This study investigated different shapes of solar ponds at two salt gradients. Ponds of rectangular and circular shapes with similar cross sections and volumes were examined. The results indicated that, with respect to shadow areas formed in both ponds, the maximum temperature of rectangular and circular solar ponds reached 74 degrees C and 71 degrees C, respectively, as a result of the smaller area of the shadow created in the rectangular solar pond. Moreover, the glazing plastic cover prevented heat from escaping the pond. This caused the temperature between the UCZ in both solar ponds and ambient to be 13 degrees C at the end of the test, hence causing a reduction of temperature difference from top to bottom of the ponds. Likewise, it was concluded that dusty weather negatively affected the efficiency of solar ponds and decreased the temperature in solar ponds in such a way that with weather returning to the normal condition (as it was before dust), the temperature of pond hardy went back to what it was after several days. On the other hand, plastic covers were applied to avoid turbidity of water in the pond as well as avoiding the entry of dust into the water, proving to have a positive effect on the preservation and sustainability of solar ponds. (C) 2015 Elsevier Ltd. All rights reserved.