Studies on Monitoring Land and Water Management in Pakistan

The purpose of this study is to monitor land and water management using remote sensing and Geographical Information System (GIS). The Fourth Drainage Project, which is located in the center of Punjab Province of Pakistan, was selected as a research field. The Project was launched in 1983 to combat the twin menace of waterlogging and salinity; the depth of the water table in 77% of the area was 0-1.5m, and 43% of the land was saline. A newly introduced subsurface drainage system and a remodeled surface drainage system by the project have gradually reduced the waterlogging problem. The salinity problem, however, still remains. Analyzing Landsat-TM, GIS and ground truth data, following results were obtained. Waterlogging and salinity problems are mainly distributed along the drainage canals. The main reason is that the water table along the drainage canals is shallower due to the relatively low location. The Normalized Difference Vegetation Index (NDVI) tends to be lower along drainage canals and higher along the irrigation canals. It is mainly because of the unbalance of water distribution as a result of the locational disadvantage of downstream farmers. By contrast, an enterprise farm near the project does not show these locational unbalances but exhibits high NDVI values almost all over the farm, except for fallow. It is due to the fact that the water management there is demand-oriented, thus more flexible, and sufficient water is supplied.