The present investigation involves the study of qualitative, quantitative study of epipelic algae and some environmental parameters of Al-Hilla River for the period from April 2009-March 2010. Six sites have been chosen along the studied river. The study included measuring some physical and chemical properties of water and sediments, and quality and quantity of epipelic algae as well as the measuring of chlorophyll a and phaeophytin pigments monthly. Results shown the following ranges: (7-40.5 ºC), (10-36.5 ºC), (11-35.5 ºC) for air, water and sediment temperature respectively. Values of pH showed a narrow range, TDS ranged (219-1280 mg/L), TSS ranged (12-75 mg/L), (600-895 μs/cm) and (0.384-0.572‰) for EC , S‰. While (0.15-0.45) m/Sec, (4.8-11) mg/l, (0.6-4.6) mg/l for water flow, DO and BOD5. Light alkalinity, very hardness values were recorded, while the concentrations of calcium were higher than magnesium. The concentration of nutrients ranged (N.D-9), (N.D.-82), (N .D-39-7) mg/l for nitrite, nitrate, and phosphate respectively. Silicates values varied between (0.35-39.5) μg/l. The sediment texture tended to be silty-clay and high values of TOC in sediments were recorded. Diatoms were the most dominant species among the identified algae followed by chlorophyceae, cyanophyceae and Euglenophyceae. A total of 58 genus with (116) species were recorded in site1, (55) genus, (121) species in site2, and (54) genus with (120) species in site3, (56) genus with (121) species in site4, and (55) genus, (112) species in the fifth place and (56) genus with (112) species in site 6. The most common taxa were Cyclotella, Scendesmus, Oscillatoria, Melosira, Synedra, Cocconeis and Nitzschia. High total number of epipelic algae observed in March 2010 in site 3, while the lowest number was recorded in August 2009 at site 4. Chlorophyll1 and Phaeophytin ranged (0.2-16.6) μg dm-2 and (N.D-9.05) μg dm-2 respectively. Closely values of Shannon index were recorded in all sites and Chandler scores was used in this study.
