Qualitative Performance of Different Soil and Water Conservation Structures in Raholi Watershed abstract
Introduction: With the limited scope of development of irrigation potential, rain water management plays an important role to supplement the surface water for domestic, irrigation and industrial uses. Therefore, efficient conservation and scientific management of harvested water is crucial for optimum utilization for crop production. Soil and water conservation structures create temporary storage of water and help in groundwater recharge.Materials and Methods:
Watershed is geographical area that drains to a common point, which makes it an attractive unit for technical effort to conserve soil and maximize the utilization of surface and subsurface water for crop production. The research was carried out during 2015-16 at Raholi watershed (602 ha) of Maharashtra state of India. The Raholi watershed is situated in Hingoli district of Marathwada region, which is 9 Km away from Hingoli city. It is located at 19⁰70’ N latitude and 77⁰07’ E longitude. The watershed has been developed by Department of Agriculture, Government of Maharashtra in the year 2010-11. Different soil and water conservation structures namely graded bunds, earthen nala bund, cement nala bunds and continuous contour trenches were undertaken in the watershed. Representative soil and water conservation structures were selected to study their effect on reducing soil erosion and soil loss in the area. On an average reduction in cross sectional area of graded bund was found to be 29.46 per cent (23.81 to 35.71 per cent) over a period of four years after their construction.Results: On an average reduction in cross sectional area of Continuous Contour
Trenches (CCT) was found to be 39.61 per cent (33.33 to 64.71%) over a period of four years after its excavation. Reduction in cross sectional area of earthen nala bunds was found 19.14 per cent over a period of four years after their construction where as its storage capacity reduced by 3.91 per cent for the same period. No change in the dimension of three cement nala bunds was found at the post development stage of the watershed. Reduction in the storage capacity of the cement nala bunds was found in range to be 2.43 to 4.50 per cent over a period of four years after their construction.Conclusions: It can be concluded that average depth and area of silt deposited at different Cement nala bunds (CNB) including CNB 1, CNB 2, CNB 3 were 0.13, 0.16 and 0.15 m and 1073.25, 746.32, 510.00 m2 respectively. The weight of silt deposited at CNB 1, CNB 2 and CNB 3 were found to be 184.16, 157.62 and 100.98 tonnes respectively. The total silt deposited in all cement nala bunds was found to be 442.76 tonnes during the period of four years after their construction. The per cent reduction in storage capacity of CNB 1, CNB 2 and CNB 3 was found to be 2.43, 2.79 and 4.5 per cent respectively over the period of four years from their construction. The reduction of storage capacity was due to deposition of silt in the nala on the upstream side of these cement nala bunds.