GUWAHATI, March 5 � Contrary to the popular belief, the base flow or the lean period flow of the Siang, which is the major contributor to the Brahmaputra, the lifeline of Assam, has not diminished. At least the Central Water Commission (CWC) data available with the official sources here suggest so. Siang�s contribution to the total discharge of the Brahmaputra is worked out to be 33 per cent at Pandu in the city.
Moreover, the base flow of the Brahmaputra at Pandu has also not dropped, said the official data maintained by the State Government.
According to the CWC data, the Siang at Passighat recorded a water level of 147.43 metre on February 28, 2010. At the same place, the river recorded a water level of 148.01 metre on February 14, 2011 and it recorded a water level of 148.86 metre on February 6, 2012.
The discharge rate of the river at the same place was 1262.11 cubic metres per second (cumecs) on February 29 last, while it recorded a discharge rate of 2651 cumecs on March 1 and 2699 cumecs on March 2, say the CWC figures.
The Brahmaputra recorded a minimum water level of 102.61 metres at Dibrugarh on February 19 this year. It recorded a minimum water level of 101.03 metres on January 30, 2002, 102.04 metres on December 29, 2003, 101.93 metres on February 28, 2004, 103.72 metres on December 14, 2005, 103.15 metres on February 15, 2006, 103.40 metres on December 28, 2007 and 103.38 metres on December 31, 2008.
On December 31, 2009, the river recorded a water level of 103.13 metres at Dibrugarh. It recorded a water level of 102.12 metres on December 30, 2010 and 102. 74 metres on December 31, 2011 at the same site.
The Brahmaputra recorded a maximum discharge of 43158.17 cumecs at Bessamara, opposite Neamatighat, on August 4, 2000. It recorded a minimum discharge of 119.77 cumecs at the same place on December 28, 1980. These were the highest and the lowest discharge rates recorded by the river in the period between 1980 and 2000 at the site.
At Pandu, the river recorded a maximum discharge of 61015 cumecs on August 29, 1988 and a minimum discharge of 2497 cumecs on February 25, 1987. These two discharge rates were the highest and the lowest discharge rates recorded by the river between 1987 and 2010 at Pandu.
In 2011, the river recorded a lowest January water level with 41.06 metres at Pandu at 8 am of January 31, 2011. It recorded the lowest February water level in that year at 8 am of February 24 with 40.91 metres.
In the current year, the river recorded its lowest January water level at Pandu at 8 am of January 27 with 40.60 metres and its February lowest water level during the year was recorded at 8 am of February 29 with 40.46 metres.
It also maintained that the incoming water level in the Siang at Tuting, close to the International Border in the month of February 2012 varied between 403.44 metres to 403.78 metres and the river flows between 932.9 cumecs to 1035.88 cumecs and there are no abnormal changes in the river�s flows at the point of its entry in India.