Damage done as the drought deepened in last six months of 2019 means much more rain is needed in the Kariega River catchment before dams downstream start filling up, say farmers in the area. That’s despite the fact that record keepers indicate January 2020 has been the wettest January for that area since 1956, and the all-time highest for Makhanda.
Makhanda’s water shortage is caused in part by drought, which has depleted dams that normally supply the west of the town. Settlers and Howieson’s Poort dams are in the Kariega River catchment and are the main supply dams feeding Grahamstown West and the town centre. According to the Institute for Water Research, these normally supply 77% and 11% of the total western supply system respectively. Water is pumped from Settlers to Howieson’s Poort Dam and then up to Waainek Water Treatment Works for purification before being released via gravity through the pipe reticulation and lower level reservoirs to the taps in the western half of Grahamstown.
The ongoing drought means these rain-fed dams have been at a level too low to be pumped and so all
areas of town now rely on a limited supply of water from the Orange-Fish River scheme via the James Kleynhans Water Treatment Works east of Makhanda. In a statement last week, Makana Municipality said until the facility’s upgrade is completed in 2021, it is able to supply only 12 megalitres a day. The town’s consumption is greater than 12ML, Makana said, explaining throttling and outages. In addition, loadshedding has reduced the time available to process and pump water.
Many residents want to know if the unusually high rainfall in both the catchment and in town over the past five weeks means the dams west of the city have filled up and the problem is over. The answer is unfortunately no.
Mosslands, above Settlers Dam, has rainfall records dating back to 1908. Richard Moss says January 2020 has been the second wettest January since 1956, second only to 1974.
Mosslands’ rainfall total for 2019 was 331mm. January 2020 alone brought 114mm, with Tuesday bringing another welcome 4mm. “And today [Thursday] we’ve had 28mm so far.”
But that doesn’t mean there’s water running in the river yet.
“Normally 120mm in a month will result in runoff,” Moss said. “But it’s been so dry that the rain has just soaked into the soil.”
Dale Howarth, Director of Pumba Private Reserve and Chairperson of the Central Albany Agricultural Association (representing farms from Sidbury to Makhanda), says the rain has been fantastic for the veld.
“The grass has recovered 75%. The bush is at 55%: it’s slower growing so it will take much longer to recover. Also we’re looking at serious damage caused by the last six months of last year.”
The good news is that because of the timing and nature of rainfall over the past month, the soil has absorbed the water well.
“The roots are binding the soil, which is good news because it means the topsoil isn’t all washing away,” Howarth said. “If we have more of this and the guy upstairs opens the taps in about three weeks, I think we could have some good runoff!”
Figures for the area over January range from 70mm to 135mm and most measurements reported for February so far are around 45mm.
January figures are as follows: Sidbury – 75mm; Highlands – 130mm; Kwandwe – 135mm; Pumba – 130mm; Carlisle Bridge – 130mm; Riebeeck East – 130mm.
In town, the rain-watchers who generously share their weekly measurements with our readers also recorded unusually high totals. Gill Maylam, in Sunnyside, recorded 58.6mm in the week 30 January to 5 February. During the same period Jim Cambray, in the Kingswood area, recorded 48.5mm, with temperatures ranging from 17.5-36C.
“Total rainfall for January was 136.5mm which is an all-time high for us,” Cambray said. “The average for the month is 59.6mm and the mean is 54.5mm with a previous range of 26mm (2003) to 113.5mm (1994).”
Updating the situation on Friday 7 February client liaison officer at the South Aftican Weather Service Garth Sampson is that there will be light rain showers today and overnight a few moderate showers. It will start clearing over the west tomorrow morning.
Rainfall in Makhanda yesterday was 54.8mm SAWS reported.
“This rainfall has done nothing to solve our water crisis and people must continue to use water sparingly,” Sampson said.
It’s not better yet
Reporting back from a meeting on 6 February of the city’s water joint operations committee, Grahamstown Residents’ Association chairperson Philip Machanick posted as follows:
Why it is worse than last year…
Two factors are worse than the situation in the later part of 2019, when James Kleynhans was fully functioning. Loadshedding is putting a lot of stress on the system and there is no longer any water (other than an insignificant amount from three boreholes) from Waainek [Water Treatment Works].
Loadshedding…
The water plants and pumps are fed from a separate high voltage line so it is not correct that if you are in the vicinity of James Kleynhans and see no loadshedding that the water system must still be receiving power.
Stage 2 loadshedding can be up to five hours per day; this reduces capacity by up to 3 megalitres per day, so instead of pumping 12Ml to Botha’s Hill (BH) reservoir, only 9Ml can be pumped. Limiting factors are the speed of the pumps and the amount of water the plant can process before quality drops unacceptably; 12Ml/day is already 20% more than the design capacity of James Kleynhans.
Turning major equipment like pumps that are designed to run continuously off and on increases the chances of faults. Additionally, the existing pumps are very old.
Each pump uses 530kW; across the whole system they add up to nearly 1.6MW and generators on this scale would be massive and very expensive.
Solar power is also not practical as it needs batteries to back up to cover fluctuations in solar power and loadshedding at night. A battery bank to cover 1.6MW for up to 2.5 hours would be extremely expensive (and this is just for the pumps: the plant needs power as well).
Redirecting power from the wind farm also would not work as it shuts down when the external Eskom power shuts down and output is also highly variable.
Why High Levels on the west are starved…
The way water feeds to the west is from James Kleynhans which is being pumped to the BH reservoir: BH in the east flows via gravity to the Intermediate reservoir in the west. If Botha’s Hill is not very full, that reduces flow to the west.
The Intermediate Reservoir water then is pumped to the High Level Reservoir. But if the Intermediate is not full enough, pumping to High Level is not possible. Lower levels are fed by gravity from Intermediate so demand from lower levels on the west can prevent Intermediate from topping up enough to pump to High Level.
If people in lower levels can save as much water as possible, there is more chance that the higher levels get some.
Addressing the issues…
Eskom has been asked to exempt James Kleynhans from loadshedding and there are attempts to understand why the further upgrades of James Kleynhans are being held up in litigation (this project is being managed by Amatola Water, not Makana).
Better communication strategies are being worked on, particularly to inform the public of how the water system works and what they can do to mitigate starvation of higher levels.
https://www.grocotts.co.za/2020/02/06/neighbours-fire-fighters-battle-as-lightning-sparks-veld-fire/
