Sand dunes and the St. Lucia estuary issues

 Greetings to all who read here. It is Thursday  20 October 2022 and WE need to do something soon, coz the problems are growing faster than the solutions are being discussed, never mind the implementation issues.

The April / May 2022 floods have caused many different problems, and in my mind, the biggest problem for our fish breeding grounds is the vast quantiles of silt that has dropped out at the most inconvenient places for nature to have any chances of restoring any sanity to the now dysfunctional natural breeding grounds for many marine fish species and other creatures like crabs, jellyfish and prawns that used to flourish in our local ecosystems within the Greater St. Lucia Wetlands Park.

One needs to remember that the St. Lucia Estuary Mouth was closed when these flood waters struck our waterways in May 2022. These many different waterways, in the area each have distinct and separate issues. some of these water ways  that matter more are 

1. The Northern sections of Lake ST. Lucia
2. the tidal interaction channels between The Northern sections of the lake and the Ocean itself
3. Hells gate and the Nibela peninsula / False bay lake zones
4. Makataan swamp forest and adjacent fresh water input zones
5. The immediate Mouth Zone where the Umfolozi and Mzunduze river interact with the Tidal interaction channels as in 2 above
6. The tidal zone at the mouth and tidal interactions of
7. (a) the Umfolozi river
8. (b) the Umzunduse tributary of the Umfolozi river
9. the Umfolozi flats and associated banana farms on both the North banks and South Banks of the Umfolozi River
10. the Monzi sugar lands and associated flat lands
11. The Umfolozi flats
12. the Sokhulu sand flats
13. the Mapelane  swamp lands
14. Teza Pan and associated waterways

another issue to consider is that the lake water levels were already a bit high when the big rains in May 2022 struck our waterways with a rather intense speed. The speed that the Umfolozi River flood waters entered the northern sections of the lake needs to be properly understood, as does the vast quantity of river-born silt that dropped out at the zone where the Narrows opens up and fans out into the Sothern edge of lake St. Lucia. 

 

This caused a rather large un-natural blockage to grow into a nasty problem. coz when the mouth opened due to rising flood waters, the water within the Northern sections of the lake was trapped, and did not have the energy to remove the waterborne sediments that had accumulated in the system, at the spot where the water slowed down,  due to the GEF 2017 project, which connected the Umfolozi river directly to the St. Lucia lake systems, bypassing the natural silt traps of the Umfolozi flats, the Monzi flood plains and the other lower areas near Sokhulu and Mapelane. this silt dropuut was hectic.

So the vast amounts of silt that came along for the ride in the April / May Floods and dropped out at various problem zones needs to be clearly understood, as this silt is now problematic in many different areas. At the Mouth of the ST. Lucia estuary, the reeds, sedges, grasses and other riverine plants have enjoyed this silt and are now doing very well. These are all growing in the mud flats, which should be sand flats,  These well-established plants are now acting as a final sand arrestor, at the western end of the fast-growing sand dunes that are getting very problematic. this wind born sediment is joining the water-born sediment and forming a distinct top layer which is fast turning the mud layer into very hard bentonite-enriched  sand sludge that will soon be setting into very nasty river-born sediment and other  stuff.  

What would this be called? we need some scientists to come and explain more about this  cement-like stuff to the public so that the public can start to use this information to force the issues and ensure that we get government interventions and make sure that our fish breeding grounds are repaired and made functional before too much damage is caused, coz with ZERO juvenile recruitment there will soon be no fish. If our fish breeding grounds are not functional there will be no juvenile recruitment.

So please help the 4u2fish campaign to put pressure on the relevant political structures so that the problem can be addressed as soon as possible. read more at our FB Pages facebook.com/4u2fish

October 2022 udate to a 2018 post disussing marine water flow

 It is now October 2022 and the mouth of the St. Lucia estuary is currently open.  but ... there are now even bigger problems, coz the silt that came along for the ride, during the April / May 2022 floods, and stayed behind in problem zones,  is preventing the flood waters from returning to the ocean.

I am not an artist, and can't find somebody to draw a few pics to explain the issue, so let us test my storytelling skills.. and find out if I can tell the rather nasty story around the silt issue in just words...with no images...

Well, the story is all about the SILT and debris that come along with flood waters.

So when water is flowing fast it can pick up stuff and carry that stuff along for the ride. what stuff are we talking about here? Well, any small loose stuff like topsoil, leaves, dead grass, plastic bags, and any wind-blown items. this all ends up in the river.

So not all this stuff ends up at the bottom end of the water flow pattern, which is the ocean. Sea water evaporates, it rains, the rainwater flows back into the sea then the cycle continues. but the debris and stuff carried to the lower end of the water flow cycle is the issue.  this stuff can not be evaporated by the sun, so it just accumulates and accumulates more.   Now the 2017 GEF-funded project which connected the Umfolozi River System to the Northern sections of Lake St. Lucia needs to be very carefully added to the narrative here, coz this nasty crime against the environment was supported with great vigour and pleasure by the IWPA, which had alternative agendas that the iSimangaliso Wetland Park Authority needed to address. 

Removing the natural renewable resources from the local environment would suit these guys (IWPA) very nicely, coz that would bankrupt the local folks, and thus prevent them from acquiring legal assistance during their expulsions from the area,  why? coz t is a world heritage site, so the locals must pack up their bags and leave.   The locals however showed the IWPA a very big toffee, and basically stayed put, and are now indigent and living in a space that should be abounding with nature, but is a rather nasty-looking space where drought has taken its toll, and the environment is in a very bad way.

The fact that the elites operating high-end International tourism businesses from the town / village of St Lucia, see these local folks as "POACHERS" and undesirable is due to the extremely successful public perception management strategies applied by one ANDREW ZALOUMIS as CEO of the IWPA, following instructions from the national tourism bodies... Remember the Transfrontier park Any way let's focus on the mud stuff.

If water is carrying stuff (SILT) along coz it has some speed, where will this stuff all end up? 

Well, that answer is simple... wherever the water slows down... the slower it gets the more stuff drops out.  Now the issue suddenly becomes where does the water slow down enough to cause dropouts to start happening?

Now the area from the N2  (National Road) to the ocean is rather far, about 25 KM, and with some twists and turns in the Umfolozi River pathway, that ends up at around 30 Km. Within this space, the Umfolozi river floods its banks and starts filling up the Monzi flood plains, the Umfolozi flats, the Sokhulu swamps and Mapelane bogs, but still flows rather strong in the true flow zone. 

the water flowing in the true flow zone of the Umfolozi River soes not actually slow down, and rushes along carrying its silt load all the way, back inalnd through the St. Lucia narrows, coz of the 2017 GEF Project.

This means that the water in the true flow zone is still carrying gross volumes of silt.  During the last few years in the post-2017 GEF project years, this has repeated many times over, with enormous volumes of silt being deposited at the Northern edges of the narrows, where the St. Lucia Narrows join the ST. Lucia lake system, at the lake's most southern tip. 

So the Northern end of the narrows (Fast flowing water) meets the Southern edge of the lake,(Standing water)  and then stops flowing instantly.  This causes the most horrid scenario where the silt just builds a big wall of heavy silt dropouts.  

During flood times the water arrives at this build point shown in the Google Map Below, and this is serious.  coz why? coz the silt carrying water continues to arrive   .. and continues for days, last time in the April / May 2022 floods the water carried on coming for more than 6 weeks... think about that for six weeks !!!!!!

60 seconds in a minute... then

60 minutes in an hour... then

24 hours a day... 

then 7 days a week ...   

for six weeks?   6 whole weeks..?

All this water was carrying silt, and the silt all dropped out where the water slowed down...  the wall that is still there now is a true nasty problem, and we as human beings need to do something, coz we as human beings caused that silt to rnd up in that space. If nature was left to take its own course, this would never have happened. The mouth would have opened, and the silt would have been deposited in the ocean. The ocean is a high-energy zone, and the silt would have been distributed over a very large area, causing minimal negative impacts. The opposite is now true, where the silt has accumulated in a very small area, and now acts as a dam wall keeping the Umfolozi Flood waters within the Lake St. Lucia system.