Evapotranspiration model selection for estimation of actual evaporation from bare soil, as required in annual potential groundwater recharge studies of a semi-arid foothill region

This study attempted to delineate and map potential groundwater recharge zones of the Singida, semi-arid, fractured crystalline basement aquifer using open source remote sensing and GIS software. Various thematic maps such as lithology/hydrogeology, soil, land-cover/use, slope, lineament density, drainage density and rainfall distribution were integrated in QGIS software. Vector input layers were rasterized and resampled using QGIS wrap projection function to make sure that the grid cells are of the same size. Reclassification using SAGA and GRASS reclass algorithms in QGIS was carried out to realign the factor classes in a consistent scale, and reclassification to a scale of 1 to 5 was carried out to harmonize the results. The study identified a number of potential areas for groundwater recharge, groundwater exploration, groundwater development and potential areas for artificial groundwater recharge. Potential groundwater recharge zones for the Singida semi-arid fractured aquifer are restricted to areas with high lineament density, cultivated areas, grassland and flat to gentle slopes. The potential of groundwater recharge is also observed in areas with low drainage density. The delineated zones provide a good understanding of the potential recharge zones, which are a starting point for recharge zone protection. This blended approach can be utilized for carrying out suitability analysis using the weighted overlay analysis approach. Areas designated good and very good are recommended for artificial recharging structures as an alternative technique for enhancing groundwater recharge through rainwater harvesting. This will help to augment groundwater storage in this semi-arid environment.

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Assessment of Traditional Rainwater Harvesting System in Barren Lands of a Semi-Arid Region

10.22541/au.161156065.56890657/v1 ◽

2021 ◽

Author(s):

Basant Yadav ◽

Nitesh Patidar ◽

Anupma Sharma ◽

Niranjan Panigrahi ◽

Rakesh Sharma ◽

...

Keyword(s):

Groundwater Recharge ◽

Rainwater Harvesting ◽

Root Zone ◽

Animal Husbandry ◽

Small Scale ◽

Monsoon Period ◽

Barren Land ◽

Sustainable Water Resources Management ◽

Potential Groundwater ◽

Semi Arid

In semi-arid and arid regions, groundwater is the primary source for domestic, agricultural, and industrial supply. Scattered and erratic rainfall in these regions makes groundwater recharge more complex. Small-scale rainwater harvesting using both traditional and modern rainwater harvesting structures has been seen as a solution to the deepening groundwater crisis in India. In this study, shallow infiltration ponds locally known as Chaukas were studied to understand their groundwater recharge role and pastureland development. Potential groundwater recharge from these shallow infiltration ponds was estimated using the HYDRUS-1D model, simulating the sub-surface processes in the root zone. Field data collected in the year 2019 is used to calibrate the model for field conditions, while monsoon period data (July-August) of 2020 is used to validate the developed model. The developed model was then used to predict the potential groundwater recharge for the monsoon periods of the year 2019 and 2020.The shallow infiltration ponds allow approximately 5% additional rainfall to be available as potential recharge. The near soil surface moisture also helps develop natural grass cover used for pasture in the early dry periods. Analysis of the vegetation in the past 10 years suggests that these shallow infiltration ponds have converted barren lands into eco-hydrologically productive pasturelands. These Chauka systems have helped in sustainable water resources management in these water stressed regions along with the additional livelihood support through developed pasturelands for animal husbandry. They have potential wide application across India and beyond, as they simply require slightly sloping, barren land above an unconfined aquifer.

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