An assessment of impact of landscape farm dams and climate change on catchment runoff

This report documents the state of knowledge of the secondary, or indirect, impacts of climate change and prioritises topics for investigation in the MD-WERP climate adaption theme.

Science and research

MD-WERP theme	Climate adaptation
MD-WERP theme 1 project	Climate adaptation foundational science
Research lead	CSIRO
Authors	David E. Robertson, Jorge L. Pena-Arancibia, Hongxing Zheng, Francis Chiew, Santosh Aryal, Martino E. Malerba, Nicholas Wright
Author contact details	David Robertson
Date of publication	December 2024
Report full title	An assessment of impact of landscape farm dams and climate change on catchment runoff
Keywords	Murray–Darling Basin (MDB); landscape farm dams; private farm water storage; future climate; climate change impacts; catchments; catchment runoff; remote sensing imagery; streamflow; hydrological modelling
Summary of output	Farm dams are constructed to support agricultural activities, intercept catchment runoff and therefore reduce streamflow. However, the impact of farm dams on runoff projections has received little attention. This study established datasets to assess farm dam development over time and used these datasets with hydrological modelling methods to estimate the impact of farm dams on runoff projections. The following journal articles are referred to: Journal article: Characterising the regional growth of on-farm storages and their implications for water resources under a changing climate Authors: Jorge L. Pena-Arancibia, Martino E. Malerba, Nicholas Wright, David E. Robertson Journal article: How sensitive are catchment runoff estimates to on-farm storages under current and future climates? Authors: David E. Robertson, Hongxing Zheng, Jorge L. Pena-Arancibia, Francis Chiew, Santosh Aryal, Martino E. Malerba, Nicholas Wright
Key findings / recommendations	Since 1990, the total volume of landscape farm dams is estimated to have grown from 500 GL to 2500 GL. The growth in the volume of farm dams slowed considerably after 2005 when state governments began to introduce policy controls. Using the new farm dam data improved the ability of hydrological models to simulate observed streamflow, compared to traditional approaches that do not consider farm dams. The current level (as at 2022) of farm dam development in the Murray-Darling Basin is estimated to reduce annual catchment runoff by 13% (in the range of 8%–19%) under the current climate across the 113 catchments investigated in this study. In a drier future climate, farm dams are likely to be empty for longer periods and intercept a greater proportion of catchment runoff. Under a future climate scenario with reduced rainfall, explicitly modelling farm dams produces reductions in mean annual catchment runoff that are on average 10% greater than estimates generated using traditional rainfall-runoff modelling.
Target audience	Water managers, researchers, Australian Government, state governments, local governments, community, water and environmental consultants

Journal article
Publication title	Published	File type	File size
An assessment of impact of landscape farm dams and climate change on catchment runoff	17 Dec 2024	PDF	546.38 KB

Published date: 19 May 2025