National Water Development Agency

2. National Water Development Agency, Ministry of water Resources, Govt. of India

NECTAR has taken up a major water resources planning project in Odisha. The project has been entrusted by the Ministry of Water Resources, Government of India. The scope of the project involved high precision 3D Mapping of approximately 450 sq km area to study the submergence area , number of villages to be inundated and to quantify the approximate volume of water capacity by the reservoir (RL91m) forming due to the proposed construction of Dam over Mahanadi River near Barmul Village in Odisha. The project had a feasible survey component of link canal of about 20 km length from the proposed dam to join Mahanadi-Rushikulya- Godavari link (M-G link) project.

The Mahanadi River was filled with water in the gorge area up to 19 km upstream from the axis of the proposed dam site. The water was not only infested with crocodiles but also the surrounding area was covered with thick forest living with wild animals. In spite of that NECTAR team has accomplished the survey work done. About 22682 high resolution aerial photographs with GSD 5 to 8cm were acquired from Drones flying over the catchment & link canal area. About 140 numbers of High precision Ground Control Points(GCPs) were surveyed over the area using satellite based differential GPS technique. To estimate the accurate water capacity of the catchment, river bed profile data was collected using laser based Echo sounding technology/instrument. The data sets ( High resolution image, GCPs & river bed profile ) were processed into high definition Surface Models for both the catchment area and 20 km link canal area with 22cm vertical accuracy. The surface model of catchment area was analysed for the water capacity / volume & extent of submergence of reservoirs to be formed at different dam height levels and surface model of the link canal area was analysed for the correct alignment for smooth flow mechanism of water from dam site to the M-G main canal. The number of affected villages due to the submergence level and their size (Major/Minor) were listed for selection of dam height feasibility analysis

Fig 2(a): Ground pictures of DGPS Survey, Aerial Imaging and Bathymetry survey conducted for the Project

Fig 2(b): Graphical Representation of the dam Capacity with respect to Dam Height as outcome of the study