The 3×25 MW Doyang Hydro Electric Plant in Wokha District of Nagaland developed by NEEPCO on the river Doyang, one of the tributaries of Brahmaputra. The Project comprises of 92 m high rock fill Dam having live storage capacity of 216.5 MCum at EL 324.0 M and intercepting a catchment area of 2606 sq.km.
The entire quantum of power from the plant has been allocated to all seven states of NE Region where Assam has a share allocation of 43.8 %. A meeting was convened on 17.05.2018 by DDMA, Golaghat with NEEPCO for better coordination for early warning and flood forecast and discuss the modalities of flood preparedness.
The meeting focused mainly upon the early and effective warning regarding rise of water level and release of excess water from the Project. Due to incessant rainfall in the upper catchment area, the reservoir water level started increasing abruptly since 25.07.2018. The inflow to the Doyang reservoir was more than 600 Cum/Sec since 27.07.2018 and it went more than 1150 Cum/Sec on 31.07.2018 which is much higher than the normal range of inflow.
This has necessitated release of excess water by opening the gates. NEEPCO had to open the radial gates at 5:30 hrs of 27.07.2018 to release the excess water in controlled manner. The excess water beyond the capacity of the reservoir flows to the downstream area which cannot be absorbed by the reservoir. The information in regard to increase of water level has been shared with the Golaghat District Disaster Management Authority on regular basis as decided in the meeting held on 17.05.2018 at conference hall of DC office, Golaghat.
It is clear that the Doyang Dam cannot absorb the water beyond its capacity at any point of time and rather, Doyang Dam did contribute to flood moderation to its present water holding capacity upto EL 324.0 M.
The recent flood in the Golaghat District is due to unprecedented rainfall in the entire catchment of Dhansiri river of which the Doyang catchment is only a part. Due to the existence of Doyang storage reservoir, the flood peak is getting moderated to the extent the capacity of the reservoir permits. Doyang Project authority is maintaining a close contact with the concerned District administration and information regarding release of excess water through the spillway gate is being shared well in advance enabling actual flood forecasting. (PR)