Shaun Kim

Flood inundation modelling

This paper reviews state-of-the-art empirical, hydrodynamic and simple conceptual models for determining flood inundation. It explores their advantages and limitations, highlights the most recent advances and discusses future directions. It addresses how uncertainty is analysed in this field with the various approaches and identifies opportunities for handling it better. The aim is to inform scientists new to the field, and help emergency response agencies, water resources managers, insurance companies and other decision makers keep up-to-date with the latest developments. Guidance is provided for selecting the most suitable method/model for solving practical flood related problems, taking into account the specific outputs required for the modelling purpose, the data available and computational demands. Multi-model, multi-discipline approaches are recommended in order to further advance this research field. This paper reviews state-of-the-art flood inundation models.It explores their advantages and limitations.It highlights the most recent advances and discusses future directions.It addresses how uncertainty is analysed and identifies opportunities for handling it better.

A new river system modelling tool for sustainable operational management of water resources

The eWater Cooperative Research Centre of Australia has developed a river system modelling software called eWater Source that can be used to assist water managers and river operators in planning and operating river systems. It has been designed and developed within Australia to provide a consistent approach to underpin a wide range of water planning and management purposes. The software provides tools for the prediction and quantification of water from catchments to the end of a river system by integrating continuous rainfall-runoff and river system models. It includes three modes (catchment runoff, river management and river operations) for different applications. This paper introduces the operations mode of Source and compares its functionality with the existing tools used for daily river operations in Australia, with the Goulburn River as the case study. A 5-year period is used to compare modelled and observed results. Forecasts from Source and the existing tools are compared to observations over 7-day forecast periods that include an environmental water release. Source provided acceptable or improved results and required less user input than the existing method. Source provides a flexible software tool in which various forecast models can be incorporated. The application has demonstrated the potential of Source to provide an improvement on the existing river operations models in Australia at both the daily and seasonal time steps.

An automated multi-step calibration procedure for a river system model

Predicted climate change impact on future water availability in the Murray-Darling Basin (MDB) has highlighted the need for a whole of basin model that incorporates various physical and management characteristics for planning and operational purposes. Modelling platforms such as eWater Source Integrated Modelling System (Source) offer a useful framework in this regard, but at present lack automated calibration techniques to parameterise river system models.This paper presents an automated river system calibration procedure which is robust, repeatable, transparent and systematic. The procedure allows for river network calibration (as opposed to isolated reach by reach calibration), since this has more utility for basin planning and prediction. The calibration procedure routs upstream flow, estimates ungauged inputs via rainfall-runoff (RR) models, and estimates flow based split (distributary) functions and loss functions in complex river systems.This procedure was tested in the Northern Murray-Darling Basin (MDB) and results from the Border Rivers catchment are presented. The results from the Border Rivers case study demonstrate the applicability of the procedure with median calibration and evaluation NSE values of 0.88 and 0.79, respectively. The use of this procedure in the Border Rivers region has highlighted the likelihood of changing stream channel connections at higher flows in the lower reaches of the river network. A simple, robust auto-calibration/simulation procedure for river systems is presented.The model shows good predictive ability in the test catchment.The procedure has utility for detecting structural problems in conceptual model.

Examining Two Different Approaches to Modelling Management and Operation Rules in a Single River System Model

Different water agencies use different modeling tools for water resources planning and management. For example, different jurisdictions in Australia use a variety of river system models and these models vary considerably in approach and assumptions, including different time steps (monthly and daily), flow routing (different types of routing and no routing), ordering solution (optimization and heuristic) and representation of management and operational rules. These fundamental differences in approach make it difficult to integrate existing models of connected river systems at a basin scale. A collaborative joint venture (the eWater CRC) between research, industry and government partners has recently developed an integrated river system modelling tool called “eWater Source” to improve on the existing river system models in Australia. One of the major advances in Source is the implementation of two decision algorithms, heuristic and NetLP approaches, for water distribution modelling in the same modelling platform. This paper describes the implementation of heuristic and NetLP approaches for water delivery under management and operations rules in Source, and compares the performance of the two approaches through a case study in the Goulburn-Broken-Campaspe-Loddon (GBCL) river system in south-eastern Australia. The key performance measures used to compare the approaches include the efficiency and equity of water delivery to water users, impacts on the reliability of supply, agreement with storage operating targets, and model application run time. The results demonstrate that the heuristic approach implemented in Source can replicate the performance of the NetLP approach for a model of reasonable complexity. This is important because the run times of models with heuristic approaches are shorter than models with NetLP approaches, so this will allow more complexity to be represented than was previously practical in equivalent NetLP applications. Agreement between jurisdictions to move to the single river system modelling platform will contribute to overcoming the problems faced by river managers in Australia in transboundary river basins.

An integrated modelling framework for building a daily river system model for the Murray–Darling Basin, Australia

ABSTRACT The Murray–Darling Basin (MDB) is home to two million people and accounts for about 60% of the water use in Australia. The MDB river system is a highly complex and mostly regulated system covering four states (Queensland, New South Wales, Victoria and South Australia) and one territory. Different jurisdictions used different models for water resources and planning. A number of difficulties were faced in combining those models (of different characteristics and spatio-temporal resolutions) for basin-wide water resources planning. In order to overcome those difficulties and enhance the consistency and transparency in modelling outcomes across multiple jurisdictions, this paper proposes a homogeneous agent-based integrated modelling framework. Each agent is used to represent a region in the MDB. Its behaviour is modelled by a newly built Source river model. The interactions between agents are modelled based on the hydrological connectivity in the real-world river systems. A three-level parallel computing mechanism is developed to significantly increase its efficiency and reduce computational time. Due to its homogeneousness, it largely reduces the system complexity and makes modelling results consistent, explainable and comparable. By nature, the agent-based system is flexible and portable. All these unique features of the platform suit the modelling needs of various states to federal government water resource management agencies.

A Method for comprehensively Assessing Economic Trade-Offs of New Irrigation Developments

To meet the anticipated increase in global demand for food and fibre products, large areas of land around the world are being cleared and infrastructure constructed to enable irrigation, referred to herein as ‘greenfield irrigation’. One of the challenges in assessing the profitability of a greenfield irrigation development is understanding the impact of variability in climate and water availability and the trade-offs with scheme size, cost and the sensitivity of crop yield to water stress. For example, is it more profitable to irrigate a small area of land most years or a large area once every few years? And, is it more profitable to partially or fully water the crop? This paper presents a new method for efficiently linking a river system model and an agricultural production model to explore the financial trade-offs of different management choices, thereby enabling the optimal scheme area and most appropriate level of farmer risk to be identified. The method is demonstrated for a hypothetical but plausible greenfield irrigation development based around a large dam in the Flinders catchment, northern Australia. It was found that a dam and irrigation development paid for and operated by the same entity is not, under the conditions examined in this analysis, economically sustainable. The method could also be used to explore the impact of different management strategies on the agricultural production and profitability of existing irrigation schemes within a whole of river system context.