Abstract: A submersible reservoir management system for large water reservoirs comprising a submersible pump assembly including a frame that is removably attached to the pump assembly. The frame stabilizes the pump assembly when it is submerged and floating and supports the pump assembly when it is resting on the bottom of the reservoir. The frame can comprise a base and struts or, alternatively, a tripod. One or more ballast tanks can be mounted onto the frame with the submersible pump is positioned between the ballast tanks. Water is used as ballast to submerge the system so that it rests on the bottom of the reservoir. The submersible pump assembly adds disinfecting chemical when necessary to control water quality and produces a jet stream to provide circulation of the chemicals and temperature uniformity within the reservoir.