Cape Town s Water Crisis

Transcription

1 Cape Town s Water Crisis Paul Rhode Water & Sanitation Department 7 th Regional African Water Leakage Summit The Lord Charles Hotel, Cape Town 29 August 2017 Presentation Outline 1. Bulk water supply system 2. Status of water resources and water use 3. Water restrictions 4. Water resilience planning 5. Looking ahead 1

2 Where does Cape Town get its water from? Comparative Water Use from WCWSS (2014/2015) Agriculture: 158 Mm 3 (29%) Other municipalities: 37 Mm 3 (7%) Cape Town: 345 Mm 3 /a (64%) 2

3 City of Cape Town Bulk Water Infrastructure Dams (DWA & City) 15 Water Treatment Plants 12 Production Capacity 1650 Ml/day Current Capacity utilisation 45 % Reservoirs 24 Storage Capacity 2740 Ml Average demand storage 3 days Peak demand storage 2.5 days Pipelines 655 km Water Allocation and Demand Allocation from System 400 Mm 3 p.a. 2014/15 Demand 345 Mm 3 p.a. 2015/16 Demand 330 Mm 3 p.a. 2016/17 Demand 287 Mm 3 p.a. Water Sources (Based on Registered Allocations) COCT - Small Dams 2% COCT - Ground Water 2% WCWSS -COCT 23% WCWSS -DWS 73% 3

4 Water Use in Cape Town (2015 / 16) Government, 2.5% CCT Departments & Council-owned premises, 5.2% Other, 6.2% Industry, 3.9% Retail & Offices, 11.0% Houses, 55.6% Informal Settlements, 4.7% 70 % Residential Domestic other, 1.8% Flats & complexes, 9.2% Population Growth and Water Use Efficiency Water Treated per year (million m 3 ) Reducing per capita water consumption Population (millions) Water Treated Population Expon. (Population) 4

5 Theewaterskloof Dam (28 April 2017) Current Dam Storage and Production (28 August 2017) 5

6 WCWSS Dam Levels 19 Year Record Wemmershoek Dam Rainfall Record 6

7 Steenbras Dam Rainfall Record Steenbras Dam Rainfall Record 7

8 Water Restriction Campaign Timeline Level (10% saving) Level 2 January 2016 (additional 10% voluntary saving) Official DWS 20 % curtailment September 2016 Level 3 November 2016 (additional 20% saving) Level 3B February 2017 (restriction measures amended) Official DWS curtailment (Urban -20%, Agriculture 30%) March 2017 Level 4 May 2017 Level 4B July 2017: targeted use at 87 litresper person per day Water saving measures and usage tariffs Tariffs designed to encourage water saving Curtailment of non-essential water uses required (incl Municipal) Promotion of alternate water sources Treated effluent Groundwater Greywater Rainwater harvesting Water Restriction Campaign (continued) Communication Strong political support Constant media attention and awareness campaigns Enforcement Targeting high water users Improved enforcement Increased bylaw contravention fines Minimisation of water losses Losses reduced from 25% (2009) to 15% (2017) Increasing capacity to respond to leaks and bursts Expanding automated and manual pressure management 8

9 Full Domestic and Bulk Supply Water Tariffs (2017/18) Tariff Step (KL) Step1 (0-6) Step 2 (6-10.5) Step 3 ( ) Step 4 (20 35) Step 5 (35 50) Step 6 > 50 Level 1 (10%) Level 2 (20%) Level 3 (30%) Level 4 (40%) Bulk Supply Drought Disaster Declaration Executive Mayor declares a local state of disaster due to the drought, gazetted on 3 March Premier of the Western Cape declares a provincial state of disaster, due to the magnitude and severity of the drought affecting the Western Cape, which is gazettedon 24 May Outcomes: Assistance from Provincial and National governments (financial and technical) Re-allocation of municipal resources to manage water situation Assistance with regulatory processes 9

10 Impact of Restriction Campaigns on Water Supplied Ml/day WCWSS 2016 Annual Operating Analysis vs Actual Levels (Updated 1 August 2017) AOA 2016: SC1b: INTEGRATED SYSTEM STORAGE PROJECTION 1000 Boxes 100% 99.5% 99% 95% 90% 75% storage level & 0% & 0.5% & 1% & 5% & 10% Volume (million m 3 /annum) Boxplots derived from 201 sequences Years (Planning Year: Nov to Oct) 10

11 Scenarios (as presented to Executive Mayor on 29 May 2017) Grind it Out The drought is temporary in nature, and will break. There will inevitably be some amount of rain in the winter of Ramp it Up The 2017 winter rainfall will be substantially lower than the historical record. The drought continues for at least one more year. The New Normal Previous climate models cannot be relied upon. We are experiencing the harsh impacts of climate change. Over reliance on surface water is a risk. A re-look at the New Normal Scenario The New Normal scenario is even more relevant today As was anticipated during May scenario planning, the winter rainfall thus far is substantially lower than the median, and significantly lower than both the 2015 and 2016 rainfalls. Dam levels as of 21 August are at 32.5% compared to 57.9% same time last year. There is no reason to expect that rainfall will recover in August or September 2017, and it would be irresponsible to plan for it. There is no reason to expect that 2017 is the last low winter rainfall season. We must plan for the drought to continue well into 2018 and beyond. The enterprise risk management approach is affirmed Without new augmentation schemes & significant reduction in demand it is now highly probable that acute water shortages will be encountered in the first half of It is reaffirmed that the Grind it Out scenario is not accepted. 11

12 Management Approach Take a resilience approach to planning our water supply system Embrace the new normal scenario Develop non-surface water schemes Consider decentralised/localised water schemes Innovation Value of water Take a portfolio perspective: A multiplicity of actions to avert a disaster and ensure that we do not find ourselves in this situation again Take an enterprise risk management approach: Risk must be distributed over time Phased Approach Emergency Phase (short term) Tactical Phase (medium term) Strategic Phase (longer term) Focus for now: Emergency Programme Strategic intent is to provide 500Ml/day of production from sources other than dams, through temporary/permanent augmentation schemes, including: Groundwater Desalination, land based and ships/barges Water re-use for drinking water use Strategic intent is to simultaneously drive down consumption to 500Ml/day, through aggressive demand management and water restriction measures, including: Further water restriction measures, targeting high volume consumers Optimised reticulation pressure management zones Further/aggressive reticulation pressure management Bulk water system pressure management 12

13 Current Status Engineering Consultants have been appointed Designs in progress Bids registered on Demand Register BIF s signed Bid Specification Committees appointed Bid Specifications in progress First bids advertised on 16 August 2017 Envisaged Non-Surface Water Production Immediately: Granger Bay Immediately: Hout Bay Immediately: Red Hill / Dido Valley #REF! Immediately: Cape Flats Aquifer Immediately: Atlantis & Silverstroom Aquifer Immediately: South Peninsula Aquifer Immediately: Hottentots Holland Aquifer Immediately: Zandvliet WWTW 1st Tranche: Woodbridge Island 1st Tranche: Harmony Park 1st Tranche: Silverstroom 1st Tranche: Belville WWTW 1st Tranche: Athlone WWTW 1st Tranche: Cape Flats WWTW 1st Tranche: Macassar WWTW 1st Tranche: Koeberg 1st Tranche: Strandfontein 1st Tranche: Monwabisi 1st Tranche: Paarden Island Extreme: Desalination Barge 1 Extreme: Desalination Barge 2 Extreme: Desalination Ship 1 Extreme: Desalination Ship 2 Extreme: Desalination Ship 3 13

14 Strategic Programme Purpose: To enable long-term adaptation to climate variability and water scarcity To diversify water supply on a permanent basis to avoid overreliance on a single source, notably surface water, in case of shock Actions: Scale up groundwater extraction Install permanent large scale desalination Scale up household and business adaptation Improve efficiency across the Western Cape Water Supply System Introduce measures to improve storm water capture and reuse Integration of new systems (including decentralised technologies) with larger network Rehabilitation of water catchments / courses WCWSS Reconciliation Strategy (2016 Update) Driven by long-term population and water demand growth Voelvlei Augmentation million m 3 p.a. R300m CAPEX and R0.5m OPEX National DWS to implement TMG Aquifer million m 3 p.a. (in phases) Cost to be determined Wastewater Reuse 80 million m 3 p.a. R4.5b CAPEX and R0.5b OPEX Desalination 164 million m 3 pa (450 Ml/day) R15 b CAPEX and R1.2b OPEX 14

15 Future Water Outlook Key considerations: Growing regional demand and competition for water Climate change requires diversification of water sources and improved water use efficiency Unit cost of water is likely to increase as more costly alternatives to surface water schemes are implemented The current water crisis must be viewed as a game changer Reposition Cape Town as a Water Sensitive City that: Optimises and integrates the management of all available water resources (surface water, ground water, wastewater and stormwater) to improve resilience Places high value on water and strives to increase water use efficiency through water sensitive urban design Is a liveable city with healthy waterways and coastal waters Thank You 15