Abstract: In this paper, we propose a system for river monitoring based on wireless sensor network (WSN) technology. This system consists of sensor nodes that periodically measure several environmental parameters such as flow rate, water level, rainfall and pollution level. Each type of sensor node has two threshold values and measured data is compared with them at the end of the reporting interval. Based on the current situation in WSN and measured data velocity sensors can use three different frequencies of reporting. Simulation of river monitoring system is done using Matlab software tool and the results of river mainte-nance during one WSN life cycle are presented. Two possi-ble hierarchical system architectures are considered and their performance is compared. The optimal system archi-tecture for this WSN application is discussed based on the obtained results.