II. ENVIRONMENTAL IMPLICATIONS OF UNSUSTAINABLE DEVELOPMENT
A. Major green environmental problems and causes
6. Natural hazards: droughts, floods and earthquakes
Periods with less then 40 per cent normal precipitation are considered as drought conditions. In NWFP, with the exception of southern districts, drought conditions are not very serious. But occasionally rainfall fails to occur as a result of complex climatic conditions in the province that cause damage to the barani areas where yield is very low. Therefore it would be worthwhile undertaking a study of those underexploited resources with the objective of increasing cropping intensity and productivity in NWFP. The provincial government has already started a barani area development project through which efforts are being made to increase agricultural productivity by constructing reservoirs for collecting rainwater as well as small-scale check dams, and by levelling land and improving other inputs.
Flood problems are also related to the physical conditions of the province. Large-scale deforestation and overgrazing in the upper catchments is causing heavy soil erosion and landslides with subsequent siltation of rivers and dams, and flooding of adjacent areas. That, in turn, causes damage to human settlements, crops and the infrastructure. Vertical erosion is also occurring in the upper areas where fertile agricultural land is being eroded. A major problem has been noted in NWFP near the major Indus, Kabul, Kunhar, Dor, Sarin, Kurram and Gomal rivers.
The floods of September 1975 and 1992, and July-August 1995 in Swat Hazara and elsewhere in the country were mainly caused by physio-climatic conditions as well as by deforestation and other human factors. The study, carried out by the Department of Geography, University of Peshawar in 1995 in the Swat valley, revealed that 175 villages were affected by the flooding, resulting in more than 100 lives being lost, and heavy land, property, infrastructure losses, including 14 bridges. A total of 63 houses were totally destroyed and another 339 houses were partially destroyed, while the local infrastructure was damaged badly. The houses, belonging to low-income families, had been built on an active flood plain. In addition, 1,242.8 hectares of agricultural land, 155 animals and 26 water mills were washed away. Standing crops of maize and vegetables as well as orchards were destroyed. The total estimated cost of the damage was estimated at PRs 456 million.
In September 1992, rainfall amounting to 390 mm in two days was recorded in Hazara Division. As a result, rivers rose rapidly in the mountainous regions, some by more then 6 metres in narrow gorges. Large-scale land slides occurred, bridges, and solid structures of concrete and steel suffered massive infrastructure damage near Gari Habibullah, Kohala and other parts of the Division when they were struck by massive boulders. A total of 263 people were killed, 5,337 houses, 825 shops and standing crops on 11,485 acres were badly damaged. The loss to forests, property, irrigation channels and communications amounted to PRs 900 million (Hussain, 1992). The resultant siltation in the Tarbela reservoir reduced its holding and generation capacity, as well as its economic working life from 170 years to 50-60 years.
In Pakistan, no area is completely safe from earthquakes. However, some areas are more vulnerable than others. The western and northern mountains are more susceptible to seismic activity then the Indus plain. Two high-intensity seismic zones are located in the mountainous north: the Karakoram region which is associated with the Karakoram fault, and a second area located in the south in Abbottabad, Mansehra, Kohistan and Swat districts. Many earthquakes have occurred in those regions. The biggest recorded earthquake, known as the Pattan earthquake, occurred on 28 December 1974 with a magnitude of 6.5 on the Richter scale (Davis, 1984); it caused enormous damage in Pattan, Dubair, Palas and other villages nearby. According to the Outline Development Plan of March 1975, the Pattan earthquake caused 5,000 deaths and left 15,000 people injured. Extensive damage occurred villages lying in a north-south strip of land in the Indus Valley. The number of houses destroyed totalled more than 13,000, while a further 18,000 houses were partially damaged. The Karakoram highway, which connects Pakistan and China, was also seriously damaged over a distance of 80 km (Khan, F.K, and others, 1986).