Lake conservation in Hyderabad yields good underground water

2004
By Syed Akbar
Hyderabad, Dec 4: Twin cities received a bonanza in the form of good recharge of underground water thanks to conservation of 10 important lakes by the Hyderabad Urban Development Authority.
According to a hydrogeological study of the ground water table in localities around 10 select lakes, which were taken up for conservation recently, the water level went up by about 10 metres in most of the places. The study was conducted about a fortnight ago and the results have prompted the urban development body to take up conservation of all the lakes in and around Hyderabad.
The Huda monitored ground water recharge in 10 out of 87 lakes that dot the city geography. The study was carried out by monitoring ground water levels in open hand dug wells and borewells that showed sympathetic response to the lake water level fluctuations.
The study involved monthly monitoring of water levels in 109 representative wells 10 months spread over the 10 lakes. Water quality samples were also analysed for two periods over 10 months. Infiltration studies (one time) were carried out in the lakes to measure the seepage from the dry lake bed as well as from the lake bed with standing water column.
It was found that ground water recharge was high in areas surrounding the lakes due to seepage from the lake bed. Aquifer recharge was reported in all the monitored lakes. The lakes showed varying seepage losses from the lakebed for different months of the year (few mm to as much as 50cm/day).
"The seepage losses from the lakes are controlled largely by the regional hydro-geological conditions, groundwater development in the immediate neighbourhood of the lake, lake water column and lakebed profile. The lakes fed the local grounder system as recharge for most of the months but for certain periods Safilguda, Banda Cheruvu (one month), Mukkidi Cheruvu (two months), Nalla Cheruvu (six months) and Hasmathpet Cheruvu (eight months) receive groundwater inflows into the lake," a Huda report points out.
A notable feature observed in the study was that the hardness of ground water in the surrounding areas decreased due to seepage from the lake. Groundwater level monitoring in the wells around the lakes reveal the intrinsic relationship between the lakes and groundwater system.
Hyderabad used to have more than 500 artificial and natural lakes. Artificial lakes were formed by constructing bunds across seasonal streams. Lakes were interconnected so that during high intensity rainfall, higher lakes overflowed in lakes lower down the watershed.