00;00;03;15 - 00;00;36;09
Bridget Scanlon
Welcome to the Water Resources podcast. I am Bridget Scanlon. In this podcast, we discuss water challenges with using experts, including topics on extreme climate events, overexploitation, and potential solutions towards more sustainable management.
I'm delighted to welcome Dale Barrow to the podcast. Dale is the director of GEOSS in South Africa. We met recently. We were both attending the International Association of Hydrogeologist’s meeting in Davos, Switzerland.
00;00;36;11 - 00;00;56;14
Bridget Scanlon
So GEOSS is a groundwater consulting company that provides expertise on groundwater exploration, geophysical services, deals in water quantity and water quality analyses along with numerical modeling. So I really appreciate you taking the time to chat today. And thank you so much for joining us.
00;00;56;16 - 00;01;00;07
Dale Barrow
Thank you Bridget, it was wonderful meeting you earlier this year and thank you for having me.
00;01;00;10 - 00;01;39;02
Bridget Scanlon
So Cape Town made a huge reputation for itself with the Day Zero in 2015 to 2017. And I guess that was linked to El Nino conditions and also maybe not very resilient system for water management in Cape Town being totally reliant on surface water reservoirs, I guess about six reservoirs. And it seemed that they decreased from ~90% of capacity at the beginning in 2014 to 50% in 2015 and 15% in 2017, and the threshold for this year, I think, was 13.5%.
So maybe you can describe what you did during that time and how you're managing water resources now in Cape Town?
00;01;47;06 - 00;02;09;29
Dale Barrow
Yeah, thanks. Thanks, Bridget. As you mentioned, the city supply system is not that resilient. It was entirely dependent on surface water, again, with some token groundwater abstraction schemes, but almost entirely dependent on surface water. That said, we did go through a drought. There's different return periods that have come through in the literature, but it was at least a 1 in 100 year drought.
It was a phenomenon and it wasn't a pleasant one. I don't know if you've ever experienced a drought, but there's certainly heightened levels of anxiety. You can live without electricity, without power, as we know you're in South Africa, that you can't live without water. And you can see that people know that and they start to panic. So it was a real time of uncertainty.
But I think looking back in hindsight, there were some positives that came from it. And I think we'll touch on them as we go through there on the podcast today. But to come to your question, how did the city respond? I think in terms of bringing on additional supply capacity, it's very challenging to rush an alternative supply source.
So whether that's desalination, which the city did do some, they looked at implementing a couple of small schemes, because they bounded by the coast. They also progressed in advance. They ground water development programs from the aquifer and the Table Mountain aquifer. But to bring on any meaningful volumes from these schemes doesn't happen overnight. So there wasn't much in terms of additional supply that came online.
They also looked at reuse and they're looking at reuse. And I think there's a lot of benefits that have come out of the drought in terms of looking at these alternative supply sources. And the city is increasing its resilience to future droughts because we know they will come. But I think getting through the drought itself, it was much more around demand management, looking at water saving technologies, the cost of water and penalizing big users and restrictions on water usage.
And then I think probably the biggest success was the public awareness campaign around the Day Zero, that that term that just captured what was possibly going to happen, that the taps would literally run dry. And as I mentioned, you can't survive without water and whether that's a household concerned about their livelihood or having to stand for water, whether it's a business that won't be able to manufacture or keep its doors open.
There was a lot of anxiety. And as I said, I mean, I think that's where there were some benefits that came out. And I think for groundwater, when you're faced with no surface water supply source or a municipal supply source that's going to run out, where do you turn? Well, one of the positive attributes of groundwater is it's pervasive.
It's literally under our feet. And that's what almost everyone looked at. And as a company operating in that space, it was a crazy time. But in hindsight, there were some positives that came out of that. And we saw residents industry just drilling like crazy. And in South Africa, we don't really have a governed industry when it comes to becoming a driller.
So you could literally come South Africa, buy drill rig, and tomorrow you could be a driller. And many people did that. So similar to what we have when we've got periods of load shedding, which is a lot of people coming into the solar market, we had almost everyone who was at a loose end trying their arm at borehole drilling.
So we had hundreds of boreholes being drilled on any given day. We had the price of drilling going up, you know, 400%, and the phones were ringing off the hook. People desperate to make sure that they do not run out of water.
00;05;20;12 - 00;05;44;08
Bridget Scanlon
It's interesting. I mean, we can't waste a good crisis to improve the situation. So I think in the long term, then we can make ourselves more resilient. And depending on surface water, almost entirely before the drought, six major reservoirs. And then it went down to maybe 15% of capacity. And it was obvious because you can see surface reservoirs, you know, people could see it.
And then and then even that surface reservoir storage had not been keeping pace with the population growth in Cape Town. I mean, I was reading that, you know, population grew from 2.5 million in 1995 to 4.1 million in 2015. So that was like a 70% increase in population. And your reservoir storage capacity only increased about 17%. So yeah, even the surface water storage was not keeping pace with the population growth.
00;06;14;22 - 00;06;34;22
Dale Barrow
You're quite right. I think there's a phenomenon happening in South Africa called semigration, where people migrated within S Africa to Cape Town. So the population has boomed. And I think, yes, the growth in the reservoir capacity hasn't matched that. But it must also be said that it was a 1 in 100 year drought and it was climatic factors.
And you mentioned, you know, these drying up dams, my parents farm on one of the biggest supply dams to the city. And it's just amazing what the change does to one. You know, normally you look out over about this expanse of water and it became a desert. And as the storms come across that desert, now you have dust storms, everything coated in dust, the apples coated in dust.
It was actually a really depressing time to be in Cape Town and in the surrounds.
00;07;01;20 - 00;07;26;08
Bridget Scanlon
And I guess the one thing is having an intense drought. But then when they last for a long time, it gets even worse. The cumulative effects are even more difficult and more challenging. But as you mentioned, groundwater is you big buffer. Groundwater is everywhere to some extent. And so people could drill wells. So people in Cape Town, then it seemed like they were hiring drillers and drilling wells in their backyard.
I assume the residents, and yes, even the commercial small industry is also drilling to have groundwater supplies during that time. So that was one of their ways. I mean, I guess it's like putting solar panels on your roof. You're taking yourself off the grid, and you're making yourself resilient by having your own source of water.
00;07;46;17 - 00;08;07;05
Dale Barrow
Yes. And and that was incentivized by the custodian of our water resources, Department of Water and Sanitation was encouraging our residents to develop their own source where they could, as was the City of Cape Town. Obviously, after the drought, there's the revenue, the loss of revenue aspect which comes into play. But during the drought, it was just if you can get water to sort yourself out, go for it.
00;08;07;07 - 00;08;42;10
Bridget Scanlon
So between the demand management during the drought, conservation was a big factor because as you said, you cannot bring on new sources of water overnight. It takes a long time to plan and to develop the infrastructure and all of that sort of thing to develop new sources of water. So the main approach then was demand management and you mentioned when we spoke before that there were like 6 or 7 different phases of demand management, going from 100 liters per person per day to 25 L per person putting in the city to reduce and then I think, I guess these, groundwater supplies did help to offset that. So people could use less of the water mains in the city.
00;08;52;16 - 00;09;29;08
Dale Barrow
So typically, you know, in our summer months, the City of Cape Town's water usage can exceed a thousand megalitres per day. And there was this target set to get that down below when the region of 500 megalitres per day. So it was to halve that typical consumption of the city. And again through the Day Zero awareness campaign, they also published a weekly dashboard on how the levels were doing, what the consumption was looking like, and they even went so far as to publish the big users of water, which was fairly controversial and maybe we wouldn't do that again.
But yes, it was all around driving down consumption. And as you mentioned, when you've got groundwater as an alternative, are you really going to let your beautiful garden run dry or are you going to let your swimming pool go empty, or are you going to close your factory? If you can afford not to, you're going to invest in in groundwater.
And we just saw hundreds of boreholes going in all over the place, typically in your more affluent areas or your industrial areas and people growing their dependance on groundwater. And I think groundwater was the unsung hero of the drought. I think we came close to that Day Zero scenario, and I think a big contributing factor was people offsetting their use. So not necessarily reducing, but turning to groundwater as a supply source.
00;10;17;14 - 00;10;29;19
Bridget Scanlon
Even in these. I mean, the climate in Cape Town is what is the average annual rainfall. And then you have you probably have all these lush gardens like you're living in the UK.
00;10;29;21 - 00;10;41;20
Dale Barrow
Yeah, the rainfall varies quite spatially. But, you know, 800 mm per year. But some areas, you know, around 2000 and higher. And a lot of the supply dams are actually in the mountainous catchments which get a little bit more rainfall.
00;10;41;22 - 00;11;24;29
Bridget Scanlon
Right. So we both know that irrigated agriculture is the elephant in the room in terms of water use. And there's a lot of agriculture. Yeah. Around Cape Town, vineyards and orchards. And you mentioned your parents farm with apple orchards. So how would be impacted during the drought? Because oftentimes in the US, cities would purchase water from the irrigated agricultural people in the surrounding areas if they can, if they're growing annual crops or things like that, that they will the farmers will fallow the land and then the city will buy the water, like San Antonio or Phoenix or L.A. or these places. So I don't know if Cape Town has any those sorts of agreements or anything with the farmers.
00;11;31;25 - 00;11;59;07
Dale Barrow
Yeah. I mean, I suppose it would be feasible, to consider an approach like that in terms of governing legislation, but nothing like that was implemented during the Day Zero scenario. So these big supply dams, they sit in the upper mountain catchments. So they have releases which sustain agriculture. And there's also allocations from these dams that are intended for agriculture and the custodian of the water, the Department of Water Sanitation.
When faced with this imminent Day Zero scenario of a big city running dry, they just curtailed the usage of water for agriculture. And while there was all this anxiety and panicking within the city, we actually never suffered from being water conscious to maybe showering with a bucket. There was always water in the taps for us, but the real victims of the drought was the agricultural sector.
So they had their usage for cattle reduced by up to 50%, these different schemes. There was a study done in a local area, where there is a river that flows out from one of the supply dams. And there were more than 3000 jobs lost in the agricultural sector, and we saw 44% reduction in the production from that agricultural region.
So there was huge losses from the agricultural sector and those that could, just like industry, just like private residence, they looked to groundwater. When you're faced with your livelihood being taken away from you, you're going to go for whatever you can grab onto. And that was often groundwater, be that legally or illegally. So again, coming out of Day Zero, the drought scenario, there's a bit of a hangover effect of untangling and dealing with the legality of some of the water uses that have arisen.
00;13;19;20 - 00;13;47;15
Bridget Scanlon
And much of the agriculture in the vicinity of Cape Town. It's mostly vineyards and orchards and things like that. So they're perennial plants, and so you can't fallow them. They're not annuals, so you cannot readily fallow them. So I guess that's another thing that affects your ability to respond to droughts. I mean, California also has seen a big increase in almond orchards and things like that because of the economics of this but then it means that they've hardened their demand, whereas in the past they might have been able to fallow crops for annuals, but now they can't do that because that's a big investment in orchards or nut trees or things like that. So I guess it's a similar situation that you were facing, you know, they couldn't readily fallow.
00;14;08;12 - 00;14;19;14
Dale Barrow
Yeah, it was a tough one for the farmers. I mean, we saw them taking the crops off the plants just to try and keep the plants alive. But many of them, that was the goal not to try and produce anything, but just to get through.
But some form of compensation would have been, yeah, would have certainly been advantageous and helpful to the agricultural industry.
00;14;27;25 - 00;14;56;15
Bridget Scanlon
I think we'll be seeing more of this in the future. You know, as cities keep growing and they need more water, they may be buying water from the agricultural sector because they've been using the most water in the past. So if they can come up with an approach to compensate farmers or to manage use, you know, I think that will be one of the buffers that the cities would be looking at is buying water from rural areas and transporting it to the cities.
And we've seen that in the US and southwest quite a bit. So. So you work for a company and I met Julian Conrad, who began GEOSS in 2001. I was doing a short course on recharge with Ricky Healy about ten years ago. We were invited by Yongxin Xu at the University of Western Cape. We thoroughly enjoyed that visit and learned a lot. It was wonderful. So maybe you could describe the company and what you have been doing to expand groundwater development since Day Zero, and the different types of efforts that you are, approaches that you using to explore for groundwater.
00;15;37;26 - 00;16;01;19
Dale Barrow
Okay. Yeah. Thank you for that question. So GEOSS really specializes in hydrogeology. And, you know, leading into that Day Zero scenario, we were a team of groundwater scientists, 5 to 10 people. The company was started in the early 2000s by Julian Conrad as you mentioned and we've sort of grown organically since then. I joined in 2008. Again, it's that Day Zero scenario.
I felt like we were just a team of hydrogeologists working together, and what one of the positives I mentioned, there were some positives from the Day Zero from the drought. One of the positives was we just had to deal with this massive increase in demand, so we needed to bring on a lot more hydrogeologists into our team. Obviously, the question being at the time is how sustainable is this?
But there was something positive that came from that. I think it's almost as if there's a critical mass in terms of the number of scientists you want your organization where you go from being sort of five people doing the same thing to a team of 15 to 20 scientists specializing in the different avenues of hydrogeology. And I feel like that's one of the big positives that we've taken from there.
So to sort of foster excellence in the different spheres of hydrogeology, we established business units, focusing on exploration, yield and quality testing and an aquifer parameter testing, the governance and legality around water use monitoring and management, numerical modeling, impact assessment and contaminated land. So we were able to sort of specialize and develop these business units. And we typically serve a South African client base.
Although we are implementing international best practice, we do a fair bit of work on the continent of Africa. And then this year also in Saudi Arabia. So we're looking to work all over the place implementing and best practice. But being located in South Africa, we find most of our work is in South Africa.
00;17;29;20 - 00;17;53;00
Bridget Scanlon
Well, I really enjoyed, you know, learning from Julian and what he was doing early on. And when we visited several years ago. And what I liked about the work that he was doing, monitoring groundwater levels and determining if the irrigators were managing the water sustainably by just looking at the groundwater levels. I guess you can think of groundwater as sort of like a bank balance or a credit card balance.
And so you can look at how much you're depositing and how much you're withdrawing. And but you can also just look at the balance and just see, you know, is it stable, is it declining or is it increasing. And so a lot of people are concerned in sub-Saharan Africa about overexploitation of groundwater. But the monitoring programs that you guys do looking at this, I think I was very impressed.
And he was describing the central region in southwestern part, where there are a lot of potato farmers growing potatoes in that region and using, a lot of center pivot irrigation. I really liked that approach. It's fairly straightforward, but it's extremely important.
00;18;34;06 - 00;18;53;06
Dale Barrow
I think you're so right, Bridget. I think people often trivialize the value of like you mentioned, it's fairly straightforward of groundwater level monitoring. So that is a big part of what we do. I think being located in the Western Cape, we are a little bit different from a lot of the other hydrogeological consulting companies which have been established around the mining industry.
So we focus quite a lot on supply schemes, and we've got a team that's doing monitoring monthly at it's quite an intensive schedule because it's far reaching. That does typically require feet on the ground. We have tried to sort of follow a citizen science type approach, but invariably what we find is we need to go out there. We need to measure those levels, typically with water level pressure transducers.
So you just get the higher frequency readings. And you mentioned the Sandveld monitoring Julian was doing that before he founded GEOSS. And he still goes out there on an annual basis to collect that data. So there's a wealth of data and information which is being translated into knowledge. Now around the sustainability of that industry. And I think that's thanks to groundwater level monitoring.
So certainly something that we have to keep doing and advocate for.
00;19;38;09 - 00;19;56;22
Bridget Scanlon
Yeah. And you mentioned there's a lot of surface water in Cape Town. You have some of the big aquifers up for the Table Mountain Group and the Cape Flats. So when I visited many years ago, I went to to climb Table Mountain because my sister had been on vacation there before me, and she climbed it and I thought, well, if she can climb it, it's no big deal.
But I understood that there like 30 different ways of going up the mountain, and I was petrified with the route we were taking. But whatever we do is a really fun, you know, maybe you can describe these aquifers, you know, the Table Mountain Group aquifers and also how it's connected to the surface water. That's another thing. You you emphasize that you are a group of hydrogeologists, but you also look at the linkage between groundwater and surface water.
And I think that's very important to then. And maybe you can describe some of those studies.
00;20;31;15 - 00;20;57;19
Dale Barrow
Okay. I'd love to speak in terms of the Table Mountain Group aquifer or let's talk about the geology, the Table Mountain group. It's a succession of, predominantly silica sandstones. about 1000 m thick, separated into two main aquifer units. The Peninsula Formation, being the lower mass unit, is what you hike that when you climb Table Mountain called quartzitic sandstone.
You would have seen how resistant to erosion they are and would have been a very steep slopes. And then there's also the upper aquifer, also called silica sandstones, also about 500m thick. So you've got this fantastic fractured rock aquifer. It's been intensely folded and faulted. It rains all along our south coast to Port Elizabeth, hundreds of kilometers long, our south coast, and it also up our west coast to the Cederberg highly folded, highly faulted, fractured sandstones, typically forms our mountainous regions because it's resistant to erosion.
And a number of our dams are in the upper in the mountain catchments. So, in other words, proximal to the Table Mountain Creek, it's outcrop. And the city has actually been looking at the Table Mountain Group aquifer since the early 2000. So they actually initiated some baseline monitoring, trying to investigate what the potential would be of taking out groundwater from the aquifer, what that impact would be on the groundwater dependent ecosystem.
So I don't know if you noticed when you climb Table Mountain, but if you go hiking in these, these margin regions, even if you go at the end of our dry season, which is our summit, if you hike in the mountains, you see these wetlands, you see these streams that are flowing. Even though we haven't had, we've had minimal rainfall for a couple of months, suggesting that they've got a groundwater contribution that's sustaining them.
So the city initiated this baseline monitoring in the early 2000. And then with the drought, they just intensified their efforts and launched into exploration, drilling, production, borehole drilling targeting both the upper aquifer or boreholes in the region of 200, 300, 400 m deep. They also targeting the deeper, confined Peninsula Formation, which proximal to the dam is at around 800 900 1000 m deep.
Difficult drilling. Very hard quartzite sandstone. But that good quality water and they've targeted it around the dam, as well as some of the other, major supply dams. For now, they've only got production boreholes around the dam. So we've initiated a monitoring network the stretching back to 2007, 2008, but obviously being enhanced and improved upon since then, where we're looking at groundwater levels, we're looking at shallow water levels within the Watkins Valley.
We're looking at soil moisture data. And then we're also working with ecologists and botanists to translate the link between soil moisture and groundwater level to how well the ecology is doing of these sites. So we've got quite a wealth of data. And what the drought actually did was it gave us a period of water stress. So we were collecting this data in a lot of catchments where there hasn't been groundwater extraction, but going through a drought scenario, what we could see was what happens when the groundwater levels do drop slightly.
So that that's been interesting data. And what we're currently wrestling with now is just that relationship between groundwater level and soil moisture. And we're looking at maybe building a SWAT (Soil and Water Assessment Tool) model currently integrating that with a numerical flow model, just to unpack what impact abstraction would mean to the soil moisture with these wetlands.
00;24;10;12 - 00;24;39;27
Bridget Scanlon
So I guess the long-term drought in before the Day Zero was like a test then to how well these wetlands withstand drought. And so it's sort of like a proxy then for impacts of groundwater abstraction and and so it's great data to have to see how resilient those wetlands are. And as you mentioned, you know, after a few months of almost no rain during summer, they're still flowing small streams and wetlands and stuff fed by groundwater.
And that's really interesting. So groundwater dependent ecosystems and very important to maintain those and then not to lower the groundwater levels too much so that you cut that connection and then you destroy those ecosystems. You're doing a lot of monitoring then. And that's fantastic. That's really time consuming to maintain those monitoring programs. And but being out in the field a lot and doing those monitoring programs, you get to understand the dynamics of the system and the response of the system and how it adapts and how resilient it is.
So that's very interesting. And you mentioned, you know, some of these wells there, 400 m deep or up to 1000 m deep. It must take a lot of energy then to pump groundwater from those depths. So is that the energy from the grid or what's the energy source for those wells that they're planning on using?
00;25;35;25 - 00;26;01;20
Dale Barrow
Yeah. So we have a national energy supplier, Eskom. And while they've had the issues in the past, they typically seem to be providing stable power, at least for the last, I think, half a year. But in effect, actually, even though these boreholes have drilled 200 m, 300m depth, typically when we target the confined aquifer, the formation it's artesian. So these there's a lot of aquifers recharged in your mountainous regions around the catchment.
So there's artesian and then even the aquifer. The levels are close to the surface. So it's certainly not too expensive in terms of pumping. The Eskom power has been an issue, and it's actually been a fault that's hindered the commissioning of the wellfield. So that's something that they're working on. But literally as we speak, you know, within this month, we're expecting some of those boreholes to come online.
And the big focus now is around managing that extraction so that we don't exceed these thresholds where we start to do damage these amazing ecosystems.
00;26;33;02 - 00;26;54;13
Bridget Scanlon
And so you mentioned that now the groundwater is artesian under pressure and stuff. But as you extract water and extract water from these, then you would slowly depressurize it and it would probably no longer be artesian after some time, I would assume, and then it get more and more expensive to to pump the groundwater.
00;26;54;15 - 00;27;12;01
Dale Barrow
Yes. Yeah. That's correct. I mean, I think the pumps probably wouldn't be deeper than 150 m. So from that sort of depth there is a greater cost in terms of pumping. These target areas have been chosen based on their proximity to supply dams, in terms of getting the water into the supply system relative to the accessible for the city.
And I think in terms of impacts on groundwater dependent ecosystems, the lower aquifers are certainly of a of a lesser risk. It's confined and geologically you can see the contrast, the confining layer. So we don't anticipate a major issue there. And that was certainly the initial target, you know, to target the confined aquifer and therefore not impact on these groundwater dependent ecosystems.
I think given the challenging nature of accessing that confined deep aquifer, the cost of drilling and also the yields, which maybe aren't exactly as they were anticipated to be in that lower aquifer, a lot more as focus as they put on the upper aquifer, which we will anticipate more, interaction with these groundwater dependent ecosystems. So we're in a situation currently where we need to manage this very carefully and look very closely at how we utilize these bores, particularly in this aquifer.
00;28;06;18 - 00;28;32;07
Bridget Scanlon
And so getting back to the city itself, Cape Town, there's a shallow aquifer there that's contaminated from industrial discharges and other things, and that is connected to the surface water. And I was very interested to read about the Liveable Urban Water Ways Project in the Sand River, which I thought that was fascinating. Maybe you could describe that a little bit.
00;28;32;09 - 00;28;56;01
Dale Barrow
So the Cape Flats aquifer is one of our we don't have many primary aquifers in South Africa, but the Cape Flats Aquifer is one of them. It's these channels where that sand thicknesses can be maybe up to 50 m thick and fairly high yields. But as you mentioned, the various impacts on the quality of this aquifer. So there's quality concerns around the groundwater, but also from the city's perspective, the number of rivers.
And if you assess a city's health by the health of its rivers, the City of Cape Town has a few issues. And some of them are legacy issues, land use planning, affecting rivers. You know, the philosophy was very much just get the water out to sea as quickly as possible. So we've got these canals. So the city of Cape Town, I must commend them for this project.
And they came up with this concept of a livable waterway. It's similar to sponge cities or water sensitive cities. And really it's just about a city being able to adequately absorb and manage its surface water effectively. And as part of this livable urban waterway concept, the city came up with six criteria that define what a livable urban waterway is.
And each of them, they define key performance indicators associated with that in terms of water quality and livability. The waterway needs to have acceptable water quality, free from sewage, free from litter, supporting indigenous aquatic life. And the API for that would be amount of litter in the river, nitrogen and phosphorus concentrations. The other criteria were Cape Flat management. So whether the river could handle the flood levels without posing a risk to the surrounding community, ecological functioning is it providing a healthy habitat, allowing the movement of aquatic life and plants and animals along the waterway?
One of the four criteria is connectivity to the water table to the floodplain. So that speaks to that concept of analyzing our rivers and actually what we want to do now is actually re-establish that connection between our groundwater and our surface water systems. We also have legacy land use challenges in South Africa with, you know, 1992, apartheid government and land use zoning, where we often our communities were separated and that could be a railway line, could be a road or even a river.
And certainly that's not what they were created to do. They rivers should foster community engagement. So the fifth criteria of a livable urban waterway is it's to connect the communities, come together. And then the sixth criteria being ecosystem services and benefits. We want our urban waterways to give us the sort of undefined benefits in terms of potential water quality improvements, social well-being, typically harder to define and potentially even economic benefits.
And I think this is the study in the Sand River. But that really came to the fore because you've got the Zandvlei Estuary, which is a beautiful estuary with potential as a water sports hub. You've got reason to make the beach a tourist destination and on account of the water quality challenges at these sites, they had to be closed in terms of the Sand River and they were newspaper articles on the museum, the beach water quality and obviously if you want to solve the water quality at the estuary, you actually have to look at the whole catchment. And that's the approach that the city's taken to this. So it was a fantastic study. We brought the groundwater expertise and there was a whole panel of specialists, from landscape architects to ecologists and botanists, that just wonderful to be working on a project of this nature with the city to address one of its rivers. And they are rolling this program out at other rivers now as well.
00;32;08;15 - 00;32;23;18
Bridget Scanlon
That's fantastic. That comprehensive approach there. And, you know, looking at all aspects and trying to improve the situation is all the wastewater treated in Cape Town. So you don't have any discharge of untreated wastewater, do you.
00;32;23;20 - 00;32;46;26
Dale Barrow
So that is an issue. And some of our target sites were based around now where we suspect the city sewerage infrastructure is leaking or where they are sewage leaks. So certainly the goal is to have all wastewater treated within the city of Cape Town. They are areas outside of the Sand RIver. Oh yeah, I think outside of the Sand River catchment where we've got informal settlements.
And that poses a significant risk to groundwater quality. So there's some real concerns in areas where we don't have sewage treatment, but for the most part we do. But even where we do have these leakages that are affecting river quality. So some of the improvements were because also our stormwater quality poses a risk to these systems. So some of the recommendations that came out of our study was a stormwater sort of holding bay, because what we were finding was that the really poor quality stormwater was in your dry season where you don't have that dilution effect.
So just having a full bay where you could retain that a trap. And the main recommendation coming from our study, as well as some of the other specialists, was around slowing the flow down, creating over general wetlands riprap sections within the river to slow the flow, allow for infiltration, interaction with groundwater and some of the natural attenuation from these wetlands and river sites.
00;33;42;06 - 00;34;01;15
Bridget Scanlon
So I guess these are some of the what we call nature based solutions now to improve water quality and even out the water discharge and stuff. And so you mentioned that in the past, a lot of the rivers were canalized to try to get the water out as fast as possible. So are you actually removing the concrete and relocating some of these canals? That must be fascinating to re-engineer to make it more natural.
00;34;05;22 - 00;34;22;11
Dale Barrow
Yes. So I think we had the easy job of looking at the groundwater levels and what I expect would happen. So it was interesting. It was obviously a disconnectedstream, and you could see that in the hydraulic levels between the river and the groundwater, and we could make predictions in terms of what was going to change when they removed the canal lining.
But we didn't have to then wrestle with the flood mitigation. So we've got hydrologists on the team that are then modeling the impact of removal of these canal linings and making recommendations to ensure that, as per livable urban waterway criteria. Number four, I think it was number four that the river doesn't pose a risk to the communities living adjacent to it.
00;34;45;15 - 00;35;13;03
Bridget Scanlon
The sponge city concept. I mean, I learned about it first from work in China and stuff. So I think to try to make a more interconnected system so you can reduce flooding impacts and maybe have a more connected surface water groundwater system and then improve ecosystems. So it's a really a nice approach and less gray infrastructure and more nature based solutions with wetlands improving water quality, all of these sorts of things.
And as you mentioned, interaction with the groundwater to filter water to. So that's very interesting. The Cape Flats aquifer, that's a shallow aquifer underneath Cape Town. I'm not sure how deep the water table is, but because it is shallow water, it's vulnerable to contamination and industrial effluent and leaking sewers and stuff. Maybe you could describe to people that, you know, you've got these paleo channels with the sands and stuff, and how are you going to protect the groundwater? And with the water quality in the Cape Flats? and are a lot of the residents that drill boreholes during the drought period, are they accessing your flats aquifer and now the the water quality that they're getting good. Or are they just using it for the lawn irrigation and things like that?
00;36;03;26 - 00;36;22;15
Dale Barrow
So certainly, yes, there were some residents drilling into the Cape Flats aquifer, although typically a lot of the affluent suburbs are off the Cape Flats and they're called the Cape Flats because it's these sand lands or Trinity deposits. A lot of the more affluent suburbs on the slopes are Table Mountain, so they don't really have access to the Cape Flats aquifer.
It is not the high yield portion of the aquifer that they typically drill into what we wouldn't consider significant aquifers. But as you mentioned, the Cape Flats aquifer has significant risks and even legacy impacts in terms of the land activities that are taking place, then their impacts on groundwater. It's called sand deposits with very shallow water table. And this is quite interesting.
So we've spoken about these the big six supply dams. They're all situated in ternary catchments outside of the city of Cape Town. So the city is effectively importing water from these catchments into the city. And the Cape Flats Aquifer underlies a large portion of the city, and from discharges from wastewater treatment works or from leaching infrastructure. There's a lot of return flow that's going back into the aquifer actually imported from these catchments. And what we're finding is that we've actually got very shallow water table across the Cape Flats, even flooding, lots of ponding. And that obviously also exasperates the potential for contamination if you fly into Cape Town, one of the first things you see is just this massive, sprawling, informal settlement.
So then again, we come back to this issue of waterborne sewerage, and we don't have that within these these locations. Often the waste handling is not sufficient. So there's a massive impact on groundwater in this region. And the Cape Flats aquifer is also one of the strategic supply sources identified for the city of Cape Town. So they're looking at getting 30,000 million liters per annum from the Cape Flats aquifer probably amounts to, but probably less than 5% of their total volume of supply.
But in a drought scenario that that percentage would increase and one of their big concerns is this water quality. So to mitigate that risk, they're looking at treating wastewater to potable standards and injecting that as a barrier to prevent further ingress of contaminated water, of saline water, because there's also the saline intrusion risk and hopefully in time to improve the water quality within the aquifer.
There are still pockets where there's good quality water. There's a whole agricultural region, which also poses a risk in terms of water quality, but that's dependent on that same aquifer. The Philippi Horticultural Area is using a lot of that to produce food for the city. So it's a fantastic resource. But the potential impacts on quality are many. And I think that probably goes for most urban aquifers.
00;39;05;18 - 00;39;27;00
Bridget Scanlon
I was just visiting in in Brazil this fall. And so the city in Bauru north of Sao Paulo, it has a shallow aquifer also that they like to use. But but it's very vulnerable to contamination from urbanization and all the related aspects. You know, after the Day Zero drought, a lot of things, they're changing. You try to develop more resilient systems and stuff.
So one of the things was the Table Mountain Water Source Partnership was established. And maybe you can describe that a little better Dale.
00;39;36;20 - 00;39;58;01
Dale Barrow
Okay. So strategic water source areas, they've been defined as areas within the country that provide a district unit amount of water relative to the surface area or provide strategic water sources. One of the things that came out of this delineation of these strategic water source areas was that 50% of our water comes from less than 10% of our land surface.
So we've got these strategic areas that we need to protect in terms of our water security as a country. And the Table Mountain water source area. It's both a groundwater strategic area as well as a surface water. So from both perspectives, Table Mountain itself is almost like a water tower generating additional precipitation. And there's a number of dams on the mountain as well.
From both these perspectives and particularly coming out of the drought, there was this concern, you know, what is the impact of all this unregulated drilling and groundwater development on the foothills of Table Mountain and across the city? This is a strategic water source area. We need to make sure that the water that's yeah, is available for future generations and yes, maybe private residents.
And using that much water that made it to death by a thousand cuts. That was one of the terms. That was when during that period, and we actually had quite a nice project, which really preempted the formation of the Table Mountain Water Resource Partnership, that it was around a citizen science project where we engaged residents in suburbs where there was a lot of groundwater development.
So to more affluent suburbs, we did a hydro census, literally door to door, trying to get a sense of how many boreholes there were. You know, we found borehole densities in excess of 800 boreholes per square kilometer. So if evenly spaced, that's a borehole every 50 m. So obviously this is a shared resource where residents are going to be impacting on each other.
And what we did in these six communities where we did this project, which were the higher density regions, was we offered water table pressure transducer. So we said, listen, we don't want to know how much you're using because typically residents were reluctant to share that. But we can monitor water levels from your well we would appreciate that data.
And we had buy in from residents across these areas. And we initiated a monitoring network around Table Mountain. And then it was in, I think, 2021, that the Table Mountain Water Source Partnership was officially established. WWF played a key role, both in terms of our project and establishing the partnership and now what the partnership seeks to do is through monitoring to inform management and the protection of this water source area.
So we asked to volunteer on that. As part of that partnership. And really what you're trying to do is just integrate data into a single repository and make that accessible so that users who are using a shared resource are aware of the health of that resource, what the water levels are doing.
00;42;25;28 - 00;42;55;21
Bridget Scanlon
That's fantastic. I hadn't heard the term hydro census before. When people can see what's happening, I think it really helps them understand and then maybe be more diligent about what they're doing and more connected to water issues of where it's coming from and how it's changing over time. So I think that is amazing. And I think, you know, making those data accessible to people through dashboards and stuff that they can look up readily.
And these monitoring networks are fantastic. It's the same, I think, all over the world. Nobody wants to tell how much water they're using. And so it was interesting when you said, that during the drought, did they actually publish to high end users? So we've had a little bit of that sometimes here in Austin even, but making people aware and in San Antonio, which is near Austin, it’s a karst system. And so it's a very dynamic aquifer system. And they often reported the water levels in key wells in the news every evening, you know, so people can understand, you know, how the drought situation is on the groundwater levels and things like that. So very important to communicate these things to the public and the stakeholders.
00;43;40;18 - 00;44;00;02
Dale Barrow
You're so right. And I think in terms of the city, they've got it right in terms of the surface water resources. So during the drought, they started publishing these dashboards in terms of consumption as well as the dam levels. And still, even after the drought, people are watching the dam levels. We need to get there in terms of groundwater and typically groundwater is actually a little bit misunderstood.
It's out of sight. But that's certainly what the Table Mountain Water Source Partnership is trying to achieve, just to make that data available and to communicate it in a way that makes sense to your everyday citizen. Now for the city.
00;44;11;26 - 00;44;37;20
Bridget Scanlon
I'm not sure if it was last year, but the United Nations had the problem of Groundwater making the invisible visible. So I think doing some of these activities and stuff and getting the citizens involved in monitoring would make it more visible. So I really enjoyed looking at your website. You guys do a great job of portraying all the different activities and stuff the GEOSS is involved with in all of the different approaches you use.
So it seems like you were also working with various municipalities around South Africa, and there were a number of different project descriptions where you're looking at groundwater for small cities, you know, populations of 3000 to 5000 people. And I guess in those regions, oftentimes groundwater is the only option. So maybe you can describe it in Phantom Karoo project or some of these other projects a little bit in how you help them with developing the resources.
00;45;09;25 - 00;45;29;15
Dale Barrow
Yeah. So South Africa is a country of contrasts. And we've spoken a lot about the city of Cape Town, which is possibly arguably one of the best running municipalities in the country. So we've got a lot of other municipalities that are not on the same level in terms of investment in their supply sources or attention in terms of groundwater.
So the City of Cape Town is one of, I think, two municipalities that actually employs a hydrogeologist. This is despite the fact that we've got numerous municipalities where groundwater is the only supply source. But that doesn't mean they employ hydrogeologists. So we've got a long way to go in terms of groundwater management and at a municipality level, and just recognizing the need for hydrogeological skill sets, municipalities and other municipalities within South Africa have faced they've actually realized a Day Zero scenario.
I think what, you know, Cape Town was prominent. It's a big city that a lot of people know about, but we've got lots of cities, small towns actually, that have actually had to do water shedding and typically, you know, what's resulted in that? Yes, drought conditions. But we've got huge issues with vandalism and theft. So often these droughts are now almost made worse by the loss of resources, lots of boreholes to that supply town.
So we've done numerous towns in terms of developing additional supply, and we currently busy with Lamberts Bay. That's a town that's close to running out. And we've gone through the process of firstly doing a hydro census similar to what we did in the Hunter Karoo, as you were asking about. So hydro census is really just trying to establish what yield and quality brown water is available in the region surrounding the town, and that's typically our starting point for any groundwater exploration and development project.
We follow that up with some geophysical surveys depending on if you in the Karoo, we've got these dolomite intrusions which, they can't control in terms of groundwater flow. So a magnetometer which while for picking up the dolerites, otherwise electromagnetics or resistivity surveys and typically about geophysical survey as we go into exploration, drilling and production, borehole drilling and and then obviously it becomes a wrestling match because where the water is most of the time, it isn't very convenient in terms of incorporating it into the town supply. So that's always a factor as well. I think one of the challenges we face with our municipalities is that the budgets only really become available when the crisis is being realized for these intervention projects, so we're hoping that's changing. The Department of Local Government is investing in assessing water security across the province, but we need more of that at a municipal level, investing in the long-term supply sources for these towns.
And then we are also involved in some of the other towns in terms of their resourcemanagement. As I mentioned, they typically don't employ hydrogeologists. What we find is that often they're not equipped to even measure a water level borehole or to collect a water sample, and they don't know what the water quality is that they're supplying to the town.
So using fairly simple hydrogeological skills, measuring a water level, collecting a sample and interpreting that data, you can actually have very meaningful results in terms of saying, you know, don't use this borehole. The nitrate levels are dangerous. Rather, use this one, rather pump this one. So it's quite rewarding work, I find, because without doing too much rocket science, you're able to make a real difference in a very tangible way, which is, yeah, one of the blessings of working in this industry and the space that we do.
00;48;41;17 - 00;49;00;26
Bridget Scanlon
When you describe these hydro sensors, it reminds me when I began my career in was doing research in southwest Ireland. I was on a bicycle and I had my water level meter in the basket in front of my bicycle and going around. I was really fit because I was riding 30, 40 miles a day doing the census, you know, measuring water levels and everything.
So it was amazing. Yeah, I wish I could go to that maybe these days. and you mentioned, you know, a lot of these small communities, they don't have a hydrogeologist, but, I mean, they really don't have the expertise. And we had the same issue in the US. We have these small rural systems. I mean, even in Texas, they're like 4600 public water supply systems.
And a lot serving very small communities. And then if you have a drought and they don't really know when their well is going to go dry or things like that, they're supposed to let the State know when they've got so many, you know, 180 days supply, these sorts of things. But I don't think they know that. So it's a real issue managing these small rural systems.
And in terms of both quantity and quality, because we have, you know, systems with a lot of contamination just from natural sources like arsenic and fluoride and things like that. And non-point source agriculture, like nitrates, like you mentioned, plenty of challenges there. So plenty of work for GEOSS for many years, the future. So it's very interesting.
You hosted the International Association of Hydrogeologists meeting last year in South Africa. And this coming year you will be hosting the International meeting for a managed aquifer recharge ISMAR, which I hope I would be able to attend. Very dynamic, very integrative globally. And you've got a good community and maybe you can describe as well what your outlook is for water management in the future in South Africa.
Are you optimistic about the situation and increasing resilience to these climate extremes? And as we were just talking at the beginning, you mentioned, you know, you talked maybe you might be facing another drought issue without El Nino conditions. But I was looking at the reservoir data and they're all almost full at the moment. So you didn't see that. And then you mentioned something about atmospheric rivers, which I've talked on the podcast with some people in California.
So these intense events, they're very interesting. And when I was talking to folks in Brazil, they call them flying rivers. So we're always learning new things. So it makes it, fun that I think.
00;51;16;14 - 00;51;39;02
Dale Barrow
Yeah, it is a lot of fun. I heard about atmospheric rivers at World Water Week in Stockholm just before the Davos conference, and it's absolutely fascinating. And apparently that's what saw the deluge that we got. I think it was in July months this year, which actually, you know, they were concerned, as you mentioned, around potential dry year. It's not that long ago that we had the Day Zero scenario.
So people were watching the dam levels. And then we had a lot of rainfall and atmospheric rivers played a role. But I think you can certainly teach me more about what that is. I just think it's fascinating from the little I've seen that issue. Right. And we've got a very active and engaged hydrogeological community here in South Africa.
We actually took a photo at the World Groundwater Congress, and I think about 15 of us that made it all the way to Switzerland. And our currency does not go far when it comes to Swiss francs. And just to see that representation there, that was very positive. And then I think we've got a lot of towns that are very dependent on groundwater, particularly fractured rock aquifers.
And so over the years I think we've developed fairly good practice and a fairly established groundwater industry. we've got the groundwater division, which forms part of the Geological Society of South Africa, and they're very active in terms of training, developing, doing topical talks. So I think we've got a fantastic community. And yeah, it's a privilege for us to be able to host the groundwater conference like we did last year.
And then coming up next year. And I think it's just yeah, we're very blessed to work in this space that we do. It's such an interesting, rewarding field and there's so much opportunity to use it to do good. Yeah. In South Africa and on the African continent, you know, I think in many African countries and even parts of South Africa, there's actually groundwater that can be developed and used to support development.
Groundwater is often underutilized. Yes. In South Africa, we've got areas where we need to focus more on the management and protection and management take into consideration surface water systems. But there's a lot of large parts of Africa where there is groundwater to be used, which could sustain communities and used in agricultural and industrial development to benefit those countries.
And so I think we've got a big role to play in that. And like I mentioned, even and you mentioned it as well, just measuring water levels can lead to some fairly powerful detections, whether the use of the resource is sustainable, how it's performing in a drought, scenarios there fairly easily, we can make a big difference. And yes, I am privileged to be in this, the space and working in the industry that I am.
And then you asked me optimistic, I think so, in South Africa, there's a slightly heightened level of optimism at the moment, not just from a water perspective, but we've got a government of national unity, which is really what we need with such a diverse country, so many different languages, and cultures. And we've got a government that represents that for the first time in a while.
And so everyone's feeling a little bit of optimism. We haven't had loadshedding, which is when they turn the electricity off for more than half the year. And in terms of water supply, certainly in the Western Cape, things are looking better for. I know further abroad, southern Africa will be potentially looking at another drought as we're going into the summer season, which is a rainfall season up north and northern Namibia, Angola, Zambia.
I've heard it said that if they don’t get the summer rains, you know, we could be looking at a famine. So it's quite a big region that's covered. But again, I mean that just speaks to the need for scientists to be willing and ready to use our skills to uplift and help those around us.
00;54;49;12 - 00;55;10;14
Bridget Scanlon
That's fantastic. And I agree, and the world Bank did a report on the groundwater use in Africa, emphasizing that there was a lot more potential for groundwater development And others have talked about that in the past in the podcast. So I think that's great. And that's a challenge we need to meet as hydrogeologists.
You mentioned a potential drought further north. And I know in the Horn of Africa, the Famine Early Warning System group. And Chris Funk was one of the first people I interviewed. You know, their ability to forecast droughts up to six months out and get the organizations together to avoid famines is very powerful. And so a lot of ways to adapt to these things and science helps.
So our guest today is Dale Barrow. He's the director of GEOSS in South Africa, a Groundwater Consulting company. Thank you so much for your time and for describing the situation in Cape Town and surroundings. I really appreciate it.
00;55;50;03 - 00;55;52;01
Dale Barrow
Thank you for the conversation, Bridget. I've enjoyed it.
