The current disaster inUttarakhand:
Although, the current disaster on June 16-17, was triggered by massive rain and hence was a natural disaster, it was aggravated many folds because of these dams and HEPs as Uttarakhand has bumper-to-bumper dams that lie at every 18 km and became a manmade disaster because of the following reasons:
Relentless blasting and throwing of muck and debris: While blasting weakened the mountain joints and foundations of houses, throwing of muck and debris blocked the flow of the rivers and rivers were forced to flow out of their nature course and entered into people’s homes and villages. It also created landslides. Sringara HEP, a project near completion, near Srinagar town was responsible for silt entering into several houses of the town after this disaster, as it threw about 5 lakh tons debris.
Wrong operation of hydropower projects: It created greater disasters in the downstream areas. For example the operators of 400 MW Vishnuprayag HEP on Alaknanda River did not open the gates when the river was flooded on June 16-17, possibly to maximize power generation. However, this lead to accumulation of massive quantities of boulders behind the dam, so much so that that there was no space for water to flow. The river then bypassed the dam and started flowing by the side of the dam, creating a new path for its flow. This created a sudden flashflood in the downstream area, creating a new disaster there. Similarly, the incomplete, broken and ill designed protection wall of the Maneri Bhali projects in Uttarkashi lead to erosion and landslides in the downstream areas.
Many HEPs released water: Many HEPs released water after the flood in Uttarakhand as their reservoirs were over flooded. This caused extensive damage in downstream areas. For example, Tehri Dam Reservoir released 500 cumecs of Bhagirathi water.
Damaged hydro projects
A large number of hydropower projects are likely to have suffered damage due to the flood disaster in Uttarakhand. Some of the projects that have suffered damage include:
The 520 MW under construction Tapovan Vishnugad HEP In August last year also, the flash floods had caused serious damages in the coffer dam of the project.
400 MW Vishnuprayag HEP of JP Associates: It has suffered serious and un-assessed damage. The project has also been cause of damage in Lambagad villag.
76 MW Phata Byung HEP of Lanco: In Mandakini Valley.
99 MW Singoli Bhatwari HEP of L&T: Also, in Mandakini Valley as the water level of the river has gone up due to the silt dumped by dams. This is likely to be due to the Phata Byung and Singholi Bhatwari HEPs.
Kali Ganga I, Kali Ganga II and Madhyamaheshwar HEP: All in Mandakini Valley.
Assiganga projects: On Assiganga river in Bhagirathi basin.
5 MW Motighat I HEP: In Goriganga basin in Pithoragarh
280 Dhauliganga Project of NHPC: In Pithoragarh district.
5 MW Himalaya Hydro (HH) Tanga Phase I: Located along the Paina gad in Goriganga basin, is badly damaged.
The 5.5′ diameter head race water pipes taking water to the HH Phase II, located on the Gori opposite Seraghat: The generator and housing for the HH Ph II has collapsed into the river.
Stopping power generation temporarily
Due to high silt content, including Maneri Bhali I and II, Tanakpur, Dhauli Ganga, Kali Ganga I, some of the Yamuna basin projects among others.