The Terai has higher rainfall than the plains .
The downward - rushing rivers of the Himalaya slow down and spread out in the flatter Terai zone , depositing fertile silt during the monsoon season and receding in the dry season .
The Terai has higher rainfall than the plains , and the downward - rushing rivers of the Himalaya slow down and spread out in the flatter Terai zone , depositing fertile silt during the monsoon season and receding in the dry season .