**6. Ecological and environmental adversities**

Since the prehistoric era, changes in irrigation system have a strong link with climate change [39]. Due to the increase in agricultural area and productivity, the human population has been increased in the Indus basin, followed by urbanization and industrialization, boosting the water demands for household, food production, and energy and industrial sectors. Population increased due to the availability of resources and settlement areas. A large area was converted into the urbanized area, and some of the native species vanished from the Indus Basin. In order to protect the urban area, a natural path of the Indus River should be restored along with its natural floodplains and wetland area. The presence of highly populated areas in the floodplains of rivers makes a large number of people prone to the flooding. In such circumstances, more economic loss has been observed by the flood as it happened in 2010 in Pakistan. In Kashmir region, the majority of the dams are constructed in a hazard-prone area and are called as "water bombs" by a glaciologist. About 15 dams were built by the Indian Government in the Himalayas, which were not recommended due to fragile mountainous land. The temperature in this mountainous region is increasing by human-induced global warming, and glaciers are retreating, creating a temporarily high flow in the Indus River, which may cause damage to the structures built [43]. The sediment load is constantly increasing in the river resulting in avulsion. With the passage of time, the storage capacity of the reservoirs started to decline due to the siltation increasing the area under inundation [53]. Reduction in the storage capacity increases the chances of flooding in the surrounding areas in high flow seasons. A detailed information about the impacts on the Indus River and mitigation measures is provided in **Table 3**.

**91**

*Vulnerability of Environmental Resources in Indus Basin after the Development of Irrigation…*

Since 1851, the salinity problem has been observed in different areas of the Indus basin. Firstly, the salinity issue was identified in the Jammu and Kashmir regions. Similarly, in Punjab, salinity problems were also reported. To check the overall groundwater level in the basin, a series of observatory wells were installed across the basin. In open water table wells, Punjab showed the remarkable increase in the water table level induced by man-made irrigation system in the area. The main reason for the high level of the water table, salinity, and water logging observed in the basin, although it was not that much prominent, was considered to be the diversion of the river channel and the construction of unlined irrigation canals during 1850–1950. The situation in Punjab is still considered better than Sindh because in this area water logging was more common than salinity due to salt-free upper layers and better drainage and topography. Salinity problems in Punjab were only confined to the areas with poor drainage and topography. In the central Indus basin, i.e., lower Punjab and upper Sindh, the water table was found to be highest in the 1940–1950s followed by the highest level of waterlogging in the 1960–1980s. Salinity conditions in this area are in transition to the upper and lower areas of the basin. The productivity of 20–30% of irrigated land was affected due to salinity and waterlogging during 1970–1980s [63]. A shift in climatic patterns and over the use of surface water reduced the availability of water, forcing the people to rely on groundwater aquifers, resulting in rapid depletion of subsurface water resources. The shift from surface irrigation to groundwater is the inability of the Indus basin irrigation system to accommodate the changing water requirements of crops over different seasons due to inefficient water management. Increase in food requirements due to population growth and economic competition emerged due to over demand of crop yield, and the farmer community moved from a conventional irrigated agriculture to more water-intensive agriculture that was beyond the capacity of the existing irrigation system. More than 80% of groundwater is extracted by small tube wells because of cheaper installation and easy operation. In the irrigated areas, groundwater is of poor quality, and its frequent use in agricultural has resulted in salinity of a large portion of the agricultural area in the Indus basin [53]. The Indus River delta is facing the high risk of salinity in upper parts due to vertical and lateral movement of saline groundwater into the fresh shallow aquifers [64]. Secondary salinization has been observed in 4.5 million hectares of land, and half of the lands are in the Indus basin irrigation area. About one million hectares of agricultural land is facing waterlogging problems due to seepage of canal water and poor irrigation techniques [45]. Food grain crops have been replaced with high-price crops, which require more water than the food grains, resulting in increased water demand. The canal water system, fed by Indus River, adds almost 16.6 million tons of salts into the irrigated and deserted strata of Indus basin including groundwater aquifers. Rainstorms cause a lot of agricultural and economic damages due to the restricted surface and subsurface water drainage, because of the plain topography of Indus basin [40].

*Environmental and ecological problems in Indus Basin, their mitigation and recommendations [53–62].*

*DOI: http://dx.doi.org/10.5772/intechopen.86722*

**Table 3.**

*Vulnerability of Environmental Resources in Indus Basin after the Development of Irrigation… DOI: http://dx.doi.org/10.5772/intechopen.86722*


#### **Table 3.**

*Irrigation - Water Productivity and Operation, Sustainability and Climate Change*

at the expense of Sindh's share of the Indus River [45].

**6. Ecological and environmental adversities**

Indus River and mitigation measures is provided in **Table 3**.

Similarly, interprovincial conflicts also exist in Pakistan over the unequal distribution of Indus waters among the dominant province of Punjab and other smaller provinces mainly Sindh [52]. Unlike India, these conflicts have been limited to the political platforms. In the mid-nineteenth century, the construction of large canal structures by the British Government in Punjab gave birth to these conflicts. In 1945, Interprovincial water distribution was ensured by signing a treaty in which the Indus River water along with its tributaries was distributed between Sindh and Punjab. According to this treaty, majority of water from the eastern tributaries of Indus (94%) were allocated to Punjab and remaining to the Sindh. Meanwhile, Sindh was allocated with 75% water of the Indus main channel and Punjab with the remaining 25%. The Indus Water Treaty made the construction of link canals necessary for Pakistan in order to compensate for the upstream loss of water. As a majority of the link canals and storage reservoirs were to be constructed in the Punjab region, Sindh's population perceived it as a conspiracy to compensate Punjab

To settle the issues among the provinces, the "Water Accord 1991" was endorsed in which Indus water was distributed on the basis of average flow. Even after the accord, some insecurities existed in smaller provinces because the large quantity of water was allocated to only Punjab and Sindh [52]. Kalabagh Dam has been a focus of attention for many years due to political insecurities on the construction of the dam. People of Sindh claim that after the construction of the dam, water flow will be reduced causing droughts and saltwater intrusion in downstream areas. They also claim that Sindh is far more dependent on river waters because more than 80% of groundwater is saline in the region and construction of the dam will compromise their water requirements. This project was developed in the light of past destructive events of droughts in Sindh and subjected to opposition from politicians and bureaucrats of the Sindh province [45].

Since the prehistoric era, changes in irrigation system have a strong link with climate change [39]. Due to the increase in agricultural area and productivity, the human population has been increased in the Indus basin, followed by urbanization and industrialization, boosting the water demands for household, food production, and energy and industrial sectors. Population increased due to the availability of resources and settlement areas. A large area was converted into the urbanized area, and some of the native species vanished from the Indus Basin. In order to protect the urban area, a natural path of the Indus River should be restored along with its natural floodplains and wetland area. The presence of highly populated areas in the floodplains of rivers makes a large number of people prone to the flooding. In such circumstances, more economic loss has been observed by the flood as it happened in 2010 in Pakistan. In Kashmir region, the majority of the dams are constructed in a hazard-prone area and are called as "water bombs" by a glaciologist. About 15 dams were built by the Indian Government in the Himalayas, which were not recommended due to fragile mountainous land. The temperature in this mountainous region is increasing by human-induced global warming, and glaciers are retreating, creating a temporarily high flow in the Indus River, which may cause damage to the structures built [43]. The sediment load is constantly increasing in the river resulting in avulsion. With the passage of time, the storage capacity of the reservoirs started to decline due to the siltation increasing the area under inundation [53]. Reduction in the storage capacity increases the chances of flooding in the surrounding areas in high flow seasons. A detailed information about the impacts on the

**90**

*Environmental and ecological problems in Indus Basin, their mitigation and recommendations [53–62].*

Since 1851, the salinity problem has been observed in different areas of the Indus basin. Firstly, the salinity issue was identified in the Jammu and Kashmir regions. Similarly, in Punjab, salinity problems were also reported. To check the overall groundwater level in the basin, a series of observatory wells were installed across the basin. In open water table wells, Punjab showed the remarkable increase in the water table level induced by man-made irrigation system in the area. The main reason for the high level of the water table, salinity, and water logging observed in the basin, although it was not that much prominent, was considered to be the diversion of the river channel and the construction of unlined irrigation canals during 1850–1950. The situation in Punjab is still considered better than Sindh because in this area water logging was more common than salinity due to salt-free upper layers and better drainage and topography. Salinity problems in Punjab were only confined to the areas with poor drainage and topography. In the central Indus basin, i.e., lower Punjab and upper Sindh, the water table was found to be highest in the 1940–1950s followed by the highest level of waterlogging in the 1960–1980s. Salinity conditions in this area are in transition to the upper and lower areas of the basin. The productivity of 20–30% of irrigated land was affected due to salinity and waterlogging during 1970–1980s [63].

A shift in climatic patterns and over the use of surface water reduced the availability of water, forcing the people to rely on groundwater aquifers, resulting in rapid depletion of subsurface water resources. The shift from surface irrigation to groundwater is the inability of the Indus basin irrigation system to accommodate the changing water requirements of crops over different seasons due to inefficient water management. Increase in food requirements due to population growth and economic competition emerged due to over demand of crop yield, and the farmer community moved from a conventional irrigated agriculture to more water-intensive agriculture that was beyond the capacity of the existing irrigation system. More than 80% of groundwater is extracted by small tube wells because of cheaper installation and easy operation. In the irrigated areas, groundwater is of poor quality, and its frequent use in agricultural has resulted in salinity of a large portion of the agricultural area in the Indus basin [53].

The Indus River delta is facing the high risk of salinity in upper parts due to vertical and lateral movement of saline groundwater into the fresh shallow aquifers [64]. Secondary salinization has been observed in 4.5 million hectares of land, and half of the lands are in the Indus basin irrigation area. About one million hectares of agricultural land is facing waterlogging problems due to seepage of canal water and poor irrigation techniques [45]. Food grain crops have been replaced with high-price crops, which require more water than the food grains, resulting in increased water demand. The canal water system, fed by Indus River, adds almost 16.6 million tons of salts into the irrigated and deserted strata of Indus basin including groundwater aquifers. Rainstorms cause a lot of agricultural and economic damages due to the restricted surface and subsurface water drainage, because of the plain topography of Indus basin [40].

Development of irrigation system structures such as dams and barrages has led to the fragmentation of Indus River into 17 sections which resulted in extirpation of dolphins from 10 sections. They were found to be present in only 6 out of 17 sections of the river due to the usage of river water for irrigation and low water discharges in the dry season. Spatial and temporal distribution patterns were affected by habitat fragmentation, and, combined with habitat degradation, it contributed to the decline of the dolphin population [55]. The whole length of the Indus River used to be the habitat of dolphins, but this area has now been restricted to only 20% of total length due to habitat fragmentation. Chemical pollution and accidental death by fishing gears are some of the potential factors for the decline in the dolphin population [65]. Sometimes, dolphins get trapped in the canals, fail to return back into the river, and eventually die. In the downstream area of Sukkur Barrage, the river channel is highly constricted, and dolphins are subjected to intensive fishing activities mainly in the winter season [66].

Natural processes have the potential to contaminate water resources, but with the development of irrigation system and residential colonies, the agricultural system became widespread, and a large number of industries came into existence. Anthropogenic activities in agriculture and industries cause discharges of fertilizers, pesticides, chemicals, heavy metals, and pathogens that can degrade the water quality and can cause negative effects on human health. Fertilizers and pesticides used in the agricultural areas are washed off and drained into surface and groundwater aquifers. The water requirements are high in the urban areas, and they contribute to water pollution by the production of municipal sewerage and leaching from solid waste generated. Water affected both qualitatively and quantitatively making it unsuitable for the human and animal consumption. As the Indus River flows downward, the effects of deterioration are intensified as a large volume of untreated effluents from agricultural, industrial, domestic, and commercial areas enter into the river on its way. Throughout the river channel, concentrations of nitrogen, phosphorus organic matter, pesticides, and mercury are present at an alarming level. Most of the effluent dumped into the river comes from the agricultural sector alone, while industries, households, and urbanized areas being the other major sources [67].

Indus delta is rich in biodiversity, and mangroves were a very important ecological resource in the lower Indus basin. Reduced water flow, pollution of rivers, and usage of mangroves as fodder and fuel have reduced the mangrove species. The population of mangroves has declined to a threatened level by pollution and anthropogenic activities [68]. With the decline in mangrove population, the spawning and rearing sites of many fish and macroinvertebrate species have been destroyed causing a decline in the population of those species. The flow of water in Sutlej River has almost gone to zero due to upstream storage by India. The river channel has been converted into a sandy desert with no water at all losing all the scenic values associated with its original aquatic ecosystem. As the river dried up, agriculture declined, and biodiversity was rapidly declined which disturbed the regional ecology. People moved from the dry areas, and all the developed infrastructure was destroyed. Sutlej Valley developed because the river began to die as the people migrated out of the area due to perished livelihood. Much of the culture of this valley has already been lost, and if not managed for a few more years, the civilization will be completely vanished [69].
