Siirt province is a settlement area in the northeast of the Southeastern Anatolia Region, which attracts attention with its rich water resources and mountainous topography. In this context, it is important to evaluate the streams passing through the province in terms of geography, ecology, and economy. Bashur Stream is an important stream among these sources, merging with Kezer Stream and reaching the Tigris River via Botan Stream.

Geographic Location and Source

Bashur Stream takes its source from the high and rainy regions surrounded by the Muş Güneyi Mountains in the northern parts of Bitlis. This area is an important basin that feeds the water volume of the stream with its high altitude and climatic characteristics. The stream, which is approximately 45 kilometers long within the borders of Siirt province, is one of the most important water sources of the region.

Flow Direction and Route

Bashur Stream flows from north to south and enters the borders of Siirt province. It merges with the Kezer Stream 2 kilometers south of the Bashur Bridge on the Siirt-Kurtalan highway. This merger point is the most important passage area for the stream to reach the Botan Stream. The course of the Bashur Stream follows a short but effective route in the mountainous and rugged geography of Siirt.

Merger Point with the Kezer Stream

Bashur Stream merges with the Kezer Stream and increases the water volume. Kezer Stream originates from the Güzeldere location in the east of Bitlis and is formed by the merger of the Kırkçeşme waters and the Şeyh Cuma Stream. Kezer Stream, which progresses by breaking through the İskambo Mountains in the direction of flow, draws an arc in the west of Siirt and meets the Bashur Stream in front of the Mağaralı (Hümriyan) Hamlet. This merger increases both the combined flow rate of the streams and the amount of water reaching the Tigris Basin.

Flow Values ​​and Water Volume

The average flow rate of the Bashur Stream is measured as 19,715 m³/s. The flow rate of Kezer Stream is at the level of 18,851 m³/s. The water mass formed by the merging of both streams reaches Botan Stream and then joins the Tigris River. The flow rate of Botan Stream is 144,549 m³/s. This situation shows that the Bashur and Kezer streams make a significant contribution to the Tigris River. The flow rates of these streams increase, especially with the melting of snow and ice in spring and summer.

Environmental and Agricultural Impacts

Although Bashur Stream does not form wide valleys on its route, it indirectly supports agricultural activities in the region through the contribution it provides to Kezer Stream. Vegetable farming can be done in the valleys developed along Kezer Stream, and the additional water source from Bashur Stream helps the continuity of this production. Considering that agricultural areas are limited due to Siirt's mountainous and rugged structure, the importance of this contribution becomes even more evident.

Location in the Tigris Basin

Bashur Stream functions as a sub-branch of the Tigris Basin and merges with the Kezer Stream and reaches the Tigris River via the Botan Stream. The Tigris Basin is the fourth largest water collection basin in Türkiye after the Euphrates, Kızılırmak, and Sakarya basins. In this context, the contribution of the Bashur Stream to the Tigris Basin is remarkable in terms of both regional water balance and ecological integrity.

Geological and Geographical Structure

The areas through which the Bashur Stream passes are mostly composed of geological formations with a calcareous structure. High areas such as the Muş South and Siirt East Mountains shape the stream's water collection basin, and the precipitation regime feeds the stream's flow. These features ensure that the stream maintains a certain water level throughout the year.