Abstract: A portable device for measuring parameters of water includes: a shield spherical in shape; an instrument capsule maintaining a water-tight seal with the shield, isolating water inside the shield from water outside the shield; electronic sensors extending from the capsule for measuring chemical, physical, hydrological, and/or biological properties of water; a computer control device within the capsule for programming operation and data storage for the electronic sensors; a battery within the instrument capsule for powering the electronic sensors and computer control device; an electronic signal generator to transmit an acoustic or radio signal into water surrounding the instrument capsule; an electronic signal receiver to receive an acoustic signal in water surrounding the instrument capsule; a supply of compressed gas within the instrument capsule; an assembly capable of trapping gas released from the instrument capsule; and a valve capable of connecting the supply of compressed gas within the assembly.