Photo: A black rubber duckbill check valve attached to a pipe coming out of the shore. The pipe is about half submerged. Tall grass and a dock behind pipe.

Figure 8. Photo of a duckbill check valve at the end of a pipe outfall.

Photo: A black rubber duckbill check valve attached to a pipe coming out of the shore. The pipe is about half submerged. Tall grass and a dock behind pipe.

Photograph by Thomas Thelen.