Exploring Rainwater Harvesting Potential for Irrigation in Lackatoorah Tea Garden of Sylhet, Bangladesh

Abstract

Sylhet division is the major tea-producing region of Bangladesh. This study was conducted to explore the potential of rainwater harvesting by a designed model to fulfill the water requirement of the Lackatoorah tea garden during the dry season. Data were collected from both primary and secondary sources, and remote sensing data were analyzed using ArcGIS 10.7 to assess soil texture and slope. Four potential sites of (1.5 m ×1m) area were identified to estimate the volume of runoff water in the study. Four tanks with a capacity of 4000 liters were placed to store water as a reservoir for four sites. This study reveals that the study area received maximum average rainfall during June (742.7 mm - 839.2 mm) and July (667.7 mm - 787.2 mm) and the months from October-March received minimum rainfall (<200 mm) over 30 years. In this research, the rainwater was harvested in 2022 and the yearly harvested water for site 1, site 2, site 3, and site 4 are found as 1.99 m3/m2, 1.69 m3/m2, 1.99 m3/m2, and 2.58 m3/m2 respectively. Harvesting the yearly rainfall (5118 mm) in the Sylhet region can meet the net irrigation requirement of 394.48 mm for tea gardens. The catchment area should be taken as (15% - 23%) of a targeted irrigated area with varying runoff coefficients and the total volume of the reservoirs needed for one-hectare tea garden should be made about 3844 m3 based on the average depth of the reservoirs.

Keywords

• net irrigation requirement
• rainfall
• rainwater harvesting
• runoff co-efficient
• tea garden