BMC floats bids for DPRs for Rs 7,345.9-crore Mumbai flood-mitigation works

Mumbai receives most of its rain during the southwest monsoon season, which typically lasts from June to Sept. Representation pic

The Brihanmumbai Municipal Corporation (BMC) has moved to the next stage of its flood-mitigation plan, inviting bids for consultants to prepare detailed project reports (DPRs) for works estimated at Rs 7345.9 crore. The proposed works cover three broad areas - nature-based solutions and stormwater management, automated flood protection gates and coastal embankments, and pumping stations and drainage augmentation. The consultancy will involve surveys, investigations, designs and DPR preparation before the civic body takes up the actual works.

The big package: Pumps + drains

The third package, worth Rs 3009.35 crore, includes

Rs 500 crore
Water management system and pumping stations proposed to tackle chronic flooding at the Andheri subway.

Rs 2509.35 crore
Augmentation of various nullahs and improvement of the drainage network across Mumbai and its eastern and western suburbs. The consultants will first establish what needs to be built, where and at what capacity before detailed execution plans are prepared.

What the consultants have to do:

1. Survey the city's flood problem
>> Topographical surveys
>> Hydrological surveys
>> Geotechnical investigations
>> Bathymetric surveys
>> Environmental and social surveys
>> Asset mapping

2. Design the interventions
>> Assess feasibility
>> Prepare engineering designs
>> Prepare drawings
>> Determine required capacities and specifications

3. Prepare the DPRs
>> The final reports will set out the proposed works, designs, technical requirements and other details needed for implementation.

What is a bathymetric survey?

Think of it as a survey of the underwater terrain. Where a nalla meets a creek, a natural water body or the sea, consultants will map the underwater profile to understand:
>> Depth and underwater topography
>> Sedimentation
>> Water storage and flow capacity
>> Areas vulnerable to erosion or deposition
>> Data needed for flood and hydrodynamic modelling

The Rs 13,000-crore plan

BMC earlier proposed a comprehensive R13,000-crore integrated flood-mitigation plan under the Urban Flood Risk Management Programme (UFRMP).

The proposed funding pattern is
40% - NDMA
30% - Maharashtra government
30% - BMC

The broader plan includes drainage augmentation, pumping stations, automated floodgates, coastal resilience measures, nature-based solutions and other flood-mitigation interventions. BMC's July plan was pegged at about Rs 13,014 crore in its detailed component-wise breakdown.

What has already been prepared?

According to BMC

Rs 2200 crore
Approximate value of works for which DPRs have already been prepared, including projects related to:
>> Mithi River
>> Mogra Nalla
>> Mahul pumping station

Rs 7345.9 crore
Works for which BMC has now floated tenders to appoint consultants for DPR preparation.

What happens next?

Now
BMC invites bids for consultants.

Next
Consultants conduct surveys and investigations.

Then
Feasibility studies, designs and DPRs are prepared.

After DPR approval
BMC can move towards tendering and executing the actual flood-mitigation works.

Quickview

Rs 7345.9 crore
Value of works for which DPRs are being prepared

Rs 13,000 crore
BMC's broader integrated flood-mitigation plan

Rs 110.17 crore
Estimated cost of appointing consultants, according to BMC

3 packages
Nature-based solutions; flood gates/coastal protection; pumping and drainage works

Rs 11,000 crore
Approximate value of actual works under the Rs 13,000-crore plan, excluding GST, according to BMC

Where the 7345.9 crore will go

Work Estimated cost
Nature-based solutions and Rs 2139 crore
stormwater management
Automated flood protection Rs 2142.55 crore
gates and coastal embankments
Pumping stations and Rs 3009.35 crore
nalla/drainage augmentation
Total Rs 7345.9 crore