This book sheds light on the monitoring of the water quality in the Lake Manzala because of its economic importance and an important source of fish production. Therefore, results of this book showed the effect of discharge of agricultural and industrial wastes on some physical, chemical, and biological properties of surface water of the lake Water. Samples were collected seasonally from nine different sites from the southern and eastern part of the lake. The obtained results will be useful for the management of the lake.