Evaluation of Earthen Nala Bund in Kangwai Watershed

Earthen nala bund (ENB) is water retaining structure constructed across the slope. The objectives of this study were to study the ENB in respect of design dimensions and compare and evaluate the design parameters of selected earthen nala bund with standard design under similar hydrological condition. To achieve these objectives ENB constructed at Kangawi watershed of Dapoli Tahsil the Department of Agriculture, Maharashtra State was selected. The ENB selected was constructed in the year 2011. The area of watershed is 45 ha with average slope of about 2.67%. For the existing and standard design dimensions of ENB structure there was difference between standard design and existing design. The depth of existing flood spillway for the ENB was found to be more than the desired depth. The velocities of flow of water trough the design sections of flood spillway were within safe limit. The cost of construction of existing nala bund was found to be higher than the cost calculated for the structure, designed by standard design procedure. The ENB constructed by considering the hydrological, hydraulic and structural design of the nala bund.