The Nature of Hahamongna
This video, shot by M. Fellow just after the January 2010 storms, is a terrific introduction to the nature of Hahamongna. The markers on the dam show that the flood level reached elevation 1035, although that level is carefully controlled by the dam-keepers through the use of releases through the dam and a tunnel.
At about 2:00 the video shows the area where the City of Pasadena now intends to place athletic fields and a parking lot. You can see that the ponds and pools brought by the storm in that immediate area. This is what creates the rare and invaluable wetlands/riparian habitat that would be destroyed by athletic fields.