New lease on life for Sukkur Barrage
A nearly century-old diversion dam, commissioned under the British Raj, and the backbone of Sindh’s agriculture is finally getting attention and a new life.
The Sukkur Barrage, the world’s largest irrigation system of its kind, whose construction started in 1923 and operations began in 1932, will now undergo rehabilitation and modernization as the Sindh Government, with the assistance of the World Bank, has approved a plan to do so.
The legendary artificial barrier which was known as the Lloyd Barrage at one point in time, has seven off-taking canals, of which four are situated at its left pocket, while three of them are constructed at its right pocket. The canals situated at the left pocket are Khairpur Feeder East, Khairpur Feeder West, Nara, and Rohri Canal, while the three canals to its right pocket are Kirthar, Rice, and Dadu Canal.
Sukkur barrage, with its seven off taking canals irrigates 8 million acres of agricultural land, a whopping 75% of Sindh’s agriculture land.
Khairpur Feeder East irrigates agricultural land starting from Khairpur city, passing through Kotdiji, Faizganj, and other cities and towns, eventually ending near Shaheed Benazirabad district, which was previously known as Nawabshah district - a small canal, which takes off from Khairpur Feeder East, known as Patni stream, is responsible for the irrigation of lands in Kandhra, Salehpat and Shadi Shaheed. Its counterpart, Khairpur Feeder West, which also passes through Khairpur city, is responsible for irrigating lands in Pir Jo Goth and Piryaloi.
One of Sukkur Barrage’s largest canals, the Nara Canal, provides water to lands in Mirpur Khas, Sanghar, Tharparkar, and its final destination Umerkot. On the other hand, Rohri canal passes through the main Indus highway and irrigates land in Thehri, Kandiaro, and ends near Hyderabad, which is Sindh’s second-largest city.
The off-taking canal on the right pocket, Kirthar, passes through Garhi Yasin, Shahdadkot and other cities, and concludes its journey in Dera Murad Jamali, in Balochistan, the birthplace of the late Prime Minister of Pakistan, Zafarullah Khan Jamali.
Rice canal, also on the right pocket of the barrage, is the water body for non-perennial crops, meaning it is open for six months from May to October and is closed for the other six. True to its name, the canal supplies water to rice growing areas in Larkana, Khairpur Nathan Shah, and Mehar.
The third off-taking canal of the right pocket, Dadu canal, irrigates land in Naudero, Dadu, and Sehwan, which is its ending point.
The remaining 25% of Sindh’s agricultural lands are watered by the Guddu and Kotri barrages - which goes to show the Sukkur barrage’s mammoth importance to the Sindh’s agricultural economy.
The 1.5 kilometer long Sukkur barrage, has 66 spans and every span is 60 feet in length. After its commission in 1932, studies showed that a heavy amount of silt began accumulating in the right pocket of Sukkur barrage, causing hindrance to the smooth water supply to the right side canals. After thorough research, it was decided to permanently close ten spans, ranging from span 6 to 14, and 23 - which helped in resolving the issue of silt accumulation on one hand but it reduced the capacity of Sukkur barrage from 1.5 million cusecs to 1.2 million cusecs.
Since its construction, the pre-independence era barrage has braved more than 50 floods, of which 12 were super floods from a period of 1976 to 2010. According to Abdul Aziz Soomro, incharge of the Sukkur barrage control room, different types of floods have passed through Sukkur barrage since its commissioning. “A flood carrying around 200,000 cusecs water is called a low flood, while a flood carrying water from 300,000 to 500,000 cusecs is termed as a medium flood. High floods carry water from 500,000 to 700,000 cusecs and very high floods are known to carry water from 700,000 to 900,000 cusecs. Any flood carrying more than 900,000 cusecs of water is known as a flash flood,” he explained, while talking to the Express Tribune.
After celebrating the barrage’s golden jubilee or 50th anniversary, the following year in 1983, one of its flood gates at span 31 developed a crack and the authorities had to take immediate action. Experts and technicians from the Karachi Shipyard were called, who ended up removing gate 31 and replacing it with one of the permanently closed gates - gate 10, thus averting an emergency.
However, that was not the end of the barrage’s troubles. Once again, in 2004, a 50 feet deep pit developed in the pavement of the diversion dam, between gate 1 and 2, after which the Sukkur barrage authorities immediately started stone dumping the affected site, but to no avail. Later, consultants who were called in, after a thorough inspection, recommended that the work should be assigned to the Frontier Works Organization (FWO). The FWO constructed a coffer dam near Dadu canal to stop water from flowing and after dewatering, the repair work of the pavements and blocks was done thus saving the Sukkur barrage from a possible disaster.
In 2019 another flood gate, gate 39, developed a crack, which was immediately welded by the team of Karachi Shipyard. However, during a thorough inspection of the other gates, the team of consultants and engineers recommended replacing six floodgates - 30, 31, 34, 35, 39, and 40. Currently, under the Sindh Barrages Improvement Project, all six of the flood gates are being replaced, while the remaining floodgates of the Sukkur barrage and its off taking canals will be replaced soon.
Every year from January 6 to January 20 all the floodgates of Sukkur barrage are opened to discharge water upstream and only water equivalent to pond level is maintained for the purpose of water supply. During these fifteen days, the pavement and blocks of the main barrage and its canals are inspected thoroughly and if any deficiency is found, it is removed.
Besides this, flood gates of the main barrage and all the seven offtaking canals are inspected for any damage and greased properly, because these gates mostly remain under water throughout the year.
The Sindh Government in its Environmental and Social Assessment Executive Summary has put forth the Environmental and Social Assessment (ESA), which consultants will adhere to during the rehabilitation and modernization of Sukkur Barrage.
As per the executive summary of the Sukkur Barrage Rehabilitation and Modernization Project, it is a project for rehabilitation of the 89-year old Sukkur barrage to enhance its useful life to safeguard the reliable supply of irrigation water to about 3.33 million hectares of land. The Government of Sindh has requested funding for the project from the World Bank through additional financing (AF) under ‘Sindh Barrages Improvement Project’ (SBIP). Sindh Irrigation Department (SID) which is the executing agency of the project, prepared the comprehensive ESA for it. Furthermore, mitigation measures are described and included in the Environmental and Social Management Plan (ESMP) to address potential impacts as well as to enhance the environmental and social benefits of the project.
The executive summary further elaborates: agriculture is the mainstay of Sindh economy - about 60% of the 42 million population of the province live in rural areas and are dependent on agriculture and related activities for their livelihood. 30 to 35% of Sindh’s population lives below the poverty line, and a majority of the poor are settled in rural areas. Pakistan produces over 108 million tonnes of agricultural commodities worth over 13 billion dollars annually and Sindh contributes about 23% to the country’s agriculture Gross Domestic Product (GDP). In recent decades, agriculture’s contribution to Pakistan’s GDP has declined; however, it still accounts for 21.6% of GDP. Agricultural GDP consists of 32.8% major crops, 11.1% minor crops, 53.2% livestock, 2.9% fisheries and forestry. Through its production, agriculture contributes 60% to the country’s export earnings and 45% of the nation’s labor force. Pakistan is among the top 20 global producers in over 48 different agricultural commodities and Sindh substantially contributes towards production of rice, sugarcane, wheat, and cotton. Rain-fed agriculture is not possible in Sindh since it falls under ‘hot desert climate’ - where annual rainfall is very low, about 100 millimeters (mm), compared to annual potential evaporation, which is over 2,200 mm. About 78% of groundwater in Sindh is generally saline, except along the Indus, and not suitable for irrigation. Thus without canal irrigation, agriculture is not possible in Sindh. Even before the construction of barrages, for centuries some areas in Sindh had depended on flood water of the Indus for agriculture through its old Inundation Canal System - artificial inundation canals that were linked to the Indus and received water when there were high flows or floods. Inundation canals generally provided uncertain and precarious supplies during crucial sowing and maturity periods. Further, due to upstream construction of barrages, this region received only marginal supplies for inundation canals.
Therefore to modernize the barrage, as per the summary, two sites have been identified, one on the right bank and the other on left bank, for placement of material to be excavated from the right bank canals and from the barrage. These locations have also been used for excavated material placement during previous dredging works and are part of the river bed, where there is no cultivation or humans residing. Hence, no land acquisition or resettlement is required for the two sites. The catch, however, is squatters and illegal construction. Excavated material from the barrage site will be placed on the left bank placement area; while the excavated material from the first 7 kilometer (km) length of canals will be placed at the right bank placement area. The material excavated beyond the 7 km of the Rice canal, will be used to strengthen the existing embankment. However, the material excavated from the first 7 km of the canals cannot be used for strengthening of canal embankments, since they are occupied by about 300 squatters’ households and illegal constructions.
The Indus and its riparian forests have a unique freshwater ecosystem that supports both terrestrial and aquatic biodiversity. In Sindh, 105 species of plants, 150 species of avifauna, 16 species of mammals, 15 species of reptiles, 4 species of amphibians and 67 species of fish are reported. Among the animal species only the Indus River Dolphin is the endangered species located close to the barrage area. Hilsa and Barramundi are the two migratory fish species and commercially very important fish species in the Indus. Hilsa, which is locally known as palla, is an anatropous fish that migrates to Indus reportedly as far as up to Multan, which is located about 300 km upstream of Guddu, for breeding before the construction of barrages. However, the construction of barrages has restricted the migration of Hilsa up to only Kotri barrage. Barramundi, in contrast, is a catadromous fish that lives in the Indus, close to the coast, and migrates into the sea for breeding.
A 170 km stretch of the River Indus between the two irrigation barrages Guddu and Sukkur, is the designated national protected area for Indus River Dolphin, and is known as Indus Dolphin Game Reserve - the total area of the reserve is 125,000 hectares and has a 3 km buffer zone on the floodplains. This dolphin game reserve was also declared as a Ramsar site, a wetland of international importance, in 2000. According to estimates in 2011, the reserve held a population of 918 dolphins. The Indus River Dolphin, locally known as Bulhan, is one of the four river dolphins of the world and used to inhabit Indus and its tributaries in Pakistan and India, but now most of their population is restricted to lower Indus. In the 2011 survey conducted by Sindh Wildlife Department between Guddu and Sukkur barrages, 18 major schools of dolphins were noticed with a total population of 918 dolphins in which 804 were mature 47 were the young and 67 were juvenile. While in the 500 km stretch between Sukkur and Kotri barrage only 29 dolphins were noticed. Dolphins are generally noticed in the deepest river channels where fish prey is high and are less common in secondary channels and small braids. Dolphins rely on vocals for communication and identification of prey because of their poor eyesight and there is no particular season for breeding of dolphins since calves are born at different times throughout the year, but appear to peak during July and August. The gestation period for the dolphins is approximately 10 months and a single calf is born every two years. Juveniles are weaned at around one year of age, but do not reach sexual maturity until around 10 years of age. This species is thought to live at least 28 to 30 years in the wild.
In contrast, in 1975, only 150 dolphins were recorded from this reserve, which signifies the conservation efforts carried out by the Sindh Wildlife Department.
The natural ecosystem in the project area, however, was altered by the clearing of lands for cultivation and livestock grazing. Common tree species such as acacia and eucalyptus are generally planted along the margins of agricultural lands. Seasonally inundated floodplains within the marginal bunds of the barrage and shoals, locally known as belas, found to consist of 105 grass species, predominantly tamarix species, belonging to 81 genera and 36 families. These species are generally cut and carried for fodder by local communities. 86 species of birds were recorded within the game reserve out of which 41 species are migratory but due to the developmental activities around the project areas urban bird species are dominant. The riparian forests between Guddu and Sukkur along Indus were once reported to provide a habitat for fishing cat and hog deer, which were classified as endangered by the International Union for Conservation of Nature (IUCN), and smooth coated otter, which were classified as vulnerable by the IUCN, but none of these species are now reported to be present in these areas due to conversion of these forests into agricultural lands and plantation areas, and poaching. The Otter population is reportedly declining due to pesticide laden return flows from agricultural fields and development of fish farms along the Indus.
The summary is quite clear about protecting all this marine life and other species living in the Katcha forest while taking up the much needed rehabilitation and modernization work of Sukkur barrage and its canals.