Simplify the following text for a Grade 8 native English-speaking person.
Original: It includes the Kunar River , which rises in Nuristan province of Afghanistan , and the main Kunar River , which rises in the eastern Pamir Mountains before flowing through Chitral in Pakistan into the upper Kunar Valley in Afghanistan .
Simplified: It is then called the Chitral River , before flowing south into the upper Kunar Valley in Afghanistan , where it is referred to as the Kunar River .