Part 2: Treated wastewater
Minor Irrigation Department is pumping Treated wastewater from Sewage Treatment Plants to KC Valley where lakes in Kolar and Chikkaballapur region are filled up. This was implemented as a drought mitigation strategy which enables groundwater recharge. Similarly treated wastewater from STPs in HN valley is also been pumped to fill up lakes. Devanahalli is receiving treated wastewater from the mid of 2020.
Currently treated wastewater is been pumped to Doddakere, Sihineerkere and Bettakote lakes to name a few. MID was pumping TWW in alternate weeks when it just started pumping. According to the water man of Devanahalli town, MID is aiming not to allow the lakes to go dry. MID monitors the water level in the lakes and if the water level is less than 50% it pumps TWW immediately.
Doddakere lake was slightly de-silted before pumping treated wastewater and the bund was strengthened by the TMC. Sihineerkere lake's waste weir must be repaired and bunds must be strengthened. TMC says yield of borewells near Sihineerkere lake have increased drastically. TMC is yet to check the borewells near Doddakere to find out if there is an increase in the yield.
Farmers perceptions on treated wastewater: Farmers are very happy about the entry of treated wastewater. Farmers have noticed the increase in the yield of borewells. Treated wastewater has led to the increase in yield of borewells and open wells have seen water after decades.
In the words of farmer Mahesh, " Open wells of Devanahalli haven't seen water since two to three decades. After the entry of treated wastewater open wells have seen 30ft water. Borewells yield has increased twice. It is very important Doddakere lake fills up completely. If Doddakere lake is full it benefits all the open wells and borewells of Devanahalli. Recharge zone of Sihineerkere lake is limited to very few zones. We are extremely happy to see water in our open wells. If Doddakere lake is full my open well will overflow. Treated wastewater benefits all the farmers and it also reduces migration."
TMC's open wells: here are two open wells within 100m from the lake belonging to Town Municipal Corporation. These two open wells went dry for two decades. The open in the shape of a lock is referred as heritage well. Heritage well is yet to be cleaned and desilted. The other well is cleaned up, desilted and stones are strengthened.
Pump test and water quality tests were conducted to this well. According to the pump test the aquifer yields about 70,000-80,000litres per day. Water quality test results indicated the water is fit for drinking with little chlorination. The current water level is at 12ft from the ground level. It is expected to increase as the water level in Sihineerkere lake increases. Water level in the heritage well is at 16ft from the ground level. Yes, the measurement might vary since the lake has solid waste accumulation.