The dendritic drainage pattern evident in tliis areal photograph is a result of the action of water movement 

 over the substrate during ebbing and flooding tides. This pattern effectively increases the surface area of the 

 interface between the sediments and the contiguous waters facilitating the exchange of nutrients, gases, and 

 other materials. Photo by Wiley M. Kitchens, U.S. Fish and Wildhfe Service. 



VI 



