This river originates from 3 Hezar mountains (south of Tonekabon). Than 2 Hezar - 3 Hezar River forms by joining of this stream to 2 Hezar River in Chaleh locale. This river is called Cheshmeh Gileh River in Caspian beach plain. Cheshmeh Gileh River passes from Tonekabon County and than it cuts Ramsar-Tonekabon coastal road in km: 25+500. Area for drainage basin of this river is more than 1300 km2.
Morphology: Cheshmeh Gileh River has a river valley pattern with several meanders in Caspian beach plain and this river is as high gradient & narrow valley in mountainous region. Index of meander for this river is mean to high. Stream-gradient is about 45° and it is 12/1000 (1.2 percent) in Caspian beach plain. Local base level (LBL) of this river is -23 m.
Width of stream-bed (water flow-bed): 40-60 m
Main terraces in beach plain for Cheshmeh Gileh River:
- H1 (River terraces with down surface level): height: 2-3 m (It is not observed in all of places)
- H2 (River terraces with high surface level): height: 5-6 m (Construction place of building)
Materials of terraces consists coarse-grained alluviums (6-60 cm) and without cement (unconsolidated & slumping) with high erodibility.
Recession rate of terraces: High
Vegetation: There is not vegetation in active flood plain.
Human interference in active flood plain of Cheshmeh Gileh River:
- Construction and development of agronomy and economic activities in the area that can be affected
- Construction of engineering structures with unfit quality and geometry
- Accumulate of structural rubbishes and municipal wastes in around of river
- Extraction from sand and gravel of stream-bed
History of flood in Cheshmeh Gileh River: Spring and summer floods happen yearly. Floodwater of 1380 was the most devastating floods of Cheshmeh Gileh River.
Flood risk: Flood risk in mountainous region: 1 & flood risk in Caspian beach plain: 2
Hydrography station has not been observed in river path.
Characteristic of flood plain for Cheshmeh Gileh River:
- Width of total flood plain: more than 200 m
- Width of active flood plain: 60-80 m
- Width of alternative flood plain: 80-100 m
Vulnerable area of Cheshmeh Gileh River is mountainous parts due to existence of mountainous flash flood. Also this area in beach plain is between 2.6 km of southern Tonekabon and 300 m of northern Tonekabon.
- Displacement of the buildings far from floodwater area
- Accomplishment of exact investigations about how of occurrence and reasons of intensity of damages result from summer floods and presentation of executive methods in order to decrease damages of floods and suggest floodwater control structures and watershed management plans
- Study of the role of extraction of sand and gravel from stream-bed
- Restriction of waste accumulation in the flood plain, increase of vegetation, accomplishment of yearly dredging