MADIKERI: According to the India Meteorological Department (IMD), heavy rains have been forecast for the coastal and south interior districts of Karnataka including Kodagu over the weekend due to a low-pressure trough that is expected to form over Arabian Sea.
A low pressure is likely to concentrate into a depression and move north-westwards to form into a cyclone, the bulletin from IMD said.
Four districts of Karnataka – Chikkamagaluru, Hassan, Kodagu and Mysuru – received excess rainfall this year. Kodagu received the highest-ever daily rainfall when it recorded 300mm in a single day on August 17, 2018.
Neighbouring states of Kerala and Tamil Nadu are also likely to receive heavy rain due to the low-pressure effect.
MADIKERI: Other than causing huge loss in terms of infrastructure, property and crops, the recent floods and landslides in Kodagu have led to indirect losses that are long-term and complex. For example, these landslides have brought significant sediment load in the drainage channels and connected water reservoirs
One such impacted reservoir is the Harangi dam, which is located close to the northern affected areas near Kushalnagar. Using pre-landslides and post-landslide open source satellite images and advanced GIS image processing, WRI India generated map showing Total Suspended Solid (TSS) concentration within the Harangi reservoir has increased by almost 100 times due to flow of increased load of soil and sediment within the reservoir. It is believed such high load of soil and sediment inflow causes sedimentation within the reservoir and thereby significantly reduces the water holding capacity of the dam.
Silting is a natural hydrological and sedimentological process in which sediments flowing from the upstream catchment area get deposited in the reservoir.