A comparative evaluation of conceptual rainfall–runoff models for a catchment in Victoria Australia using eWater Source

Hydrological modelling at a catchment scale was conducted to investigate the impact of climate change and land-use change individually and in combination with the available streamflow in the Painkalac catchment using an eWater Source hydrological model. This study compares the performance of three inbuilt conceptual models within eWater Source, such as the Australian water balance model (AWBM), Sacramento and GR4J for streamflow simulation. The three-model performance was predicted by bivariate statistics (Nash–Sutcliff efficiency) and univariate (mean, standard deviation) to evaluate the efficiency of model runoff predictions. Potential evapotranspiration (PET) data, daily rainfall data and observed streamflow measured from this catchment are the major inputs to these models. These models were calibrated and validated using eight objective functions while further comparisons of these models were made using objective functions of a Nash–Sutcliffe efficiency (NSE) log daily and an NSE log daily bias penalty. The observed streamflow data were split into three sections. Two-thirds of the data were used for calibration while the remaining one-third of the data was used for validation of the model. Based on the results, it was observed that the performance of the GR4J model is more suitable for the Painkalac catchment in respect of prediction and computational efficiency compared to the Sacramento and AWBM models. Further, the impact of climate change, land-use change and combined scenarios (land-use and climate change) were evaluated using the GR4J model. The results of this study suggest that the higher climate change for the year 2065 will result in approximately 45.67% less streamflow in the reservoir. In addition, the land-use change resulted in approximately 42.26% less flow while combined land-use and higher climate change will produce 48.06% less streamflow compared to the observed flow under the existing conditions

Development of a framework for the valuation of Eco- System Services of Green Infrastructure

With the rapid urban growth and development, the quality of green space available is consequently been degrading. Furthermore, many land characteristics have been altered such that the whole water cycle has been significantly changed. Some of the considerable adverse effects occur by these changes include the increase of runoff which can lead to flooding and the poor quality of receiving waters. Therefore, to improve the quality of the prevailing surface conditions whilst managing the stormwater, Green Infrastructure (GI) have been introduced which is becoming one of the promising practices of restoring the natural environment across many countries around the world. The term GI in the literature is commonly referred as Low Impact Development (LID), Best Management Practices (BMP), Sustainable Urban Drainage Systems (SUSD), Water Sensitive Urban Design (WSUD) and Low Impact Urban Design and Development (LIUDD) in different contexts (Eliot and Trowsdale, 2006). GI in broader terms can be defined as an "interconnected network of green space that conserves natural systems and provides assorted benefits to human populations" (McMahon and Benedict, 2006). GI can be grouped into two main categories structural and non-structural. The former include green roofs, rainwater tanks, wetlands, bio swales, pervious pavement, stormwater detention systems, planter boxes, cisterns, rain barrels and downspout disconnection amongst others. Nonstructural GI is designing the buildings or roads to minimize the imperviousness, improvement of the infiltration ability of soils by amending the properties and improving the vegetation of specific site or region. (Eliot and Trowsdale, 2006