The degradation of river water quality becomes one of the major environmentalrnproblems that we are facing today. Because of most of the industries are directlyrndischarging their waste into the water bodies near to them without any treatmentsrnand there is no law which prohibit them not to do so. Currently Akaki Rivers usedrnas receivers of all kinds of wastes; industrial wastewater is the primary causes ofrnwater pollution, followed by domestic wastewater and human excreta.rn(Assessment report, 2005).rnAccording to the study conducted by AAWSA and THAL in 1992, from the totalrnwater supplied to Addis Ababa 70% returned as sewage, of this 60% returnedrnthrough Big Akaki river and 40% returned thought Little Akaki River. Thernequation (water supplied in Addis Ababa X %returned flow X %returned through)rnis used to calculate the minimum river discharge.rnA database (Akaki) and software(Akaki waterpollution),is developed to find outrnall the pollution sources into Akaki Rivers, get recent information about thernclimate and hydrology of the catchments and identify the types of industriesrnaround the Akaki rivers. Besides, it is possible to calculate the contribution ofrnliquid waste discharged into Akaki Rivers using the software and the contributionrnof liquid waste deducted from rivers discharge, which will help to take thernamount/percent of liquid waste discharged into Akaki Rivers during different timernof the year.rnKeywords: minimum discharge, liquid waste, database, software