An Illustrated Study on Mapping of Soil Erosion Zones of Meghadrigedda Catchment, Visakhapatnam, India for Conservation– A Geospatial Approach

In the Deccan Platue, Bengaluru is an important Cosmo Metropolitan city comprised of more than ten
million of human population. The city is located at an average elevation of about 900 Meters from
these a level with highly undulating terrain of upper profile good red soil. Due to this character, the
areas under occupied township have large number of manmade tanks primarily constructed for the
purpose of agriculture/horticulture irrigation and drinking up to twentieth century. The tanks are
scattered in series of clusters linked to each other through gradient channels in that cluster. All the
tanks in the city are the part of either of Hebbal valley or Rishbhavathi valley or Kormangla-Chelghatta
valley. The constructions of tanks in the city have a long history and goes back even to Ganga
Dynasty (350 to 1000 AD), Bellanduru tank was constructed in that period. There were 845 tanks in
Bangalore Urban district. The tanks in Bengaluru are the Heritage of the city and caused to call “City
of lakes”. Most of the tanks are polluted and unfit for human use. There are infrastructures created to
treat about 1068 MLD sewage in the city. Reuse of secondary treated water is one of the most difficult
tasks before the Authorities. Treated water from STPs of Koramangla-Chelghatta valley is being used
to fill the tanks of Kolar district. Fifty-one tanks of 4.25 TMC treated water are filled till the last repot.
About 4535.21 acres of tank beds are encroached. This article covers the essence of research works
done in last thirty-four years.