Event Debrief: Talk on Groundwater Development (GWD YP Committee)
Moderators: Oudi Modisha and Awodwa Magingi
This Webinar - organised by the Young Professional Committee, GWConfEx2021 - focused on the development of groundwater resources including the status of groundwater in South Africa, major technical and social challenges within the industry and ways to address these challenges. It also highlighted groundwater management strategies in Transboundary aquifers as well as case studies in groundwater development.
The three presenters Collen Nkosi (GPT), Danita Hohne (DWS) and Kes Murray (GEOSS SA) shared great insights with the GWD membership and other interested parties:
- View the full Talk via the GWD YouTube Channel : https://youtu.be/aQc8aWxGHC4
Speaker 1: Collen Nkosi
(Refer recording. Starts at 03:44)
Talk addressed 1) Transboundary aquifers and governance framework 2) Groundwater development (Tuli Basin) 3) Hydrogeological principles for the sustainable development of groundwater resources 4) Groundwater information sharing
Refer to Dr Rian Titus, Groundwater School - https://www.waterbusinesscollege.co.za/
SADC Protocol on Shared Watercourses Basin/ Catchment Management (Limpopo River): http://limpopo.riverawarenesskit.org/LIMPOPORAK_COM/INDEX.HTM
Q: Challenges encountered between different countries and how did you overcome them?
Q: How important is information sharing between stakeholders in Transboundary Aquifers?
A: (summarised) It is a major challenge between so many stakeholders, all want to know the quality of surface and groundwater because they rely on it. And with the many large scale Citrus Fruit farmers in the area and we need to support them with little information we have from monitoring around mining sites. So an information sharing agreement between all the stakeholders would benefit all. This data would then assist to feed into a Hydrological Conceptual Model that can help develop these frameworks for management
Speaker shared his email address for any further engagements - [email protected]
Speaker 2: Danita Hohne
(Refer recording. Starts at 19:02)
Talk addressed: 1) Background 2) Location of Sutherland and its boreholes 3) Comparing rainfall data and monitoring data from the past 9 years 4) Weekly monitoring data from 2019 5) Interventions 6) Do interventions work?
Future outlook: Balance the reserve in the light of new development e.g. wind farms and solar farms
Q: Are additional GW exploration being considered by the Municipality?
A: (summerised) Yes, a bit of a struggle but we did receive some funding and hopefully drill 5-8 boreholes to help with water supply. Always looking for new resources but it is important to consider what would happen if there is no recharge in the next 50 years (currently some places 12 years without a recharge event)
Q: Is the deep water levels seen in Sutherland (50 - 80 mbgl) related to little recharge or geology?
A: (summerised) Good question. Probably geology because it is fractured rocks and your shallow waters as shown in monitoring data of Borehole 2, the water level is always between 24-39 meters and then dropped to around 50m and then run dry.
Q: It looks like the boreholes are founded in different aquifers, Is it possible to tap the aquifer of borehole 2 in order to tap that aquifer for additional water.
A: (summerised) There is a dam near borehole 4, so if dam is depleted there is no water coming in (almost like an AR system) if the is dam full, water flows better. Currently we put too much strain on aquifer and now have to manage the pumping. All about operating pumping rules and how you manage that.
Q: Not sure if Sutherland is one of the potential 'fracking' areas....if so, with these ground(water) availability issues what's your take on the fracking story in terms of water sources?
Speaker 3: Kes Murray
(Refer recording. Starts at 35:08)
Talk addressed: 1) Professional Development and the Dunning-Kruger Effect 2) Standards and Guidelines to get you through Mount Stupid and the Valley of Despair 3) Groundwater Supply Project Lifecycle 4) Sidenote(s) on how groundwater is NOT sustainably developed (or identifying opportunities for wasteful expenditure) 6) MAR (addressing over abstracted aquifers) 7) Example: Desktop Studies 8) Example: Field Data Collection 9) Example: Data Collation 10) Example: Drilling 11) Drilling Supervision 12) Example: Test Pumping (SANS 10299-4:2003) 13) Example: Data Analyses 14) Example: Monitoring & Management 15} Summary
Refer to SABS: SANS10299 Guidelines & SANS 241: Drinking water https://store.sabs.co.za/
Q: How would you differentiate between safe yield and sustainable yield?
A: Different concepts relating to borehole yields (e.g potential yield, safe yield, sustainable yield exploitable yield, etc.). Goes down to definitions and there is a published definition as part of the FC Method on Sustainable yield of a borehole that revolves around not dropping water levels below a defined point within a borehole (when looking at a single borehole), When looking at long timeframes - and sustainability is about longer timeframes - we need to start looking at recharge and it is possible to do that through the FC method but the Mathematical definition of the method does not require us to take recharge into account. ….The point of all the definitions is to assess what the impact of the abstraction is on a borehole/ aquifer/ wellfield and to ensure that it is repeatable in the future without depletion.
Q: How best would you suggest to Tertiary Institutions to incorporate what you shared?
Defer to the Ground Water Division poll and my extensive response on that. My opinion is that exposure will happen when you start working. Most important is that students should become scientifically sound and understand the scientific method before entering the workplace.
Thank you to all speakers and participants.
Look forward to the next YP Committee Event.
This event also LIVE STREAMED on the GWD YouTube Channel