Upper Orange River Reserve Study.
The protection of water resources in South Africa is safeguarded in the National Water Act (No. 36 of 1998) via the implementation of Resource Directed Measures, in which it is mandated that the Reserve (i.e., the water allocated for human use and reserved for the environment) must be determined for significant water resources. In sum, a Reserve aims to determine a balance between water needed to protect and sustain water resources and water needed to allow for reasonable human use and economic development.
The Upper Orange River catchment, including rivers, wetlands, and groundwater, is a vital water resource area in southern Africa, which required careful and comprehensive determination of the Reserve. GroundTruth were engaged to co-lead determination of the Reserve across the entire, transboundary catchment.
The Upper Orange River catchment is an internationally shared watercourse, forming part of the Orange-Senqu River Basin. The study area covered approximately 106,000 km2 and included two of the regions’ largest reservoirs, the Gariep and Vanderkloof Dams, large transfer schemes, including the Orange-Vaal Transfer that supplies the majority of Gauteng’s water, and several sites of significant conservation and cultural importance, including the Golden Gate National Park, Tussen-die-Riviere Nature Reserve, and Mokala National Park.
Within this large study, GroundTruth worked with a diverse team of experts and government personnel to i) review and analyse existing information, ii) identify and address ecological gaps, iii) identify the priority resource units for surface water, groundwater, and wetlands, iv) quantify Ecological Water Requirements and basic human needs for the priority resource units, v) assess and evaluate water use operational scenarios, vi) determine Ecological Specifications (Ecospecs) and protection measures to support the Reserve requirements, and vii) engage in continual communication and liaison for skills development and knowledge transfer within and across project teams and the government. The project approach and methodology followed the requisite 7 step process outlined by the South African government:
Step 1: Identify priority quaternary and sub-quaternary catchments that are potentially important due to their presence, extent or condition of water resources with a focus on rivers, wetlands and groundwater driven systems. Initiate the basic human needs and Ecological Water Requirement assessments.
Step 2: Determine eco-regions, delineate resource units select priority study sites and where appropriate, align with Step 1 of the water resource classification procedure.
Step 3: Determine the reference conditions, present ecological status, ecological importance and sensitivity, recommended ecological category and Ecological Water Requirement for the priority selected study sites.
Step 4: Determine the basic human needs and Ecological Water Requirement for each of the selected priority study sites.
Step 5: Determine the operational scenarios / rules and ecological consequences for meeting the Reserve (aligned with the classification procedure).
Step 6: Evaluate the scenarios with stakeholders.
Step 7: Design appropriate Reserve templates, eco-specifications and monitoring programme including monitoring requirements.
Eco-categorisation
Eco-categorisation refers to the determination and categorisation of the Present Ecological State of various biophysical attributes of rivers compared to the natural (or close to natural) reference conditions. To ascertain the Eco-categorisation, scientific data were collected on driver (i.e., geomorphology, hydraulics, and water quality) and the response (i.e., fish, aquatic macroinvertebrates, riparian vegetation, and instream-riparian habitat integrity) components, during two river surveys.
Ecological Water Requirements
Setting Ecological Water Requirements draws on the results of the Eco-categorisation assessment, using various approaches depending on the specific conditions and impacts at the EWR sites. Within this study the approaches used included i) Habitat Flow Stressor Response (HFSR) and Desktop Reserve Model (DRM) within Spatial and Time Series Information Modeling (SPATSIM) for the integration of data produced from the field surveys and Eco-categorisation, ii) a conceptual Flow Management Plan for the Orange River downstream of Gariep and Vanderkloof Dams, and iii) development of an initial approach for the integration of rivers, wetlands, and groundwater.
Basic Human Needs
A basic human needs determination aims to ensure that the essential water needs of individuals, specifically people not serviced by formal (municipal) water supply and directly dependent on surface and groundwater, are provided for. It was calculated that 13 271 people (1%) rely directly on river/stream sources and 102 755 (7%) on groundwater sources for household water use within the study area.
Socio-economic
The socio-economic assessment for the Reserve determination pertains specifically to human water use and socio-economic context within the study area. The socio-economic profile for the study area was assessed, providing the baseline for evaluating the socio-economic consequences of potential changes to operational river flow scenarios.
Wetlands
Though the Ecological Water Requirements for wetlands were not determined in this study, several key recommendations were made regarding the quantification of the Ecological Water Requirements for specific priority wetlands, and for where integration between groundwater and/ or rivers and wetlands is crucial.
Groundwater
Groundwater was assessed in terms of the present status based on existing data and assessment of the Reserve, though a Groundwater Quantification and Qualitative approach which established the contribution of groundwater to sustaining the Ecological Water Requirements and basic human needs. Ultimately, the study resulted in a determination of the quantity and quality of groundwater potentially available for allocation to users and potential users.
Eco-specification
Ecospecs are intended to provide the quantifiable and enforceable descriptors of the quantity, quality habitat and biotic integrity as they pertain to the ecological objectives for a particular water resource. They can be incorporated into Water Use License conditions to allow for monitoring and auditing of the condition of the wetland resources. Ecospecs are generally reported as the values of parameters (usually maximum concentrations) required to meet the Recommended Ecological Category for a water resource. Ecospecs were determined for the study area, covering all key zones and sites with essential recommendations for monitoring and management.
In short
The results from the study aim to guide the South African government with data, methods, and best practice recommendations to meet national objectives for monitoring, managing, maintaining, preserving, and if possible, improving the state of the water resources within this catchment for the benefit of people and the environment.