By storing effluent (partly purified sewage water) in reservoirs, the effluent is prevented from flowing into the environment, thereby preventing pollution of rivers, soil, underground water sources and bodies of water into which the waters flow (the Mediterranean Sea, the Sea of Galilee - Lake Kinneret, the Dead Sea and the Red Sea). The Israeli rivers’ restoration projects would have no meaningful significance unless the flow of sewage and effluent into the rivers is stopped by means of controlled storage in reservoirs that are custom-made for the task.