Sea intrusion, sinking of Indus delta threaten coastline
KARACHI: Increasing sea intrusion along with the sinking of the Indus delta due to the phenomenon of land subsidence poses a serious threat to Pakistan’s coastline that needs to be addressed through immediate short- and long-term measures, said experts at a briefing held at the National Institute of Oceanography (NIO) on Monday.
They were briefing the members of a sub-committee of the senate standing committee on planning, development and reforms and journalists on the status of sea intrusion and its possible solutions to secure the coastal areas of Sindh and Balochistan.
It emerged during the discussion that the coastline was undergoing a continuous change, as the waves hitting the coast during the monsoon period were extremely powerful. Therefore, all coastal development activities (including land reclamation) needed to be carried out after taking a detailed scientific input, the experts said.
Also, natural barriers such as mangroves and islands guarding against sea-based calamities should be protected, they said.
“Land subsidence (a gradual settling or sudden sinking of the earth’s surface that occurs when groundwater, oil, gas etc are taken out in large quantities) along the coast is alarming. There is also a gradual increase in the level of sea due to climatic conditions.
“These conditions have hastened the degradation process manifolds and if we experience a repeat of the 1999 cyclone, which caused widespread infrastructural damages and claimed hundreds of human lives, our losses will be much higher,” said NIO director general Dr Asif Inam, who is also part of a cell tasked by the federal ministry of science and technology to scientifically assess sea intrusion. He said sea intrusion had widened the creeks and the areas which were relatively protected stood exposed at present.
Giving a presentation on sea intrusion, Pakistan Navy commander Salman Ahmed Khan informed the audience that it was a global phenomenon and, according to a United Nations study, at least 20 major cities including Karachi and Mumbai were exposed to sea intrusion.
“The level of sea intrusion is different at different locations. It is, however, estimated that 50 million people across the world will be affected by the phenomenon,” he said.
No international studies had mentioned data on sea level rise specific to Pakistan (because they didn’t have the country’s data) but if sea level rise occurred at the rate being predicted globally, its compounded effect (along with sea intrusion) could be devastating, he added
According to him, both Sindh and Balochistan coasts have their own dynamics and there is a dire need to conduct detailed studies on these coasts. He said that irrigation structures had either damaged or completely destroyed natural estuaries. “Seawater ingress is increasing. Khobar Creek is the only creek left to nourish the Indus delta,” he said. His presentation included slides on the impact of land subsidence in Indonesia, Turkey and parts of Sindh.
Prof Sarfaraz Solangi of Sindh University said the Sindh coast was a soft coast it was composed of silt and clay. The gradual increase in sea level was a major threat to the coast as it was already below the sea level.
“Reduced silt in the delta owing to negligible flow of freshwater makes it very vulnerable,” he said while showing maps of intruding sea and water availability downstream Kotri before and after the construction of Kotri barrage, Mangla and Tarbela dams.
Sea instruction was directly linked to the reduced size of the Indus delta, he said. In reply to a question by a lawmaker, Dr Inam said water was a medium that supplied silt and sediments to the delta. “We need to have sediments if we want to stop sinking of the Indus delta.”
Dr Mansha of Space and Upper Atmosphere Research Commission (Suparco) said preliminary findings of a recent study indicated that the problem of sea intrusion was very much there. The area of Waddi Khuddi Creek (of Sindh) studied under the research showed that the water had intruded 2.10 kilometres into the land.
“Different coastal locations will have different level of sea intrusion. The coastline has changed and our study indicates that the process continues. Many creeks have disappeared today that existed decades ago,” he said.
The programme saw an intense debate on water discharge downstream Kotri.
The Sindh government officials, however, preferred to remain silent on some important points raised by an official of the Indus River System Authority Khalid Rana, Pakistan Tehreek-i-Insaf leader Dr Arif Alvi and Dr Farooq Sattar of the Muttahida Qaumi Movement. The Irsa official said no province, including Sindh, had ever complained in writing about water shortage in the Council of Common Interests. Dr Alvi and Dr Sattar questioned the Sindh government stance on deforestation of mangrove caused by coastal development and land reclamation.
“A case between the government and the DHA over coastal land is pending in the court. The dispute in not over destruction of mangroves but rather over land ownership. The Sindh government should explain its stance over an advertisement recently published in newspapers about a major commercial project planned to be built on the Karachi coast [that also involved land reclamation],” said Dr Alvi.
Balochistan government officials spoke about acute water shortage that the provinces had been facing for a long time and said the province faced the challenge of its survival. Thorough studies needed to be conducted on the Balochistan coast that had a completely different dynamics, they said.