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HARC is pleased to welcome Robert Keessen to the team. Robert is a leader in urban water planning with 25-years’ experience as a consultant and 15 years as a senior manager at Sydney Water. Robert is well known in the industry and recognised as a forward-thinker and someone who strives to drive innovation to meet contemporary standards.

At Sydney Water he led planning teams in the areas of environmental management, wastewater planning, corporate planning and innovation in water cycle management. His work is underpinned and strengthened by his strong communications skills and his strategic approach to engagement. His qualifications in business administration and utility experience provide a high level of business acumen. This supports his ability to provide insight and advice for decision-makers seeking strategic advice on asset and business planning in the public and private sectors and support for those engaged in organisational change.

Robert’s expertise complements and builds on HARC’s urban water service offering. It spans integrated Water Cycle Planning, water, wastewater and recycled water asset and service planning, business case development and change management. Across his career, Robert has utilised his communication and engagement skills to understand and develop solutions to meet client objectives. These objectives may be in terms of commerciality, sustainability, risk and resilience, customer service standards or community expectations.

We warmly welcome Robert to the team.

Ella Guthrie has joined HARC’s Melbourne office, as our newest recruit.

Ella completed her Engineering studies at @Melbourne University with a focus on hydrology and water resources, exploring the environmental and technical aspects of river management. As part of her studies, Ella travelled to Colorado in the United States to learn about river management in Central US.

Ella recently completed a Masters of Engineering, working with Engineers Without Borders as part of a team developing appropriate technologies to improve indoor air quality and ventilation for houses in remote areas of Nepal.

Prior to joining HARC, Ella worked in the renewable energy sector, supporting the planning and development of wind and solar projects across Australia

Welcome Ella, we are delighted to have you on board.

We are pleased to announce that Alessandra Razera has joined the HARC team, in our Parramatta office. Ale has 13 years experience in the water industry assessing water supply and sewerage systems and developing strategic water solutions for Local Water Utilities in NSW.

Ale has prepared and managed several best-practice management projects including Integrated Water Cycle Management strategies, demand management plans, drought management plans, development servicing plans and audit reports, strategic business plans and financial plans. Most of these projects have required community consultation and workshops with councils and other stakeholders.

Ale has expertise in demand management, including options modelling. She has experience developing customized end-use and demand management models and has done so across NSW, including for the complex Riverina Water County Council water supply schemes as well as CENTROC councils.

Ale has participated in the review and consultation process of the Developer Charges Guidelines and Strategic Business Plan guidelines and Financial Plan manuals facilitated by the Department of Industry Water. Her knowledge about these plans has added great value to the guidelines and the manual.

Her extensive knowledge and experience in best-practice management frameworks allowed her to coach and train staff in the development of Integrated Water Cycle Management Strategies, Demand Management Plans and Strategic Business Plans.

We warmly welcome Ale to the team.

As an industry leader in dam risk and safety, HARC is excited to be presenting at the 2019 NZSOLD | ANCOLD conference in Auckland this week.

We have four papers on day one and look forward to sharing our insights and learning from our colleagues.

Our thanks and best wishes to the organising committee.


Day 1 – 10 October 2019 – Session 1 – Resilient dam design

Towards consistency in unit cost rates for economic consequences – David Stephens

Estimation of the potential economic consequences of dam failure is becoming an issue of increasing importance in the Australian dams industry. As a result of the ongoing investment in dam safety upgrades, societal risk profiles for many dams are generally reducing.  Additionally, there is evidence of the potential magnitude of economic and financial costs from recent overseas dam incidents.  Whilst there is a well-established framework for estimation of economic consequences, based on concepts of direct/indirect and tangible/intangible damages, there is a dearth of recent literature on the application of modern unit cost rates for various asset classes.  This is particularly important in cases where direct, tangible damages are an important component of economic consequences.

Currently, unit cost rates used to estimate direct tangible economic consequences in Australia are typically taken from older sources such as the floodplain Rapid Assessment Method (RAM). The appropriate cost rates are then factored by CPI to represent ‘current day’ estimates of these costs.  However, since the time when the RAM was first developed, there have been changes to the categorisations used to identify economic assets such as businesses in common databases such as the census.  Additionally, there have been a number of large, recent flood events in Australia which provide very useful data to assist in deriving updated unit cost estimates.

This paper presents proposed unit rates for damaged and destroyed residential and commercial structures (including stage-damage curves) consistent with the Australian Bureau of Statistics categorisations used in the census data, agricultural land and assets such as roads. These rates have been derived based on a range of sources.  The purpose of producing these unit rates is to promote ease-of-use and consistency, especially for large consequence assessment studies where numerous assets are impacted.  A case study is presented showing the application of these unit cost rates and highlighting the variability in direct, tangible damages in different circumstances

Day 1 – 10 October 2019 – Session 6 – Design modelling for resilience

Modelling Reservoirs with a 2D Hydraulic Model – Andrew Northfield

 In recent times two dimensional (2D) hydraulic modelling has become the most common type of modelling for undertaking dambreak assessments. Direct map outputs such as depth and depth-velocity product are very useful in assessing risk across a floodplain.  The temporal output from 2D models also enables the tracking of flow across a floodplain, helping practitioners and dam owners alike make informed decisions on warning time and evacuation routes.  These outputs form essential input to packages such as HEC-LifeSim an agent-based simulation model for estimating life loss by simulating population redistribution during an evacuation.

A number of investigations have shown the hydraulic model, TUFLOW, is able to simulate the hydraulic conditions expected in a dambreak flood wave, giving confidence in the model’s ability to correctly capture the flood wave propagation. Notwithstanding this ability, there remains uncertainty over the best methodology to adopt when assigning a breach hydrograph to the model and in turn the impact this choice has on assessing downstream populations at risk.

A commonplace method of assigning dam breach hydrographs is to model the reservoir and dam structure with a 1D model or spreadsheet, where the storage is represented with a stage storage relationship and outflow through a time-varying breach is calculated using level-pool routing. The resulting hydrograph is then applied directly to a 2D model immediately downstream of the dam to model the propagation of flow downstream.

An alternative approach consists of representing the entire reservoir, dam and downstream floodplain in the 2D model. This allows for the dynamic effects of bathymetric constrictions in the reservoir to be accounted for which could greatly impact on the timing and shape of the dam breach hydrograph. However, this comes at a cost, as representing the reservoir in 2D requires bathymetry data which can be expensive to capture and also may require a major extension of the model domain.

In this paper the ‘Fully 2D’ and ‘Stage storage relationship 1D/Spreadsheet’ approaches are compared for a number of case studies.

Day 1 – 10 October 2019 – Session 7 – Emergency preparedness to ensure resilient communities

Estimating the individual risk from dam failure – Simon Lang

The ANCOLD (2003) Guidelines on Risk Assessment contain criteria regarding the tolerable level of individual risk from dam failure. Maslin et al. (2012) describe an approach to estimating individual risk from dam failure, using exposure factors, warning and evacuation factors, and fatality factors. These factors vary according to the people at risk, the anticipated warning time, the flood severity and the shelter people are likely to be in. Maslin et al. (2012) provide step-by-step instructions, which means their approach can be applied in a consistent manner from dam to dam.

However, the recommended fatality factors are based on Graham (1999) and DHS (2011) definitions of high, medium and low severity flooding which have been superseded by the Reclamation Consequence Estimating Methodology (RCEM). Therefore, in this paper modifications to the Maslin et al. (2012) approach are proposed, so that estimates of individual risk from dam failure are consistent with RCEM-based estimates of societal risk. The potential to use RCEM itself or simulation models to estimate individual risk from dam failure is also briefly discussed.

Day 1 – 10 October 2019 – Session 7 – Emergency preparedness to ensure resilient communities

Lessons learnt from evacuation modelling for dam failure consequence assessments – Hench Wang

The use of simulation models to assess dam failure consequences has progressively advanced in Australia over the past few years. For example, it is now common for HEC-LifeSim to be used to estimate potential loss of life from the failure of large dams with large populations at risk downstream. Since its introduction to Australia, numerous presentations and papers have been provided by USACE and industry professionals that highlight the benefits of using HEC-LifeSim for a range of different case studies.

Whilst the majority of the literature published to date have focused on the benefits of simulation modelling, this paper identifies some of the technical challenges that can arise, particularly in the evacuation modelling component of HEC-LifeSim. The techniques that have been used to overcome these challenges are also discussed using three case studies.

The first case study demonstrates the sensitivity of the life loss to changes in cell size and the output interval of the gridded hydraulic data. This is done by comparing the differences in life loss between high-resolution and low-resolution models for three dambreak models. The second case study illustrates the importance of the road network representation in HEC-LifeSim because the resolution of the road network is important to achieve plausible estimates of the fatalities along roads, and logical animations of the mobilisation. The final case study demonstrates the implications of coincident flow modelling on the life loss, and therefore the importance of understanding the hydrology of the target and neighbouring catchments.

This paper provides a checklist that prompts practitioners to consider some of the lessons learnt over the last few years and is envisaged to be a working document that improves the defensibility and robustness of HEC-LifeSim estimates throughout the industry.

Michael Cawood, one of Victoria’s most experienced flood risk and emergency management professionals, is joining forces with the HARC team from July 1, 2019.  Michael has close to 40 years of experience, a proven track record and an extensive resume of flood and emergency management related projects here in Australia and internationally.  He is also uniquely credentialed on all aspects of the total flood warning system and is one of only a very limited number of Level 3 accredited Flood Analysts working with Victorian State Emergency Service.  Michael has previously worked closely with HARC to deliver a number of high-profile studies in Victoria and NSW, and will now provide his services as an integrated member of the HARC team.  This will result in a natural and seamless extension of HARC’s highly regarded technical and flood modelling skills into the broader areas of floodplain and emergency risk management, as well as incident management training in response to statutory and other drivers.  We are excited about the opportunities ahead for our clients and our business.


HARC is excited to announce that it has joined the Water Sensitive Cities Cooperative Research Centre (WSC CRC) as a Subject Matter Expert (SME) member.



Our membership continues a history of staff engaging with, and participating in CRC’s. HARC’s Director Peter Hill was a Project Leader with the CRC for Catchment Hydrology, while Dr Phillip Jordan and Dr Matthew Hardy led the catchments and water quality and urban water product streams in the eWater CRC.

Our membership highlights our commitment to bringing leading research to industry practice and recognises the value this can offer.  Initially HARC will be working with Dr Christian Ulrich and the Tools and Products (TAP) team to develop and apply the CRC’s Design Platform.