Base Information

Topography

River wall gradient is variable from 40 to 65°. The valley is generally V-shaped and is symmetrical. High altitudes of the project site reach to almost 450 meter.

Meteorology

Within the project zone limit, winters are mild and short and summers are hot and long. The average annual temperature in the region is 32.5° and the minimum average annual temperature is about 20° C. Dam site is equipped with a meteorology station and the annual average rainfall is about 372.7 millimeter.

Hydrology

Measurement of catchments area at the site of construction is about 32425 km2 and four hydrometer stations are installed in site of Godar, Gotvand, Shooshtar and Lali dams.

Flood

Studies related to the flood are not finalized yet.
But different floods and their returns period are as follows:

Return period (Year)	10	20	100	500	1000	10000
Discharge (m3/s)	3740	4590	6730	4140	10300	14620

Water quality

Studied zone have geological and physiological diverse structure and several geological structures proportionately affect water quality. TDS in studied zone is variable between 240 milligram/liter to 740 milligram/Liter.

Sedimentation

River sediment volume after 100 years is about 535 million m3. This amount is totally 15% of water volume of reservoir and has 43 m of height.

Planning the water resources

According to the studies by Moshanir consultant; in case of 1000 MW power generation, power house operation is recommended to be 11h and 20m and in case of 2000 MW, power house operation is recommended to be 6 h. These figures should be reviewed carefully in future.

Geology

Dam structure at bed-rock has an anticline, which its two wings slope are toward abutments. The bed-rock is from Aghajary Sazand and includes stone-sands, stone and clay layers. In both abutments Aghajary Sazand is covered with Bakhtiary Sazand conglomerates.

Seismicity

Dam construction site as one of geological seismocity zone of Zagros is highly potential of earthquake. Most of huge earthquakes in this zone happen up to 1500 m of heights. Historical important earthquakes have happened in 840 in Ahwaz and in 1052 in Bagh Malek which were 6.8 Richter and the earthquake of Zagros which was 6.5 Richter. Important faults near the construction area are Pir Ahamd fault and... Certainly faults of Golestan, Togah, Lali and Masjed Soleiman are some of faults in 60 km distance range of the site, which can have seismocity potential.

The maximum acceleration of geo-structure for different levels is as follows:

	PGA
	CBL	DBL	MDL
Horizontal	0.155	0.27	0.361
Vertical	0.101	0.197	0.275

Dam reservoir

Reservoir volume in PMF level (244 m) is about 5.17 billion m3. At maximum operation level that is 234 m, the volume is approximately 4.34 billion m3. Gotvand dam reservoir is located in a region with the length of 90 km within the area including Aghajary, Bakhtyari and Gachsaran Sazands.

Gotvand Project