Whirling System of Water Exchange in Breeding Pools

To secure the proper conditions of life for sea mammals existing in closed systems one has to maintain the character of the breeding basins (i.e. shape, dimensions, facing of walls and bottom, quality and motion of water) as natural as possible. An appropriate system of water exchange plays a very important role here. A full renewal of water is time-consuming, expensive and troublesome, so can be made only periodically, and should be supported by a complementary continuous exchange . This operation improves the water quality and can form the proper velocity field in the breeding basins. The investigated breeding basins are located in the sealarium in Hel (Poland), which belongs to the Institute of Oceanography of the Gdansk University. The tracer measurements, carried out in these reservoirs allowed for evaluation of the intensity of the continuous water exchange. It was stated that this intensity wasn’t sufficient (occurrence of large dead zones in the basins, short detention time), and thus a correction of the existing system was proposed (tangential position of the inlet, centrally placed outlet). On the base of a simplified model of circulative water flow it was shown that the corrected hydraulic system can considerably improve the situation.