Multipurpose use of Hazir khal by making provision for community proposed flow control gate at a culvert

Abstract

Hazir Khal is thc main souJ"C<of: surfuc<;walcr in lh~ Muns!,ir Char vilbge located in thc South- Central region of Flangladesh, The region is a tidal floodplam, and the SOurCCOfluM warer m the Hazir Kh.,.] is the Shingair River Every year the people of the village construct a tempor:ny earthen cn,,~-darn during mId of April al upstream of a culvert In the Hazir KhaL It is iutended mainly 10serve three purposes: (i) to prevent saline water intrusion in order to save the dry season crop from flooding by salt ",.,,(erduring spring Ildcs. (ii) to maiutain low depth flooding durmg wet scasOn in the agricultural land for cultivation of Deep Walcr Aman (a local variety of Monsoon rice) ond (iii) for fish cnlture dnriug the wet Sl'''Son,Moreover, the retained water also provides opportumty for domestic uses like Ilvcstock watering, batlllng, washing utensils and cloth etc, The cross-dam is cut during mid October to drain out the water, which is required at the flowering stage of Aman. ThlS loe.,.]"ater mauagem~'lltpractice has been going on for many ycars. Now the local people are faemg scarcity of eonstruellon material from local sources. The villagers have requested the Local Gm'erument Engineering Department (LOCD), wh'eh is responsible for planning, de~ign and implementation of small scale wator management project. to construct a sluice gate at the culven, The LGED responded positively to the request of the people, and decided to cOni>1ructa gate in 2008. Construction of the gate will provide additional benefits because orthe flexibility in the control ofwator The local water management practice as mentioned above was the subject matter of present study, A social survey was conducted to collect information on local water management practice, history of Hazir khat dam conslnlction process, multiple uses of " khal, expected additional benefits from the sluice gate and opinion on gate operation Measurement of tidal water level and salinily was oamed out in Hw.ir Khal to assess the tidal characteristics and salinity concentration in the study area, Availability of tidal water during flood tide was assessed to estimate the volume of water that can be retaiued by closing the gate at each tide during the dry seasoll. The agricultural area that oan be served by the available tidal water during the dry season was estimated based on water for dry season crop A round the year gate operation rule was developed according to crop calendar. fish life cycle, tidal cycle, requirement for country boat plying, requirement for water retention, requirement for prevention of saline water intrusion. requirement for drainage, and opinion of the local people.