Transcript Introduction

Water Requirements and
Availability Reconciliation
Strategy for Mbombela Municipal
Area
Study Steering Committee,
6 October 2012
Introduction
• Water Resources Infrastructure and Supply
– Where is the water currently coming from and
who is it being supplied to?
• Water availability
– How much water do we have?
• Water Requirements
– How much water do we need, now and in the
future.
• At the 1st Study Steering Committee
Meeting the background and baseline
information to the study was presented.
• The purpose of this meeting is to present
the Preliminary Strategy.
• Based on guidance obtained from the
SCC, the Preliminary Strategy will be
updated into a Final Strategy
• The Strategy report will:
– Identify resource management and
development options, and
– Recommend and sequence management and
structural reconciliation interventions.
• A Strategy Maintenance phase will follow
on from this study.
General Principles
• Sound water management principles supported
by policies and regulations of the Department of
Water Affairs and the vision of the Inkomati CMA
as captured in their CMS.
• Recognise South Africa’s International
Obligations.
• Balance the social and economic water
requirements and the protection of the
environment to achieve sustainable
development.
Principles cont.
• Ensure that water is used efficiently.
Principles cont.
• The following founding principles for water
allocation in the Mbombela LM can be
considered.
• Principle 1: Water for basic human needs in the study
area must be made available.
• Principle 2: The Ecological Water Requirements (EWR)
must be met as soon and as best as practicable.
• Principle 3: Water for economic growth in the study area,
within the policy parameters of the government, will be
taken into account.
• Principle 4: This study is not focussing on expansion in
irrigation and forestry.
Water conservation and
water demand management
• One of the general principles of water allocation
is that water use must be efficient.
• Hence, before DWA can approve a water use
licence the efficiency of the existing water use
must be clearly demonstrated.
• A WC/WDM analysis has therefore been carried
out to quantify the water supply situation in
terms of acceptable benchmarks.
• Benchmarks:
– Per/capita water use
– Water use per household
– Non-revenue water
– Losses/unaccounted for water
Nelspruit
White River / Rocky Drift
Hazyview
Nsikazi North
Nsikazi South
Karino/Plaston corridor
Matsulu
Irrigation: Overall conclusions
Irrigated agriculture in the Mbombela Municipal area is
generally under serious threat due to a number of key
factors including:
• Reducing assurance of supply due to growing erosion of
available water resources to other sectors
• Reducing water quality
• Rapidly escalating pumping (electricity) costs which are
effectively forcing higher levels of water use efficiency.
• Low morale in the agricultural sector (affecting
investment and productivity).
• Consequently the irrigation sector is
unlikely to be willing to further reduce its
supplies through water trading.
• Cutting back on unlawful water use is
one way of making more water available
to legitimate users, or for further licence
allocations.
Over-Arching Strategies
• Strategies to reduce water demand are common
to all demand centres and will be the first priority
in terms of implementation.
• Strategies to increase the water resources can
be broadly grouped into a Crocodile strategy,
and a Sabie strategy.
• If and when absolutely necessary a new dam in
the Crocodile catchment could be constructed
to meet the future water requirements of the
demand centres in the Crocodile (not the Sabie)
Crocodile - Infrastructure
options
• The following possible structural interventions
were identified:
–
–
–
–
–
Boschjeskop Dam
Montrose Dam
Mountain View Dam
Raising the Ngodwana Dam
Strathmore off-channel dam
• Preliminary costing of these dams has
been completed.
• Based on this, the Montrose Dam and
raising of the Ngodwana Dam can be
eliminated as options.
• The Boschjeskop Dam could provide
enough additional water for domestic and
industrial use in the Mbombela municipal
area.
Crocodile over-arching strategy
• The economic optimum for Mountain View and
Strathmore Dam is at a much higher yield than
the future municipal requirement.
• The opportunity for a joint scheme with the
irrigation sector therefore presents itself.
• While the Mountain View and Strathmore Dams
are downstream of the municipal area, the
benefit of these dams can be realised as follows:
• Water can be supplied to Matsulu under
gravity.
• Water currently supplied to irrigators in the
lower Crocodile from the Crocodile system
can be supplied from the Mountain View
hence freeing up water for other urban
centres in the Crocodile.
• The ecological implications of this water
‘swop’ will need to be evaluated.
Sabie strategy
• A review of the ecological requirements
could allow a useful increase in use.
• Other users in catchment (outside
MLM)must be part of planning and saving
water.
• Construction of a dam is very undesirable.
• Transfer from Crocodile Catchments is not
an option.
• WC/WDM, Trading, Groundwater etc offer
Water Balance For Nelspruit Without
Interventions
Intervention Options for the
Crocodile
Envisaged
Intervention
Expected Expected Time to
Starting Full Yield/
Benefit
million m3/a
Date Saving (Y)
WC/WDM (15%)
1.9
2014
5
Removal of IAPs
2
2014
16
Groundwater development
(Mataffin)
0.1
2014
1
Dam Option (e.g. Boschjeskop)
19.5
2018
5
Water Balance for Nelspruit with
Interventions – No Dam
Water Balance For Nelspruit With
Interventions & Boschjeskop Dam
Conclusions For Nelspruit
• Low growth water demand scenario can be fully satisfied
over the entire planning horizon without a dam
• 15% WC/WDM saving for Nelspruit is very conservative.
Current use is 721 litres/capita/day. Nelspruit should be
able to save at least 30%
• With 30% WC/WDM saving, the high growth water
demand scenario can be satisfied over most of the
planning horizon
• Boschjeskop Dam, or alternative dam, would provide the
necessary water (at high cost) but (i) should be
postponed as far into the future as possible (ii) cannot be
considered until WC/WDM is successfully implemented.
Urgent Actions Required
• Development of the WC/WDM plan and implementation
strategy
• Current IAP removal plan needs to be studied to check
whether IAP removal can be accelerated
• Borehole siting for Mataffin
Towards Final Strategy – Further
Information Required
• Extent of IAP infestation upstream of Kwena Dam
• Extent of unlawful irrigation water use in Crocodile River
Catchment (and Sabie)
• Area of fallow irrigation lands with water entitlements
which can possibly be earmarked for purchase