RESUMEN
The establishment of open drain network in the Nile Delta has begun in the second quarter of the last century. That network is in continued expansion to cope with increasing quantities of irrigation water particularly after the construction of Aswan High Dam, and the stress need to increase cropping intensity, in addition to horizontal expansion of the newly reclaimed lands. All open drains in Upper Egypt and some drains in South Nile Delta discharge into River Nile while the remaining main drains in the Nile Delta are either discharging into the Mediterranean Sea or into coastal lakes. Due to over population in the area, and increasing water demand, more Drain water is reused for irrigation. Drain No. [1] is a part of the open drain system in the Nile Delta. Drain No. [1] is situated to the north west of Damietta Branch of the Nile Delta extending from south to north for about 65 km through the Gov's of Gharbia, Dakahlia, and Damietta. The Drain stretch extending from Talkha City till the final pump station [48.700 km] is receiving the most pollutant discharges. The number of the most important tributary drains that discharge along Drain No. [1] are 23 tributary drains. The aim of this study is to evaluate the environmental effects of different pollution sources on water quality of Drain No. [1] in comparison with limits delineated by the Law 48/1982. The length of the studied Drain stretch is about 55.250 km. The part of the studied stretch that extends from Talkha City till the final pump station [about 48.700 km] was divided into 5 segments in addition to the final discharge portion [about 350 m]. During the study period, from Nov. 2000 to October 2001, twelve monthly sampling points were chosen along the studied Drain stretch. The sampling points were at the beginnings and ends of each segment, in addition to sampling point 1 located before segment 1 and sampling point 12 at the final discharge. Furthermore, four samples were collected during the year from the 23 tributary drains at discharging point to Drain No. [1]. Physical, chemical and biological analyses were carried out according to the Standard Methods for the Examination of Water and Wastewater