Though classified as "dry land species", we found one area in N. California where plants littered the edges of a stream bed with most bulbs covered by running water. This stream though getting smaller with the passing of each day in July still covered most of the bulbs we found. By late August or early September, these lilies would have been on "dry land" once again indicating that the seed was dropped there during a period of low water and had to germinate to get a root hold before the winter rains and the swelling of the creek flow.
Inset photo is of another plant growing up over the edge of a river boulder. It was not possible to climb down without ropes to know for sure, but it seemed as if this bulb also was totally covered with flowing water.