A New Methodological Framework for the Determination of Water Resource Classes and Resource Quality Objectives: A Case Study for the Mzimvubu to Tsitsikamma Water Management Area 7 (WMA7)

The current paper determined water resource classes and Resource Quality Objectives (RQOs) for significant water resources in the Mzimvubu to Tsitsikamma Water Management Area 7 (WMA7) to facilitate sustainable use of the water resources while maintaining ecological integrity. A novel stepwise quantitative and qualitative method was developed to ensure water resource protection in the study area. The methodological approach is proposed as a model framework that could be adopted as guideline and transferable to other catchments in the implementation of Resource Directed Measures (RDMs). The method used water quality and quality components of water resources to determine the classes and RQOs. The study’s major findings were that nineteen Integrated Units of Analysis (IUAs) were delineated, and ninety-five Resource Units were identified and prioritized for both surface and groundwater. Driving water quality variables (nutrients, electrical conductivity, and Escherichia coli) were observed and primary water users (irrigation, settlements, and wastewater treatment works) were identified per Integrated Units of Analysis. Five water resource scenarios were developed and evaluated to capture a likely water resource condition for the present and future. The scenario analysis showed impact is expected under any of the operational scenarios assessed at selected reaches. The water resource classes were determined, with eleven IUAs classified as Class lll, seven IUAs as Class ll, and one IUA as Class l. Water quality and quantity RQOs were set to ensure that both river and groundwater resources are compliant and protected. Therefore, the study recommends that this methodological framework, where classes and RQOs were determined, needs to be implemented and tested.