Flood Management
Kolkata Metropolis Drainage
Drainage Problems In and Around Kolkata Metropolis and their Disposal
The Metropolis of Kolkata is already more than 300 years old. "Chance erected, chance directed", as described by Rudyard Kipling, the city of Kolkata had been facing its acute drainage problems since its very birth burgeoning over three marshy and obscure hamlets since 1690. Kolkata lies on the left bank of river Hooghly about 130 kms. upstream of its confluence with the Bay of Bengal. The bank of the river has developed as a natural levee and the general slope of the land is eastwards from the river bank. Initially, the drainage of this city had been effected against the general slope i.e. westwards through the now defunct creek which ran from Salt Lake (now reclaimed) in the east to Hooghly river at Princep Ghat on the west. Later on, excavation of Maratha Ditch (present Circular Road), which circumscribed the city in 1742 rang the death knell of the creek. River Bidyadhari has since then served as an outlet for the drainage of the city for a long period from 1856 to 1928.
The earliest drainage cum navigation was taken up by Major Tolly who submitted a proposal to use the bed of the almost dead channel of Adi Ganga as a private venture, excavated the channel named after him as Tolly Nullah which was opened in 1777. The total stretch of 17 miles (27.2 kms) used to outfall into Bidyadhari at Samukpota or Tardaport. Excavation of Circular Canal from Entally to Hooghly river was done in 1820 while construction of Chitpur Lock was completed in 1833. Subsequently, canalisation of Bhangor Khal was taken up in 1897-98 and excavation of Keshtapur Khal in 1910, a navigation channel, connecting Kolkata with Nona-Gong-KultiGung .
With the deterioration of Yamuna, the Bidyadhari lost much of its upland flood water supply and could not survive and was finally abandoned by the Govt. in 1928. Finally, Dr. B N De, an eminent Engineer of Calcutta Corporation came up with his new famous "Kulti Outfall Scheme". Apart from augmenting the capacity of drainage channels, installation of extra pumps and sedimentation tanks, an important step had been taken to take the drainage by long-lead channels towards east and south-east to the Kultigong outfall which is connected with the live Raimangal estuary. The outfall scheme consists of execution of two parallel channels from Bantala to Kulti (17 miles / 27 kms) to carry storm water and dry weather flow of the city separately.
The city of Kolkata and its adjoining metropolitan areas are thus drained by a network of drainage channels excavated, handed over and maintained over years by the Irrigation & Waterways Department. Around 1970, a number of new channels were excavated in the areas adjoining the main city where people started to live after the partition of Bengal by the fund available from the Calcutta Metropolitan Development Authority (CMDA). Subsequently, in absence of adequate maintenance fund, increasing encroachments on the canal banks and their slopes, extension of human settlement in the low lying areas in fringe areas of the city, aggravated the drainage congestion not only in the city core area but the Greater Metropolitan District also. Apart from the drainage channels a number of pumping houses located at Uttarbhag, Chowbhaga, Keorapukur in South 24-Parganas district are rendering great service towards removal of drainage congestion in their respective areas. Particulars of pumps and their capacities under Irrigation & Waterways Directorate are as below :
Drainage Infrastructure in KMC area and adjoining Municipal areas of North and South 24 Parganas Districts
| 1 | The sewerage and storm water from KMC and its adjoining municipal areas are drained through different drainage channels, mostly into river Bidyadhari and in some cases into river Hooghly. |
| 2 | Number of I&WD maintained drainage channels in KMC and the municipal areas of North and South 24 Parganas =177 nos. Total length = 1420.58 kms,under AMC =751.43 kms,under OTC = 192.415 kms |
| 3 | The number and length of drainage channels responsible for draining out storm water from KMC and adjacent municipal areas are 45 in numbers and 328 kms in length. The total catchment area covered by these 45 canals is aprox. 700. sq. km |
| 4 | Most of the drainage channels have their outfall into river Bidyadhari due to the natural slope of Kolkata towards eastern side. Some of the drainage channels also outfall into river Hooghly in the western side. |
Apart from gravity flow, storm water is also drained through 11 numbers of pumping stations of total capacity of 7078 cusecs situated on different drainage channels in KMC and adjoining Municipalities
| No. | Pumping Station & | Capacity (Cusecs) & | Location and draining channels covered |
| 1 | Bagjola Pumping Station | 1650 | At the outfall of Bagjola Khal into River Bidhyadhari at Kulti, N24P. The Bagjola Canal System is covered |
| 2 | Chowbhaga Pumping Station (CPS) | 450 | At the outfall of T.P. Khal into S.W.F at Paschim Chowbhaga, S24P. T.P. Canal System is covered |
| 3 | Additional CPS (ACPS) | 500 | At the outfall of Intercepting Channel into S.W.F Khal at Paschim Chowbhaga, S24P. Intercepting Canal is covered |
| 4 | 2nd ACPS | 500 | At the outfall of Intercepting Channel into S.W.F Khal at Paschim Chowbhaga, S24P. Intercepting Canal is covered |
| 5 | 3rd ACPS | 1100 | At the outfall of Intercepting Channel into S.W.F Khal atPaschim Chowbhaga, S24P. Intercepting Canal is covered |
| 6 | Keorapukur | 750 | At the junction of Keorapukur Khal and Tolly Nullah at Regent Park, Keorapukur, S24P. Keorapukur Khal is covered |
Continued…
| SN | Pumping Station & | Capacity (Cusecs) & | Location and draining channels covered |
| 7 | Uttarbhag Pumping Station (UPS) | 1000 | At the outfall of SAMD khal into River Piyali at Uttarbagh, Baruipur, S24P. SAMD System is covered. |
| 8 | Additional UPS (AUPS) | 250 | At the outfall of SAMD khal into River Piyali at Uttarbagh, Baruipur, S24P. SAMD System is covered. |
| 9 | 2nd AUPS | 850 | At the outfall of SAMD khal into River Piyali at Uttarbagh, Baruipur, S24P. SAMD System is covered. |
| 10 | Kalagachia | 20 | At the junction of Kalagachia Khal and Churial Canal. It covers Suti Canal catchment in Wards 125, 126, and 144 of KMC |
| 11 | Kabardanga | 8 | At the junction of KMC drain and Keorapukur Khal at Haridevpur, KMC. It covers catchment of ward 142, Haridevpur and Thakurpukur Cancer Hospital |
| TOTAL | 7078 |
Pumping Stations
Location of different Pumping Stations for Kolkata Drainage System along with Installed Capacity in Cusec / Litre per Sec.
| No. | Main Pumping Station of C.M.C. | Installed Capacity in Cusec |
| 16 | Ballygunge DRG Pumping Station | 1233 |
| 11 | Palmar Bazar Pumping Station | 1184 |
| 09 | Dhapa Lock Pumping Station | 480 |
| No. | Intermediate & Small Pumping Stations of C.M.C | Installed Capacity in Cusec |
| 15 | Topsia Pumping Station | 65 |
| 20 | Jodhpur Park Pumping Station | 20.64 |
| 21 | Chetla Lock Pumping Station | 24 |
| 24 | Mominpur Pumping Station | 142 |
| 23 | Nimak Mahal Pumping Station | 12 |
| 14 | Kulia Tangra Pumping Station | 40 |
| 12 | Pagladanga Pumping Station | 48 |
| 07 | Maniktala Syphon Pumping Station | 24 |
| 06 | Ultadanga New Pumping Station | 440 |
| 05 | Ultadanga Old Pumping Station | 28 |
| 04 | Belgachia Pumping Station | 8.01 |
| 01 | Birpara Pumping Station | 50 |
| 08 | Manicktala Pumping Station | 97 |
| No. | Pumping Station Under P.H.E | Installed Capacity in Cusec |
| 03 | Duttabagan Pumping Station | 48 |
| 02 | Laketown Pumping Station | 23.77 |
| 10 | Kashipur Dum Dum Drainage Pumping Station | 156 |
| No. | Pumping Station Under C.M.W.S.A | Installed Capacity in Cusec |
| 13 | Chingrighata Pumping Station | 100 |
| No. | Pumping Station Under C.M.D.A | Installed Capacity in Cusec |
| 25 | Baranagar Noapara Pumping Station | 300 |
Drainage Infrastructure in KMC area and adjoining Municipal areas of North and South 24 Parganas Districts
| No. | ||
| 1 | The sewerage and storm water from KMC and its adjoining municipal areas are drained through different drainage channels, mostly into river Bidyadhari and in some cases into river Hooghly. | |
| 2 | Number of I&WD maintained drainage channels in KMC and the municipal areas of North and South 24 Parganas =177 nos. Total length = 1420.58 kms,under AMC =751.43 kms,under OTC = 192.415 kms | |
| 3 | The number and length of drainage channels responsible for draining out storm water from KMC and adjacent municipal areas are 45 in numbers and 328 kms in length. The total catchment area covered by these 45 canals is aprox. 700. sq. km | |
| 4 | Most of the drainage channels have their outfall into river Bidyadhari due to the natural slope of Kolkata towards eastern side. Some of the drainage channels also outfall into river Hooghly in the western side. | |
Apart from gravity flow, storm water is also drained through 11 numbers of pumping stations of total capacity of 7078 cusecs situated on different drainage channels in KMC and adjoining Municipalities
| SN. | Pumping Station | Capacity(Cusecs) | Location and draining channels covered |
| 1 | Bagjola Pumping Station | 1650 | At the outfall of Bagjola Khal into River Bidhyadhari at Kulti, N24P. The Bagjola Canal System is covered |
| 2 | Chowbhaga Pumping Station (CPS) | 450 | At the outfall of T.P. Khal into S.W.F at Paschim Chowbhaga, S24P. T.P. Canal System is covered |
| 3 | Additional CPS (ACPS) | 500 | At the outfall of Intercepting Channel into S.W.F Khal at Paschim Chowbhaga, S24P. Intercepting Canal is covered |
| 4 | 2nd ACPS | 500 | At the outfall of Intercepting Channel into S.W.F Khal at Paschim Chowbhaga, S24P. Intercepting Canal is covered |
| 5 | 3rd ACPS | 1100 | At the outfall of Intercepting Channel into S.W.F Khal at Paschim Chowbhaga, S24P. Intercepting Canal is covered |
| 6 | Keorapukur | 750 | At the junction of Keorapukur Khal and Tolly Nullah at Regent Park, Keorapukur, S24P. Keorapukur Khal is covered |
| 7 | Uttarbhag Pumping Station (UPS) | 1000 | At the outfall of SAMD khal into River Piyali at Uttarbagh, Baruipur, S24P. SAMD System is covered. |
| 8 | Additional UPS (AUPS) | 250 | At the outfall of SAMD khal into River Piyali at Uttarbagh, Baruipur, S24P. SAMD System is covered. |
| 9 | 2nd AUPS | 850 | At the outfall of SAMD khal into River Piyali at Uttarbagh, Baruipur, S24P. SAMD System is covered. |
| 10 | Kalagachia | 20 | At the junction of Kalagachia Khal and Churial Canal. It covers Suti Canal catchment in Wards 125, 126, and 144 of KMC |
| 11 | Kabardanga | 8 | At the junction of KMC drain and Keorapukur Khal at Haridevpur, KMC. It covers catchment of ward 142,Haridevpur and Thakurpukur Cancer Hospital |
| TOTAL | 7078 |
Major Canals System in and around Kolkata flowing towards West
Existing infrastructure of pumping out from drainage canals in to outfalling rivers or in between canals.
The Irrigation and Waterways Department operates 11 existing pumpingstations of total capacity 7078 cusecs in KMC and adjoining areas.These pumping stations pump out the storm water into out falling rivers or from branch channel in to major channels. The details of the 11 pumping stations are stated below in tabular form.
| Sl | Name of Pumping Station | Location | No of pumps | Total pumping capacity |
| 1 | Old Chowbhaga PS | Chowbhaga | 9 | 450 cusec |
| 2 | 1st Addl Chowbhaga PS | Chowbhaga | 10 | 500 cusec |
| 3 | 2nd Addl Chowbhaga PS | Chowbhaga | 10 | 500 cusec |
| 4 | 3rd Addl Chowbhaga PS | Chowbhaga | 10 | 1100 cusec |
| 5 | Uttarbhag PS | Uttarbhag | 4 | 1000 cusec |
| 6 | Addl Uttarbhag PS | Uttarbhag | 5 | 250 cusec |
| 7 | 2nd Additional Uttarbhag PS | Uttarbhag | 7 | 850 cusec |
| 8 | Keorapukur PS | Kudghat | 7 | 750 cusec |
| 9 | Bagiola PS | Haroa | 19 | 1650 cusec |
| 10 | Kabardanga PS | Prantik Pally | 4 | 8 cusec |
| 11 | Kalagachia PS | Kalagachia | 4 | 20 cusec |
Existing infrastructure of regulator gates and lock gates on the drainage channels, maintained by Irrigation & Waterways Department.
These regulator or lock gates are integral part of drainage system. The gates allow the canal water go into the river or major channel during low tide and arrest the tidal water to enter in to canal system from river during high tide.
| Sl | Penstock Gates | Name of Canal | Present status |
| 1 | Bantala – 10 gates | THC | Gates are in operating condition. |
| 2 | Topsia – 2 gates | DWF | Gates are in operating condition. |
| 3 | Keorapukur – 2 gates | Keorapukur Canal | The storm water from Keorapukur Canal is drained into Tolly’s Nullah through Keorapukur Pumping Station at Kudghat. |
| Sl | Penstock Gates | Name of Canal | Present status |
| 1 | Bantala – 10 gates | THC | Gates are in operating condition. |
| 2 | Topsia – 2 gates | DWF | Gates are in operating condition. |
| 3 | Keorapukur – 2 gates | Keorapukur Canal | The storm water from Keorapukur Canal is drained into Tolly’s Nullah through Keorapukur Pumping Station at Kudghat. |
| 4 | Outfall into River Hooghly, Chitpur – 4 vents | Circular Canal | Gates are in operating condition. |
| 5 | Outfall into River Bidyadhari, Kulti – 14 vents | Bhangarkata Khal | Gates are in operating condition. |
| 6 | Outfall of Cantonment Khal, Kestopur – 4 vents | Cantonment Khal | Gates are in operating condition. |
| 7 | Dum Dum Park – 2 & 5 vents | Connect Upper Bagiola & Kestopur Khal | Gates are in operating condition. |
| 8 | Kulti – 9 & 10 vents | Lower Bagiola Khal | Gates are in operating condition. |
| 9 | Churial Main Khal – 5 vents | Churial Main Khal | Gates are in operating condition. |
| 10 | Churial Diversion Khal – 10 vents | Churial Diversion Khal | Gates are in operating condition. |
| 11 | Monikhali-Akra – 6 gates | New Monikhali Canal | Gates are in operating condition. It has recently been handed over to Kolkata Metropolitan Development Authority (KMDA) by I&WD on 26.12.2025. Copy of Government order is at Annexure-I. |
| 12 | Bagiola-VIP Road – 6 gates | Upper Bagiola Canal | Gates are in operating condition. |
| 13 | Ghusighata – 16 & 20 vents | SWF Channel | Gates are in operating condition. |
Separate detail of Bagjola Khal system: -
Bagjolakhal originates from B.T.Road near Dunlop bus stand. It traverses through various municipalities and Kolkata Municipal Corporation wards from West to East direction before its outfall into Bidhyadhari river at Kultigang in Bhangore block of South 24-Parganas. The initial stretch from B.T. Road to VIP Road crossing of length 9.28 KM is known as Upper Bagjolakhal and the stretch from VIP Road crossing to its outfall in to Bidyadhari river at Kultigang of length 28.8 KM is known as Lower Bagjolakhal. The Upper Bagjola stretch traverses fully through urban areas of high population density whereas the Lower Bagjola stretch runs initially through urban areas like Newtown, Rajarhat and then through rural areas. The total catchment area is around 162.14 Sq KM.
Maintenance of Drainage channel network:
Removal of water hyacinth, municipal garbage from all the channels is being carried out through Annual Maintenance Contract (AMC) by I&WD. Such regular cleaning on one hand maintains un interrupted flow and on the other hand helps to curb spreading of vector borne diseases.The intensity of cleaning varies depending on the population density and nature of adjoining catchment. The drainage channels are classified into two categories such as Type-A (in urbanized areas) where frequency of cleaning is twice in a week during monsoon and once in a week during non-monsoon period and Type-B (in heavily Urbanized areas) where frequency of cleaning is thrice in a week for monsoon and twice in a week for non-monsoon period. The total length of Type-A canals is 138.36 K and that for Type-B canals is 212.934 KM.
Future Planning of theIrrigation and Waterways Department for improvement of drainage in Kolkata
(A) Augmentation of Kulti Pump house at the outfall of Bagjolakhal by 2400 cusecs is ongoing.
(B)Survey is being conducted to evaluate further need of dredging at different stretches. Based on the survey required dredging will be taken up as and when required.
(C)New Pumping stations, one of capacity 1600 cusec at the outfall of Main Charial Khal at its confluence with Ganga at Charial, one of capacity 1060 cusecs at the middle of Charial Main Canal near Mahishgat Setu, one at Chowbhaga of capacity 800 cusecs over T.P Khal and other at the confluence of Begore khal with Manikhali khal near Gopalpurkhaler pole, are primarily planned through mathematical model analysis. The locations of the proposed new pumping stations are shown in the map, enclosed as Annexure-II.