hyderabad the historic himayatsagar lake across the river esi a tributary of the musi is virtually on the deathbed with its catchment area fast disappearing thanks to unchecked concretisation there has been insufficient inflows into the lake in the just concluded monsoon season though the catchment recorded excess rainfall though the water level in the himayatsagar is higher than that of last year the inflows were not commensurate with the heavy rainfall recorded during septemberoctoberconstructed in 1927 by the nizam vii mir osman ali khan on the advice of eminent engineer sir m visvesvaraya the himayatsagar lake is an engineering marvel of its times its twin osmansagar lake was constructed in 1920 across the musi together they form the heritage lakes of hyderabad that can still be tapped as drinking water sources after proper chemical and biological treatment while other historic lakes like hussainsagar has turned highly polluted the ibrahimpatnam lake has dried upafter serving the drinking water needs of hyderabad for several decades the himayatsagar is now faced with two problems encroachments in its catchment and pollution several industries with high levels of pollution are located in its basin the pollutants are released unchecked into the lake consequently the water quality index of himayatsagar is bad if assessment of water quality in the lake all through the year is taken into account the pollution levels in the lake fluctuate depending on the inflowsthe area surrounding himayatsagar has ample possibilities of organic pollution heavy metals and pesticides contamination from various sources domestic waste water agriculturehorticulture runoff laboratory waste from educational institutes solid waste disposal vegetation in the lake and human activities as a result the water quality index of the lake has come down to 4824 indicating slightly poor water quality reveals a research study conducted jointly by vnr vignana jyothi institute of engineering and technology hyderabad and the centre for environment jawaharlal nehru technological university hyderabadthe researchers recommended a clear demarcation and fencing of the boundaries of the lake to prevent encroachments and human interference they also suggested introduction of certain fish species that clean up the lake emptying of municipal waste from nearby localities should be curbed sewage treatment plants should be set up to allow only treated water the study was published in the recent issue of the scientific journal journal of environmental science toxicology and food technologythe researchers warned that himayatsagar would dry up by 2036 if no immediate remedial steps were not taken to save the historic lake even if the lake managed to survive beyond 2036 it would turn into another hussainsagar which is infested by deadly bacteria that have become resistant to powerful antibiotics