Water Resources Engineering

in the Limpopo River Basin part of the WaterQ2 project

Satellite River Gage

This technique uses daily satellite imagery from Planet Labs to monitor flow in smaller rivers. First, we manually measure the discharge of a river and plot the cross-river profile. From this, we use hydrologic relationships to parameterize a model of river width to river flow. From satellites, we measure the width of the river over time. The historical satellite record allows us to populate river flow back almost ten years and continue to monitor the flow. The technique shows promising results when compared to the standard river gages, which are sparsely used. We are scaling up our validation of this method now.

This work is supported by the United States Agency for International Development, Southern Africa Regional Mission, Fixed Amount Award 72067419FA00001. This work utilized data made available through the NASA Commercial Smallsat Data Acquisition (CSDA) Program and the Planet Labs Education and Research program.

Satellite Groundwater Monitoring

Precipitation, topography, and land cover data were used to populate a model (USACE HEC-HMS) that estimates runoff to rivers and infiltration into groundwater. Results from the model were compared to data from the GRACE satellites, which measure changes in groundwater over time by detecting the change in mass near the surface of the Earth. This analysis will allow the estimation of the recharge rate of the groundwater in the area. We expect that this technique will highlight the importance of unique groundwater features in the Limpopo Basin that are currently not monitored but support downstream economic productivity.

Saltwater Intrusion in the Limpopo River

The water balance in coastal regions is critical for water supply and to keep saltwater out of rivers and groundwater. The Limpopo River delta in Xai Xai, Mozambique has reported saltwater intrusion. This project seeks to evaluate the relative risk of land movement, groundwater changes, and river flow changes on water security in the coastal region. This project uses GRACE and Sentinel InSAR data combined with ground-based observations to build up a water balance for Xai Xai.

The Human Right to Water

Safe drinking water is needed for a healthy population. Furthermore, access to water resources is needed for economic development. The International Covenant on Human Rights has declared potable water as a human right, which was clarified in General Comment no. 15. The right to water is recognized by section 27 (1)(b) of the South African Constitution and South Africa has defined concrete minimum standards for safe drinking water in the Water Services Act 108 of 1997, and in regulations passed under the terms of this Act.

Video of the sediment-rich wet season flow past the intake for the local water treatment facility. The sediments may cause a treatment challenge as well as maintenance issues.

This work investigates the extent of the realization or non-realization of the right to water in a rural region of South Africa and its implications for the provision of water in South Africa and beyond. Despite constitutional obligations to provide safe water, accessibility and quality of water remain problematic in South African rural communities. Previous and current studies conducted in the Mutale River basin demonstrate that, in spite of existing infrastructure, water supply is unpredictably intermittent, which does not satisfy the required levels of access. The research also indicates that the water quality does not at all times adhere to the prescribed South African minimum standards, nor the recommended guidelines set by the World Health Organization for safe drinking water.

University of Venda

University of Venda

Drs. Kahler (left) and Edokpayi (right) in front of a weather station set up at a primary school in Limpopo, South Africa. Data from the station will support research in the region and STEM outreach at the school.