|WRC/DWA framework document for the revision of water quality guidelines: Facilitation of workshops for the risk-based water quality guidelines update
|Expanded Title:||In 2007 a number of specific issues came to the fore that made it necessary to re-examine the philosophical basis used for determining and using the South Africa Water Quality Guidelines (SAWQG) published in 1996. These included, inter alia, the classification of water resources under the National Water Act (Act 36 of 1998) which will ultimately result in the determination of Resource Quality Objectives. The concept of risk was also seen as potential common basis for decision-making in various contexts. At the time it was also noted that there had been advances in guideline determination internationally and that the 1996 guidelines were not necessarily based on the latest, most appropriate science and practice. In addition there were water quality variables, such as organic substances that were not included in the 1996 guidelines. Site specificity was another aspect that was lacking as the 1996 SAWQG were very generic in nature.
At the time of the 2007 project initiation three phases were planned, however only phase 1 was implemented.
• Phase 1: Project delineation and development of philosophy;
• Phase 2: Application of philosophy and development of prototype guidelines; and
• Phase 3: Development of tools for higher-tier site-specific guidelines.
To resuscitate the project, the WRC commissioned a Short Term Research Project focused on interactive workshops. The purpose of the workshops was to get a common understanding of the risk-based guideline theory as is reported in the Phase 1 study within the research community and within the WRC and DWS; and to align the approved irrigation water quality guideline project with the future guideline review and update projects.
The approach that was followed included an initial workshop with the irrigation guideline project team (4 August 2014), internal discussions, a second meeting with the irrigation project team (September 2014) and then a broader specialist workshop was held with a wider stakeholder group in February 2015.
The outcomes of the workshops and discussions are summarised below.
It is important to review the need for each guideline, existing or possibly new water use sectors, by asking questions such as:
• Why do we need a guideline for a particular use;
• Who will use the guideline;
• How will the guideline affect the way in which we manage water resources; and
• How will the guidelines link to existing legislation and regulations, such as SANS 241, Water Resource Classification and setting of Resource Quality Objectives?
Once the need for each guideline has been justified, the gaps in the current guidelines should then be determined in respect of aspects such as application, probability of exposure, additional variables and new science and approaches.
In deriving risk based water quality guidelines for the various sectors the following critical steps must then be considered.
1. Select suitable candidate end-points and by iteration (if necessary) select a suitable common end-point for all stressors and target combinations (for example, crop yield). An end-point must, at least in principle, be quantifiable, but not necessarily unique to a stressor;
2. Set up a fault tree for each stressor-endpoint combination that describes the salient environmental and target processes;
3. Evaluate the state of knowledge about each process: uncertainties, variability and quantitation of relationships as well as interactions with other stressors;
4. Formulate a suitable hazard expression for each stressor;
5. Consider the stressor exposure model – these models do not necessarily have to be numeric/ mathematical models at first but should be amenable to quantitative output;
a. How best to approach the numerical expression of risk, i.e. probabilistic versus possibilistic expression.
b. How the main user output requirements (fitness for use-class versus class-related stressor profile) can be generated – this involves considering what risk numbers would reasonably correspond to expected outputs; and
c. How stressor time series inputs must be handled.
7. Consider various realistic exposure scenarios and how they could be quantified;
8. For the Tier II and III guideline, formulate a risk assessment protocol for each stressor-target combination. Of importance is the description of the input and output quality, important calculation aids such as algorithms and models, caveats and skills requirements.
9. From the risk assessment protocol, select key exposure and hazard variables with known typical values that can be used in the risk calculation. The exposure scenarios in 6 above might be used as basis to obtain inputs from the user to generate more generic but still workable site-specific risk calculations. This is the Tier II guideline.
10. Consider what combination of stressor, target and water use scenarios would generate the highest risk values. Use these to generate the Tier I output.
11. Consider what qualitative or quantitative outputs would be most useful at each tier to guide the user to a sensible decision (for example: danger signs, water treatment or improvement options, further guidance via internet links and reference material).
The results from the above must then be packaged into a Decision Support System (DSS). When developing the DSS as part of the update for each guideline it is proposed that a demonstrator/ prototype system is developed that would include a user manual. Each developer will need to consider IP issues and controlled access to tiers; as well as putting forward recommendations on guideline updating issues and (perhaps) protocols.
It is recommended that the various demonstrator/ prototype systems be integrated by an independent team to develop an overarching DSS and user manual.
In considering the DSS some important questions to be answered are:
• Should there be one database, or one per sector;
• Who will maintain the database; and
• Who will be the ultimate owner of the DSS?
Collaboration with DWS is essential so that the department endorses the product to create a statutory environment to use as part of water resource management. In addition to this collaboration and the steps described above the following aspects need to be taken in to consideration as part of each guideline volume update.
• Assess how the guideline will link to existing standards, for example in the domestic sector SANS 241 must be considered and any update must not be in contradiction to the standard. In this respect collaboration with the relevant teams or organisations developing standards in any of the sectors must be take place;
• The guidelines therefore need to refer to the standards relevant to that sector and clearly state that the guidelines themselves are not standards;
• Application on how to use the guidelines is of utmost importance. Capacity building initiatives for this aspect will need to be clearly thought through and programmes developed and presented to the various uses of the guidelines including sector users and regulators, who would need to know how to integrate the guidelines from a resource manager perspective.
The update of the guidelines and the development of the DSS should be seen as a long term project over the next 12 years with the following proposed timeframes per project.
Task Proposed timeframe
Technical review and risk assessment, including prototype/ demonstrator DSS per sector; 2 years International review; 1 year but can be initiated in the second year of the technical review and risk assessment process
Overall DSS integration and roll-out of integrated system; 2 years
Tier 1 adoption and implementation; Immediate as guidelines are reviewed and finalised
|Document Type:||Research Report
|Document Subjects:||Ecosystem - Biodiversity protection
|Document Keywords:||Guidelines, Policy and regulation, Water Quality
|Document File Type:||pdf
|Research Report Type:||Consultant
|WRC Report No:||KV 333/15
|Authors:||Boyd L; Moodley P; Jooste S
|Organizations:||Golder Associates (Africa) Pty Ltd; Department of Water and Sanitation
|Document Size:||965 KB