Why monitor river health?
Authorities in China recognise the need for a systematic, national approach to river health monitoring. The historical approach of simply measuring water quality does not go far enough to indicate the true ecological state of a river system, which must consider many different aspects. The River Health and Environmental Flow (RH&EF) project team is working towards designing a framework for river assessment that can be applied anywhere in China. The team’s recommendations build on an analysis of similar programs in Australia and around the world.
River health has been described as the ability of a river ecosystem to support and maintain a balanced, integrated and adaptive community of organisms that resembles the natural habitat. In practice, river health is measured using various indicators of environmental disturbance from the healthy state, relative to some benchmark or reference condition.
The overall aim of monitoring river health is to provide information on the ecological state and functioning of a river system. This will guide rational river management decisions and actions.
The appropriate agencies are seeking a more rigorous approach to monitoring river health in China that reflects all aspects of a river’s ecological condition. Under this approach, a nationally consistent program would underpin the monitoring of river conditions, evaluate the impact of management actions, and assist to prioritise rivers and river catchments for particular management attention.
A river health-monitoring program in China would be one component of a holistic, asset-based framework for evaluating river health, environmental flows and water re-allocation in the country’s major river systems, as part of the new river basin master plans. Monitoring should not be restricted to a single set of indicators, and each set should be chosen to suit local conditions and local objectives. It may be necessary to select a broad range of factors for assessment in pilot studies, and then select those that best respond in the specific river situation.
The main components of a modern river health strategy incorporate:
- Catchment processes
- In-stream physical processes – hydrology and geomorphology
- Water quality and sediment chemistry, including contaminants
- Aquatic and riparian life – flora, fauna and ecosystem processes.
These components are linked through physical, chemical and ecological processes, and a monitoring program may concentrate on one component or a combination. This choice will again depend on the local ecosystem conditions, management issues, and available resources. Clearly, the more comprehensive a program is, the more information it generates about the status of river health, the cause of identified problems, and the management approach to improve river health.
To design a health-monitoring program for rivers in China, the RH&EF project team has started with a generic monitoring framework (shown in Figure 1). The framework details how to set objectives for a program, what and how to measure, and types of benchmark for assessing the relative health of a river.
This framework is being used to develop draft monitoring frameworks for the three pilot rivers. Each pilot program will be based on the local situation and management priorities. As such, the types of river health indicators that will be measured in each basin will be selected with regard to local conditions.