Assessment of Diara Land under Koshi River in Bihar Using Remote Sensing and GIS Techniques

Diara represents unique geographical features created in the middle of the river as a result of the deposition of sand over the decades. The Koshi River Diara is a flood plain located in the northeastern region of Bihar, India. It is formed by the Koshi River, which is also known as the Sorrow of Bihar, due to its tendency to flood, causing devastation to the surrounding areas. The Koshi River Diara is a vast area of low-lying land that stretches for over 233 kilometers along the banks of the Koshi River. The Koshi River flows through different districts of Bihar, including Supaul, Saharsa, Madhubani, Madhepura, Khagaria, Bhagalpur, Purnea, and Katihar. It has fertile land that is ideal for agriculture, where farmers grow crops such as rice, wheat, and maize. Despite its fertility, Koshi River Diara is flood-prone, particularly during the monsoon season when heavy rains cause the river to swell and burst its banks. Remote sensing and Geographical Information System (GIS) techniques are being used to assess the Diara land of the Koshi River in the Bihar region. The area of Diara land varies from year to year. In 2005, it was 22,775 ha, in 2014, it was 16,406 ha, and in 2022, it was 28,710 ha. The largest area of the Diara land was found in the Supaul district among all other districts. In the Bhagalpur district, there is a substantial increase in the Diara land area during the 3-year study period.