@mastersthesis {bnh-5690, title = {Approaches for investigating wildfire impacts on catchment hydrology}, volume = {Doctor of Philosophy}, year = {2018}, month = {10/2018}, school = {The University of Sydney}, address = {Sydney}, abstract = {

Wildfire has serious impacts on the hydrological cycle and water quality of forested catchments. Forested catchments are commonly used as an important source of drinking water supply in Australia and internationally. Monitoring short-term and long-term post-wildfire catchment hydrology (water quantity and quality) change is important for catchment management. Past studies are limited by data availability and method used. In this thesis, we firstly used empirical (linear mixed model and k-mean clustering) and physical-based hydrological model {\textendash} Soil and Water Assessment Tool (SWAT) to detect the effect of wildfire on forested catchment hydrology and then built scenarios using physical-based model to investigate the cause of the catchment hydrology change and identify the wildfire sensitive areas in catchments for catchment protection. The case study used here is the 2001/2002 Sydney wildfire, 10 years of pre-wildfire and 10 years of post-wildfire water quantity and quality data were collected by WaterNSW and used in this study. We have successfully used linear mixed model and SWAT to detect the wildfire effect on catchment hydrology in the thesis. As a result, the empirical model observed a long-term (5 - 10 years) post-wildfire water quality change; this change is more considerable during post-wildfire event period. The result from physical-based hydrological models also indicated a long-term change in total suspended sediments concentration during post-wildfire period. In addition to the change detected. Our scenario in physical-based models also observed that post-wildfire soil carbon change has limited effect on catchment hydrology and vegetation change is the main cause of post-wildfire catchment hydrological change. Out models also suggested that sub-catchments with higher slope increases, shorter slope, and smaller soil top layer bulk density, clay, and carbon content, are the most wildfire sensitive areas and should be protected the most.

}, keywords = {soil and water assessment tool, soil carbon, TSS, water quality, Wildfire}, url = {http://hdl.handle.net/2123/20565}, author = {Mengran Yu} } @mastersthesis {bnh-6159, title = {The impact of bushfires on water quality}, volume = {Doctor of Philosophy }, year = {2018}, month = {01/2018}, school = {RMIT}, type = {Doctorate}, address = {Melbourne}, abstract = {

Population growth in urban areas leads to a higher demand in water use. Quality of water is an important factor not only from an aesthetic view, but also for ecological health purposes.

This paper presented research that is designed to develop a spatial approach to support the planning of the water quality in the areas subjected to bushfires, using a case study from state of Victoria. In particular, this research involved the implementation of a hydrological model in order to predict the river water quality, to assist in the decision-making process. The impact of bushfires on water quality can be highly variable for the most of the individual water quality parametres. This variability is caused by a number of landscape influences and climatic factors, most notably rainfall. High magnitude and intense rainfall events soon after fire generate the largest impacts on water quality and sometimes trigger extreme erosion events.

There are many important water quality parameters that must be taken into account when the water is delivered to the population. For some of the water quality parameters there is very little information available, which makes it difficult to draw conclusions about bushfire impacts. The monitoring campaigns are very expensive, and better options are the modeling tools.
The model used in this research is eWater, a conceptual, semi-distributed model, which applies the flow accumulation principles. eWater Source - Australia{\textquoteright}s National Hydrological Modelling Platform (NHMP) {\textendash} is developed by eWater CRC, Australia. It is designed to simulate all aspects of water resource systems to support integrated planning, operations and governance from urban, catchment to river basin scales including human and ecological influences.

The catchment analyzed can be divided into sub-catchments and functional units. The model integrates rainfall runoff, constituent generation and filter models, which are parameterized. The user must find the best set of parameters that is suitable for that catchment. After calibration and validation, the model can be used in the same catchment for any period of time, and it will be able to predict the pollution levels in the catchment, with a good accuracy. Also, a user can follow the same steps, to calibrate the model for any other catchment. This method is time consuming, but it doesn{\textquoteright}t require many input data.The fires and the rain are classified in 3 classes each. Then, the landuse, the burnt areas and the areas with rain are combined and parameterized separately.

The outputs from the developed model are good correlated with the measured data, and show higher concentrations of suspended sediment and nutrients after bushfire followed by rain. To improve the model performance, the measured water quality data must be daily data with a better accuracy.

}, keywords = {bushfires, modeling, water pollution, water quality}, url = {https://researchbank.rmit.edu.au/view/rmit:162351}, author = {graducan} }