Water Metro - Kochi Metro Rail Ltd.

Water Metro

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Kochi, often referred as the commercial capital of Kerala, is one of the most densely populated district in the state of Kerala. Inland water transport was once the primary means of freight and passenger transport on the Vembanadu lake. The system has been declining over the last few decades and has seen minimal investment and technology upgrade. Water transport is inherently more energy efficient than either rail or road transport. The project is expected to reduce pollution and traffic congestions in the city and also ease access to business areas on the mainland for urban households situated along the Kochi lakeshore. The Kochi water metro project envisages the development of 15 identified routes, connecting 10 islands along a network of routes that span 78 km with a fleet of 78 fast, electrically propelled hybrid ferries plying to 38 jetties. More than 1,00,000 islanders are expected to benefit from the water metro. It is envisaged to be a socially inclusive transport system than being just a transport service with focus on improved livelihoods through commercial property development and tourism-based initiatives. The Kochi Water Metro Project intends to introduce modern, energy efficient, environment friendly and safe boats with low wake and draft characteristics at a high frequency to increase ridership.

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The water transport system envisaged for Kochi focuses not only on the ferry services as the mode of public transportation but also envisions a holistic development of the areas being connected by waterways as well as integrating the waterway system as a part of the entire public transport system of the city. Apart from the ferry service development, the project also looks into developing the existing and new roads providing increased access to the jetties and also within the islands, ensuring safety and security to all its users by way of active and well-lit streets, promoting use of small occupancy feeder modes to access the jetties, promoting property development around the jetties and place making.

The Kochi Water Metro project has a total value of 819 crores and major part of which is financed under Indo-German Financial Cooperation with a long-term loan agreement of 85 million Euros (Indian Rupees 579 Crore) with German funding agency, KfW ( Kreditanstault fur Weideraufbou) , for the development of an integrated water transport system for the city of Kochi.


The Kerala backwaters are a network of brackish lagoons and lakes lying parallel to the Arabian Sea coast (known as the Malabar Coast) of Kerala state in southern India, as well as interconnected canals, rivers, and inlets, a labyrinthine system formed by more than 900 kilometers (560 mi) of waterways. Kochi is the largest city in the south Indian state of Kerala and the second largest along India’s western coastline, after Mumbai. In Kochi’s case, thanks to its location on the lower west coast of the Indian peninsula, it is less vulnerable to storm surges or cyclones compared to cities on the eastern coast of the country. The city sits within a complex estuarine system comprising Lake Vembanad and the many rivers flowing into the lake, including the Periyar and Muvattupuzha rivers.

Kochi is abundantly blessed with waterways with over 1,100kms of waterways available. However, only 40kms out of these are considered navigable for motor boats since, according to the Inland Waterways Authority of India (IWAI) regulations a minimum depth of 2m is mandatory for their operations. The currently operational water transport system such as their routes, deployment of boats and its integration with the other existing modes of transport. State Water Transport Department (SWTD), operates the water transport in Kochi.



The project is intending to use the inland waterways in and around Kochi the major share of the waterways are -National Waterways ( NW3) – 40%, Cochin Port Trust Waters – 33%, existing routes under irrigation – 20%, other inland waters -7%. The proposed Water Metro Project comprises of fifteen (15) identified routes connecting thirty eight (38) jetties across ten (10) island communities and 2 boatyards. The overall length of the line lengths of these 15 routes is 76.2 line kilo meters. The water depth required (-2 to -2.50m CD) in channels and -1.50mCD in approach and jetty pockets. Since major part of the channels are already in use, dredging in these are not significant whereas the approaches from the navigational channel to the terminal area constitute the main part of the dredging. The total dredging is estimated to be in the range of 0.65 million cubic meters.

There are 15 routes planned as part of this project. These are highlighted in the sketch shown below. The headways shall vary between 10 minutes to 20 minutes across various routes at peak hours. There will be Navigational buoys and night navigational assistance throughout the routes. Water weed and floating waste management is envisaged in this project.

                 Fig.1. Identified Routes



The various components involved in the Kochi Water Metro Project are:

  • Boat Terminals and Access Infrastructure
  • Boats
  • Boatyards
  • Dredging along the identified routes and terminals
  • Systems – Navigation, AFC, PIS, VCS, CCTV and Operation & Control Centre



There are three types of boat terminals in the order of their size and capacity. Major. Intermediate and Minor Terminals.

Features of the Terminals

Kochi Water Metro terminals are designed/planned as a space for public gathering. Terminals are planned based on the Peak Hour Traffic (PHT). Accordingly, terminals having 1000PHT falls under major, less than 300PHT falls under minor, terminals with 300-1000PHT were considered as intermediate terminals.

All boat terminals are divided into paid and non-paid area. Ticketing facility, Ticket vending machine, Station control etc. were in unpaid area. Waiting area, Toilets etc are provided in paid area. All terminals are facilitated with Automated fare collection and turnstile system for passenger counting.

Fig.2. Typical View of a Terminal

Floating Pontoons

Floating jetties adopted to facilitate embarkation and disembarkation of physically challenged elderly commuters. Concrete pontoons proposed, Pontoons would be installed in the terminal waterfront where the water depths would be about -1.5 m CD to -2.5 m CD. Pontoons are connected to the terminal by means of a Aluminium gangway. The floating pontoons are provided to cater the tidal variation. Since the floating pontoons are designed with a freeboard of 0.8m in line with the freeboard of the boats, the same level will be maintained in case of tidal variations which in turn will facilitate the wheel chair movement.

                  Fig.3. Schematic Layout

3.2. BOATS

There are 78 eco-friendly boats for passenger service 23 of them are 100 pax and the remaining 55 are meant for 50 passengers. In addition to these passenger boats, there are four numbers of Rescue cum Workshop vessels for supporting the main fleet in case of emergency and for maintenance.

Twin-screw Catamaran hull is chosen for a better stability, safety and to cater the draft restrictions and low wake properties. The objective of the boat design was to develop a boat meeting the following requirements.

  1. Low Draft: The estuarine condition creates a challenge for restricted depth which decreases to less than 1meters in certain stretches. The silty mud which exists in the channels poses a challenge in terms of dredging. Consider the above it was decided to achieve a draft of 0.9 meters.
  2. Low Wake: The backwaters in Kochi are densely inhabited by fisherman communities and traders. The waterways are used extensively for fish farming and fishing. Hence it was necessary that the boats have low wake characteristics to subdue the wake and wash effects.
  3. Low Energy and Environmental Friendly: It was declared that boat would be environment friendly by the state Government and KFW. In order to achieve the objective it was decided that the boat would be electrically propelled and will have no outward discharge.

The objective of the concept design led to the conclusion to adopt an Aluminum Catamaran hull twin screw electrically propelled vessel, which will operate at a draft of 0.9 meters. The vessel would be designed to achieve a speed of 8 to 11 knots in different speed regimes.

Aluminum Hull

Shipbuilding Aluminum Alloy plates and extrusions are costlier but can reduce the overall weight of the hull when compared to carbon steel alloys further more aluminum alloys have excellent corrosion resistance and is comparable to the minimum yield strength requirement of mild steel or normal strength steels. The improvement in fabrication technology for aluminum has enabled shipyards to effectively undertake fabrication and production of Aluminum hulls even though it would account to a nominal increase in the overall cost of the vessel. However the Aluminum hull was favored by KMRL considering the lower cost of maintenance also. Moreover, the less weight of the boat will give less resistance and hence the less power requirements. The cost and weight of battery is a serious concern and the reduction in weight will yield a lesser power requirement and hence the battery size.

Catamaran Hull  

Catamaran hull designs are more stable when compared to mono-hulls of the same capacity. Catamaran can also be designed to achieve lower draft and lower wake characteristics. The demi-hulls will be designed with better flow characteristics. The distance between the demi-hulls will be adjusted in such way that these will generate minimum waves or rather the effective wave height will be less. Thus the wave making resistance is made to a minimum to again take advantage on the power requirements. A proper model testing will be carried out to ascertain the actual power requirements.



Electrical Propulsion

Electrical propulsion or the use of the electrical motors to drive the screws of a boat eliminates the following requirements:

  1. Connection of the engine to the propeller.
  2. Alignment of the engine and the propeller.


In addition, it also provides the builder with other options or added features like:

  1. Incorporation of a battery to store power.
  2. Acoustic decoupling of hull and engine to reduce noise pollution.
  3. Avoidance of the diesel driven internal combustion engine as the prime mover.


The Water Metro exercised the option of using batteries to store energy and drive the vessel upto 8 knots with this power. This speed regime will generally serve all practical requirements of the vessel. However, the greater challenge was to identify suitable battery chemistry and charging regime for the batteries. The following battery characteristics were analyzed and The Lithium Titanate Oxide (LTO) technology was zeroed in:

  • Lithium – ion
  • NMC

The primary aim for the battery selection was to yield a better life time with maximum number of cycles and fast charging. The project has multiple number of fast charging stations capable of charging the batteries in less than 15 minutes.


Carbon Emission

Boats planned for Kochi Water Metro Project are electrically propelled. A detailed model shift for the project has been carried out. Considering the model shift, the reduction in carbon foot print is estimated. In addition to reach this reduction in other pollution were also calculated in way of decongestion on the roads reducing the number of line buses, own vehicles like cars and motor bikes etc. on the roads and the impact is worked out as shown below:


Parameter Reduction in Emission of pollutants (Tonnes/Year)
2019 2021 2025 2035
CO2 3103 8578 10237 16278
CO 21.01 60.10 72.21 114.28
HC 7.71 22.06 26.51 41.95
NOX 20.24 57.88 69.55 110.07
PM 1.06 3.02 3.63 5.75
Total 3153.02 8721.06 10408.9 16550.05

                                    Table.1. Carbon Emission 


  1. DPR
  2. Final EIA Report
  3. MoEFC Clearance Report
  4. Annual Report 2021-22