Ferns        
Polystichas proliferatum Mother Shield-fern

X (divisions)

   
Blechnum spp. fern    

X

Grasses  

 

 

 

Poa ensiformis  

X

X

 
Poa  helmsii Broad leafed snow grass

X

X

 
Poa sieberiana Tussock grass

X

X

Yarrangobilly Native Seed and Straw Farm

Elizabeth MacPhee and Gabriel Wilks

Yarrangobilly Caves is a tourist destination within Kosciusko National Park (KNP), New South Wales. The Yarrangobilly Caves Wastewater Treatment Plant (WTP) has been established to treat greywater produced at the tourist centre, to stop nitrogen moving into the limestone karst system of the caves.

To optimise benefits from the WTP, the Rehabilitation team undertook the planting of locally native grass species in the discharge area, with a view to producing seed and weed-free mulch for use in the KNP Former Snowy Sites restoration program.

Effluent is initially treated using a bacterial blivet and then undergoes an ultra-violet treatment process so that it is within a “greywater” classification. It is then stored in a 200,000 litre tank and released under pressure to a discharge area. Prior to being discharged the effluent is diluted with fresh water to an average ratio of 7:3 (effluent:fresh water) in order to reduce the total nitrogen in the irrigated water to around 10 mg/L, which has been used as a threshold figure for nutrient loading. Once at the right concentration, the effluent is discharged in a large flat sedimentary rock area of about 1 ha in size.  The irrigation area in which the plant species are grown is approximately 0.5 ha.

Vegetation treatments. From 2006 to 2010, some 20,000 plants of a number of species of the grass genus Poa were planted in the discharge area of the WTP, at 50cm spacings (Fig 1).  The four main species were: Poa costiniana; P. fawcettiae, P. sieberiana and P. ensiformis; all native to KNP. Over the last 6 years, more than 300 kilos of highly viable Poa spp. seed has been collected and used in restoration works across the Park. The thatch (seed heads and cut off straw) has also been harvested and used as mulch on some of the sites.

Other species needed for rehabilitation in KNP have also been planted in the site over the last two years. Bossiaea foliosa and Lomandra longifolia have been grown for seed production and a variety of difficult to germinate shrubs have been grown to provide cutting material for propagation.

Soil sampling and soil treatments. Sampling was conducted prior to and after plant harvest to gauge the soil’s physical and nutrient status.  The samples (10cm cores of topsoil and subsoil) were sent to the Environmental and Analytical Laboratories at Charles Sturt University for analysis of Total Phosphorus and Total Nitrogen. (ammonia and nitrates as Nitrogen and phosphorus as Phosphorus (Bray)).

As early soil tests showed that pH reduced, Lime was applied to the discharge area in 2010 at 1 – 1.5 tonnes to to raise topsoil pH approximately 1 unit.

Results.

Seed and mulch production: Within the first 18 month period, nearly 100 kilos of seed was collected. To date over 300 kilos of highly viable Poa spp. seed has been collected and used in rehabilitation across the park, with the 2011/2012 harvest producing approximately 58 kilograms of seed. In the 2012-12 harvest, an estimated 288 kilograms of thatch was removed for use as mulch in restoration areas in the Park.

Soil fertility. More nitrogen and phosphorus was discharged during the 2011/2012 season than could be removed by plants season, with the native species having naturally low nutrient removal rates. Annual soil monitoring and peizometer monitoring of the ground water is keeping track of the use and movement of nitrogen in this landscape and to monitor any changes in soil chemistry.

 Suggestions for improvements:

  • Review irrigation scheduling to ensure the bulk of irrigation is occurring from November to March when nutrient uptake will be at its highest (rather than in the cooler months).
  • De-thatch the grass species at the start of spring to encourage fresh re-growth and therefore improve nutrient uptake over the spring and summer months
  • Test effluent on a regular basis to assess salt load;
  • Further treat effluent to reduce the nitrogen, phosphorous and sodium load;
  • Monitor and adjust pH as required; and
  • Reseed bare patches to maximise nutrient uptake by plants.

 In 2012 a progressive replacement planting program commenced, where sections of the oldest plants were poisoned and replaced with young plants. This continual renewal replanting will ensure the plantation remains actively growing, taking up maximum levels of nutrient and producing high quality seed and mulch.

Acknowledgements.  Funding for this project came from The Former Snowy Sites Rehabilitation project with soil and plant nutrient data provided by D.M McMahon (2008, 2012): Environmental Monitoring Use of Effluent for Irrigation, Yarrangobilly Caves, NSW. Environmental Consultants (agronomy) Wagga, Wagga.

Yarrangobilly grasses ready for harvesting

Yarrangobilly grasses ready for harvesting

The plantings are mainly four local species of Poa

The plantings are mainly four local species of Poa

Sustainable Streets Program, Byron Shire Council, NSW

Graeme Williams

Byron Shire Council’s ‘Sustainable Streets’ program aims to foster community-inspired sustainable behaviour change at a neighbourhood level. The program consists of regular neighbourhood gatherings and sustainability education workshops on topics, including: organic gardening; bush-friendly backyards; rainwater harvesting; solar power and energy efficiency; ethical shopping; green cleaning and, cooking with local produce.  .

Activities. In each participating neighbourhood, residents get together for sustainability workshops and build bonds in the neighbourhood, whilst raising points to fund their own local sustainability project. Currently seven streets in neighbourhoods across Byron and Tweed Shire Councils have participated in the Sustainable Streets program, including: Brunswick Heads; Mullumbimby; South Golden Beach; Mullum Creek; Murwillumbah; Cabarita Beach; Uki.

Analyses of the street’s consumption of energy, water and ecological footprint (i.e. the number of planets needed if everyone lived that lifestyle) were made prior to the program and calculated again after 6 months. (Results are shown in Table 1.)

Table 1. Decreases in energy, water and eco footprint of residents in participating Sustainable Streets in the Tweed-Byron area.

Location of Street Energy Water Eco Footprint
South Golden Beach 5.0% decrease 43.0% decrease 5.5% decrease
Uki 13.0% decrease 23.0% decrease 14.5% decrease
Mullumbimby Creek 13.5% decrease 62.0% decrease 21.0% decrease
Cabarita 26.0% decrease 23.0% decrease 20.5% decrease
Brunswick Heads 12.3% decrease 41.5% decrease 15.3% decrease

Results to date.

Energy. Participants have changed to Greenpower, with 8 families having installed their own solar power system. Other changes have been changing consumption patterns including turning off standbys, installing low wattage lights, wearing jumpers instead of turning on heaters, manual operation of electric hot water boosters, adjusting pool pumps minimum use or converting to a natural pool and insulative cooking.

Water. Five families have installed water tanks, others use shower timers, less frequent bigger clothes and dish washing loads.

Food and garden. Participants have converted to efficient composting or worm farms or installed poultry. Others meet more regularly for neighbourhood food and plant swaps and and buy more local food from a nearby organic farmer and at the Farmer’s markets.

Fuel emissions. Changes included reducing air travel, downsizing the family to more fuel efficient models, increased carpooling and pushbike use.

Environment. Nine families cleared their land of invasive weeds

Lessons. A major aspect of the project has been the strengthening of social connections in the neighbourhood, with many participants drawn into the program to ‘get to know their neighbours’. In an increasingly isolated society, the enhancement of social capital has been one of the most significant achievements of the program and platform to develop local sustainability. It is hoped that additional streets will be launched in the future.

Contact Byron Shire Council’s Sustainability Officer on 6626 7305. Also see http://www.byron.nsw.gov.au/sustainable-streets-program to access the ‘Sustainable Streets doco’ which can be borrowed from local libraries.

Sustainable Streets residents (Photo Byron Shire Council)

Brunswick Heads Sustainable Streets participants (Photo Byron Shire Council)