The Hattah-Kulkyne National Park is situated in north-west Victoria, adjacent to the Murray River. The National Park contains a complex of more than 20 semi-permanent freshwater lakes known collectively as the Hattah Lakes.

Hattah Lakes is home to a diverse range of flood-dependent vegetation that changes with the topography of the landscape.  Regulation of the Murray River has significantly reduced the frequency and duration of small to medium-sized natural floods in the Hattah Lakes system. An environmental watering regime has been implemented to help overcome the challenges brought about from River regulation.

Many data sets are collected across the Hattah Lakes system and ongoing review of this data, and assessing the relationships between the data, is needed to improve the understanding of the benefits of the environmental watering program. 

Water Technology were engaged by the Mallee Catchment Management Authority to:

• Determine if there is a relationship between delivery of environmental water and natural flooding and changes in groundwater levels across Hattah Lakes, and
• Determine whether there is a relationship between groundwater levels and the health of the woody vegetation

The work undertaken included:

• Collating, reviewing and utilising the data sets from the significant monitoring undertaken across the Hattah Lakes and adjacent systems
• Summarising the natural flooding and planned watering events and their extents
• Identifying groundwater level and salinity responses to different environmental watering events
• Identifying any relationships between the magnitude of the watering event and the magnitude of the groundwater level and/or salinity change
• Reviewing the tree condition health data in comparison with rainfall, natural flooding and environmental watering events and groundwater levels and groundwater salinity