Time and tide not on Sukhna’s side

Ramkrishan Upadhyay

Tribune News Service  

Chandigarh, May 20  

By starting the de-silting process in Sukhna Lake, the Chandigarh Administration has not only ignored the advice of experts, but has also unheeded the report of the National Institute of Hydrology (NIH), Roorkee.

The NIH  had prepared the  report on the request of the Administration. It was submitted four years ago and had clearly stated that de-silting would deplete the water level if the monsoon was below normal. 

 “It is more reasonable and plausible to take up de-silting for the eradication of the weed-propagation source in the soil,” stated the  report.     

The NIH had suggested that silt up to 0.5 m depth be removed from the top of the lake bed for  the  removal of the  weed.

But the Administration has started the  process again. As per the report,  the  capacity of the lake is  524.222  ha.m. (5.24 Mcum). This means that 5.24 Mcum water is needed to fill up the lake completely.

Since the normal rainfall recorded in Chandigarh is about 1,100 mm, the lake will obviously be completely filled up only during the years when the rainfall is more than normal.

 The report  says the lake will not fill up in case of deficit rain. “In such a scenario, the question that arises is — do we really need an increased capacity of the lake, especially if there is not enough flow of water. Efforts should be put in to ensure flow of water into the lake, particularly in years when there is deficit rainfall. If we increase the capacity of the lake by de-silting, there is a possibility of the lake drying up. 

 On the  other hand, one of the officials of the Administration said  the administration would soon  start the  process  to   do a comprehensive study to look at various options of providing additional water to the lake as directed  by VP Singh Badnore, Governor of Punjab and Administrator.  

What NIH study suggests    

The  NIH  study has suggested a slew of measures to check evaporation for water preservation. The report says that certain evaporation retarding chemicals are available which are known to reduce evaporation, but  to avoid any possible negative impact of such chemicals on the flora and fauna of the lake, they are not recommended for Sukhna Lake. Instead, it is suggested that a physical method such as reduction of exposed water spread area be adopted for the lake because evaporation is predominantly a surface phenomenon. The report made it clear that deficiency in rain, coupled with evaporation, played havoc with the lake.  In deficit rainfall years when the water level is significantly low, evaporation is the single most important factor determining water losses from the lake.