SALINE WATER INGRESSION IN UPPER PART OF BALESWAR RIVER NEAR NAZIRPUR UNDER PIROJPUR DISTRICT: A CASE STUDY

Abstract

A five year project was undertaken to address the salinity problem in the upstream of Baleswar river. The information generated during this period have been presented in this paper. Previously the Madhumati-Baleswar river system was completely non saline throughout the year. Recently upstream fresh water flow from the Madhumati river through the Baleswar river passing in between Chitalmari and Nazirpur Upazila is about to cease due to prolonged siltation on the river bed. During intensive monitoring work (1995-1999) some canals such as the Chitra river, Vasa canal, Santoshpur canal, Lara canal etc. are identified as the portals of saline water in the upstream of the Baleswar river in dry season. Due to tidal effect they carried saline water from Daratana river to Baleswar river. As a result high water salinity prevailed in Baleswar river in between February and May. Maximum water salinity EC_w 17.6 dS/m and soil salinity EC_e 4.4 dS/m were recorded in May. Water extraction for irrigation in the riparian area was restricted due to high salinity. To minimize this salinity problem upstream fresh water flow from the Madhumati river to the Baleswar river has to be increased. Increased volume of upstream fresh water flow will push saline water back to downward direction. The major portals namely Chitra river and Vasa canal may be closed seasonally by constructing sluice gate with proper engineering design to prevent entry of saline water in the Baleswar river.