Rainwater harvesting potential for farming system development in a hilly watershed of Bangladesh

Abstract

Water resources management is an important part in farming system development. Agriculture in Chittagong Hill Tracts of Bangladesh is predominantly rainfed with an average 2210 mm monsoonal rain, but rainfall during dry winter period (December-February) is inadequate for winter crop production. The natural soil water content (as low as 7 %) of hillslope and hilltop during the dry season is not suitable for shallow-rooted crop cultivation. A study was conducted to investigate the potential of monsoonal rainwater harvesting and its impact on local cropping system development. Irrigation facilities provided by the managed rainwater harvesting reservoir increased research site's cropping intensity from 155 to 300 %. Both gravity flow irrigation of valley land and low lift pumping to hillslope and hilltop from rainwater harvesting reservoir were much more economical compared to forced mode pumping of groundwater because of the installation and annual operating cost of groundwater pumping. To abstract 7548 m 3 of water, equivalent to the storage capacity of the studied reservoirs, from aquifer required 2174 kWh energy. The improved water supply system enabled triple cropping system for valley land and permanent horticultural intervention at hilltop and hillslope. The perennial vegetation in hilltop and hillslope would also conserve soil moisture. Water productivity and benefit-cost ratio analysis show that vegetables and fruit production were more profitable than rice cultivation under irrigation with harvested rainwater. Moreover, the reservoir showed potentiality of integrated farming in such adverse area by facilitating fish production. The study provides water resource managers and government officials working with similar problems with valuable information for formulation of plan, policy, and strategy.

Rainwater harvesting system as a strategy for adaptation on climate change: A review

“…Et al. [46] conclude that the collection of rainwater increased the intensity of the crop up to 300%, mainly in vegetables compared to cereals and horticultural crops. On the contrary, Zdeb M. et al [40] considers that rainwater is not a safe source to irrigate fruit crops or others that are going to be consumed directly due to the presence of bacteria that indicate faecal contamination.…”

Exploring the Major Climate-smart Agricultural Practices for Dry Season Crop Production in Salinity Affected Fallow Land in the Coastal Areas of Bangladesh

“…Harvested rainwater is considered as a climatesmart irrigation technology for sustainable crop production in water-scarce and salinity prone areas [15][16][17][18][19]. Islam et al [20] found profitable horticultural production in hilly areas of Khagrachari district of Bangladesh using harvested rainwater. Rainwater harvested in Mini-Pond is being used to provide supplemental irrigation even for boro rice cultivation in northwestern drought prone areas of Bangladesh [21][22][23] where the altitude is much higher (11-48 m) than the coastal areas (0-2 m) but the amount of rainfall is much lower than the other parts of the country.…”

Streamflow characteristics of Sangu-Matamuhuri watershed in the southeastern part of Bangladesh

“…There is excess water in the monsoon and scarce in the dry season which create a situation of water insecurity in this area. It affects the water supply for domestic, crop production and fisheries [ 13 ]. Incessant rain in different period of the previous year lead to flash floods by overflowing Sangu-Matamuhuri rivers causing sufferings to many peoples of this area.…”