Drainage in Asia (II): Manifold drainage problems and their remedial measures in India

摘要

Emphasis has been placed on drainage improvement to overcome irrigation-induced drainage problems in arid and semi-arid regions. The main land drainage and reclamation problems in India may be classified into the following four categories: 1) rainfall-induced drainage problems, 2) irrigation-induced drainage problems, 3) drainage problems in the reclamation of saline lands with natural salinity, and 4) major flooding problems. Flood control is now being implemented mainly in the Ganga River basin. The rainfall-induced drainage problems are mainly identified in the river plains and deltas of the east coast. Only gravity drainage is applied in those areas. The difficulty of drainage management stems from the large size of the drainage blocks. Rearrangement and downsizing of drainage systems with proper size of drainage blocks is needed, Since semi-arid regions also experience rainfall-induced drainage problems, proper drainage improvement is required to cope with both problems.