Publications by Year
Spatiotemporal Dynamics of Riparian Land-Cover Change and Impervious-Cover Expansion in a Rapidly Urbanising Himalayan Capital City Land
Urbanisation and impervious-cover expansion are reshaping riparian landscapes, particularly in mountain cities where steep terrain concentrates development along valley floors. This study examined spatiotemporal land-cover change within the regulated riparian corridors of…
Urbanisation and impervious-cover expansion are reshaping riparian landscapes, particularly in mountain cities where steep terrain concentrates development along valley floors. This study examined spatiotemporal land-cover change within the regulated riparian corridors of Thimphu City, Bhutan, over a 25-year period from 1997 to 2022 using Landsat imagery, Random Forest classification and Google Earth Engine. Results show substantial transformation of riparian land cover, with impervious cover increasing from 26.14% to 32.63%, equivalent to an overall increase of 24.83%, while agriculture/barren/low-vegetation declined from 30.59% to 26.01%, equivalent to an overall decrease of 14.98%. A modest increase in detectable vegetation cover was also observed, although this should be interpreted cautiously because the study measured land-cover extent rather than vegetation condition, floristic composition or ecological quality. Classification performance was robust, with overall accuracies ranging from 89.9% to 94.5%, exceeding the commonly accepted 85% benchmark, although uncertainty remains in narrow riparian corridors due to Landsat’s 30 m spatial resolution. Mann–Kendall analysis provided supplementary evidence of monotonic land-cover trends, but the limited number of temporal observations means these results should be interpreted as indicative, rather than definitive. Spatial analysis revealed uneven transformation, with the southern valley recording the greatest increase in impervious cover. These findings demonstrate sustained development pressure within legally regulated riparian buffers and highlight the need for routine spatial monitoring, place-specific buffer management and stronger integration of riparian protection into urban planning. The study provides a quantitative baseline for assessing future riparian land-cover change and supporting more resilient land governance in rapidly urbanising Himalayan mountain cities.
Does poor regulation lead to pollution? Key takeaways from a systematic review.
Formal recycling of used lead acid batteries (ULAB) is a multibillion-dollar industry, valued at US$12.12 billion in 2024, and expected to grow to more than $26 billion within eight years. Demand for…
Formal recycling of used lead acid batteries (ULAB) is a multibillion-dollar industry, valued at US$12.12 billion in 2024, and expected to grow to more than $26 billion within eight years. Demand for recycled lead (Pb) for new batteries grows in developing countries where costs limit the uptake of lithium-ion batteries. ULAB recycling in these regions poses significant danger to human health and the environment. Stringent regulatory approaches for ULAB recycling in developing countries, intended to reduce pollution, have thus far been ineffective as they typically do not adequately cover small-scale informal recycling in rural and remote communities. We examine what characterises effective environmental regulation for ULAB recycling in developing countries through the use of a systematic review of 85 papers covering three decades of literature from 1977 to 2023, and applied constructivist grounded theory-informed thematic analysis using NVivo 14 to code and analyse data. We generated three key frameworks that characterise regulatory conditions associated with effectiveness in developing countries: well-crafted policies, adequate governance mechanisms, and mitigation measures to avoid pollution. The results indicate that effective regulation emerges from complex interactions that are simultaneously flexible and structured, inclusive yet focused, and locally relevant while also considering global efforts to address pollution-related Sustainable Development Goals.
Contrasting effects of impervious cover on riparian plant and soil bacterial communities in a rapidly urbanising Himalayan city.
Rapid urbanisation—particularly the expansion of impervious surfaces—is reshaping riparian landscapes worldwide. These areas are frequently targeted for development due to their favourable topography, abundant water resources, and aesthetic appeal. However, the impact…
Rapid urbanisation—particularly the expansion of impervious surfaces—is reshaping riparian landscapes worldwide. These areas are frequently targeted for development due to their favourable topography, abundant water resources, and aesthetic appeal. However, the impact of increasing impervious cover on soil bacterial communities in biodiverse urban riparian zones remains poorly understood, especially in developing countries, raising concerns about potential declines in essential ecosystem functions. In this study, we investigated the effects of impervious cover, quantified as the Percentage of Total Impervious Area (PTIA), on the taxonomic and functional diversity of riparian soil bacteria in Thimphu City, Bhutan. Using plot-based taxonomic profiling and metagenomic analysis across a PTIA gradient, we tested the hypothesis that bacterial diversity and functional pathways would decline beyond 40 % PTIA, mirroring patterns observed in riparian plant communities. Contrary to our hypothesis, plots with PTIA exceeding 40 % exhibited greater bacterial richness and functional diversity. These findings suggest opposing responses to impervious cover, with belowground microbial communities increasing in diversity while aboveground plant diversity declines. A significantly lower carbon-to‑nitrogen ratio in urban plots—likely driven by nutrient enrichment—emerged as the primary factor promoting bacterial diversity in high PTIA areas. This enrichment appeared to favour copiotrophic bacteria, enhancing both diversity and functional capacity. Our results suggest that bacterial communities may be effective bioindicators of riparian ecosystem health than plant communities. Incorporating microbial metrics into urban riparian management and monitoring could therefore provide valuable insights for sustaining ecosystem functions in rapidly urbanising regions
Urbanisation and specifically impervious cover alter riparian plant communities in a rapidly urbanising landscape in the Himalayas.
Impervious covers, such as roads, pavements, buildings, and parking lots, prevent water infiltration, thereby increasing surface runoff. The expansion of impervious cover along riverbanks in urban areas poses a significant threat to…
Impervious covers, such as roads, pavements, buildings, and parking lots, prevent water infiltration, thereby increasing surface runoff. The expansion of impervious cover along riverbanks in urban areas poses a significant threat to riparian ecosystems by altering species diversity and composition through hydrological changes. As dynamic ecosystems at the interface between aquatic and terrestrial environments, riparian areas play a crucial role in aquatic ecology, particularly in terms of biodiversity, bank stability, nutrient dynamics, and hydrological processes. Employing plot-based floristic sampling, this study investigated the effects of urbanisation, particularly impervious cover (quantified as PTIA, Percentage of Total Impervious Area), on riparian plant communities in the rapidly urbanising landscapes of Thimphu City, Bhutan. Additionally, other environmental variables and soil chemical properties were examined to determine whether they confounded the impacts of PTIA. The results showed that PTIA had a significant impact on the diversity and composition of riparian plant communities. Overall, higher levels of PTIA supported a greater number of plant species, including exotic species, but exhibited the lowest α-diversity and reduced tree abundance compared to reference sites (p < 0.001). These areas favoured Rumex nepalensis–Equisetum spp. community, while low PTIA supported the Calamagrostis scabrescens–Elaeagnus umbellata community. Significant changes in species diversity and community structure were observed at a PTIA threshold of approximately 60% (p < 0.05), indicating substantial ecological alterations beyond this point. Except for soil pH, which influenced plant communities independently rather than confounding PTIA’s effects, other environmental variables and soil chemical properties did not have any significant effects on riparian plant communities. Our study revealed that PTIA was the primary predictor for changes in plant communities in rapidly developing urban riparian landscapes. The relationship between PTIA and plant communities highlights the importance of considering PTIA in urban biodiversity management, as it can predict the extent of vegetated land required to sustain healthy riparian ecosystems. These findings suggest that rapidly urbanising cities can realign their urban development and riparian biodiversity management strategies by assessing existing impervious cover and establishing appropriate PTIA thresholds to balance urban growth with the conservation of riparian environments.
Microplastic Pollution in Riparian Soils of the Rapidly Growing City of Thimphu, Bhutan
Plastic has become a vitally important material for humans; however, the large amount of plastic waste generated annually pollutes the environment. Plastic decomposition generates microplastics (MPs), which have emerged as a concerning…
Plastic has become a vitally important material for humans; however, the large amount of plastic waste generated annually pollutes the environment. Plastic decomposition generates microplastics (MPs), which have emerged as a concerning global environmental pollutant because of their potential to be more harmful to the environment than their larger counterparts. This study examined the occurrence and abundance of MPs in riparian soils (RS) of a rapidly growing city in Thimphu, Bhutan. Additionally, the study investigated the relationships between the abundance of MP and several variables, such as the physicochemical properties of the soil, land use, the distance to impervious cover (IC), the plot IC%, surface plastic, textile waste, and the distance to upstream drainage outlets within the riparian zone (RZ). A density separation technique was used to extract MPs. The results showed that RS in urban sites had higher concentrations of MPs (93.3%) than in other land use (7.7%, p = 0.04). Blue MPs (46.2%) were the most common plastic colour. In urban RS, MPs ranged from 0 to 500 particles/kg. MP concentration showed a positive correlation with available phosphorus (p = 0.01) and the distance to the upstream drainage outlets (p = 0.01). Our findings highlight the nature and pathways of MP pollution in rapidly growing cities, where economic growth often overshadows environmental management. We also identify opportunities for these cities to mitigate MP pollution by reclaiming surface plastic and textile waste, stepping up recycling initiatives, and disposing of plastic-ridden waste in low-impact landfills.
Closing pit lakes as aquatic ecosystems: Risk, reality, and future uses.
Mine pit lakes are formed when open-cut pits flood with water, and these lakes occur by the thousands on every inhabited continent. The remediation and closure of pit lakes is a pressing…
Mine pit lakes are formed when open-cut pits flood with water, and these lakes occur by the thousands on every inhabited continent. The remediation and closure of pit lakes is a pressing issue for sustainable development and provision of freshwater ecosystem services. While pit lakes can be spectacular examples of recreation and renewal, pit lakes may be better known for their poor water qualities and risks to communities and the environment. Often the public wants to simply “fill the pits in” to restore a terrestrial landscape, but this is not always possible. Therefore, planning for remediation and future uses is likely to provide the best outcome. Poor water quality is not necessarily a barrier to future use, although it may limit the number of uses. Short-term future uses tend to require commercial viability, active infrastructure investment, and maintenance, and should transition to complementary long-term uses that promote biodiversity. Long-term future uses require relatively less ongoing maintenance beyond the initial investment and adhere to the principles that pit lakes should be safe, sustainable, and non-polluting in perpetuity. Pit lakes will eventually develop “ecosystem values,” and the time to do so depends on the nature of the intervention and the values ascribed by the community. Where possible, closing pit lakes as sustainable ecosystems is the most realistic goal that permits a variety of future uses that is likely to see pit lakes valued by future generations.
Non-charismatic waterbodies and ecosystem disservices: Mine pit lakes are underrepresented in the literature.
Aquatic Ecosystems of the Anthropocene: Limnology and Microbial Ecology of Mine Pit Lakes.
Foreword to the Special Issue on Pit Lakes: The Current State of Pit Lake Science
IMWA Insights: Discussion of the public perception of a new open pit in As Pontes, Spain.
The Importance of Catchments to Mine-pit Lakes: Implications for Closure.
Saline Pit Lakes – What Biodiversity Values Can They Offer At Closure And Beyond?.
Macroinvertebrates and Microbes (Archaea, Bacteria) Offer Complementary Insights into Mine-Pit Lake Ecology.
Incorporating Microbes into Environmental Monitoring and Mine Closure Programs: River Diversions as Test Beds
Sedimentation Rates In Two Pit Lakes: Implications For Riverine Flow-Through As A Closure Strategy
Seasonal River Flow-through As A Pit Lake Closure Strategy: Is It A Sustainable Option In A Drying Climate?
Trophic roles of tadpoles in tropical Australian streams.
Biophysical Closure Criteria Without Reference Sites: Evaluating River Diversions Around Mines.
Waste Not, Want Not – Using Waste Hay to Improve Pit Lake Water Quality
Are Microcosms Tiny Pit Lakes?
Microcosm experiments are frequent precursors to field trials for the treatment of acidic pit lakes using organic matter. We conducted field and microcosm experiments to test the effectiveness of hay to remediate…
Microcosm experiments are frequent precursors to field trials for the treatment of acidic pit lakes using organic matter. We conducted field and microcosm experiments to test the effectiveness of hay to remediate two small, shallow acidic pit lakes. ‘West’ Lake was treated with 19 t of hay and ‘East’ Lake was untreated. Microcosms mimicked key lake trends in water quality, increasing pH and reducing metal concentrations to a greater extent and faster than the field trial. However, microcosms are not tiny pit lakes because they provide an overly optimistic picture of remediation efficacy.
A global analysis of terrestrial plant litter dynamics in non-perennial waterways.
The measure of success.
Pit lakes are a global legacy of mining: An integrated approach to achieving sustainable ecosystems and value for communities.
Effectiveness of S-Methoprene briquettes and application method for mosquito control in urban road gullies/catch basins/gully pots in a Mediterranean climate: Implications for Ross River Virus Transmission.
Assessment of factors limiting algal growth in acidic pit lakes – A case study from Western Australia, Australia.
Pit falls of gold mine sites in care and maintenance.
Bio-physical closure criteria without reference sites: realistic targets in modified rivers.
Genotypic and morphological variation between Galaxiella nigrostriata (Galaxiidae) populations: implications for conservation
Impacts of Artisanal Small-Scale Gold Mining on Water Quality of a Tropical River (Surow River, Ghana).
Setting goals and choosing appropriate reference sites for restoring mine pit lakes as aquatic ecosystems: a case study from south west Australia.
Effects of anthropogenic acidification on aquatic ecosystems.
Regulation of artisanal small-scale gold mining (ASGM) in Ghana and Indonesia as currently implemented fails to adequately protect aquatic ecosystems.
Are We Approaching Pit Lake Closure from the Wrong Perspective?
What do elevated background contaminant concentrations mean for AMD risk assessment and management in Western Australia?
Omnivory and opportunism characterize food webs in a large dry-tropics river system.
Dynamics of habitats and macroinvertebrate assemblages in rivers of the Australian dry tropics.
Mine closure of pit lakes as terminal sinks: best available practice when options are limited?
Upper and lower concentration thresholds for bioremediation of Acid Mine Drainage using bulk organic substrates.
Importance of catchment vegetation and design to long-term rehabilitation of acidic pit lakes.
Breach and decant of an acid mine lake by a eutrophic river: river water quality and limitations of use .
Macroinvertebrate assemblages in rivers of the Australian dry tropics are highly variable.
Gut content and stable isotope analyses provide complementary understanding of ontogenetic dietary shifts and trophic relationships among fishes in a tropical river.
Importance of topography and topsoil selection and storage in successfully rehabilitating post-closure sand mines featuring pit lakes.
Recreational use of acidic pit lakes – human health considerations for post closure planning.
Pit lakes in Australia.
Proceedings of the International Mine Water Association (IMWA) Conference. Bunbury, Australia.
Upper and lower concentration thresholds for bioremediation of Acid Mine Drainage using bulk organic substrates.
The Collie Pit Lake District, Western Australia: An Overview.
Closure Planning in a Developing country – a case study from the Phu Kham Mine, Laos, South-east Asia.
Riverine breach and subsequent decant of an acidic pit lake: evaluating the effects of riverine flow-through on lake stratification and chemistry.
Breach and subsequent decant of an acidic brackish pit lake in the Collie Coal region in south-western Australia occurred during flooding of a pre-mining diverted eutrophic river. Inflowing fresher river water with…
Breach and subsequent decant of an acidic brackish pit lake in the Collie Coal region in south-western Australia occurred during flooding of a pre-mining diverted eutrophic river. Inflowing fresher river water with high alkalinity and nutrient concentrations settled over more saline and acidic pit lake water. This created a halocline with better mixoliminion water quality and monimolimnion water quality typical of the pre-breach lake. Flow-through may represent the best long-term mine closure option for this and other pit lakes in the state and internationally where pit lake water quality degrades over time when excised from regional water systems.
Pit lakes as evaporative ‘terminal’ sinks: an approach to best available practice mine closure.
Pit lakes may form when open cut mining operations extend below groundwater level and then fill at cessation of mining and associated dewatering operations by ground and surface water influx. Pit lake…
Pit lakes may form when open cut mining operations extend below groundwater level and then fill at cessation of mining and associated dewatering operations by ground and surface water influx. Pit lake hydrogeology may function as an evaporative “sink” when pit lake water evaporation rates exceed influx rates.Although not ideal closure, management of local surface and groundwaters contaminated by Acid and Metalliferous Drainage (AMD) through entrainment toward an evaporative terminal pit lake may provide a best-case scenario for protection of regional water resources required by typical mine closure time scales of hundreds to thousands of years. We present two case studies from Western Australia; the first where closure of above ground landforms such as waste dumps by covers would arguably not be successful over long terms (1,000 years or more) and another where Potentially Acid Forming waste (PAF) management is limited by current waste rock dump location and suitable cover materials. Pit lake water balance modelling indicates both case study pit lakes will function as hydraulic sinks if they are not backfilled above their equilibrium water levels. A best closure outcome for these pit lakes may be to be backfilled with PAF encapsulated with alkaline/neutral waste and then filled as rapidly as possible to minimise PAF oxidation and ensure an evaporative sink pit lake is formed.
Sourcing organic materials for pit lake remediation in remote mining regions.
How does storage affect the quality and quantity of organic carbon in sewage for use in the bioremediation of acidic mine waters?
Ecological engineering of a novel lake district: new approaches for new landscapes.
Regulator guidance and legislation relevant to pit lakes
Bioremediation of pit lake water by sulfate reduction.
Health and Safety working around pit lakes,
Water Quality of Mine Void Pit Lakes Used for Recreation.
Potential of sewage and green waste for acidic pit lake bioremediation.
Bacterial sulfate reduction-based bioremediation was trialled in an acidic pit lake, divided into two sections by an earth wall. Sewage and green waste was added to the smallest section, while the other…
Bacterial sulfate reduction-based bioremediation was trialled in an acidic pit lake, divided into two sections by an earth wall. Sewage and green waste was added to the smallest section, while the other was kept untreated as a control. Bioremediation initially increased the pH of the hypolimnion of the treatment lake but after 12 months the pH suddenly returned to pre-treatment levels. This proved to be only temporary and pH bounced quickly back to previous highs. The pH decreases appeared to be associated with heavy rainfall events. These rainfall events affected the bioremediation by mixing the lake and increasing acidity inputs from the catchment.
Evaluating the factors limiting algal biomass in acidic pit lakes of the Collie Lake District, Western Australia.
Acidic pit lakes often have elevated metal concentrations, very low nutrient concentrations and very low algal primary productivity. A microcosm experiment was performed to identify the main limiting factor(s) for algal biomass.…
Acidic pit lakes often have elevated metal concentrations, very low nutrient concentrations and very low algal primary productivity. A microcosm experiment was performed to identify the main limiting factor(s) for algal biomass. Nutrients (N, P and C) were added in all possible combinations to pit lake water in the presence or absence of pit lake sediment. Microcosms without sediment showed higher chlorophyll a concentrations compared to the treatments with sediment. Microcosms where nitrogen and phosphorus were added showed highest chlorophyll a concentrations. Results suggest that algal biomass in pit lakes may be primarily limited by low nitrogen and phosphorus concentrations.
How representative are pit lakes of regional natural water bodies? A case study from silica sand mining
In many regions, regulators view pit lakes akin to natural lakes and impose similar guidelines for water quality and biodiversity. At Kemerton (south Western Australia), extraction of silica sands is creating a…
In many regions, regulators view pit lakes akin to natural lakes and impose similar guidelines for water quality and biodiversity. At Kemerton (south Western Australia), extraction of silica sands is creating a large deep dredge pond. This is progressively split into smaller lakes, which are then rehabilitated. The water quality and macroinvertebrate communities of a rehabilitated pond, 3 other artificial wetlands, and 13 nearby natural wetlands were investigated. Catchment rehabilitation has successfully returned some terrestrial vegetation, however the pond edge lacked a developed riparian zone. Species diversity and abundance was substantially lower (≈ 50% and 10% respectively) than in natural wetlands. Overall the macroinvertebrate communities and water quality of artificial wetlands were significantly different to the natural wetlands.
Limiting factors for crayfish and finfish in acidic coal pit lakes
World-wide, open-cut mining operations often leave pit lakes at closure. The Collie Lake District in south-west Australia has 13 pit lakes from open-cut coal extraction, with more expected. Many lakes may offer…
World-wide, open-cut mining operations often leave pit lakes at closure. The Collie Lake District in south-west Australia has 13 pit lakes from open-cut coal extraction, with more expected. Many lakes may offer beneficial end uses as fisheries habitat for biodiversity or for recreational species. However, pit lakes may have degraded water quality due to Acid and Metalliferous Drainage (AMD). A literature review and survey for marron (endemic crayfish of biodiversity and recreational value) and fin-fish (of only biodiversity value) found that crayfish were likely more limited by habitat and food availability, and fin-fish by water quality. Management of these mild acidic water bodies must address both issues if sustainable fisheries and aquatic biodiversity are desired beneficial end uses.
Modelling a pit lake district to plan for abstraction regime changes.
Mining pit lakes can form in open cut mining pits that extend below the groundwater table. Final lake surface levels generally represent the greatest risk of pit lake closure to stakeholders through…
Mining pit lakes can form in open cut mining pits that extend below the groundwater table. Final lake surface levels generally represent the greatest risk of pit lake closure to stakeholders through potential to overflow and discharge to regional surface water bodies and groundwater resources. An essential prerequisite for managing this risk is a good understanding of the lake’s water budget. Pit lakes in the Collie Coal Basin ,Western Australia form a lake district currently consisting of 13 lakes exceeding a total volume of 200 GL of acid and metalliferous (AMD) degraded water. Given long-term risks for off-site contamination, regulatory agencies often rely on geochemical predictions of future pit lake water quality to evaluate closure strategies that protect the surrounding environment. Using an existing regional groundwater model, we modelled representative pit lake types in the Collie Lake District, south-western Australia, to determine different regional groundwater abstraction regime effects on pit lake water levels. PITLAKQ was used to model three different lakes representing three distinct lake types identified by conceptual modelling: Historic (around 50 years old), New/Rehabilitated, and New/ Un-rehabilitated (both around 5–15 years old). An accurate representation of the water level-volume relationships was developed before all available data on major hydrological sinks and sources such as groundwater inflow/outflow, surface water inflow/outflow, as well as precipitation and evaporation were considered in lake water budget calculations. Although we found large deviations between measured and calculated water levels we could show reasonable limits for groundwater inflows and outflows by examining different scenarios. Reciprocally, this improved the groundwater model(s) suggesting coupling fine-scale pit lake models with groundwater models to identify the data quality for sinks and sources as an approach for other pit lake models. Our modelling scenarios showed that planned groundwater abstraction regime changes would lead to only limited changes in lake water depth compared to modelling uncertainties resulting from limited available data and the use of a regional groundwater model. This example illustrates pit lake modelling with low data availability still allows useful scenario testing under different operational scenarios.
Model-based investigations of acidity sinks and sources of a pit lake in Western Australia.
Lake Kepwari is a rehabilitated lake in the Collie Basin lignite mining area in Western Australia. The water quality of Lake Kepwari was modeled with the pit lake hydrodynamic and water quality…
Lake Kepwari is a rehabilitated lake in the Collie Basin lignite mining area in Western Australia. The water quality of Lake Kepwari was modeled with the pit lake hydrodynamic and water quality model PITLAKQ. Based on a hydrodynamically validated model, water quality scenarios were used to quantify the sensitivity of different acidity sources including groundwater exchange, surface runoff and erosion, providing new insights into the system. The technique of monthly aggregation of all sources and sinks of acidity, based on detailed model output, provided the basis for useful conclusions. Model results suggest a new focus of field investigations to improve modeling certainty and a follow-up, improved phase of modeling.
Setting restoration goals for restoring pit lakes as aquatic ecosystems: a case study from south west Australia.
Pit lakes may form when open cut mining leaves a pit void that then fills with ground and surface waters. This often replaces terrestrial ecosystems that existed prior to mining with an…
Pit lakes may form when open cut mining leaves a pit void that then fills with ground and surface waters. This often replaces terrestrial ecosystems that existed prior to mining with an aquatic ecosystem, affording an opportunity to improve regional aquatic biodiversity values through targeted aquatic restoration (McCullough and van Etten, 2011). Restoration theory provides guidance when restoring disturbed systems towards landscapes that are of regional value and relevance. But how do we identify a restoration target for a novel aquatic habitat that only exists in the new post-mining landscape? This paper presents a process of first identifying and then surveying local representative aquatic systems, to provide a direction for pit lake restoration efforts and achievement criteria for pit lake relinquishment, using a case study from a sand mining operation amongst wetlands in southwestern Australia. The company mines silica sands following mechanical removal of topsoil and then extraction of the ore from below the watertable by dredging. Assessment of wetland and riparian vegetation was achieved through the establishment and measurement of temporary monitoring transects acrossfive natural wetlands in the Kemerton area. Several more regional wetlands were also visited and observations made to supplement and validate these data. Distinct vegetation zonation was found across each wetland, although typically wetland basins were unvegetated or filled with younger woody plants with patchy distributions. Fringing riparian vegetation consisted of few species (commonly the paperbark Melaleuca rhaphiophylla and the sedgeLepidosperma longitudinale), but community composition and structure were variable between wetlands. The pattern of vegetation seen across natural wetlands was best explained by topography and soil chemistry, with low lying wetland areas more likely to experience regular flooding and accumulate organic matter and nutrients. In conclusion, where they are available, regional natural waterbodies may constitute the best valid restoration goal. Nevertheless, the goal may need to consist of a range of closure design opportunities, rather than a single target.
Sand mining restoration on the Swan Coastal Plain using topsoil – learning from monitoring of previous rehabilitation attempts.
This paper reports on the results of several years of monitoring rehabilitation at a silica sand mine on the Swan Coastal Plain, south of Perth. Mining here occurs below the regional watertable…
This paper reports on the results of several years of monitoring rehabilitation at a silica sand mine on the Swan Coastal Plain, south of Perth. Mining here occurs below the regional watertable and leaves a post-mine landscape of dredge pond voids (pit lakes) with surrounding battered slopes. The restoration we recommended was to develop the pit lakes as wetlands of regional analogue and value. Several different restoration techniques have been applied to re-vegetate pit lake slopes over many years which have enabled an evaluation of reasons for success/failure of different restoration approaches. Learning acquired clearly showed the benefits of using fresh topsoil for restoration over topsoil that has been stockpiled for several years. Most topsoil used in restoration was from seasonal wetlands and consequently restoration was most successful in the riparian zone from the edge of pit lakes to about 2 m vertically above the water table. Topsoil restored areas above this level remained poor in plant species and cover. Conversely, remedial seeding/planting proved largely unsuccessful. Permanently and seasonally flooded pit lake margins recolonised relatively quickly and successfully with native sedges and rushes. Development of rehabilitated upper slope plant communities over time was evident with loss of typical wetland species and greater growth and survivorship of upland and dampland plant species on mid to upper rehabilitated slopes. Plant communities of lower slopes showed a converse pattern of development, with a shift towards a more typical wetland composition. We believe matching topsoil to site and development of topographic profiles similar to natural wetlands of the region are the keys to optimising restoration success of sand mines with shallow water tables.
Black-stripe minnow Galaxiella nigrostriata (Shipway 1953) (Pisces: Galaxiidae), a review and discussion.
Vulnerability of organic acid tolerant wetland biota to the effects of inorganic acidification.
Aquatic toxicity of magnesium sulphate, and the influence of calcium, in low ionic strength water.
Invertebrate assemblages in dry tropical rivers challenges current monitoring programs.
Ecological dynamics of rivers in the dry tropics.
Remediation of water quality and macroinvertebrate communities in an urban artificial lake affected by acid sulphate soils.
Water resources in Australian mine pit lakes.
Bioassay toxicity assessment of mining pit lake water remediated with limestone and phosphorus.
Sustainable development of open pit mines: creating beneficial end uses for pit lakes.
Water resources in Australian mine pit lakes.
Biological remediation of low sulphate acidic pit lake waters with limestone pH neutralisation and amended nutrients.
Pit lake water in Collie is typically acidic due to Acid Mine Drainage (AMD) caused by pyrite oxidation and ferrolysis coupled with a low natural buffering capacity in surrounding geologies. These pit…
Pit lake water in Collie is typically acidic due to Acid Mine Drainage (AMD) caused by pyrite oxidation and ferrolysis coupled with a low natural buffering capacity in surrounding geologies. These pit waters have typically low sulphate, Fe and heavy metal concentrations. Nevertheless, Collie pit lakes have low biological productivity probably due to Al toxicity and low nutrient concentrations. Lake Kepwari (24 GL, max depth 65 m) is an acidic former coal open cut mine in Collie (Western Australia) that has been extensively revegetated and contoured for a water-ski park to facilitate its relinquishment back to the State. The main water treatment approach was rapid fill by river diversion but this has failed to prevent ingress of Fe2+ rich groundwater which has reduced pH to 4.8. In a manipulative mesocosm experiment using 1,200 L enclosures containing Lake Kepwari sediment and water, a control and three treatments were replicated three times. Treatment one, acidity was neutralised to pH 7 with powdered limestone, two had P concentrations maintained at eutrophic levels of approximately 20 μg L-1 (using K2HPO4), and three combined these same liming and P additions. Mesocosms were monitored for water quality (physico-chemical, nutrient and metal parameters) at 0, 77, 140, 191 and 255 days after establishment.Rainfall dilution resulted in the pH of the control increasing slowly from 4.8 to 6.5. Neutralised treatments remained circum-neutral, whilst P addition alone produced a higher final pH of >7. Sulphate concentrations fell slightly in all mesocosms by about 10 mg L-1, presumably due to SO42- reduction or secondary mineralisation. In the treatments with P additions, stimulation of NO32- reduction appeared to be the principal mechanism for increasing pH above those of the control. Addition of P had the additional benefit of reducing toxic mono-valent Al concentrations; probably by coprecipitation.This study demonstrated that P additions alone might be a useful remediation approach for the Collie pit lakes, although remediation effectiveness is enhanced with concurrent limestone neutralisation. This combined approach, in addition to ongoing alkalinity production by nitrate reduction and primary production, may facilitate these lakes remaining circumneutral over longer periods of time than single acidity neutralisation treatments alone.
More than water quality: environmental limitations to a fishery in acid pit lakes of Collie, south-west Australia.
Marron (Cherax cainii Austin) are a freshwater crayfish native to permanent waterbodies in the south-west of Western Australia. A popular aquaculture and sports species, marron are considered a potential end-use fishery species…
Marron (Cherax cainii Austin) are a freshwater crayfish native to permanent waterbodies in the south-west of Western Australia. A popular aquaculture and sports species, marron are considered a potential end-use fishery species for and have been deliberately released into several historic pit lakes of the Collie coal mining region. This study investigated what environmental factors in these acid mine drainage (AMD) contaminated pit lakes might be affecting the health and success of existing marron fisheries. Although pit lake water quality was often low (pH
Approaches to remediation of acid mine drainage water in pit lakes.
BiblioRakali: the Australian Water Rat, Hydromys chrysogaster Geoffroy, 1804 (Muridae: Hydromyinae), a subject-specific bibliography.
Field scale demonstration of the potential for sewage to remediate acidic mine waters.
Aquatic toxicity assessment across multiple scales.
Field scale demonstration of the potential for sewage to remediate acidic mine waters.
Opportunities for sustainable mining pit lakes in Australia.
In-situ coal pit lake treatment of acidity when sulfate concentrations are low
Pit lakes (abandoned flooded mine pits) represent a potentially valuable resource to mining companies, the environment and community, if appropriate water quality can be achieved. However, the water is often of low…
Pit lakes (abandoned flooded mine pits) represent a potentially valuable resource to mining companies, the environment and community, if appropriate water quality can be achieved. However, the water is often of low pH with high dissolved metal concentrations. In Western Australia coal pit lakes are acidic (pH 3–5) but with low concentrations of sulfate and metals. Low sulfate concentrations prevent microbial sulfate reduction from reducing acidity in these lakes. However, stimulation of primary production and associated alkalinity generating processes may provide a cost effective and sustainable solution to the acidity problems. A field-scale experiment (with control) involving the treatment of in-situ macrocosms (~600 m3) in a small south-west, Western Australian coal mine lake with municipal mulch and phosphorus additions to enhance primary production was undertaken between June 2003 and June 2004. One macrocosm was treated with P additions, another with mulch, a third with mulch and P, and the untreated lake formed the control. Physico-chemical and algal (chlorophyll a) sampling of the macrocosms and lake occurred at monthly intervals. The decomposition of mulch reduced nitrogen concentrations in the macrocosms to very low levels and necessitated supplementation with urea fertilizer. Phosphorus concentrations dropped rapidly after addition as it became bound to iron, organic matter and sediment. Although there was virtually no difference between treatments and control for most physico-chemical parameters measured (including pH), a PCA of the data showed that the addition of mulch sent the macrocosms on a different trajectory to the control. This difference was reflected in observations of increased abundance and diversity of biofilms and macroinvertebrates within the treated macrocosms. In conclusion, the addition of mulch and phosphorus alone was not sufficient to increase the pH of Collie mine lakes, although it does provide a number of benefits for biota in the water. We therefore recommend that liming be used to increase pH, followed by organic matter and nutrient additions to stimulate primary production.
Pit lake sustainability; what is it, and how do I get it?
Due to operational and regulatory practicalities, pit lakes will continue to be legacies of many open-cut mining lease relinquishments. Unplanned or inappropriate management of these significant geographical features may lead to a…
Due to operational and regulatory practicalities, pit lakes will continue to be legacies of many open-cut mining lease relinquishments. Unplanned or inappropriate management of these significant geographical features may lead to a short-term liability to all stakeholders during mining operations, or to ongoing liability to the local community and environment following lease relinquishment. However, the potential for pit lakes to provide benefit to companies, communities and the environment is frequently unrecognised and yet may be a vital contribution to the sustainability of the open-cut mining industry. Improved remediation technologies are offering more avenues for pit lake end use than ever before, at the same time mining companies, local communities and regulatory authorities are also becoming more aware of the benefit these water resources have to offer. Sustainable pit lake management aims to better minimise short and long term pit lake liabilities, and yet also to maximise short and long term pit lake opportunities as well.
Microcosm testing of municipal sewage and green waste for full-scale remediation of an acid coal pit lake, in semi-arid tropical Australia.
Pit lakes (abandoned flooded mine pits) represent a potentially valuable water resource to mining companies, the environment and regional communities across arid inland Australia. However, the water is often of low pH…
Pit lakes (abandoned flooded mine pits) represent a potentially valuable water resource to mining companies, the environment and regional communities across arid inland Australia. However, the water is often of low pH with high dissolved metal concentrations. The addition of organic matter to the pit lakes to enhance microbial sulfate reduction is potentially a cost effective and sustainable remediation strategy for these acid waters. However, the cost and availability of sufficient quantities of suitable organic substrates is typically limiting in these remote regions. Nevertheless, small quantities of sewage and green waste (organic garden waste) are often available in these areas from the regional towns which support the mines. This paper reports on preliminary microcosm laboratory experiments in preparation for the treatment of an acid (pH 2.2) coal mine pit lake in semi-arid tropical, inland north Queensland, Australia with municipal treated sewage and green waste. A laboratory experiment using microcosms (acrylic tubes) containing acid pit lake water and sediment were treated as follows; controls (untreated), sewage, green waste and sewage and green waste. The pH increased to a maximum of 5.5 in 145 days in the green waste and sewage treatment, with notable decreases of iron, aluminium and toxic heavy metals. Our results indicated that the green waste was a key component in alkalinity production and heavy metal removal.
Improving trapping success for rare species by targeting habitat types using remote sensed data: A case study of the heath mouse (Pseudomys shortridgei) in Western Australia.
An ecological risk assessment of irrigation in the Ord River catchment, a highly disturbed and poorly understood area in the wet-dry tropics of Australia.
An ecological risk assessment of the impact of irrigation on the ecological values of the Ord River was undertaken. The Ord River is located in the wet-dry tropics of Western Australia and…
An ecological risk assessment of the impact of irrigation on the ecological values of the Ord River was undertaken. The Ord River is located in the wet-dry tropics of Western Australia and has been highly disturbed by grazing and irrigation developments. The construction of two dams has changed the river from being seasonally dry to now having permanent flows downstream of the dams. The Ord River Irrigation Area (15,000 Ha) is fed by waters from the Kununurra Diversion Dam. Approximately 50% of the water is returned to the river downstream mixed with drainage from the farms. Comparatively little is known of the ecology of the Ord River, although recent research efforts are starting to address this. The risk assessment focused on the area between the Ord River Dam and upper boundary of the estuary. A mass balance of nutrients, sediments and water for the Lower Ord River clearly demonstrated that irrigation drainage was the principal source of nutrients. The low knowledge base for the system resulted in a qualitative risk assessment largely guided by expert opinion. Priority ecological consequences were identified as loss of biodiversity and biota kills (primarily through biocides), weeds and lastly algal blooms and channel infilling. The priorities were used to guide further research. Low stakeholder involvement in the assessment was believed to undermine the sense of ownership of the process. A low knowledge base limited the assessment to being purely qualitative and dominated by expert opinion. Further research should allow a second iteration of the process to produce more useful outcomes and some quantitative risk assessments.
Sustainable Futures for Australia’s Tropical Rivers: A strategy for developing research directions for Australia’s tropical river systems
A framework for assessing & managing ecological risks associated with irrigation enterprises.
Preliminary materials budget (nutrients and sediments) in the Ord River: Implications for current and proposed irrigation areas.
An ecological risk assessment (ERA) was undertaken of the impacts of irrigation return on the Lower Ord River catchment. A materials budget (mass balance) for nutrients and sediment was prepared for the…
An ecological risk assessment (ERA) was undertaken of the impacts of irrigation return on the Lower Ord River catchment. A materials budget (mass balance) for nutrients and sediment was prepared for the ERA process to establish the relative contribution of irrigation return to the catchment. The Ord River Dam (forming Lake Argyle) effectively splits the River catchment into two sections. The lower section ranges from downstream of the Ord River Dam to near Carlton Crossing (the upper extent of the salt wedge). This section receives irrigation return from the Ivanhoe Plains and Packsaddle Plains areas and will be the focus of this study. In addition, runoff from rangelands enters through several creeks and the Dunham River. All relevant water quality and flow data from the irrigation area or River were used to prepare the budgets. A high degree of interpolation and assumption was necessary due to the limited data availability, which limits the accuracy of the final budgets. Despite this, it appears that irrigation return water is a substantial contributor of Phosphorus (P) and nitrate/nitrite to the Lower Ord River. In comparison with rangelands, the irrigation area produced significantly higher loads of P, nitrate/nitrite and suspended sediment per unit area and in total. The return water produced a detectable increase in river P and nitrate/nitrite concentrations. This paper will discuss the impact of these results on current planning for the development of Ord Stage II and in moves towards best management practices within the current irrigation area.
Wilson Park Wetlands: Development of a strategic rehabilitation plan.
Monitoring Program of the Cities of Joondalup and Wanneroo: A Review.
The effect of toxic Microcystis aeruginosa on four different populations of Daphnia.
Predicting wetland response to nutrient enrichment: modelling temperature, algal blooms and nuisance midge swarms.
Phosphorus removal from stormwater by biofilms (periphyton) in constructed wetland systems, Western Australia.
Designing constructed wetlands for removal of filterable reactive P from stormwater/groundwater in areas of high water tables in a Mediterranean climate.
The spatial and temporal nature of changing acidity in a wetland: The case of Lake Jandabup on the Swan Coastal Plain, Western Australia
Removing filterable reactive P from highly coloured stormwater using constructed wetlands
Grappling with Filterable reactive P removal from highly coloured stormwater using constructed wetlands.
Bacteria and biofilm (periphyton) in constructed wetlands treating highly coloured nutrient enriched stormwater.
Nuisance midge (Chironomidae) plagues in urban wetlands: A catalyst for improved catchment management.
Perth has over 450 shallow urban lakes of which many have problems with nuisance midge plagues. Midges (Chironomidae) have aquatic larvae with non-biting adults emerging from the lake in the millions during…
Perth has over 450 shallow urban lakes of which many have problems with nuisance midge plagues. Midges (Chironomidae) have aquatic larvae with non-biting adults emerging from the lake in the millions during a plague. The sheer numbers severely impact on the quality of life for nearby residents. Lake Joondalup is a degraded urban lake that has experienced midge plagues over many years. Pesticide treatment is the only short-term solution currently available, however this is environmentally undesirable. Midge plagues galvanise, local communities, Politicians, Councilors and Agencies into dealing with the fundamental problem, as improved catchment management is the only long-term solution. Recent events at Lake Joondalup will be used as a case study of how plagues can result in improved catchment management.
Designing constructed wetlands for removal of filterable reactive P from stormwater/groundwater in areas of high water tables in a Mediterranean climate.
Using an environmental risk assessment approach in determining priorities related to the impact of irrigation return on river environments. A case study fo the Ord River Irrigation Area.
The National Program for Irrigation Research and Development has established a research project to develop and test a generic framework for assessing the ecological risks associated with irrigation return. Three irrigation areas…
The National Program for Irrigation Research and Development has established a research project to develop and test a generic framework for assessing the ecological risks associated with irrigation return. Three irrigation areas are involved in the study, Goulburn-Broken, Fitzroy (Qld) and the Ord River. This paper reports on the Ord River project. The aim of the study was to identify likely ecological risks associated with irrigation systems within the Lower Ord River catchment and rank the risks based on the use of conceptual models. The Ord River catchment under consideration was bounded by the Ord River Dam (Lake Argyle) and the upper extent of the salt wedge at Carlton Crossing. Despite limited availability of flow and water quality data for the irrigation area or the Ord River, a mass balance model was produced and general trends observed. A key finding was that irrigation return water was a substantial contributor of Phosphorus (P) and nitrate/nitrite to the Lower Ord River. Initial stakeholder meetings held in Perth and Kununurra identified weeds, channel infilling, biota kills, algal blooms and loss of biodiversity as key ecological consequences of irrigation. Two simple conceptual models were then produced. One shows the role water quantity plays in the risk of ecological consequences occurring. The other model takes a different approach and identifies what factors biota require for their continued health and looks at the risks irrigation poses to those factors. Risks were assigned and then averaged to produce a risk assessment matrix. Subsequent stakeholder meetings ranked the consequences in terms of priority, with biota kills and loss of biodiversity first, followed by weeds. Algal blooms and channel infilling were seen as being of least importance or not substantially impacted by irrigation. Plans for ongoing project work and how results from this study contribute to other community and research activities in the Ord will be discussed.
Removing filterable reactive P from highly coloured stormwater using constructed wetlands.
Assessment of the Ecological Risk associated with Irrigation in the Ord River catchment.
Seasonal dynamics of plankton communities and water chemistry in a eutrophic wetland (Lake Monger, Western Australia): Implications for biomanipulation.
Are Australian wetlands less productive than Northern Hemisphere wetlands under the same nutrient concentrations?
Controlling midges at Lake Joondalup and Lake Goollelal.
Midge Sampling of the Northern Mary Carroll Park wetland
Bacterial strategies for increasing pH in acidic voids. In Final void water quality enhancement: Stage III
Final Void Water Quality Enhancement Stage III: Final Report.
Modification of a Bogarov Tray to allow In Situ subsampling of preserved macroinvertebrate and zooplankton samples.
Joondalup Campus Lake.
Final Void Water Quality Enhancement Stage II.
A short-term assessment of point source pollution in the M1 irrigation supply channel with notes on agricultural discharge into the lower Ord River
Biomonitoring of the Mary Carroll Park wetlands to assess their biological health.
Can artificially generated gilvin (g440 m-1, Glebstoffe) be used as a tool for lake restoration,
Historical associations between European peoples and wetlands and rivers in the Perth to Bunbury Region of Western Australia.
Final Void Water Quality Enhancement Stage I.
A preliminary study of the potential for recycling and waste minimisation at Edith Cowan University.
Options for improving water quality at Lake Monger.
The fate of lead from duckshooting and road runoff in three Western Australian wetlands.
The use of Aluminium sulphate to control algal blooms and chironomids in Jackadder Lake, Western Australia,
The Blackwood River Classic 250 (1990)
A feasibility study of the rearing and breeding of Midge Larvae (Chironomidae) for use as fish food.
Bioremediation of acidic and metalliferous drainage (AMD) through organic carbon amendment by municipal sewage and green waste.
Restoring pit lakes: factoring in the biology.
Pit lakes: benefit or bane to companies, communities and the environment?
Due to operational and regulatory practicalities, pit lakes will continue to be common legacies of mining lease relinquishments. Unplanned or inappropriate management of these significant geographical features may lead to a short-term…
Due to operational and regulatory practicalities, pit lakes will continue to be common legacies of mining lease relinquishments. Unplanned or inappropriate management of these significant geographical features may lead to a short-term liability to all stakeholders during mining operations, or to ongoing liability to the local community and environment following lease relinquishment. Frequently unrecognised is the potential for pit lakes to provide benefit to companies, communities and the environment. Sustainable pit lake management aims to better minimise short and long term pit lake liabilities, and maximise short and long term pit lake opportunities as well. Improved remediation technologies are offering more avenues for pit lakes resource exploitation than ever before, at the same time that mining companies, local communities and regulatory authorities are also more aware than ever of the benefit of these water resources.