Application of the Fournier and Bergsma index to calculating water erosion in the Valley Niru basin in Al-Amadiya District/Duhok

Abstract

The research dealt with the risks of water erosion in the Niroh Valley basin in Amadiya district, which is administratively affiliated to Dohuk Governorate in northern Iraq. It is located astronomically between longitudes (43° 20' 0'' - 43° 50' 0'') west and between latitudes (37° 0' 0'' - 37° 20' 0'') north. The basin is located within the Sabneh basin, which is one of the tributaries of the Great Zab near the Iraqi-Turkish border. The area of the basin amounted to (1041,999 km2). In order to estimate its size, show its effects and determine its risks, and to know the amount of rain erosion, the research relied on the Fournier equation and the water gully erosion. The Bergesma equation was relied on and applied to the basin area and showed five degrees of erosion: severe erosion, very high erosion, high erosion, medium erosion and light erosion. The study area is characterized by the activity of water erosion risks due to its mountainous nature. Rain erosion in the basin showed variations between stations, and the highest station is the station Amadiya (107.05), followed by Zakho station, which recorded (94.90). According to the Fournier index, the stations in the study area fall within the range of moderate rain erosion. The application of the gully erosion equation according to the (Bergsma) system showed the emergence of five types of erosion, namely (severe, very high, high, medium, light) erosion. Medium erosion occupied the largest area of the study area, amounting to (304.45 km2) and a percentage of (29.21%). The study concluded by spreading awareness among people of the dangers of rain and gully erosion, expanding agriculture in a developed manner, according to the study, especially on slopes to stabilize the soil from the dangers of erosion, protecting trees from cutting on the slopes, and encouraging farmers to plant perennial trees on the slopes that protect the soil from the dangers of erosion, preventing overgrazing on the slopes and organizing the grazing process periodically.