Seasonal variations in abiotic ecological conditions in Al-Garaf canal one of the main branches of Tigris River at Thi- Qar province, Iraq

الملخص EN

Monthly variations in physico-chemical parameters of Al-Garaf canal, one of the main branches to the Tigris river, were monthly investigated from March 2004 to February, 2005.

Sampling location situated in the south-eastern sector of Iraq and was surrounded by vast and fertile agricultural lands.

Three stations were selected to implement the work.

The former is located at 167 km of Kut Dam north to Shatra town and closer to water supply point to both Basrah and Thi Qar provinces.

The second is situated at distance 8 km away from the former and the latter station is located at 13 km apart from the second one.

Abiotic ecological conditions were regularly studied, including water and air temperatures, transparency, salinity, dissolved oxygen (D.O.), carbon dioxide (CO2), pH, total alkalinity, total hardness and biological oxygen demand (BOD).

Results reveled that water temperature ranged from 12 to ە 36.5 C at former and latter stations respectively.

Transparency ranged from 25-68 cm.

The minimum salinity (1.5 ppt) recorded in May at station1and the maximum (5.71ppt) at station 3 in August.

D.O.

decline clearly during hotter months (July& August), the lowest (6.2 mg/L) was in August at station2.

pH ranged from 6.3- 8.1.

The minimal alkalinity value (140 mg/L) was measured at February 2005 from station 1 and the highest in March from station 3.

Maximum hardness (460 mg/L) measured in July at station 3.

Minimal BOD value (1.1 mg/L) was in March, but the highest (6.1 mg/L) encountered from station 3 at July.