lusaka water supply sanitation and drainage project · millennium challenge account zambia reducing...

Millennium Challenge Account Zambia

Reducing Poverty Through Economic Growth

LUSAKA WATER SUPPLY

SANITATION AND DRAINAGE

PROJECT

IMPROVEMENT OF MAZYOPA DRAINAGE

(CP10)

Presentation by Bismark Pule

Drainage Specialist MCA - ZAMBIA

31st March, 2015

9-Apr-15 www.mcaz.gov.zm 1200, Twikatane Road, off Addis Ababa Drive

1

The Presentation

1. Introduction

2. Objective 3. Outline

4. Safety Tip

5. The Project

6. Forms of Contract

7. Contract Packages

8. Mazyopa Drainage

9. New Drain Design 10. Construction Works

11. Construction Schedule

2 9-Apr-15 www.mcaz.gov.zm 1200, Twikatane

Road, off Addis Ababa Drive

Objective

To provide insight into the LWSSD project

areas with focus on the drainage Contract

Package 10 to enable interested bidders

submit responsive bids for construction

works



Safety Tip

4

Caught-in Between

Some Causes of Caught-in-

Between Fatalities

• Trench/Excavation Collapse

• Rotating Equipment

• Unguarded Parts

• Equipment Rollovers

• Equipment Maintenance

• Rigging accidents

4/9/2015

www.mcaz.gov.zm 1200, Twikatane Road, off Addis Ababa Drive

9-Apr-15

Safety Tip

5

Accident Prevention

1. Guarding Moving Equipment/Parts

2. Barricades

3. Proper Materials Handling

4. Shielding/Trench Boxes

4/9/2015


9-Apr-15

The Project

6

The Lusaka Water Supply, Sanitation and

Drainage Project ( LWSSDP)

Water Supply

Sanitation Drainage

9-Apr-15 www.mcaz.gov.zm 1200, Twikatane


The Project

• WTP rehabilitation

• Distribution Centres Rehabilitation

• New Pipeline Construction

• New Networks and Customer Connections

• Sewer Networks

• Ground and Elevated Concrete Water Towers

• NRW Water Reduction

• Drainage Works Construction

7 9-Apr-15


Contract Packages



CP1 Water Supply

CP2 Water Supply

CP3 Water Supply and Sanitation

CP4 Sanitation

CP5 Water Supply

CP6 Water Supply

CP7 Drainage

CP8 Drainage

CP10 Drainage

Forms Of Contract

FIDIC

• Red Book (1999)

• Yellow Book

• Green Book

• Gold Book

• Silver Book



Mazyopa Drainage



Improvement of Bombay Drainage

System

• Targeted the system stretching from the

southern part of the city (Kamwala,

Chilenje, Libala) through the CBD and

ending up just after the Kasangula

Road bridge at the Trash Trap

• Improvements to the drainage system

to result in serious flooding downstream

negatively affecting residents of

Mazyopa Compound.

Mazyopa Drainage



LOCATION AND DESCRIPTION OF THE

PROPOSED SYSTEM

• Mazyopa is a natural stream to which

storm water from the Bombay Drainage

System discharges

• Commences from the discharge point

of the proposed trash trap for the

Bombay, an open space with

vegetation on both sides.

• Approximate length of 2,600m

Mazyopa Drainage




PROPOSED SYSTEM

• At a distance of about 600m from

Trash Trap No. 1, the drain is joined

by inflow from the Luangwa and

City Airport catchments.

• The drain then meanders for about

740m along an area of informal

houses on the western bank where

the Mazyopa south settlement is

situated

Mazyopa Drainage




PROPOSED SYSTEM

• After meandering for 740m, there is a

walled private plot with a frontage

length of about 140m on the western

bank

• Immediately downstream of the

northern boundary wall, there is a

pipe bridge which is also used as a

pedestrian crossing

Mazyopa Drainage



LOCATION AND DESCRIPTION OF

THE PROPOSED SYSTEM

• At about 1,130m downstream of the

confluence there is an abandoned

weir and consequently a waterfall

immediately downstream of the

northern boundary wall

• At a distance of about 1,100m

downstream of the weir, the drain is

traversed by a recently constructed

suspension footbridge with a span of

27m

Mazyopa Drainage




PROPOSED SYSTEM

• The last section of the drain is

about 270m further downstream

with few housing units thins out

and mostly comprises farmed

vegetation.

• Downstream of the point where

the Chipata Drain enters the

Ngwerere is the proposed location

of Trash Trap No. 2 and the

energy dissipating structure

Mazyopa Drainage



Location of Abandoned weir

Location of Suspension bridge

Approximate location of Trash Trap No. 2

Chipata Drain

Confluence

Ngwerere Stream Railway Line Mazyopa Settlement

Project Location

Map showing

some prominent

features of the

Mazyopa Drain

Location of Pipe Bridge

New Drain Design



A two stage drain has been designed, the first stage is based on a

1:5yr. event lined section that generally following the existing

meandering path of the stream, plus improved unlined channel

sections on either side

New Drain Design



• Original full natural channel (app.

1:2 yr)

• Stage1 channel concrete lined.

Flow 1:5 (improved + Other

current)

• Stage 1 compacted fill (as req’d)

with stabilized surface

• Stage 1 channel, banks part

stabilized. Flow 1:20yr (improved

Bombay +Other )

• Future Stage 2 channel part

stabilized.

New Drain Design



Safety Fencing Safety concrete post and

rail fencing with child

deterrent spiked topping

will be provided in a few

areas due either to the

depth of the drains

and/or where high

velocities of flood water

may be encountered.

New Drain Design



New Drain Design



Trash Trap

Trash trap no. 2 and energy

dissipating structure will be

constructed at the end of the

improved section near the

Chipata Drain Inflow (Similar design as the one shown in the picture)

Construction

Works



Construction works are likely to proceed in the following manner:

• Clearance of vegetation from the stream;

• Removal of accumulated solid waste from the stream;

• Dewatering and diversion of dry-weather flow variously with cofferdams, flumes, gravity pipes or by pumping;

• Earthworks including excavation of rock where encountered, reshaping and improvement of the gradients where required;

• Relocation of utility services crossing the drainage (e.g. water supply and sewers) ;

Construction

Works



• Erection of the base of drains which will include: – blinding layer to the base

– Laying pre-cast sections of the central cunette or constructing in-situ as preferred by the contractor

– Blinding layer to the base

– Casting the base slab

• Erection of drain sides which will include: – side trimming

– polythene sheeting for in situ concreting of drain side walls

– free-draining material for drain side walls

– In-situ concreting or laying of pre-cast side slabs according to the contractor’s preference

Construction

Works











• Construction of access road

Construction

Works



• Diversion works

• Demolition of the abandoned weir

• Erection of the trash trap

• Transportation of other materials required for construction to site and offloading

• Erection of permanent safety fencing along the drainage

• Rehabilitation of the 27m span suspension bridge will be carried out by the replacement of the following items:

Wooden decking

Safety netting

• Besides the above, at crossing point for the pipe bridge situated some 330 metres upstream of the weir, a pedestrian footbridge constructed alongside it.

Construction Works

(Cont’d)



Corridor of Construction

• The will be confined within the total width of the proposed

two stage drain, which will have a width of 24.9 m (max)

• The width will however vary between 9.0 m and 24.9 m

Construction Works

(Cont’d)



Corridor of Construction

Construction Works

(Cont’d)

Construction Work Challenges

Location of Existing Utilities

Access to Working Areas

Weather Disruption (rains)

Dewatering and flow diversion

Undefined geotechnical risk

Known rock occurrence (2 -3m)

Groundwater in excavations

Traffic Accommodation

Public Road Traffic

Public Access Disruption

A summary of construction challenges

likely to be encountered is presented in the

following table where: KEY

Works largely

unaffected by issue

Works moderately

affected by issue

Works significantly

impacted by issue

Construction

Schedule



The Contract is proposed to start by August, 2015 and

the period of construction is 27 months

The installation of the trash trap has to done in parallel

with the other works

pre-casting works can be carried on during each rainy

season.

Construction

Schedule

31

IFB Release

Pre-Site Visit

Pre-Bid Meeting

Bid Submission

03/2015

03/2015

03/2015

05/2015

Bid Evaluation

Letter of Acceptance

Negotiations

Commencement of Work

05/2015

06/2015

07/2015

08/2015

Contract Completion 01/2018 Project

Closure 11/2018

9-Apr-15 www.mcaz.gov.zm 1200, Twikatane


The End



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