This 2.5' high AquaDam® was used for water retention in the Natal Province of South Africa. This dam was only a few years old, but already so much sediment had collected behind it that the water was only inches deep for a distance of 12 miles. 

The dam spillway was over 300' wide, with a rounded top, creating less than 5' of width to install the AquaDam® on.

The AquaDam® was used to increase the height of the dam so that the broad sedimentary plain behind it could be used to store water 18" deep. 18" of water spread over 12 miles is quite a lot of storage.