During the high water season in the spring the park's basin fills with spring water and shore birds return to nest.
One theory is that the current White Nile may have developed no more than 12,500 years ago when the basins filled and the rivers became connected.
The basin then filled with water at the end of the glacial period.
High water lines suggest the basin has filled many times, creating a lake some 105 miles (170 km) in length and nearly 300 feet (100 m) deep.
However, during the spring, when the temperature rises and the snow melts, the basin of land below the mountains fills with water.
The stone began failing within a decade, and for a while the fountain mechanism was broken and the basin filled with litter.
This shallow basin sloped down from the copestones that surrounded the tower and was half filled with rainwater.
An ornate washstand and basin, also of brass, filled one niche.
The basin or sinkhole then fills with water, causing flooding.
While the basin filled he occupied himself.