Where possible, it is much more cost effective to restore existing tanks, than to build new tanks. Restoration can involve silt removal to increase the storage capacity of the tank and reduce evaporative loss. The silt can be used to restore the earthen bund, and any remaining silt can be applied to nearby farmland. The outflow structure can also be improved. Care should be taken during silt removal not to expose highly permeable soils, which would lead to excessive seepage loss (unless the goal is to increase infiltration). Perhaps a small area that is silted-in could be retained if it has become habitat for wetland plants and wildlife. In urban or industrial areas, silt that is removed during a tank restoration program may be contaminated, and should be tested to ensure proper management.