ANNOUNCEMENTS
The national capital region (NCR) of Delhi, India, has historically been a seat of civilization with many lakes and green cover on the Aravalli mountain range and ridge. India has made progress in access to clean drinking water, the process of treatment of urban wastewater has been lagging. Rejuvenation of streams and urban lakes have become imperative to restore natural water resources in the face of growing water scarcity. This study has been taken up at local scale in NCR, Delhi for two lakes. The Hauz Khas Lake (HK), (latitude 28.55 °N and longitude 77.19 °E) is in south Delhi. The HK Lake has natural storm water storage capacity of 128,000 m3. This lake had gone dry in the past decades due to blockage of hydrological channels and heavy groundwater exploitation. Currently, the lake receives partially treated wastewater from the heavily urbanized residential area. The other lake is the low lying Basai wetlands (28.461259°N 76.98437°E), located in the NCR city of Gurugram. The basic water quality parameters (to assess pollution) selected for the two lakes are BOD, COD, TDS, TSS, Chloride, Sulphate, Total Hardness, Dissolved Oxygen and pH. Six sampling points were selected for both the lakes and sampling carried out in February and March 2021. It is found that the BOD levels in the Basai wetland is > 50mg/l and chloride is > 500mg/l confirms that raw wastewater is disposed in the wetlands in the absence of sewerage system. The BOD and chloride levels in the HK Lake are lower signifying that it is partially treated before entering the lake, yet it is above permissible limits. We recommend that a water quality index be developed to determine the health of urban lakes using the six parameters to help the civic authorities to make informed decisions.
