Groundwater use for irrigation and its productivity: Status and opportunities for crop intensification for food security in Bangladesh

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Ahmad, Mobin; Kirby, Mac; Islam, Shahidul; Hossain, Jakir; Islam, Masbahul

Ahmad, Mobin; Kirby, Mac; Islam, Shahidul; Hossain, Jakir; Islam, Masbahul


2014-03-06


Journal Article


Water Resources Management


28


5


1415–1429


Bangladesh has a large and growing population that will demand more food and place greater pressure on its scarce land resources. Currently, dry season irrigated Boro rice production plays an important role in meeting food security in Bangladesh. The main source of dry season irrigation is groundwater, but the extent to which the groundwater is currently used is not well known; this poses a key constraint for sustainable planning and management of irrigated agriculture. To address this knowledge gap, we performed an integrated analysis using remote sensing based energy balance modelling, crop classification techniques and secondary statistics to comprehensively assess groundwater use and water productivity of Boro in the northwest region of Bangladesh. For this study, 6 Landsat 5 images (path 138/row 043) from January to April 2009 to cover the Boro irrigation season in the northwest region of Bangladesh were used. The energy balance modelling results show a large spatial variation in the actual evapotranspiration from about 325 to 470 mm, with an overall spatial average of 365 mm. These spatial variations arise from the irrigation regime, soil types, and the planting and harvesting decisions by farmers which are successfully captured through remote sensing analysis. The estimated values of actual evapotranspiration correspond well with independent values obtained through field and regional scale soil and water balance modelling results. The actual evapotranspiration in the dry season derives from rainfall, irrigation with groundwater, capillary rise and (to a lesser extent) residual soil moisture, and hence we computed net groundwater use from spatial estimates of actual evapotranspiration and effective rainfall. The overall net groundwater use for Boro production in 2009 was 2.4 km3 across the modelled area of 61 Upazila sub-districts administrative units. A spatial time series (1990 to 2010) of pre- and post-monsoon groundwater depth changes in the northwest region of Bangladesh suggests that, with the current level of groundwater use, there is no immediate threat to sustainability of irrigated agriculture in much of the region but there may be a longer term concern with falling groundwater levels. In the study area, Boro water productivity in terms of actual evapotranspiration varies from 0.95 to 1.35 kg/m3. Identification of high performing “bright” and low performing “hot” spots across the region will help water managers and policy makers to devise appropriate strategies to reduce crop yield/productivity gaps and ensure future food security.


Springer Verlag


food security; yield gap; groundwater; irrigation; water management; water productivity; water accounting; remote sensing


Agricultural Engineering


https://doi.org/10.1007/s11269-014-0560-z


Link to Publisher's Version


© Springer Science+Business Media Dordrecht 2014


EP1312195


Journal article - Refereed


English


Ahmad, Mobin; Kirby, Mac; Islam, Shahidul; Hossain, Jakir; Islam, Masbahul. Groundwater use for irrigation and its productivity: Status and opportunities for crop intensification for food security in Bangladesh. Water Resources Management. 2014; 28(5):1415–1429. https://doi.org/10.1007/s11269-014-0560-z



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