|
|
INVESTIGATIONS
It is envisaged that all components of the TWP will be constructed over a period
of about 8 to 10 years. The aim of the TWP is to increase the delivery rate of raw
water to the VRS, via the Drakensberg Pumped Storage Scheme, by 15 m3/s.
Depending on operating regimes, this could add up to more than 450 million m3
of additional water being transferred per annum.
The estimated capital and compensation costs (excluding financing and operating
costs) for the TWP amount to just less than R 5 000 million in March 1998 terms.
The following main elements of infrastructure will be required in the scheme (see
diagram below):
- Jana Dam in the Thukela River situated approximately 30 km south-west of
Ladysmith and 15 km downstream of the confluence of the Thukela and Klip Rivers.
- Mielietuin Dam in the Bushman's River, situated between Weenen and Estcourt,
and immediately upstream of the western boundary of the Weenen Nature Reserve.
- 120 km of pipeline aqueduct linking the proposed dams to the existing Kilburn
Dam at the foot of the Drakensberg Pumped Storage Scheme.
Due to future uncertainties (e.g. the determination of the
Reserve) information has been made available to decision makers within a range of
project component sizes from which to eventually select an optimum scheme. A
reference scheme size has been suggested at feasibility level.
 
LONGITUDINAL CROSS SECTION
THROUGH THE SCHEME
 |
: Pump Station |
 |
: Mielietuin to Junction |
 |
: Dam Wall |
 |
: Junction to Kilburn |
 |
: Break-pressure Tank |
 |
: Kilburn to Sterkfontein |
 |
: Jana to Junction |
|
|
| COMPONENT MAIN RESERVOIRS |
JANA DAM |
MIELIETUIN |
PUMP STATIONS AT DAMS |
JANA TO |
MIELIETUIN |
| |
|
DAM |
|
COLENSO |
TO COLENSO |
| |
|
|
|
JUNCTION |
JUNCTION |
| Cumulative catchment area (km2) |
6 600 |
1 350 |
Design discharge (m3/s) |
10 |
5 |
| Cumulative mean annual runoff (million m3) |
1 446 |
288 |
Dam wall level - minimum (masl)
(note a) |
RL 737 |
RL 957 |
| Storage in catchment upstream (million m3) |
863 |
60 |
Terminal elevation (masl) (note e) |
RL 1088 |
RL 1088 |
| Total storage in dam reservoir (million m3) |
1 500 |
350 |
Number of main pumps (VSD) (note f) |
5 |
3 |
| Full supply level (masl) (note a) |
RL 860 |
RL 1025 |
Number of HL booster pumps (FS) (note f) |
5 |
- |
| Type of dam (note b) |
RCCG |
RCCTH |
Number of LL booster pumps (FS) (note f) |
5 |
3 |
| Height of dam (m) (Planning definition) (Note c) |
160 |
87 |
|
|
|
| Spillway length (m) and type (note d) |
165 FOCS |
69 FOCS |
|
|
|
| Spillway flood peak discharges (m3/s)
(Attenuated) |
|
|
AQUEDUCT PUMPING STATIONS |
RUSTENBURG |
BETHANY PS |
| 1:200 |
4 400 |
825 |
|
PS TO |
TO KILBURN |
| Regional
Maximum Flood |
6 900 |
1 700 |
|
BETHANY |
DAM |
| Peak
Maximum Flood |
12 800 |
4 200 |
Forebay water level - minimum (masl) (note a) |
RL 1061 |
RL 1211 |
| Total freeboard (m) |
11 |
9 |
Main pumps elevation (masl) |
RL 10 50 |
RL 1200 |
| Construction volumes in wall and tailpond dam |
|
|
Terminal elevation (masl) (note e) |
RL 1217 |
RL 1260 |
| Excavation (all materials incl rock) (million m3) |
3.08 |
0.34 |
Number of main pumps (FS) (note f) |
7 |
6 |
| Drilling & grouting (m) |
50 550 |
24 300 |
Number of booster pumps (FS) |
7 |
- |
| Concrete (million m3) |
|
|
|
|
|
| Roller compacted |
2.96 |
0.47 |
|
|
|
| Mass (20 MPa) |
0.6 |
0.01 |
|
|
|
| Structural (25 MPa) |
0.14 |
0.02 |
|
|
|
| Reinforcing (metric tons) |
12 000 |
1 920 |
|
|
|
| Dam wall construction
period (years) |
5 |
3 |
|
|
|
| |
|
|
|
|
|
| AQUEDUCTS (Pipeline) |
JANA TO |
MIELIETUIN |
JUNCTION TO RUSTENBURG PS |
RUSTENBURG |
BETHANY |
| |
COLENSO |
TO COLENSO |
|
PS TO |
TO KILBURN |
| |
JUNCTION |
JUNCTION |
|
BETHANY |
DAM |
| Design discharge (m3/s) |
10+ |
5- |
15 |
15 |
15 |
| Pipeline nominal diameter (m) |
2.4 |
1.8 |
3.0 |
3.0 |
3.0 |
| Length of pipeline (km) |
25.6 |
19.6 |
24.6 |
22.4 |
29.4 |
| NOTE: |
|
|
a |
masl = metres above mean sea level |
| |
RL = Reduced level |
|
b |
RCCG = Roller Compacted Concrete Gravity Section |
| |
RCCTH = Roller Compacted Concrete Thick Arch Section |
|
c |
Planning definition : Height of Fully Supply Level above river bed level |
|
d |
FOCS = Free Overflow Central Spillway |
|
e |
Terminal elevation : at next forebay/pumpstation |
| |
VDS = Variable speed drive motor |
| |
FS = Fixed speed drive motor |
| |
HL = High level (eg Jana pump elevation RL900) |
| |
LL = Low level (eg Jana pump elevation RL780) |
| Jana Dam
The Jana Dam site is situated in the Thukela River approximately 30 km
south-east of Ladysmith and 15 km downstream of the confluence of the Thukela
and Klip Rivers. The site is remote and the terrain rugged with steep valley
sides.
The Roller Compacted Concrete Gravity structure will be founded on
competent sandstone/dolomite formations. Adequate sources of aggregate are
located immediately upstream of the wall and well below the full supply level
of the reservoir.
A central stepped ogee spillway with the possibility of a gated side
channel spillway down the left abutment has been proposed. A model study of
the spillway will need to be undertaken during the Design Phase in order to
refine the design details by evaluating the hydraulic performance of the
spillway and the competence of the downstream river bed and banks during major
flood events. An option seriously considered during the Feasibility Study is
the creation of a plunge pool behind a 40 m high tail pond dam.
The capital cost, i.e. excluding design, supervision, compensation and
environmental costs, of Jana Dam has been estimated to be between R 1.2 and R
2 billion, depending on the final size and type of dam to be constructed. |

Aerial view of dam site at Jana
|
 
Jana & Mielietuin Dam Locality Map
Mielietuin Dam
Proposed
Mielietuin Dam site
The Mielietuin site is situated between Weenen and Estcourt at a narrowing of the
Bushman's River valley immediately to the west and upstream of the Weenen Nature
Reserve. The area in which the site is located is reasonably accessible and the
basin is relatively flat. The gradients of the valley sides are only steep in the
immediate vicinity of the wall site.
Exploration drilling has revealed a massive, competent, unweathered dolerite sill
underlying the wall site. Once out of the 90 m deep gorge, the more gently sloping
flanks are capped with shallow sandstone. Rock formations suitable for construction
aggregates are readily available to construct a Roller Compacted Concrete Arch dam,
with an uncontrolled central ogee spillway and Roberts splitters discharging into a
tail pond. Although outlet works will be included in the wall itself, intake works
for transferring water will be in a separate tower situated about 1 km upstream of
the wall.
The capital cost, i.e. excluding design, supervision, compensation and
environmental costs, of Mielietuin Dam has been estimated at between R 300 and R 400
million depending on the final size of dam to be constructed.
Aqueducts
An open canal was originally proposed to convey water from the
storage dams to Kilburn Dam. However, affected parties in the Thukela River
Catchment voiced their concerns, primarily environmental, over this method of
conveying water. A steel pipeline was investigated as an alternative during the
Feasibility Study.
The open canal would have a length of 183 km with three booster pumping stations en
route. In contrast, the route of the steel pipeline would be more direct (121 km)
and only two booster pumping stations would be required. Although the less expensive
steel pipeline is presently the recommended alternative, the open canal remains an
option.
Aqueducts will link the proposed dams and the existing Kilburn Dam from which
water will be transferred to the VRS via the existing Drakensberg Pumped Storage
Scheme. Three aqueduct options were investigated, viz:
- A single pipeline ranging from 1.6 to 3.4 m in diameter or double pipeline
along the same route.
- Open canals (with limited lengths of tunnel, pipeline and inverted siphons).
- A combination of open canals and pipelines.
The overall length of the pipeline option from Jana and Mielietuin to Kilburn Dam
would be 121 km. This length includes a deep cut or tunnel (approximately 1 km long
and 20 m deep) about 12 km east-south-east of Kilburn Dam.
A 30 m fenced construction servitude is envisaged. A permanent unfenced servitude
of approximately 20 m would be required after construction, without a permanent
service road. The pipeline will be covered by approximately 1.8 m of soil. Large
on-site construction housing camps are not envisaged. Accommodation for the work
force should be situated in existing towns wherever possible.
The construction time associated with a pipeline aqueduct is likely to be about
three years. The aqueduct can be sub-divided into a number of contracts, probably
five. Pipe laying would proceed at a rate of about three weeks per kilometre. The
construction of the pipeline aqueduct would also include the construction of valve
chambers, crossings under roads and railways, scour outlets and river crossings,
water hammer protection devices, flow metering equipment and inspection access
facilities. There would be a pump station at each dam plus two intermediate pump
stations along the route of the pipeline.
Importantly, because of spare capacity at Eskom’s Drakensberg Pumped Storage
Scheme, no additional pumping capacity is required to transfer water from Kilburn
Dam to the VRS. Not only does this increase the efficiency of the use of existing
infrastructure, it represents a significant capital saving.
Construction of the TWP could take eight to ten years to complete. The date of
commencement would depend on the growth in water demand in the VRS, and the
suitability of the TWP when compared to other strategic alternatives.
Regional Development
By deciding to base the TWP Feasibility Study Office in Ladysmith, the DWAF has
gained the benefit of understanding the institutional and social dynamics that drive
the uThukela Region.
The TWP Project Management Team has played an important role in establishing
various regional development and economic forums within the uThukela District
Municipality. These forums and other business and labour organisations have been
empowered with the necessary knowledge to be in a position to capitalise on and
optimise spin-offs that could accrue to the uThukela Region as a consequence of the
TWP.
Numerous benefits have been identified by a dedicated KwaZulu-Natal based team
during the course of the feasibility investigations. These opportunities can be
grouped as follows:
- Community development and social welfare
- Tourism
- Commercial and industrial
- Agriculture
- Skills training and capacity building
- Labour enhanced construction
- Materials procurement
- Logistics and communications
- Electrification
- Roads and transport
 |
Numerous benefits have been identified by a dedicated KwaZulu-Natal based
team during the course of the feasibility investigations. These opportunities
can be grouped as follows:
- Community development and social welfare.
- Tourism.
- Commercial and industrial.
- Agriculture.
- Skills training and capacity building.
- Labour enhanced construction.
- Materials procurement.
- Logistics and communications.
- Electrification.
- Roads and transport.
|
 |
It is considered highly probable that the National Government can realise many of
its policy objectives such as poverty alleviation, local economic development, job
creation and empowerment through regional development opportunities arising from the
TWP.
Another important component of facilitating regional development was to gain a
thorough understanding of bulk water supply for domestic and industrial use in the
greater Ladysmith/Emnambithi area. This investigation was necessary in order to take
full cognisance of future water requirements of this area, the main in-basin water
user. The product of this investigation, funded by the DWAF, was a comprehensive
assessment of the bulk water supply options for the area.
However, it is evident that a special effort will be required to ensure that the
benefits arising from the TWP are optimised for the people of the uThukela Region
and KwaZulu-Natal. This can be achieved by close co-operation between the DWAF, the
uThukela District Municipality, the Provincial Office of the Department of Land
Affairs, the KwaZulu-Natal Department of Traditional Affairs and Local Government,
the KwaZulu-Natal Department of Agriculture and Environmental Affairs, the
Implementing Agent, and local business and labour organisations. This is necessary
in order to align with existing development plans and even to formulate specific TWP
spin-off strategies, for example, procurement policies, SMME policies and incentive
schemes.
Environmental Aspects
During feasibility level environmental investigations, nothing was found to
indicate that the TWP should immediately be abandoned or that there was high risk in
proceeding to the next phase of investigation which will include an Environmental
Impact Assessment and Reserve Determination.
The TWP is a large and complex development intervention originating from policy
level decisions within National Government. These policies relate not only to
strategic water supply. Other policies such as poverty alleviation, job creation,
land reform, economic empowerment of previously disadvantaged people, and the
establishment of equity in resource access have also been considered.
It is a project that will have profound effects at various levels and in many
different ways over a long period of time, and will directly affect the quality of
life of large numbers of people. There is, therefore, a specific onus on the DWAF to
ensure that environmental considerations are accorded appropriate recognition and
respect in the administrative processes and planning activities which they
undertake.
The environmental feasibility of the TWP was, therefore, assessed at three
levels:
- National strategic policy level.
- Regional level.
- Site specific level.
The environmental investigations showed the following to be of particular
importance:
National strategic policy level
- The Reserve (basic social and natural river water requirements for the Thukela
River and its tributaries) has not yet been determined.
- A formal strategy is currently being developed for the management of the water
resources of the Thukela River as part of a national water resource management
strategy.
- A decision not to augment the water resources of the VRS would potentially
simulate trends synonymous with a slump in the national economy. There would be
job losses and increasing levels of unemployment, a reduction in disposable
incomes, and a shortage of funds (through taxes) for national development
initiatives.
- Implementation of the TWP would require political support at National,
Provincial and Local Government levels.
- The ramifications of negative international and domestic sentiment regarding
big dams should be considered in the decision making process.
- Issues around the effects of AIDS are not yet fully understood.
Regional level
- A comprehensive understanding of the sediment movement processes in the
Thukela River, their cause and effect, is essential and of fundamental
importance to a full understanding of the feasibility of the TWP. In the
Feasibility Study, work on the subject was started but much still remains to be
done.
- The TWP presents a unique opportunity to stimulate and kick start considerable
development and economic empowerment in the Thukela Region. However, this is
unlikely to occur if comprehensive regional development plans and spatial
planning for regional and local government structures are not implemented. To do
this effectively will require proactive participation of all institutions to
accept joint responsibility in social upliftment programmes. There is a
significant opportunity for effective liaison, communication and joint action by
National, Provincial and Local Government Departments.
- Unacceptable levels of crime and security may occur as a result of poverty,
AIDS-orphans, migration and easier access throughout the region, related to the
implementation of the TWP and the investment in infrastructure and other
services. To combat this will need policing, combined with integrated regional
development planning and implementation. There will also have to be effective
communication, liaison and joint action by National, Provincial and Local
Government Departments.
Site specific level
- Initial investigations have revealed that the construction of a dam at Jana
and flooding of the basin will bring about the loss of a large contiguous area
of Northern Valley Bushveld, which is endemic and a threatened veld type in
KwaZulu-Natal.
The loss of this habitat and potentially of certain fauna makes this issue
important, specifically because of legal principles in NEMA, and international
agreements on biodiversity, of which South Africa is a signatory.
- Flooding of the impoundments will cause economic, physical and cultural
disruption to landowners, farm labourers and communities currently resident in
the potential dam basins.
Approximately 74 private land-owners, 40 labourer families, 2 tenant families
and up to 450 households along the aqueduct route and, to a lesser extent, in the
in the dam basins could be affected either economically or physically. Both
communal subsistence agriculture and commercial farming enterprises will be
affected. This includes arable and grazing land.
- Resettlement is a highly emotive and sensitive issue. The process will have to
be planned carefully, transparently and inclusively. If not handled properly, it
has the potential to substantially disrupt the implementation of the TWP.
All of the negative impacts can be investigated and managed satisfactorily. So
too can positive impacts be enhanced by special intervention.
Although a significant amount of environmental baseline assessment has been
conducted during the Feasibility Study, it is intended that a comprehensive Reserve
Determination (in progress) and full Environmental Impact Assessment (in the future)
will complement existing information.
Financial and Economic Viability
Financial and economic cost benefit and sensitivity analyses have been undertaken
as part of the TWP Feasibility Study. Variables considered were the following:
the affect of using different discount rates, the affect of different values of
water for estimating the benefit of the water transferred, the affect of increasing
the capital cost of the TWP, and the minimum water transfer rate necessary to ensure
break-even between costs and benefits.
Results show that the benefit cost ratios are all significantly greater than one
over the full range of sensitivity tests. This is considered favourable and from a
financial and economic cost benefit perspective, the Thukela Water Project is
viable, yielding acceptable rates of returns.
Macro Economic Impact Analysis
A social accounting matrix has been developed to estimate the macro economic
impact of the TWP. Importantly, it has been assumed that the benefits or forward
linkages arising from the supply of water to the VRS would be the same, irrespective
of the source of water. This analysis was, therefore, focussed on the macro economic
impact that the TWP would have on the uThukela Region and the Province of
KwaZulu-Natal.
A summary of the major impacts is as follows:
Gross Geographic Product
Economic activity measured in terms of Gross Geographic Product should increase by
at least 10 % in the uThukela Region and 0.5 % in KwaZulu-Natal. However, if a
special effort is made to comply with Government objectives to stimulate the local
economy through pro-active intervention, then these anticipated impacts could
increase significantly.
Employment
Assuming traditional construction methods are employed, i.e. machine intensive, it
is estimated that more than 4 000 construction jobs will be created in the uThukela
Region and an additional 2 000 jobs in KwaZulu-Natal. However, if a diligent effort
is made to enhance the labour content of construction practices, then the number of
job opportunities created could be significantly greater.
Factor payments (labour)
Skilled and semi-skilled labour constitutes a high percentage of the direct and
indirect workforce required for the construction of the TWP. By inference, if
appropriate training is not provided for the local economically active workers, then
the advantages of the proposed scheme could be somewhat negated.
Commodities
The demand for various commodities, for example, construction materials, and
intermediate and consumer goods, is anticipated to be high, creating opportunities
for the manufacturing, commercial and service sectors. However, it is believed that
the entrepreneurial sector in the uThukela Region and KwaZulu-Natal will require
assistance to capture this demand to ensure that the source catchment optimises
benefits arising from the TWP.
Enterprises (capital)
As can be expected, almost two thirds of the enterprises employed during the
construction of the TWP will fall into the civil engineering sector. It is estimated
that 10 % of the total benefits accruing to enterprises will go to emerging
contractors.
This is considered reasonable given the type of construction activity to be
undertaken. However, the social accounting matrix indicates that by using
traditional implementation methodology, only a small percentage of the various
benefits will accrue to local community-based businesses. This is considered
unacceptable and, therefore, proactive intervention will be required to achieve
Government objectives.
Households (income)
It has been noted that, during the construction phase, the distribution of income
between rural and urban households, will be urban orientated. This phenomenon
requires investigation and, if necessary, counter measures will need to be
formulated in support of predominantly rural communities in the uThukela Region.
With regard to the distribution of income groups, equity was found in the
projections for the construction phase. Importantly, however, income distribution
during the operational phase tends towards the lower income groups.
Financial Arrangements
At this stage in the project cycle, only a superficial analysis of possible
institutional and funding options has been undertaken, mainly to gain a perspective
on how various models will impact on the timing of the TWP.
Various models, ranging from Government as the sole implementing
agent, through a public private sector initiative to a mainly private sector
undertaking, have been considered. However, more detailed analysis will be required
with the involvement of the Public Private Sector Partnership Task Team of the
Department of Finance.
FINDINGS
AND Conclusions + - To the top
Arising from the Feasibility Study, it can be concluded that the
Thukela Water Project:
- Is technically, environmentally (natural and social) and economically
feasible.
- Up to 15m3/s (about 450 million m3/a) can be transferred
out of the Thukela River catchment, in addition to the existing transfer to the
VRS via the Thukela Vaal Project at the Drakensberg Pumped Storage Scheme,
without negatively affecting existing and projected long-term water use in the
Thukela River Catchment, while also maintaining the sustainability of riverine
ecosystems.
- The most attractive means of transferring water from the Thukela River to the
VRS is to develop the proposed TWP comprising major dams at Jana in the Thukela
River and at Groot Mielietuin in the Bushman's River, a pipeline from the two
dams to the existing Kilburn Dam at the Drakensberg Scheme, pumping stations and
associated infrastructure.
- The proposed project is a cost-effective means of augmenting water supply to
the VRS, benefiting from the capacity of the existing Drakensberg Scheme to lift
the additional water required over the Drakensberg mountains to the VRS.
- The project can be implemented at any time to provide additional water to the
VRS (when required).
- The development proposals are situated in the relatively poor uThukela Region
of KwaZulu-Natal; the local and regional economy can enjoy potentially large
benefits from investment of the capital amounts and the creation of temporary
and permanent employment opportunities.
- Development and operation of the project can be managed in a way which can
make a major contribution to achieving Government objectives such as poverty
alleviation, employment creation, equitable access to resources, integrated
rural development and co-operative governance.
- The TWP is a strategic development option which will have consequences, both
negative and positive, in the source basin, in the VRS and throughout the
national economy.
- The two major dams comprising the development proposals are significant in
size and technically complex by world standards, and will be subject to local,
regional and global scrutiny for compliance with current best practice
world-wide and for irrefutable evidence that they represent the best available
response to the growing water demand in the VRS.
- Conceptualisation, planning, design, evaluation, implementation and operation
of the TWP will be the focus of ongoing interest and scrutiny from all quarters
and the relevant information must be made readily accessible to facilitate
evaluation.
- At a regional level, the development proposals will have major temporary
impacts during the construction phase as people move into the region with
negative social consequences. Training and skills development for local job
seekers should increase dramatically. Business and commercial opportunities in
the region are expected to expand. Infrastructure, such as roads and electricity
supply, will be developed and environmental disturbances such as noise, dust and
loss of sense of place will occur.
- Permanent consequences of the project at a regional level will be some
increase in employment opportunities, expanded road and other infrastructure,
expanded opportunities for tourism business and commerce, and a significant
change in the flow regime of the Thukela River.
- At a local level, construction of the project will have severe negative
consequences for a limited number of people directly affected by the works,
negative impacts on the environment as work areas are disturbed and destroyed,
an invasion of the privacy and lifestyle of some people close to the work areas,
and positive consequences for those who are employed on the works (perhaps for
the first time in some recently established land reform settlements).
- The project will cause permanent negative local impacts as inundation of the
dam basins, particularly the dam at Jana, destroys highly valued valley bushveld
ecosystems, some people will have to be relocated to make way for the dams and
aqueduct, commercial farmers and tourism operators will have to sell their
properties, the sense of place wilderness-like areas would be destroyed and the
sediment regime and river morphology downstream of the main dams could be
disturbed if adequate mitigatory measures are not implemented.
- Negative consequences of the TWP can be mitigated and managed in an affordable
and sustainable manner to avoid, minimise, and in some cases only compensate for
damage done. Similar affordable impact management strategies can be employed to
significantly expand and add value to the many positive opportunities which will
be derived from development of the project.
- Finalisation of project details is dependent on determination of the Reserve
for the Thukela River, the outcome of a comprehensive Environmental Assessment
and associated Environmental Management Plan.
- In order to meet the selected target date for delivery of additional supplies
into the VRS, it will be necessary to confirm the selection of the TWP from
among the alternative strategic options not later than ten year before this
augmentation date.
- Implementation of the TWP at a 1998 capital cost of R 5 billion could probably
be beyond the means of the SA Government's expenditure budget and it will be
necessary to set up an appropriate implementing agent, probably in some form of
partnership with the private sector, to raise the necessary funding,
design and construct the project and operate the system for a period of time.
This institutional development would be the critical path to successful
implementation to meet the desired target delivery date.
In summary, the Feasibility Study has identified and classified all aspects and
issues associated with the future construction of the project in sufficient detail
to enable decision makers to compare the Thukela Water Project with other strategic
augmentation alternatives. At this stage, further refinement is occurring as part of
the recently launched Decision Support Phase.
IMPLEMENTATION
TIME LINE - To the top
| The implementation time line indicated alongside has been
used during the Feasibility Study as being the soonest that VRS water
augmentation would be required. |
 |
| PROJECT TIME
LINE FROM RECONNAISSANCE TO IMPLEMENTATION |
|