The development and application of ecological risk assessment in South African water resource management

by Claassen, Marius

Abstract (Summary)
The provision of goods and services by aquatic ecosystems plays an important role in socioeconomic development and livelihoods in the southern African region. Water resource management in South Africa developed from an agrarian and pastoral focus up to 1956 to also supporting mining and industrial activities. This led to the introduction of the resource water quality objectives and pollution prevention approaches, which balanced the needs for development and protection. Prior to 1994, access to water resources was limited to riparian property owners and a minority of the population who controlled industrial and mining activities. The establishment of a democratic government amplified the need for accelerated socio-economic development, with equity, efficiency and sustainability being the principles of such development. New approaches were needed, which could achieve these development objectives and secure the resource base for future generations.

An overview of the scientific process highlighted a risk based approach as potentially supporting the much needed balance between development and protection. The aims of this thesis is to develop a framework and process for the application of ecological risk assessment to water resource management in South Africa, to use case studies to draft guidelines for ecological risk assessment and to assess the degree to which ecological risk assessment can contribute to effective water resource management in South Africa.

The United States Environmental Protection Agency’s guidelines for ecological risk assessment were identified amongst international best practice as meeting the requirements for local application. A framework was drafted for ecological risk assessment in South Africa, with the main phases being to agree on objectives, formulate the analysis plan, analyse information, characterise risk and manage risk. Modifications from the Environmental Protection Agency’s process include the order of activities in the first phase, the explicit testing of hypotheses and clarification of the evaluation of existing data or collection of new data.

An industrial effluent case study was used to assess the applicability of the proposed framework. The case study dealt specifically with the assessment of risks posed by current conditions and long term licence conditions. The framework was found to be useful to identify weaknesses in the established monitoring programme and to evaluate lines of evidence to assess the degree to which the stated conditions would have unacceptable consequences. The study highlighted several weaknesses in the suggested framework, of which the most critical is the interpretation of the risk hypothesis as a testable null hypothesis. It became clear that cause-effect relationships should be stated as the risk hypothesis, whereas the assessment should evaluate expressed or expected conditions against a risk profile for a given stressor to benefit fully from the risk assessment approach. Changes to the framework terminology were suggested as well as nested feedback loops to allow for iterative processes where new information becomes available.

The proposed guidelines incorporate the learning from the case study application as well as feedback from a peer review process. The guidelines incorporate the suggested actions under each phase as well as notes providing the rationale for each step. Three case study outlines were provided to assist users with the interpretation of the guidelines in different applications.

The proposed guidelines are applied in an ecological Reserve determination case study, which specified the ecological water quality requirements. The study found that a risk-based approach was followed in the development of the water resource management policy, but the Reserve determination method is generally hazard based, with site specific modifications of the target values being allowed on a conservative basis. The case study highlighted a lack of readiness of water resource managers to accommodate scientific results expressed as probability distributions in support of management decisions.

The thesis is concluded with a discussion of the key learning points of the ecological risk assessment development process. The evaluation highlights the move from stating and testing a null hypothesis to stating the risk hypothesis and evaluating the stated conditions against a risk profile. Several implementation challenges are highlighted, with specific recommendations made for adopting the proposed guidelines.

Bibliographical Information:


School:Rhodes University

School Location:South Africa

Source Type:Master's Thesis

Keywords:institute for water research iwr zoology entomology


Date of Publication:01/01/2006

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