5.5 North Coast System

5.5
5.5.1
North Coast System
Description
The North Coast System comprises of the Mdloti System, the Lower Mvoti System and the
Lower Thukela System (Figure 5.57). These systems have been grouped together because of the
current (and proposed) water resource interdependencies and infrastructure integration that is
required to supply bulk potable water along the coastal strip of the North Coast region. The
North Coast System is located north of Durban stretching along the coast from the Mdloti River in
the south to the uThukela River in the north (Figure 5.57). It encompasses the Nonoti River
catchment (U5), the lower Mvoti River catchment (U4), part of the Mdloti River catchment (U3) and
the lower uThukela catchment (V5).
The bulk supply infrastructure along the coastal strip is known as the North Coast Supply System
(NCSS), and currently comprises two bulk supply systems, viz:
 The Mdloti Supply System serving Phoenix, Verulam and La Mercy in northern eThekwini, a
portion of rural Ndwedwe Local Municipality, the coastal towns along the Dolphin Coast and
the low cost housing areas of Etete and Groutville; and
 The Mvoti Supply System serving the town of KwaDukuza (previously known as Stanger).
In addition to this bulk system, Umgeni Water implemented the Maphumulo Bulk Water Supply
Scheme in May 2013 to eradicate some of the backlogs and alleviate the supply problems of the
borehole schemes in the rural areas of iLembe DM. Umgeni Water further manages 32 smaller water
supply systems for Ilembe District Municipality, some of which are shown in Figure 5.57. The Mdloti
Supply System is presented in Figure 5.58. A schematic of the bulk water distribution is presented in
Figure 5.59. Other schemes that supply potable water to people in the region are Umgeni Water’s
Durban Heights WTP, eThekwini Municipality’s Tongaat WTP and Ogunjini WTP (previously owned
by Umgeni Water) and Ilembe District Municipality’s Zinkwazi, Blythedale and Darnall schemes.
304
Figure 5.57 General layout of the North Coast Supply System.
305
Figure 5.58 Detailed layout of the North Coast Supply System.
306
KwaDukuza (Stanger)
Ø 350
Darnall/Zinkwazi
LEGEND
Mvoti River
Tunnel
Mvoti
WTP
Umgeni Water Pipeline
Mvoti
Balancing
Municipal Pipeline
Ø 800
Sales Off-take
New Infrastructure
Ø 200
All diameters in mm
All flows in Ml/day
Honolulu-Mvoti PS
Ø 800
Stanger Tanks PS
Ndwedwe Retic
Kwahlope
Ndwedwe
5
Ø 250
Ø 300
Groutville
Ndwedwe
4
Ø 250
Etete
2Ml
Honolulu
Ø 300
1.94Ml
Shakas Kraal
8Ml
Umhlali
Ndwedwe
3
Ndwedwe Retic
Salt Rock PS
Ø 350
Shakas Head
Hugh Dent drive
Shakas Rock
Avondale High
Ø 350
4Ml
North Coast PL I
Ndwedwe
2
Ndwedwe Retic
Ø 1000 – 800
North Coast PL II
Ø 350
2Ml
Ballito Lea
Ø 375
15Ml
5.3Ml
Ballito and Zimbali
Tongaat
300 Backfeed
Mdloti River
Hazelmere to Bifurcation PL
Hazelmere
WTP
Ø 450
Nyalinga and
King Shaka
Airport
Grange / Verulam
Ø 300
Hazelmere
Dam
Avondale
Belvedere
Ø 700
4Ml
Ø 500
Ndwedwe
1
Ndwedwe Retic
Ø 500
Waterloo /Phoenix
Ø 375
Figure 5.59 Schematic of the North Coast Supply System.
307
La
Mercy
La Mercy
5Ml
Hazelmere Water Treatment Plant
Hazelmere Dam is the source of raw water for the Hazelmere WTP (Figure 5.60, Table 5.52). The
current yield of the dam, at a 98% assurance of supply, is 55 Mℓ/day. The WTP currently has a
capacity of 45 Mℓ/day and receives raw water through a 600 mm diameter Asbestos Cement (AC)
gravity pipeline and recently commissioned 800mm diameter steel pipeline routed from the dam to
the WTP (Table 5.53).
Figure 5.60 Hazelmere Water Treatment Plant.
The treatment process at Hazelmere WTP consists of chemical dosing, clarification, filtration and
disinfection. Sludge treatment is by means of gravity settling and a Centrifuge Sludge Dewatering
System. The characteristics of the Hazelmere WTP are shown in Table 5.44.
308
Table 5.52 Characteristics of the Hazelmere WTP.
WTP Name:
Hazelmere WTP
System:
North Coast Supply System
Maximum Design Capacity:
45 Mℓ/day
Current Utilisation:
44 Mℓ/day
Raw Water Storage Capacity:
0 Mℓ
Raw Water Supply Capacity:
90.0 Mℓ/day
Pre-Oxidation Type:
Prechlorination
Primary Water Pre-Treatment Chemical:
Polymeric Coagulant
Total Coagulant Dosing Capacity:
15 l/hour
Rapid Mixing Method:
Conventional Paddle Flash Mixer
Clarifier Type:
Clari-Flocculator
Number of Clarifiers:
3
Total Area of all Clarifiers:
1469 m
Total Capacity of Clarifiers:
45 Mℓ/day
Filter Type:
Constant Rate Rapid Gravity Filters
Number of Filters:
9
Filter Floor Type
Laterals without Nozzles
Total Filtration Area of all Filters
324 m
Total Filtration Design Capacity of all Filters:
45 Mℓ/day
Total Capacity of Backwash Water Tanks:
180 m
2
2
3
Total Capacity of Sludge Treatment Plant:
Capacity of Used Washwater System:
0.98 Mℓ/day
Primary Post Disinfection Type:
Chloramination
Disinfection Dosing Capacity:
30 l/hr
Disinfectant Storage Capacity:
Total Treated Water Storage Capacity:
25 Mℓ
309
Table 5.53 Pipeline details: Hazelmere Raw Water Pipeline.
System
Pipeline Name
From
To
Length
(km)
Nominal
Diameter
(mm)
Material
Capacity*
(Mℓ/day)
Age
(years)
North Coast
Hazelmere Raw Water Pipeline
Hazelmere Dam
Hazelmere WTP
2.42
600
AC
48.93
31
North Coast
Hazelmere Raw Water Pipeline
Hazelmere Dam
Hazelmere WTP
2.42
800
Steel
90.0
0.3
* Based on a velocity of 2m/s.
Table 5.54 Reservoir details: Hazelmere WTP.
System
Reservoir Site
Reservoir Name
Capacity
(Mℓ)
Function
TWL
(aMSL)
FL
(aMSL)
North Coast
Hazelmere WTP
Hazelmere WTP
25
Balancing
47.0
42.0
310
Hazelmere/Phoenix Sub-System
The eThekwini area of Phoenix is supplied via the eThekwini owned and managed, 375 mm diameter
Waterloo Pumping Main (Table 5.55). Water treated at Hazelmere WTP is pumped via the
Umgeni Water Waterloo Pump Station (Table 5.56) situated at the Hazelmere WTP and sold to
eThekwini Municipality at a metered point at the outlet of the pump station.
Hazelmere/Verulam Sub-System
The eThekwini area of Verulam is supplied via the eThekwini owned and managed,
500 mm diameter Grange Pumping Main (Table 5.57). Water treated at Hazelmere WTP is pumped
via the Umgeni Water Grange Pump Station (Table 5.58) and sold to eThekwini Municipality at a
metered point at the outlet of the pump station. In addition, the Grange Reservoir can be supplied
from the Durban Heights WTP via eThekwini’s Northern Aqueduct Pipeline.
Hazelmere/Ndwedwe Sub-System
This sub-system supplies the rural communities of Ndwedwe by staged pumping from
Hazelmere WTP through Ndwedwe Reservoirs 1, 2.1, 2, 3, 4 and 5 (Table 5.59, Table 5.60 and
Table 5.53). Ndwedwe Reservoir 1 also feeds the southern areas of Tongaat through an emergency
gravity line via Belvedere Reservoir. This emergency line is to augment the supply to the town of
Tongaat when the Tongaat WTP (owned and operated by eThekwini Municipality) has insufficient
water to supply the town’s needs. Ndwedwe Reservoir 1 is fed directly from Hazelmere WTP through
a 500 mm diameter steel rising main (Table 5.60) from a dedicated pump station (Table 5.61) at the
WTP.
There are three pumps in the Hazelmere to Ndwedwe Reservoir 1 and Ndwedwe Reservoir 2
pump stations of which one or two pumps are called to duty depending on the system demand.
Ndwedwe Reservoir 1 and Ndwedwe Reservoir 2 were upgraded through the construction of a
second 2 Mℓ reservoir, at each site, during 2010/2011.
311
Table 5.55 Pipeline details: Waterloo Pumping Main.
System
Pipeline Name
From
To
Length
(km)
Nominal
Diameter
(mm)
Material
Capacity*
(Mℓ/day)
Age
(years)
North Coast
Waterloo Pipeline
Hazelmere WTP
Waterloo Sales Meter
0.05
500
Steel
14.33
18
* Based on a velocity of 2m/s.
Table 5.56 Pump details: Waterloo Pump Station.
Number of Pumps
System
Pump Station Name
Pump Description
Supply From
Supply To
Static Head
(m)
Duty Head
(m)
Duty Capacity
(Mℓ/day)
KSB Omega 200-670
Hazelmere WTP
Waterloo Reservoir
112.0
125
15.55
Sulzer Bb HSC
Hazelmere WTP
Waterloo Reservoir
112.0
115*
2.80*
Number of
Number of
Duty Pumps Standby Pumps
North Coast
Waterloo Pump Station
North Coast
Waterloo Pump Station
1
1
* Assumption
Table 5.57 Pipeline details: Grange Pumping Main.
System
Pipeline Name
From
To
Length
(km)
Nominal
Diameter
(mm)
Material
Capacity*
(Mℓ/day)
Age
(years)
North Coast
Grange Pipeline
Hazelmere WTP
Grange Sales Meter
0.05
375
AC
14.30
23
* Based on a velocity of 2m/s.
312
Table 5.58 Pump details: Grange Pump Station.
Pump Description
Supply From
Supply To
Static Head
(m)
Duty
Head
(m)
Duty Capacity
(Mℓ/day)
Sulzer BPK 35
Hazelmere WTP
Grange Reservoir
68.9
96
11.52
Number of Pumps
System
North Coast
Pump Station Name
Number of
Duty Pumps
Number of
Standby Pumps
1
1
Grange Pump Station
Table 5.59 Reservoir details: Hazelmere/Ndwedwe Sub-System.
System
Reservoir Site
Reservoir Name
Capacity
(Mℓ)
Function
TWL
(aMSL)
FL
(aMSL)
North Coast
Ndwedwe
Ndwedwe 1
3.94
Distribution
209.8
205.8
North Coast
Ndwedwe
Ndwedwe 2.1
0.22
Terminal
238.6
234.6
North Coast
Ndwedwe
Ndwedwe 2
4.00
Distribution
318.4
314.4
North Coast
Ndwedwe
Ndwedwe 3
2.00
Distribution
417.4
413.4
North Coast
Ndwedwe
Ndwedwe 4
2.00
Distribution
530.9
526.9
North Coast
Ndwedwe
Ndwedwe 5
1.94
Terminal
661.8
657.2
313
Table 5.60 Pipeline details: Hazelmere/Ndwedwe Sub-System.
System
Pipeline Name
From
To
Length
(km)
Nominal
Diameter
(mm)
Material
Capacity*
(Mℓ/day)
Age
(years)
North Coast
Hazelmere to Ndwedwe Reservoir 1
Hazelmere WTP
Ndwedwe Reservoir 1
3.76
500
Steel
25.48
19
North Coast
Ndwedwe Reservoir 1 to Ndwedwe Reservoir 2
Ndwedwe Reservoir 1
Ndwedwe Reservoir 2
6.93
350
Steel
12.49
18
North Coast
Ndwedwe Reservoir 2 to Ndwedwe Reservoir 3
Ndwedwe Reservoir 2
Ndwedwe Reservoir 3
6.46
350
Steel
12.49
18
North Coast
Ndwedwe Reservoir 3 to Ndwedwe Reservoir 4
Ndwedwe Reservoir 3
Ndwedwe Reservoir 4
1.78
300
Steel
9.17
18
North Coast
Ndwedwe Reservoir 4 to Ndwedwe Reservoir 5
Ndwedwe Reservoir 4
Ndwedwe Reservoir 5
4.69
250
Steel
6.37
18
* Based on a velocity of 1.5m/s.
Table 5.61 Pump details: Hazelmere/Ndwedwe Sub-System.
Number of Pumps
Pump Description
Supply From
Supply To
Static Head
(m)
Duty
Head
m)
Duty
Capacity
(Mℓ/day)
2
KSB WKLn 150/5
Hazelmere WTP
Ndwedwe Reservoir 1
165.8
196
5.82
Ndwedwe Pump Station
1
KSB WKLn 160/5
Hazelmere WTP
Ndwedwe Reservoir 1
165.8
196
5.82
North Coast
Ndwedwe Reservoir 1 Pump Station
1
1
KSB WKLn 125/5
Ndwedwe Reservoir 1
Ndwedwe Reservoir 2
111.6
171
3.80
North Coast
Ndwedwe Reservoir 2 Pump Station
1
1
KSB WKLn 125/5
Ndwedwe Reservoir 2
Ndwedwe Reservoir 3
102.0
149
3.34
North Coast
Ndwedwe Reservoir 3 Pump Station
1
1
KSB WKLn 125/4
Ndwedwe Reservoir 3
Ndwedwe Reservoir 4
116.5
135
3.72
North Coast
Ndwedwe Reservoir 4 Pump Station
1
1
KSB WKLn 125/5
Ndwedwe Res 4
Ndwedwe Res 5
133.9
177
3.34
System
Pump Station Name
Number
of Duty
Pumps
North Coast
Ndwedwe Pump Station
North Coast
Number of
Standby
Pumps
314
Hazelmere/La Mercy/Avondale Sub-System
The Hazelmere/La Mercy/Ballito sub-system (Figure 5.58) consists of parallel pipelines, a 450 mm
and 700mm diameter steel main respectively (Table 5.62), from Hazelmere WTP to a bifurcation
point near the Tongaat Toll Plaza on the N2. One leg of the bifurcation supplies the coastal areas of
La Mercy and Westbrook Beach via the 450 mm diameter steel pipeline (Table 5.62) to La Mercy
Reservoir (Table 5.63). The other leg supplies the Avondale Reservoir (Table 5.63) in Ballito via a 700
mm diameter steel main (Table 5.54).
The 700 mm diameter Bifurcation to Avondale (Table 5.62) leg has two off-takes that can supply the
Mamba Ridge Reservoir (currently closed) and the reticulation to the Greylands/Frasers area.
Avondale/Honolulu Sub-System
Avondale Reservoir (Table 5.63) supplies the areas of Zimbali and Simbithi to the south of Ballito
through a series of gravity pipelines and reservoirs (Figure 5.58). There is a 300 mm gravity pipeline
which also supplies the areas along the Hazelmere/La Mercy/Avondale subsystem’s 700 mm rising
main (Table 5.66). In addition, Avondale Reservoir supplies water north, through the
North Coast Pipeline I (NCP-1) (Table 5.65) to Shakas Rock, Chakas Head, Salt Rock, Sheffield Beach,
and Tinley Manor. Up until December 2009, the option existed to boost pressure at the
Salt Rock Pump Station (Table 5.67) and to then supply further to Tiffany, Umhlali Village,
Shakas Kraal and the Honolulu Reservoir (Table 5.65) through the NCP-1. In 2009 Umgeni Water
commissioned the North Coast Pipeline II (NCP-2) (Table 5.66) to supply additional water from
Avondale to Honolulu Reservoir. This is a gravity pipeline with diameters ranging from 1 000 mm to
800 mm. Subsequent to the commissioning of the NCP-2, the Salt Rock Pump Station was
decommissioned.
Honolulu/KwaDukuza Sub-System
The Honolulu Reservoir, which is fed from Avondale Reservoir, supplies the areas of Etete and
Groutville and provides a supplementary feed to the Mvoti Balancing Reservoirs (Table 5.68) of
KwaDukuza/Stanger via a 200 mm diameter rising main (Table 5.69). The pressure in this
supplementary feed is boosted at the Stanger Tanks Pump Station (Table 5.70). An 800 mm
diameter pipeline and a new pump station were commissioned in November 2013 to augment the
supply of water from Honolulu Reservoir to the Mvoti Balancing Reservoirs. The pipeline and pump
station will supply water from Honolulu to KwaDukuza until the commissioning of the Lower Thukela
BWSS. Thereafter the supply to Mvoti Balancing Reservoirs will be from the Lower Thukela BWSS
and the flow in the Honolulu to Mvoti Balancing Reservoirs Pipeline will be reversed to bring water
from the northern areas of the NCSS to the south (Figure 5.59, Figure 5.69, Figure 5.70 and Figure
5.71).
315
Table 5.62 Pipeline details: Hazelmere/La Mercy/Avondale Sub-System.
System
Pipeline Name
From
To
Length
(km)
Nominal
Diameter
(mm)
Material
Capacity
(Mℓ/day)
Age
(years)
North Coast
Hazelmere to Bifurcation Pipeline
Hazelmere WTP
La Mercy Bifurcation
10.86
450
Steel
20.64*
33
North Coast
Hazelmere to Bifurcation Pipeline
Hazelmere WTP
La Mercy Bifurcation
10.86
700
Steel
49.88*
1.0
North Coast
Bifurcation to Avondale Reservoir
La Mercy Bifurcation
Avondale Reservoir
9.87
700
Steel
49.94*
15
North Coast
La Mercy Pipeline
La Mercy Bifurcation
La Mercy Reservoir
2.62
450
Steel
20.64*
15
North Coast
Avondale to Ballito Reservoir
Avondale Reservoir
Ballito Reservoir
0.83
375
Steel
19.11**
26
North Coast
300 Backfeed
Ballito Reservoir
La Mercy Bifurcation
9.79
300
Steel
12.23**
33
* Based on a velocity of 1.5 m/s
** Based on a velocity of 2 m/s
Table 5.63 Reservoir details: Hazelmere/La Mercy/Avondale Sub-System.
System
Reservoir Site
Reservoir Name
Capacity
(Mℓ)
Function
TWL
(aMSL)
FL
(aMSL)
North Coast
Ballito
Avondale Reservoir
15.0
Distribution
137.4
130.6
North Coast
Ballito
Ballito Terminal Reservoir
3.0
Distribution
117.0
112.0
North Coast
La Mercy
La Mercy Reservoir
5.0
Distribution
156.0
152.0
316
Table 5.64 Pump details: Hazelmere/La Mercy/Avondale Sub-System.
Pump Description
Supply From
Supply To
Static
Head
(m)
Duty
Head
(m)
Duty
Capacity
(Mℓ/day)
Sulzer RPK 42
Hazelmere WTP
Avondale Reservoir /La Mercy Reservoir
96
152
19.01
Samco
Hazelmere WTP
Avondale Reservoir /La Mercy Reservoir
96
135
24.00
Number of Pumps
System
Pump Station Name
Number of
Duty Pumps
Number of
Standby Pumps
1
North Coast
La Mercy Pump Station
1
North Coast
La Mercy Pump Station
1
Table 5.65 Reservoir details: Avondale/Honolulu Sub-System.
System
Reservoir Site
Reservoir Name
Capacity
(Mℓ)
Function
TWL
(aMSL)
FL
(aMSL)
North Coast
Shakas Kraal
Honolulu Reservoir
8.0
Distribution
105.0
99.8
Table 5.66 Pipeline details: Avondale/Honolulu Sub-System.
System
Pipeline Name
From
To
Length
(km)
Nominal
Diameter
(mm)
Material
Capacity
(Mℓ/day)
Age (years)
North Coast
North Coast Pipeline 1
Avondale Reservoir
Salt Rock Pump Station
7.01
350
Steel
16.65**
26
North Coast
North Coast Pipeline 1
Salt Rock Pump Station
Umhlali Off-take
3.10
300
uPVC
9.17*
26
North Coast
North Coast Pipeline 1
Umhlali Off-take
Honolulu Reservoir
6.90
250
uPVC
6.37*
26
North Coast
North Coast Pipeline 2
Avondale Reservoir
Honolulu Reservoir
17.65
800/1000
Steel
86.98**
4
* Based on a velocity of 1.5 m/s
** Based on a velocity of 2 m/s
317
Table 5.67 Pump details: Avondale/Honolulu Sub-System.
Number of Pumps
System
North Coast
Pump Station Name
Salt Rock Pump Station
Number of
Duty Pumps
Number of
Standby Pumps
1
1
Pump
Description
Supply From
Supply To
Static Head
(m)
Duty Head
(m)
Duty Capacity
(Mℓ/day)
APE Ritz
Salt Rock Pump Station
Honolulu Reservoir
44
58
3.90
Table 5.68 Reservoir details: Honolulu/KwaDukuza Sub-System.
System
Reservoir Site
Reservoir Name
Capacity
(Mℓ)
Function
TWL
(aMSL)
FL
(aMSL)
North Coast
KwaDukuza
Mvoti Balancing Reservoirs (owned by Ilembe and operated by Umgeni Water)
4.3
Balancing
146.5
142.5*
*Assumption
Table 5.69 Pipeline details: Honolulu/KwaDukuza Sub-System.
System
Pipeline Name
From
To
Length
(km)
Nominal
Diameter
(mm)
Material
Capacity
(Mℓ/day)
Age
(years)
North Coast
Honolulu to Groutville Pipeline
Honolulu Reservoir
Groutville Bifurcation
4.67
350/300
AC
12.23*
20
North Coast
Groutville Pipeline
Groutville Bifurcation
Groutville
2.95
300
AC
12.23*
20
North Coast
Stanger Tanks Pipeline
Groutville Pipeline
Stanger Tanks
0.72
200
AC
5.44*
20
North Coast
Stanger Tanks to Mvoti Balancing Reservoir
Stanger Tanks
Mvoti Balancing Reservoir
1.94
200
AC
4.08**
20
Honolulu to Mvoti Balancing Reservoir
Honolulu Reservoir
Mvoti Balancing Reservoir/
Darnall
7.33
800
Steel
65**
0.3
North Coast
* Based on a velocity of 2m/s
** Based on a velocity of 1.5m/s
318
Table 5.70 Pump details: Honolulu/KwaDukuza Sub-System.
Number of Pumps
System
Pump Station Name
North Coast
North Coast
Pump Description
Supply From
Supply To
Static Head
(m)
Duty Head
(m)
Duty Capacity
(Mℓ/day)
1
KSB WKLn 100/5
Stanger Tanks
Mvoti Balancing Reservoir
93
115*
2.69*
1
KSB Omega 200-420A
Honolulu Reservoir
MvotiBalancing and Darnall
11
45
15
Number of
Duty
Pumps
Number of
Standby
Pumps
Stanger Tanks
1
Honolulu-Mvoti
1
* Assumption
319
Mvoti Water Treatment Plant and Supply System
The primary source of potable water for KwaDukuza Town is the Mvoti WTP (Figure 5.61) situated
on the banks of the Mvoti River. This run-of-river scheme has raw water abstracted from the
Mvoti River and supplied to the WTP via submersible pumps and a short raw water rising main. The
abstraction system at the Mvoti WTP consists of a diversion channel and lateral screen wells which
supply water to the abstraction point. In addition seven boreholes situated on the banks of the river
provide access to the aquifer below the coarse river sand. Potable water is pumped from the WTP
through two potable water rising mains to the Mvoti Balancing Reservoirs and from there the water
is gravity fed to Lot 16, Memory Loyds and Saunders Street (Figure 5.62). Potable water is then
supplied via pumped systems and gravity systems from the Saunders Street Reservoir to the suburbs
of KwaDukuza.
Figure 5.61 Mvoti Water Treatment Plant.
The Mvoti WTP and supply infrastructure is owned by Ilembe Municipality, and Umgeni Water is
contracted to manage the plant and supply infrastructure up to the Saunders Street Reservoirs. The
plant capacity is 14.5 Mℓ/day (including the pressure filters) and the average demand placed on the
Mvoti WTP over the last 12 months is 16.3 Mℓ/day (Figure 5.68). A 2 Mℓ/day package plant has
been installed at Mvoti WTP to sustain the growing demand. Umgeni Water Umgeni Water is
currently
implementing
the
Lower
Thukela
Bulk
Water
Supply
Scheme
(Section 7.7.4) as a long-term option to supply, inter alia, the town of KwaDukuza.
320
Figure 5.62 General layout of the Mvoti Sub-System.
321
The characteristics of the Mvoti WTP are shown in Table 5.71.
Table 5.71 Characteristics of the Mvoti WTP.
WTP Name:
Mvoti WTP
System:
North Coast Supply System
Maximum Design Capacity:
12.5 Mℓ/day including Pressure Filters
Current Utilisation:
17 Mℓ/day
Raw Water Storage Capacity:
0 Mℓ
Raw Water Supply Capacity:
16 Mℓ/day
Pre-Oxidation Type:
Prechlorination
Primary Water Pre-Treatment Chemical:
Polymeric Coagulant
Total Coagulant Dosing Capacity:
15 l/hour
Rapid Mixing Method:
Conventional Paddle Flash Mixer
Clarifier Type:
Clari-Flocculator
Number of Clarifiers:
3
Total Area of all Clarifiers:
407 m
Total Capacity of Clarifiers:
12.5 Mℓ/day
Filter Type:
Constant Rate Rapid Gravity Filters
Number of Filters:
12
Filter Floor Type
Laterals without Nozzles
Total Filtration Area of all Filters
141 m
Total Filtration Design Capacity of all Filters:
19 Mℓ/day
Total Capacity of Backwash Water Tanks:
120 m
Total Capacity of Sludge Treatment Plant:
None
Capacity of Used Washwater System:
0 Mℓ/day
Primary Post Disinfection Type:
Chlorine Gas
Disinfection Dosing Capacity:
10 kgCl2/hr
2
2
3
Disinfectant Storage Capacity:
Total Treated Water Storage Capacity:
1.36 Mℓ
Maphumulo Water Treatment Plant and Supply System
The demand for water on the KwaZulu-Natal North Coast, and in particular the inland rural areas of
the iLembe District Municipality, are forecast to increase significantly in the future. The requirement
for potable water supply to rural backlog areas along the coastal belt has prompted Umgeni Water
to implement a new potable bulk water supply scheme with a source on the iMvutshane River and
supply to the iLembe District Municipality. Phase 1 of this scheme, known as the Maphumulo Bulk
Water Supply Scheme (Figure 5.63 and Figure 5.64) was commissioned in May 2013 and the
construction of Phase 2 is underway.
322
Figure 5.64 shows a schematic of the Maphumulo Bulk Water Supply Scheme, which includes an
abstraction works, and subsequently a dam on the iMvutshane River, a treatment plant higher up
and bulk rising and gravity mains to supply the water from the water treatment works into the
Ilembe District Municipality’s greater Maphumulo area.
The bulk infrastructure for Phase 1 includes the following:









Temporary raw Abstraction Works on the iMvutshane River at 255m mASL,
Temporary Abstraction Pumps Duty/Duty configuration 2 x 3 Mℓ/day
Temporary 355 DN uPVC raw water delivery main (length 400 m)
Raw Water Pump Station (@ 262m mASL)
Raw Water Pumps Duty/Duty/Standby configuration 3 x 3 Mℓ/day
400 DN grade X42 steel Raw Water Rising Main (length 1.850 Km)
6 Mℓ/day Water Treatment Works at 420m mASL
Extension and upgrade of Eskom supply lines to accommodate the pump electrical
load requirements.
4 km of 400 DN Grade X42 steel Potable Water Rising Main
The temporary abstraction works consists of a rock filled gabion basket structure with a concrete
base and reinforced concrete roof. This structure is constructed within the iMvutshane River course
some 50 metres upstream of the proposed dam wall. The structure has an internal dimension of 3.0
x 3.0 x 2.0 metre deep. Periodic maintenance (cleaning) will be required and this is considered to be
in keeping with the Value Engineering principles for this temporary structure.
Two 7.5 KW submersible pumps (duty/duty configuration) are provided in the abstraction structure
to pump raw water from the abstraction works to the raw water pumpstation located at an
elevation equal to the proposed iMvutshane Dam low-water draw off level @ 262 m mASL as a
temporary measure. These pumps are fitted with soft starters in order to reduce start up loads in
keeping with ESKOM requirements.
(This infrastructure will become redundant upon the commissioning of the iMvutshane Dam).
Raw water is treated at the Maphumulo WTP and pumped to a booster reservoir. From the booster
reservoir, potable water is pumped to the Maphumulo and the Nyamazane Reservoirs. The
Maphumulo Reservoir serves as a distribution reservoir for the town of Maphumulo and also
supplies the Masibambisane Reservoir, which in turn supplies Maphumulo Hospital Reservoir. The
Nyamazane Reservoir serves as a distribution reservoir, for the towns of Nyamazane and Maqumbi
(from Reservoir F). The Maqumbi Reservoir F in turn supplies both the Maqumbi Reservoir T and
Ashville Reservoirs.
323
Figure 5.63 General layout of the Maphumulo BWSS.
324
Masibambisane/
Kwasizebantu/Balcom
Maqumbi
LEGEND
Tunnel
Umgeni Water Pipeline
Municipal Pipeline
Sales Off-take
New Infrastructure
All diameters in mm
All flows in Ml/day
Ø 200
Nyamazane
Maqumbi Res T
Ø 110
Ø 300
Masibambisane
Res
Ø 350
Nyamazane
Maphumulo
Maqumbi Res F
Maphumulo
Res
Maphumulo
Hospital and
Prison
Ø 160
Ø 350
Ø 300
Maphumulo
Hosp
Ashville
Maphumulo
Booster PS
Ashville
Booster
Reservoir
iMvutshane River
Ø 400
Sindi
Ø 355
Abstraction
Pumps
Ø 400
Maphumulo
WTP
Emtanjeni
Raw Water
Pump
Station
Figure 5.64 Schematic of the Maphumulo Supply System.
325
Maqumbi
Table 5.64 Pump details: Maphumulo BWSS.
Number of Pumps
Pump Description
Supply From
Supply To
Static
Head
(m)
Duty
Head
(m)
Duty
Capacity
(Mℓ/day)
0 (Current)
1 (Future)
KSB – KRTE80-250
Imvutshane River
Raw Water Pump Station
9
18
6
2
1
KSB – WKLN 125/6
Raw Water Pump Station
Maphumulo WTP
160
178
6.9
WTW Pump Station
2
1
KSB – WKLN 125/6
Maphumulo WTW
Booster Reservoir
166
190
7
Booster Pump Station 1
Booster Pump Station 2
2
1
KSB – WKLN 100/7
Booster Reservoir (PS 1)
Maphumulo Reservoir
83
136
6.6
2
1
KSB – WKLN 100/3
Booster Reservoir (PS 2)
Ngcebo Reservoir
47
66
3.6
Maphumulo Reservoir
Masibambisane Reservoir
124
154
6
Nyamazane Reservoir
Maqumbi Reservoir F
53
83
2.9
Maqumbi Reservoir F
Maqumbi Reservoir T
85
104
1.3
System
Pump Station Name
Maphumulo
Temporary abstraction
2
Maphumulo
Raw water Pump Station
Maphumulo
Maphumulo
Number of
Number of
Duty
Standby Pumps
Pumps
Maphumulo
Maphumulo Pump
Station
2
1
Maphumulo
Nyamazane (Ngcebo)
Pump Station
2
1
Maphumulo
Maqumbi Pump Station
2
1
KSB – WKLN 100/8
KSB – WKLN 80/6
KSB – WKLN 65/9
326
Table 5.72 Reservoir details: Maphumulo BWSS.
System
Reservoir Site
Reservoir Name
Capacity
(Mℓ)
Function
TWL
(aMSL)
FL
(aMSL)
Maphumulo
Maphumulo
Maphumulo WTW Res
0.5
Distribution
424.1
420.5
Maphumulo
Maphumulo
Booster Reservoir
0.3
Distribution
585.5
582.5
Maphumulo
Maphumulo
Maphumulo Reservoir
0.5
Distribution
668.2
664.5
Maphumulo
Maphumulo
Masibambisane Reservoir
1.0
Distribution/Terminal
793.5
789.5
Maphumulo
Maphumulo
Maphumulo Hospital
0.2 or 0.25
Terminal
750
? Exist
Maphumulo
Maphumulo
Nyamazane Reservoir
1.0
Distribution
633.5
629.5
Maphumulo
Maphumulo
Maqumbi Reservoir F
0.5
Distribution
683
? Exist
Maphumulo
Maphumulo
Maqumbi Reservoir T
0.5
Terminal
769
? Exist
Maphumulo
Maphumulo
Ashville Reservoir
0.5
Terminal
440
? Exist
327
Table 5.73 Pipeline details: Maphumulo BWSS.
System
Pipeline Name
From
To
Length
(km)
Nominal
Diameter
(mm)
Material
Capacity
(Mℓ/day)
Age (years)
Imvutshane River
Raw Water Pump Station
0.4
355
uPVC
12.8**
0.6
Maphumulo
Temporary abstraction
Maphumulo
Raw Water Pipeline
Raw Water Pump Station
Maphumulo WTP
1.85
400
Steel
16.3**
0.6
Maphumulo
Maphumulo Pipeline
Maphumulo WTP
Booster Reservoir
5.08
400/300
Steel
16.3**
0.6
Maphumulo
Ngcebo Pipeline
Booster Reservoir
Ngcebo Reservoir T
3.535
350
Steel
12.5**
0.6
Maphumulo
Maqumbi Pipeline
Ngcebo Reservoir
Maqumbi Reservoir F
10.15
300
Steel
9.16**
0.6
Maphumulo
Maqumbi Pipeline
Maqumbi Reservoir F
Maqumbi Reservoir T
1.38
200
Steel
4.07**
0.6
Maphumulo
Ashville Pipeline
Maqumbi Reservoir T
Ashville Reservoir
9
160
Steel
3.5*
0.6
Maphumulo
Maphumulo Pipeline
Booster Reservoir
Maphumulo Reservoir
3.815
300
Steel
9.16**
0.6
Maphumulo
Masibambisane Pipeline
Maphumulo Reservoir
Masibambisane Reservoir
2.25
300
steel
9.16**
0.6
* Based on a velocity of 2m/s
** Based on a velocity of 1.5m/s
328
The characteristics of the Maphumulo WTP are shown in Table 5.74.
Table 5.74 Characteristics of the Maphumulo WTP.
WTP Name:
Maphumulo WTP
System:
North Coast Supply System
Maximum Design Capacity:
6 Mℓ/day for Phase 1 and 12 Mℓ/day for Phase 2
Current Utilisation:
4 Mℓ/day
Raw Water Storage Capacity:
0 Mℓ
Raw Water Supply Capacity:
6 Mℓ/day for Phase 1 and 12 Mℓ/day for Phase 2
Pre-Oxidation Type:
Prechlorination
Primary Water Pre-Treatment Chemical:
Polymeric Coagulant
Total Coagulant Dosing Capacity:
15 l/hour
Rapid Mixing Method:
Conventional Paddle Flash Mixer
Clarifier Type:
Dortmund manual clarifiers
Number of Clarifiers:
4 for phase 1 increasing to 6 for Phase 2
Total Area of all Clarifiers:
345.6 m
Total Capacity of Clarifiers:
12.5 Mℓ/day
Filter Type:
Constant Rate Rapid Gravity Filters
Number of Filters:
5 for Phase 1 increasing to 8 for Phase 2
Filter Floor Type
Laterals without Nozzles
Total Filtration Area of all Filters
80 m
Total Filtration Design Capacity of all Filters:
12.5 Mℓ/day
Total Capacity of Backwash Water Tanks:
100 m
Total Capacity of Sludge Treatment Plant:
None
Capacity of Used Washwater System:
0 Mℓ/day
Primary Post Disinfection Type:
Chlorine Gas
Disinfection Dosing Capacity:
10 kgCl2/hr
2
2
3
Disinfectant Storage Capacity:
Total Treated Water Storage Capacity:
0.5 Mℓ
329
5.5.2
Status Quo and Limitations
Hazelmere WTP Supply System
Figure 5.58 (schematically) illustrates the North Coast System in its current configuration and the
current demands being placed on the network. This schematic should be referred to when reading
this Section.
The primary source of potable water supplied to the North Coast Supply System (NCSS) is from the
45 Mℓ/day Hazelmere WTP. Over the last 12 months the average demand placed on the
Hazelmere WTP was 44.6 Mℓ/day with daily peaks as high as 53 Mℓ/day. With the demand nearing
and regularly exceeding the capacity of the plant, the operation of the plant is difficult and routine
maintenance on components of the plant is near impossible. As an interim measure to sustain the
growing demand, a 5 Mℓ/day Package Water Treatment Plant was commissioned in February 2013.
The historical demand placed on Hazelmere WTP is presented in Figure 5.65. It is evident from
Figure 5.65 that the current demand (44.6 Mℓ/day) placed on the WTP, is near the capacity of the
plant. The comparatively high supply from the WTP, when compared to the plant capacity and the
expected increase in future demand, has necessitated the upgrading of the WTP from 45 Mℓ/day to
75 Mℓ/day (98% assured yield of the raised Hazelmere Dam). The demand forecast shown in
Figure 5.65, includes the supply to Verulam (Grange) as it has not yet been transferred to Durban
Heights WTP and eThekwini Municipality’s Northern Aqueduct. The high sales from the WTP
between June 2013 and October 2013 are evidence that the Verulam (Grange) demand has not yet
been fully transferred onto the Durban Heights WTP. In addition, a number of industrial
developments have been implemented in the Greater Ballito area, and these have also contributed
to the steady increase in the demand on Hazelmere WTP.
Figure 5.65 Water demand from Hazelmere WTP.
330
An analysis of daily historical production for the Hazelmere WTP over the past year (November 2012
to October 2013) is presented in Figure 5.66, and shows that for 97% of the time the WTP was being
operated above the optimal operating capacity (80% of design capacity) and for 57% of the time the
WTP was operated at above design capacity. The previous year Hazelmere WTP was operating above
the optimal operating capacity for 97% of the time and 42% of the time above the design capacity.
This indicates that a greater demand has been placed on the WTP due to a steep growth in
development in the supply area of the Hazelmere WTP.
Sales Volume (Ml/day)
60
40
20
0
0
20
40
60
Probability
p occurrence (%)
80
100
Design capacity
Figure 5.66 Analysis of historical production at Hazelmere WTP (November 2012 to October 2013).
Mvoti WTP Supply System
The town of KwaDukuza is supplied from the Mvoti WTP via the Mvoti Balancing Reservoirs. The
average demand placed on the WTP over the past year was 17.25 Mℓ/day. The design capacity of
the WTP is 12.5 Mℓ/day. Four additional pressure filters have recently been installed and these have
increased the capacity of the filters to 15.5 Mℓ/day, however, the 12.5 Mℓ/day capacity of the
clarifiers still limits the plant capacity to 12.5 Mℓ/day. This is well below the demand and the system
is difficult to manage and to maintain acceptable water quality standards. As an interim measure, to
sustain the growing demand, a 2Mℓ/day Package Water Treatment Plant was commissioned in
November 2012.
An analysis of daily historical production for the Mvoti WTP over the past year (November 2012 to
October 2013) is presented in Figure 5.67, and shows that for 97.54% of the time the WTP was being
operated above the optimal operating capacity and for 91.8% of the time the WTP was operated at
above design capacity. Supply from this plant can be augmented to a limited extent from the
Hazelmere WTP when required.
331
20
Sales Volume (Ml/day)
15
10
5
0
0
20
40
60
Probability
p occurrence (%)
80
Design capacity
Figure 5.67 Analysis of historical production at Mvoti WTP (November 2012 to October 2013).
Figure 5.68 Water demand from Mvoti WTP.
332
100
iLembe DM has appointed a Professional Service Provider to implement a Water Demand Strategy in
the Kwadukuza Municipal area and the municipality is confident that a reduction in water demand,
by 1 Mℓ/day per year, can be achieved over the next two years .
Maphumulo WTP Supply System
The town of Maphumulo and surrounding areas are supplied from the recently commissioned
Maphumulo WTP. The average demand placed on the WTP since it was commissioned was
3.7 Mℓ/day. The current design capacity of the WTP is 6 Mℓ/day with the aim of upgrading it to 12
Mℓ/day by the year 2017.
An analysis of daily historical production for the Maphumulo WTP, since it has been commissioned,
is presented in Figure 5.69, and shows that for 0% of the time the WTP was being operated above
the optimal operating capacity and for 0% of the time the WTP was operated at above design
capacity. Although, the demand is below the sound operating level of the WTP, the raw water
abstraction pumps are only sized for 4 Mℓ/day.
Figure 5.69 Analysis of historical production at Maphumulo WTP (August 2013 to October 2013).
333
The initial demand (based on an estimate of 25 litres per person per day) at the commissioning
phase, was projected at 2.7 Ml/day increasing to 4 Ml/day towards the year 2017. The phasing of the
temporary raw water abstraction pumps was based on this projected demand.
At the commissioning stage, the actual demand was measured at 3.7 Ml/day and the levels of the
Maqumbi Reservoirs F and T could not be maintained. An investigation indicated that a high water
loss, in the region of 75%, is prevalent in the Maqumbi area, and this places a constant peak loading
onto the system. iLembe DM is currently implementing Water Demand Management initiatives to
reduce the high Non Revenue Water in this area.
North Coast Supply System (NCSS)
The total current demand, together with a breakdown of sales throughout the NCSS, is presented in
Figure 5.. There is potential for growth in the demand for water in the area currently supplied by the
NCSS. Identified development nodes include:
 The Phase 1 of the Cornubia Housing Development, planned by eThekwini Municipality near
Verulam, has already commenced. This project has a projected growth over the next 30 years
to 60 000 residential housing units and industrial and commercial sites.
 The King Shaka International Airport, which became operational on the 1st May 2010.
Demand from the airport, associated Dube Trade Port and other developments surrounding
the area is expected to grow to greater than 20 Mℓ/day over the next five to ten years.
 More than 70 development projects are proposed within the area covered by the NCSS. These
include up market housing developments such as Blythedale and Royal Palm Estates, low cost
housing developments such as the Etete Low Cost Housing Projects, the Driefontein Medium
Income Housing Project and the Nonoti Land Restitution Project and commercial and
industrial developments.
The current economic climate has resulted in a slowdown in the housing development sector.
However, many of the developments are still likely to be implemented although the timing of them
is expected to be delayed or extended. For this reason the five, ten, twenty and thirty year forecasts,
are shown in Figure 5.70, Figure 5.71, Figure 5.72, Figure 5.73 and Figure 5.74.
These figures are the same as those projected in the 2013 Infrastructure Master Plan.
334
KwaDukuza (Stanger)
Darnall/Zinkwazi
17.3
LEGEND
Tunnel
Mvoti River
Umgeni Water Pipeline
Sales Off-take
New Infrastructure
17.3
Mvoti
WTP
Mvoti
Balancing
0
Municipal Pipeline
All diameters in mm
0.5
All flows in Ml/day
Honolulu-Mvoti PS
Kwahlope /
Res 5 Retic
Stanger Tanks PS
5.5
0.5
Groutville
6.0
0.9
3.5
Ndwedwe Retic
Ndwedwe
5
Ndwedwe
4
0.4
2.4
Honolulu
1.3
Shakas Kraal
1.1
4.4
Etete
2.7
Ndwedwe Retic
1.1
Umhlali
Ndwedwe
3
Ndwedwe Retic
Ndwedwe
2
1.3
Tiffany
0.35
8.8
2.2
8.1
1.0
1.0
Ballito Lea
3.65
0.3
Avondale
Belvedere
2.8
Ndwedwe
1
Shakas Rock
2.65
Avondale High
Ndwedwe Retic
Shakas Head
Hugh Dent drive
1.0
1.0
North Coast PL I
1.0
North Coast PL II
7.1
Salt Rock PS
Grange / Verulam
Waterloo /Phoenix
300 Backfeed
Hazelmere to Bifurcation PL
Hazelmere
WTP
7.5
23.9
Ballito and Zimbali
0.8
17.5
Tongaat
45.7
22.9
1.0
Mdloti River
Hazelmere
Dam
9.4
2.0
Nyaninga and
King Shaka
Airport
La
Mercy
5.4
4.9
Figure 5.70 Demand on the North Coast Supply System as at October 2013.
335
La Mercy
Figure 5.70 Five year demand forecast for the North Coast Supply System.
336
Figure 5.71 Ten year demand forecast for the North Coast Supply System.
337
Figure 5.72 Twenty year demand forecast for the North Coast Supply System.
338
Figure 5.73
Thirty year demand forecast for the North Coast Supply System.
339
5.5.3
Recommendations
Figure 5.69, Figure 5.70, Figure 5.71 and Figure 5.72 depict the potential for growth in the NCSS
over the next five, ten, twenty and thirty years respectively. Also shown in these figures is the
configuration of the system that is planned to supply this demand. The following section provides
the details of how each subsystem of the NCSS will be affected by the growth in demand over the
next thirty years and how the configuration of the system will have to be altered and projects
implemented to supply the demand.
The Water Reconciliation Strategy Study for the KwaZulu-Natal Coastal Metropolitan Areas, inter
alia, looked at a strategy in which the water resources of the KwaZulu-Natal North Coast could be
augmented in the future (DWA, 2009). The scenarios considered as future augmentation options
included the following:



Raising of Hazelmere Dam and upgrade of the Hazelmere WTP (Section 7.7.1).
The Lower Thukela Bulk Water Supply Scheme (Section 7.7.4).
A new dam on the Mvoti River (e.g. the Welverdient or Isithundu Dam) with an associated
regional WTP.
Results from this study show that the raising of the full supply level of Hazelmere Dam is the most
cost effective and quickest means of augmenting the water resources on the North Coast. Following
this, the Lower Thukela Bulk Water Supply Scheme (LTBWSS) would be the most practical scheme
(and next quickest) to implement to supply additional water to the coastal region of the North Coast.
This scheme would be required to augment the water supplies of the Hazelmere Supply System as
the Hazelmere Dam raising on its own does not have sufficient resource to supply the demand in the
short to medium term. It is anticipated that the conveyances of the Lower Thukela BWSS would be
able to take water from the uThukela River down to the Ballito area via the North Coast Pipeline II
(Figure 5.71, Figure 5.72, Figure 5.73 and Figure 5.74).
DWA has confirmed that there is initially 20 million m3/annum (approximately 55 Mℓ/day), and up to
a maximum of 40 million m3/annum (approximately 110 Mℓ/day) of firm yield available from the
uThukela River close to its mouth. DWA’s Directorate National Water Resource Planning has agreed
that this yield is available for abstraction, treatment and supply to the KwaDukuza and Mandini
areas. This available yield is a combination of natural flows in the uThukela River and unused yield in
dams in the upper uThukela catchment.
The scheme that would take the longest to implement, and is most likely to be the most expensive,
would be to develop a dam on the Mvoti River, at either Welverdient or Isithundu. This scheme
would feed into the NCSS to augment the water supplies of the Hazelmere Supply System.
The strategic development plan for the region, that would utilise the available resources from the
Mdloti, Thukela and Mvoti systems in the most sustainable and cost effective manner, is presented
below. Details are provided in the paragraphs that follow.
 Initially supply the NCSS from Hazelmere Dam via the Hazelmere WTP.
 Raise the full supply level of Hazelmere Dam to increase its firm yield and upgrade the
Hazelmere WTP to supply up to 75 Mℓ/day to the NCSS. In addition to the upgrade of the
WTP, pump stations and pipelines within the NCSS will have to be augmented to ensure the
demand placed on the system does not exceed the capacity of the infrastructure. Pipelines
that are constructed as part of this augmentation process will be built with the ability to allow
340
for bi-directional flow to ensure that in the future water can be brought south from a WTP
situated at the uThukela River or the Mvoti River.
 Construct an abstraction works on the uThukela River with a regional WTP and associated
infrastructure to supply water south to KwaDukuza Local Municipality and north to
Mandini Local Municipality. This system would link into the NCSS. The WTP would be
constructed to initially serve 55 Mℓ/day and when demands dictate it would be upgraded to
110 Mℓ/day.
 Develop water resource infrastructure on the Mvoti River, either at Welverdient or Isithundu
with a regional WTP and associated supply infrastructure to further augment the NCSS. At
some stage in the future, the long-term water demands to the north of the uThukela River
may require the full (or majority of) allocation from the Lower Thukela WTP. In this scenario
potable water may need to be supplied northwards from the NCSS (i.e. towards the
Lower Thukela WTP) to meet the demands on the southern side of the uThukela River.
 Develop a desalination plant to link into the NCSS as a long-term strategy that would be
implemented as and when demands are predicted to exceed supply from the other systems. It
should be noted that this intervention could be developed ahead of a regional scheme on the
Mvoti River if either demands in the Mgeni System require it or if it proves of better financial
value than the Mvoti scheme (Sections 1.6 and 2)
The infrastructure to be constructed, as detailed above, would incur high capital cost and as such the
philosophy is to only develop the schemes as and when demand dictates. With the long lead time in
feasibility and design of projects of this size and nature, the intention is to undertake the feasibility
investigations and design of the schemes as early as possible and then to implement the schemes as
and when demand dictates.
The following sections detail the recommendations for development within each subsystem.
Hazelmere Water Treatment Plant
Growth in water demand at the Hazelmere WTP is expected to rise over the next five years to an
amount greater than the capacity of the plant (Figure 5.68). The Mdloti system is constrained by the
amount of water available from Hazelmere Dam. The current 98 % assured yield of the dam is
55 Mℓ/day. DWA are in the process of raising the height of the Hazelmere Dam wall through the
construction of the “piano key” structure as per Midmar Dam. This project is expected to be
completed in September 2017 and will increase the 98% assured yield of the dam to 75 Mℓ/day. In
order to meet the projected growth in demand in the region, and to make use of the additional yield
that will soon become available, Hazelmere WTP is being upgraded to a capacity of 75Mℓ/day
(Section 7.25). This project will be completed by July 2014. The possibility of increasing the size of
the works to 90 Mℓ/day (95% assurance of supply) will be investigated, if needed. The raw water
pipeline between the dam and the WTP has been augmented with an 800 mm diameter steel
pipeline to match the upgraded capacity of the WTP (Section 7.7.1).
The increase in yield that will be available once the dam has been raised is reliant on the ecological
reserve of the Mdloti River below the dam not being implemented immediately. The ecological
reserve is to be implemented in a phased manner according to a DWA developed strategy.
Since the growth in demand is expected to increase to greater than the 75 Mℓ/day assured supply
from Hazelmere Dam, an additional source of water for supply to the NCSS will be required in the
medium to long-term. The uThukela River has an available yield of 110 Mℓ/day and is considered to
be the most feasible additional source of water to the system. Construction of the 110 Mℓ/day
Abstraction Works and a separate contract for the construction of the 55 Mℓ/day Water Treatment
341
is currently in progress, which constitutes phase 1 of the LTBWSS. The anticipated completion date
for Phase 1 is December 2016. Phase 2 of the LTBWSS is the upgrade of the WTP to a design capacity
of 110 Mℓ/day and will be completed towards the end of 2017 (Section 7.7.4).
Figure 5.71, Figure 5.72, Figure 5.73 and Figure 5.74 show the interlinking of the
Lower Thukela Bulk Water Supply Scheme into the NCSS. This scheme has the potential to provide
water as far south as Ballito or even La Mercy if required.
Following the implementation of the LTBWSS, the next scheme to augment the North Coast water
supply is on the Mvoti River. Various Mvoti options were assessed by DWA in conjunction with
Umgeni Water and are discussed in Section 4.4.2. Factors influencing these assessments have
changed subsequent to the study. It is now necessary to review the findings of the selection process
in order to confirm the preferred development option before any planning investigations can be
concluded. DWA plans to undertake a review of the previous study and to undertake any further
detailed water resource development investigations that are required. Lagging slightly behind these
investigations, Umgeni Water intends undertaking its own detailed investigations into the associated
WTP and supply infrastructure to the NCSS. Figure 5.71 and Figure 5.72 show the interlinking of the
Lower Mvoti Bulk Water Supply Scheme into the NCSS. This scheme will also have the potential to
provide water as far south as Ballito or even La Mercy if required.
Hazelmere/Verulam Sub-System
The demand at Verulam (Grange) is expected to increase over the next 30 years as shown in
Figure 5.69 and Figure 5.70. This growth is attributed to the development of Cornubia and the
requirement to shed the Verulam demand back to Hazelmere WTP. This would reduce the impact
that this demand has on the Durban Heights WTP and in particular eThekwini Municipality’s
Northern Aqueduct. The sales point for this subsystem is at the Hazelmere WTP, and hence the only
infrastructure that is affected by the growth in demand is the WTP itself and the Verulam Pump
Station.
Hazelmere/Phoenix Sub-System
Natural growth in demand in Phoenix (Waterloo) is predicted as Figure 5.68, Figure 5.69, Figure 5.70
and Figure 5.71. The sales point for this subsystem is at the Hazelmere WTP and hence the only
infrastructure that is affected by the growth in demand is the WTP itself and the Waterloo Pump
Station.
Hazelmere/Ndwedwe Sub-System
Until recently, the comparatively high demand placed on the Ndwedwe Reservoirs 1 and 2, when
compared with the size of the reservoirs, made the management of the pumping systems in the
Ndwedwe Sub-system difficult. For this reason both the Ndwedwe Reservoir 1 and Ndwedwe
Reservoir 2 were upgraded by constructing an additional 2 Mℓ reservoir at each site. This project
was completed in early 2011. The pipeline infrastructure for this subsystem has sufficient capacity to
supply the required demand over the next thirty years. Umgeni Water, in close liaison with iLembe
District Municipality, conducted a reconnaissance study in 2007 to assess supplying Ndwedwe Local
Municipality with potable water. A pre-feasibility and detailed feasibility level investigation is now
being undertaken to further identify the most feasible option for supply. The completion of this
study is scheduled for the end of March 2015.
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In addition to this, the viability of an interim water supply solution to portions of Ndwedwe (KwaChili
KwaShangase) from Ndwedwe Reservoir 5 was assessed. A hydraulic analysis has been conducted.
The analysis indicate that it is feasible to supply the KwaShangase and KwaChilli areas from Reservoir
5, provided That the high water losses in the area can be reduced by 2 Mℓ/day. This volume will then
be available to on-supply to the KwaShangase and Kwa-Chilli areas. Ilembe DM has appointed a
Professional Service Provider to reduce the Non-Revenue Water in the Greater Ndwedwe area and
to design and implement a pipeline from Reservoir 5 to gravity feed the above areas within a 7km
radius.
Hazelmere/La Mercy/Avondale Sub-System
Supply to the Avondale Reservoir and the areas north of Ballito will increase to greater than
20 Mℓ/day over the next five years. This coupled with an increase in demand expected from the new
KSIA will mean that the demand on the Hazelmere to Bifurcation Pipeline will be greater than the
available capacity of the pipeline. The construction of a new bi-directional 700 mm diameter pipeline
(Section 7.7.1) to augment the Hazelmere to Bifurcation pipeline has been completed in November
2012 and is operational. This line is linked to the existing 700 mm diameter pipeline from Bifurcation
to Avondale and will become a dedicated supply to Avondale Reservoir. This line can be reversed to
supply water from Avondale Reservoir to the northern suburbs of eThekwini Municipality if
necessary. The existing 450 mm diameter Hazelmere to Bifurcation Pipeline is now dedicated to
supply the Airport and La Mercy Reservoir.
Avondale/Honolulu Sub-System
Umgeni Water has recently completed the augmentation of the North Coast Pipeline. The 1 000 mm
to 800 mm diameter North Coast Pipeline II (NCP-2) provides sufficient capacity between Avondale
and Honolulu for supply over the next 30 years. This pipeline has been constructed to transport
water in both a northerly and southerly direction. In Figure 5.68 the pipeline supplies water from the
Hazelmere System north as far as KwaDukuza. In Figure 5.69, Figure 5.70 and Figure 5.71 the
pipeline is reversed to supply water from the Lower Thukela BWSS to Avondale Reservoir and the
southern areas of the NCSS. The North Coast Pipeline I (NCP-1) is now used to supply users along the
pipeline from Avondale to Salt Rock in a northerly direction and is also used to supply south from
Honolulu Reservoir to off-takes along the pipeline route including Shakas Kraal. The Salt Rock Pump
Station will now only be used in emergency situations.
Mvoti Water Treatment Plant and Supply System
A 2 Mℓ/day package plant has been installed at Mvoti WTP to sustain the growing demand. The
intention is for the Mvoti WTP to be handed back to iLembe DM once the Lower Thukela BWSS is
able to provide water to the Mvoti Balancing Reservoirs.
Lower Mvoti Supply System
The North Coast is one of the fastest growing areas in Kwazulu-Natal due to the position of the King
Shaka Airport and the development of the Dube Trade Port. These developments will spearhead
residential and commercial developments in the respective WSA’s. The availability of a sustainable
water supply system will fast track such developments.
Umgeni Water is currently constructing the Lower Thukela BWSS to meet the future demands of the
North Coast area. However, the limited raw water resource necessitates the need to investigate
alternative sources. One such source is the lower regions of the Mvoti River.
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As part of the long-term growth plan, Umgeni Water, will undertake a Detailed Feasibility study to
assess the viability of a BWSS on the lower regions of the Mvoti River, named the Lower Mvoti
BWSS. The Lower Mvoti BWSS will include a dam, a water treatment plant, pump stations and
pipelines.
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