River health pilot study in the Pearl River basin
In early April, a group of Australian and Chinese river scientists and managers gathered in China’s Pearl River Basin to take part in a river health assessment. For some, it was the first time they’d been involved in fieldwork – and their first time in waders. For others, like researcher Dr Jane Catford, it was a chance to visit places off the usual tourist track, and an opportunity to gather data that would contribute to China’s river health efforts.
As part of the ACEDP River Health & Environmental Flows in China (RHEF) project, five Australian and 15 Chinese river scientists and managers spent eight days surveying the health of the Li and Gui Rivers in the Pearl River Basin. The Li River is a major tourist attraction, and maintaining and improving its health is a high government priority.
The aims of the field work were to trial and refine a potential river health assessment protocol for use in the region (and potentially across the whole basin), gather information indicating the current health of a representative sample of sites, and enable knowledge exchange between Australian and Chinese staff.
Dr Jane Catford (right) working with ecologists from Pearl River Water Resources Commission
The Pearl River is one of three river basins where a river health assessment strategy will be tested as part of the RHEF project. Through a series of field assessments, the RHEF project will develop and scope tools for river health and environmental flow assessments, and investigate a national framework for implementing the Project’s recommendations. Combined with lessons learned from RHEF pilot projects underway in the Liao and Yellow River basins, findings from the Pearl River study will inform river health monitoring approaches used in China.
Twenty five sites across the Gui River catchment were surveyed. Sites varied in river and catchment size, altitude, hydrology, surrounding land use, riparian and channel condition, and the level and type of disturbance caused by humans.
Water quality was measured, along with fish population health for more than 1,000 fish and about 50 different species. Macroinvertebrate assemblage composition, in-stream and riparian vegetation, and physical form were also measured.
Reliable and comparable information about the health of different rivers enables managers to prioritise restoration and remediation activities in a scientifically-robust and transparent way. Just like the ‘vital signs’ used to assess human health, a river health assessment strategy can rapidly assess the health of a river, by scoring and quantifying the condition of several aspects of its ecosystem.
The measures and variables used to assess river health vary depending on the natural characteristics of rivers, the pressures they face, and the objectives of a study or management action. For example, different methods would be used to assess the ecological health of a reservoir receiving industrial effluent, and an upland stream with minimal human influence. For this survey, the focus was on rivers with flowing water, rather than lakes or reservoirs.
Despite the long hours and the challenges associated with a large-scale pilot survey, the atmosphere among the ‘field workers’ over the eight days was incredibly positive. Both the Australian and Chinese members of the group shared their knowledge and understanding of freshwater ecology and river systems, their countries and culture – and a lot of jokes!
Senior Project Officer Douglas Wu from ACEDP Program Coordination Office (PCO) was invited to join the project team to monitor the field work.
The field trip was a great success, not only in the feedback received and the preliminary analysis of data, but in the knowledge shared and the connections created between those involved in the field work.