The Wentworth Group relies on a small secretariat to support the Group’s activities.

The Wentworth Group has been supported in its work by a number of scientists, policy analysts, lawyers, and other professionals. See our contributors list.

  • Dr. Celine Steinfeld


    Dr Celine Steinfeld is a geographer specialising in natural resource policy and management in Australia. She was awarded the University Medal in 2008 for research on floodplain development in the internationally significant Macquarie Marshes in the Murray-Darling Basin. After graduating, Celine worked in policy implementation at the Murray-Darling Basin Authority. She was the inaugural recipient of the Peter Cullen Postgraduate Scholarship in 2009 and won the international River Management Young Achievers Award at the River symposium in 2012. She joined the Wentworth Group in 2015 with a passion for using scientific evidence to advance water reform and landscape conservation in a changing climate.

  • Carolyn Swindell

    Communications and Engagement Manager

  • Tom Le Breton

    Administrative Assistant

    Tom Le Breton is in the final year of a PhD in fire ecology and plant conservation at the University of New South Wales. Prior to his PhD, Tom worked as a Senior Scientist for the NSW Office of Environment and Heritage, conducting threatened species listing assessments and contributing to the development of conservation policy. Following the 2019-20 fires Tom contributed to developing the framework for identifying which plant species were most likely to have been negatively impacted by the fires. He later led the assessment of 135 plant species for listing under the EPBC Act, that had been identified as likely being at risk of extinction using the framework.

  • Debbie Medaris

    Program Manager – Healthy Landscapes

    Debbie has a history in several Commonwealth and NSW government roles on subjects ranging from climate change adaptation to species conservation to waste management and resource recovery. Her most recent role was Assistant Director of Biodiversity Programs and Koala Health for the federal government. She has also worked in conservation research in Vietnam. Debbie is a passionate environmental services professional with a Bachelor of Science (first class honours) in Ecology and Conservation Biology from Griffith University.

  • Siobhan Isherwood

    Project Officer – Healthy Landscapes

    Siobhan has a background in large-scale renewable energy development, renewable energy advocacy, environmental assessment, bush regeneration, and waste management and resource recovery. She is a passionate environmental scientist and experienced project manager. Siobhan has an environmental science degree (first class honours) from Monash University and is currently completing a Masters in conservation biology at Macquarie University. Her academic experience includes ecology, policy development, ecological economics, remote sensing and GIS, and climate change.

  • Michael Vanderzee

    Policy Analyst – Water

    Michael was formerly the Director of Strategy and Policy and a Senior Policy Adviser – Intergovernmental in the Victorian Office of Water. Most recently he was the inaugural CEO of the Winton Wetlands Committee of Management working on restoration of the former Lake Mokoan in North East Victoria. He has worked on national and Murray-Darling Basin water reform since early 2000, including restoration of Snowy River environmental flows, the Living Murray Initiative, and the introduction of the Commonwealth Water Act. He has worked for the Victorian and Commonwealth governments advising Ministers, central agencies, and departments on broad range of environmental and natural resource management issues. Michael’s work with WG is focused on ensuring one of the outstanding and most important components of the Basin Plan is achieved – removing constraints to allow floodplain forests of the southern MDB to receive environmental water. Without this the survival of river red gum and black box forests is at risk. He also provides policy advice more broadly on the implementation of the Murray-Darling Basin Plan.

  • David Miller

    Policy Analyst – Water

    David’s expertise is in water policy and water sharing plans in NSW. He has twenty years experience in NSW NRM agencies, specialising in water sharing plans. He has worked in every river in NSW and each of the main groundwater systems. He has extensive knowledge of water allocation including legislative and policy requirements, extraction limits and water licensing.  He is currently working for the Wentworth Group as a consultant.