SPATIO-TEMPORAL VARIABILITY IN C: N RATIO

A significant spatial and temporal variability of water quality in terms of organic compounds and nutrients, with a considerable decrease in the organic matter as water flows from inlet to the outlets during the seasons devoid of macrophytes cover in the lake was observed. Varthur Lake serves as a source for irrigation to the cultivable lands and vegetable cultivation together with horticulture and floricultural activities and has a surface area of 220 ha (Figure 1). The lake was built by the Ganga Kings (Gazetteer of Karnataka) to store water. The lake initially was a deep with water which was used for drinking and other domestic purposes, intense urbanization have dwindled the catchments for the last few decades. During the last two decades there are large scale changes in land use paving way for rapid decline in the number of lakes and eutrophication.

Figure 1. Bathymetric map of Lake Varthur, Bangalore (India). The large dot with the star’s indicate the sites where surficial sediments were taken (S1-S15) and contours represent the various depths of the Lake.