Forest Fire Occurrence and Modeling in Southeastern Australia

Forest fire is one of the major environmental disturbances for the Australian continent. Identification of occurrence patterns of large fires, fire mapping, determination of fire spreading mechanisms, and fire effect modeling are some of the best measures to plan and mitigate fire effects. This chapter describes fire occurrence in New South Wales (Australia), the Australian National Bushfire Model Project (ANBMP), fire propagation modeling methods, the McArthur’s model and current forest fire modeling approaches in the state of New South Wales of Australia. Among the established fire models, PHOENIX Rapidfire predicts fire spread and facilitates loss and damage assessments as the model considers many environmental and social variables. Two fire spread models, SPARK and Amicus, have been developed and facilitated fire spread mapping and modeling in Australia

Uncertainty in streamflow rating curves : methods, controls and consequences

Discharge time series' are one of the core data sets used in hydrological investigations. Errors in the data mainly occur through uncertainty in gauging (measurement uncertainty) and uncertainty in determination of the stage–discharge relationship (rating curve uncertainty). Thirty-six flow gauges from the Namoi River catchment, Australia, were examined to explore how rating curve uncertainty affects gauge reliability and uncertainty of observed flow records. The analysis focused on the deviations in gaugings from the rating curves because standard (statistical) uncertainty methods could not be applied. Deviations of greater/lesser than 10% were considered significant to allow for a measurement uncertainty threshold of 10%, determined from quality coding of gaugings and operational procedures. The deviations in gaugings were compared against various factors to examine trends and identify major controls, including stage height, date, month, rating table, gauging frequency and quality, catchment area and type of control. The analysis gave important insights into data quality and the reliability of each gauge, which had previously not been recognized. These included identification of more/less reliable periods of record, which varied widely between gauges, and identification of more/less reliable parts of the hydrograph. Most gauges showed significant deviations at low stages, affecting the determination of low flows. This was independent of the type of gauge control, with many gauges experiencing problems in the stability of the rating curve, likely as a result of sediment flux. The deviations in gaugings also have widespread application in modelling, for example, informing suitable calibration periods and defining error distributions. This paper demonstrates the value and importance of undertaking qualitative analyses of observed records.18 page(s

Evidence of Late Cenozoic uplift and climate change in the stratigraphy of the Macquarie River Valley, New South Wales

The stratigraphy of the alluvial sediments filling the Macquarie River valley, New South Wales, was investigated to test models of landscape evolution of the rifted margin Eastern Highlands of Australia. In the neighbouring Lachlan River valley, the stratigraphy of Neogene sediments has been incorporated into a model proposing denudation and episodic passive (denudational isostatic) uplift of the highlands throughout the Neogene. In this study, we aimed to test the regional extent of this model and the influence of sediment supply on the stratigraphic record and its interpretation. The sediments of the Macquarie River valley show three major changes in the depositional regime. First, erosion of the valley basement in the Late Miocene was followed by (and possibly synchronous with) deposition of a basal clay and sand unit in the Late Miocene. Second, the valley was filled with a wedge of sediment containing abundant gravel and sand in the Pliocene; and third, the older gravelly unit was eroded and reworked in the Quaternary, and a sandy clay unit, which forms the modern floodplain, was deposited. Deformation of the Middle Miocene basalt-filled valley provides good evidence for substantial uplift of the highlands in the Middle-Late Miocene, synchronous with or shortly after widespread volcanism, but continuing no later than the Late Miocene. The Pleistocene incision is best accounted for by climate change to drier conditions, triggering a sediment-starved response by the Macquarie River, rather than further uplift. While valley incision and subsequent infilling can be viewed as a response to tectonism, the internal sedimentology and stratigraphy of the sediments appears to respond to fluctuations in sediment supply brought about by extrinsic climate change and intrinsic catchment lithology. The first-order tectonic events are not synchronous with uplift in the Lachlan valley and are restricted to relatively local spatial scales. However, the secondary climatic forcing has a broader regional expression.18 page(s

Geomorphology of upland swamps

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Reconstructing contemporary erosion of upland swamps in a fire prone forested landscape, southeastern Australia

Upland swamps on the Woronora Plateau, located to the south of Sydney, are important sediment storage features. Many of the swamps are situated within water supply catchments for Sydney and Wollongong thereby acting as a filter and buffer to produce clean, constant flows. The recent erosion of several swamps has resulted in the release of sediments and nutrients into reservoirs downstream raising water quality and quantity concerns within managing agencies. Analysis of aerial photographs dating back to the late 1940’s and covering three eroding swamps, revealed a common sequence of erosion, commencing with the formation of discontinuous scour pools cut into the swamp sediments, followed by the gradual linking of the pools (starting at the downstream end) through knickpoint retreat, leading to the eventual gully erosion through the swamp. The gully erosion results in the removal of a small slice of the swamp, rather than the whole scale removal of sediments, whereas associated impacts on swamp hydrology and vegetation are more widespread. The potential triggers of the scour pools and gully erosion are considered including wildfires, severe rainfall events and human disturbance which occurred over the same period as the air photo record (i.e. 1940’s to the present). Analysis of sediments exposed within the gully walls of the swamps revealed previous episodes of scour and gully erosion indicating that cut and fill processes are an important part of long-term swamp development and evolution over thousands of years. This is reinforced by the recent episode of erosion which shows that despite extensive disturbance and severe climatic conditions (e.g. drought, wildfires) the swamps continue to remain as resilient long-lived features in the landscape.1 page(s

Development and destruction of Holocene headwater swamps in southeastern Australia

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Evaluating the effects of fire and other catastrophic events on sediment and nutrient transfer within SCA special areas

Sydney Catchment Authority and Macquarie University collaborative research project. The primary outputs from this project are several technical reports written specifically for the SCA: Technical Report 1: Review of the hazards, triggers, mechanisms and frequency–magnitude of extreme erosion–sedimentation events in southeastern Australia with emphasis on post-fire erosion. Technical Report 2: Upland swamp development and erosion on the Woronora Plateau during the Holocene. Technical Report 3: Triggers of extreme erosion-sedimentation events on hillslopes in the Nattai catchment. Technical Report 4: Research outcomes and implications for the Sydney Catchment Authority

Upland swamp development and erosion on the Woronora Plateau during the Holocene

Technical Report 2 of the Sydney Catchment Authority and Macquarie University collaborative research project: Evaluating the effects of fire and other catastrophic events on sediment and nutrient transfer within SCA special areas. Other associated reports: Technical Report 1: Review of the hazards, triggers, mechanisms and frequency–magnitude of extreme erosion–sedimentation events in southeastern Australia with emphasis on post-fire erosion. Technical Report 3: Triggers of extreme erosion-sedimentation events on hillslopes in the Nattai catchment. Technical Report 4: Research outcomes and implications for the Sydney Catchment Authority

Research outcomes and implications for the Sydney Catchment Authority

Technical Report 4 of the Sydney Catchment Authority and Macquarie University collaborative research project: Evaluating the effects of fire and other catastrophic events on sediment and nutrient transfer within SCA special areas. Other associated reports: Technical Report 1: Review of the hazards, triggers, mechanisms and frequency–magnitude of extreme erosion–sedimentation events in southeastern Australia with emphasis on post-fire erosion. Technical Report 2: Upland swamp development and erosion on the Woronora Plateau during the Holocene. Technical Report 3: Triggers of extreme erosion-sedimentation events on hillslopes in the Nattai catchment

Post Mid-Miocene evolution of the Macquarie River Valley, New South Wales

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