The Glenelg Hopkins Catchment Management Authority (CMA) is Waterway Manager for the Glenelg Basin. Waterways connected to the Wimmera-Glenelg System include the upper Glenelg River and the upper Wannon River. Diversion of these waterways through the construction of weirs, channels and reservoirs resulted in critical impacts on the health of these rivers through to where they flow to sea. A portion of the water harvested by the Wimmera-Glenelg system is returned to the Glenelg River at Rocklands Reservoir.

The Glenelg Hopkins CMA is the regional manager of the environmental water reserve. Within the Wimmera-Glenelg system, this role involves:

• Engaging with communities to identify values to be targeted for environmental water management.
• Coordinating scientific research to identify and monitor environmental flow requirements for values in the Glenelg and Wannon rivers.
• Providing advice to GWMWater on how to maximise environmental benefits from passing flow obligations at Rocklands Reservoir.
• Providing advice to the Victorian Environmental Water Holder (VEWH) about regional priorities through the Glenelg System Seasonal Watering Proposal.
• Implement the Glenelg River component of the VEWH Seasonal Watering Plan.
• Plan for the delivery of the Glenelg River Compensation Flow to support stock and domestic requirements downstream of Rocklands Reservoir.