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Development of structure
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Angola Water Supply
Background to Angola Water Supply
Introduction
Angola has made important progress in the sanitation sector but not in the water supply sector
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Background to Angola Water Supply
Challenges
• Angola has the highest rate of diarrheal disease in the world • Poor sanitation, stormwater drainage and contaminated rivers • Angola’s urban population is growing at a rate of 4.7% with limited piped water supply
Background to Angola Water Supply
Water losses and inefficiencies
• Angola has the highest rate of diarrheal disease in the world • Poor sanitation, stormwater drainage and contaminated rivers • Angola’s urban population is growing at a rate of 4.7% with limited piped water supply
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Background to Luanda Water Supply
Challenges
• Angola has the highest rate of diarrheal disease in the world
Future Luanda Water Supply
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LUANDA CAZENGA
CACUACO
ICOLO & BENGO
VIANA BELAS
Cobertura da redeScenario de água – Cenário1 1 Water Network CoverageCenário – Scenario 1 1
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Existente Existing
Future Proposed Futuro Proposto
Future Approved Futuro Aprovado LUANDA CAZENGA Required Upgrades CACUACO Atualização para o futuro
ICOLO & BENGO
VIANA BELAS
Cobertura da redeScenario de água – Cenário1 1 Water Network CoverageCenário – Scenario 1 1
LUANDA CAZENGA EXISTING SYSTEM 1
CACUACO EXISTING SYSTEM 2
EXISTING SYSTEM 3
EXISTING SUPPLY 6 & 7 ICOLO & BENGO FUTURE SYSTEMS 4/5 & 8
VIANA BELAS
Cobertura da redeScenario de água – Cenário1 1 Water Network CoverageCenário – Scenario 1 1
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CANDELABRO
LUANDA CAZENGA MAIANGA CACUACO
NOVOICOLO & BENGO ETA AEROPORTO LuandaVIANA Sudeste BELAS
RAMIROS QUILONGA BITA GRANDE
KAPIAPIA Existing Water
Future Water
River intake
WTP Cobertura da redeScenario de água – Cenário1 1 Water Network Coverage – Scenario 1 Reservoir Cenário 1
Water
Bulk Water: Methodology
• A surface model of the terrain was generated from SRTM models in design software • Existing bulk infrastructure was identified and capacities determined by means of network analyses • A water services layout was based on the proposed town planning layout and required land use. • River abstraction works, Water treatment facilities, Reservoirs, tower reservoirs, pump stations and bulk water supply pipelines requirements were determined and positioned in consultation with the town planners. • Bulk water meters, level control valves, an pressure reducing valves was strategically placed to account for sustainable design methods
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Water
Bulk Water: Methodology (Cont.) The bulk water pipe sizes are as follows: Material Diameter (mm) Class Length (m) Ductile Iron 400 K9 23929.5 Ductile Iron 500 K9 57623.1 Ductile Iron 600 K9 54670.2 Ductile Iron 700 K9 13521.8 Ductile Iron 800 K9 35212.4 Ductile Iron 900 K9 33715.3 Ductile Iron 1000 K9 67542.1 Ductile Iron 1200 K9 50075.9 Ductile Iron 1400 K9 25012.4 Ductile Iron 1500 K9 11839.0 Ductile Iron 1600 K9 92802.4 Ductile Iron 1800 K9 197.0 Ductile Iron 2000 K9 53933.3 Total 520074.3
Water
Reticulation
Water supply terminals are divided into different The elements in a water reticulation system for the categories, those that supply water to the public or supply of water for firefighting are: the community and those that supply water to an individual household • Trunk main: the pipeline used for bulk water supply Examples of water supply terminals are: • Water storage: reservoir and elevated storage • Reticulation mains: the pipelines in the • Public standpipes reticulation to which hydrants are connected • Water kiosks • Hydrants: of various types • Supply to a tank • Vendors • Yard tanks • Roof tanks • Metered house connections • Hand pumps for boreholes • Spring supply to tanks
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Water
Design Assumptions • Average Annual Daily Demand(Flow) was • Netto People/ha was used to calculate the determined by the previous table. Average Daily Demand per ha of the different land-use types. • An average population per land-use type was used for modelling purposes. • Percentage buildable and non-buildable as • Residential Demand (kl/day) = Area(ha) x well as the land-use split figures were used Percentage x FSR x Units/ha x AADD to calculate the Average Daily Demand per ha. • Commercial and Other Demands (kl/day) = Area(ha) x Percentage x FSR x ((AADD x 10 • FSR was assumed as 0.7 for the City 000)/100) Centre, Primary Centre, Local Centre and Residential High land-uses. All remaining • Total Demand was calculated in litre/second land-use types an FSR of 0.5 was used. and input into the Civil Designer water model per area of the land-use type as provided by • An average of 5 people per unit was Broadway Malyan. A peak water demand assumed and Units/ha was calculated by distribution was applied to the network during dividing People/ha by 5 People/ha. the analyses procedure of the network.
Water
Asset Management and Maintenance - Regulating water use
The provision of Acts by government on the use of water is generally good practice. The acts can provide for the regulating of water use by authorisation to users on the grounds of certain conditions as determined for each case.
Typically, different types of authorisation can be issued for example:
• Authorisation to a user that uses relatively small volumes of water, mainly for domestic use and emergency or recreational purposes. • Authorisation to a user where limited water use is allowed without issuing a permit • Authorisation to a user where the water use exceeds that of the aforementioned conditions. A permit must be issued to such a user.
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Water
Asset Management and Maintenance - Regulating water use
Water which is essential for life, for social development and for economic growth is a public commodity and Law • National Government Determination must be regulated under law. This will assist to fairly apportion water between agriculture, industry, • Catchment Managment Agency metropolitan, urban and rural areas. Enforcement
Establishment of Catchment management Agencies and Project and • Local Government/Municipality Water Users Associations is general practice and will Domestic use assist the Governing body to actively enforce rules and
Responsible • Water Users Association regulations onto each water user for all pre-defined User catchment area
Water
Asset Management and Maintenance - Water Management Strategy
When a decision is made on the allocation of water, the governing body can give permission or the permit subject to certain requirements:
Specifying the water source or other site for The relevant discharging water source
Specifying the Relating to the The stream Relating to back-flow permissible levels of protection of: flow conditions and waste water by: certain or all chemical or physical elements Other existing and potential Specifying the users treatment of the water before discharging
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Water
Asset Management and Maintenance - Water Management Strategy
Specifying the management practices and other requirements such as water conserving measures
Demanding the monitoring, analysis and reporting from all users, by specifying the measuring equipment and manner of measuring
Demanding the compilation Require the Permit and implementation of a In the case of water management plan holder to become a extraction of water member of a Water Relating to water before discharging management by: User Association
Demanding payment for water use
Demanding, in the permit, the provision of water by the permit holder to a third party
Institute the registration of water use as a prerequisite for the use thereof, in the case of a general authorisation
Water
Asset Management and Maintenance - Water Loss Management
Water loss in a live distribution network is a reality. Unaccounted for water or unmetered water may be: Leakages may account for as much as 30%-40% of the water supplied to an area. Water from leaking defective • Pipe distribution losses (Including pipe breakages) pipes may drain into storm and sewage systems but aren’t • Firefighting and certain city construction activities detected on the surface. • Cleansing of services reservoirs • Meter errors Locating leaks may sometimes be as simple as • Cleansing of mid-town centres investigating for flow in the storm system but the • Water purification works losses (filter wash and difference in the sum of the readings from the stand clarifier sludge water losses etc.) meters and the bulk meter will also indicate the presence of losses in the system.
When making the selection of storage requirements, provision must also be made for “Unaccounted for water” and “unmetered water” and managed to some extent.
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Water
Asset Management and Maintenance - Metering
The information required for accounting and management is generated by proper metering. Meters must be installed for each housing unit, school, office building etc.
Metering of districts is also important. All volume measurements for water use must be captured on a database and inspected regularly to ensure accurate recording and billing of water use. Metering also assist in the process of leak detection and balancing supply with demand.
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