Pickstown, South Dakota.  The Missouri River is cascading through the spillway at Fort Randall Dam.  According to the Army, 110,300 cfs is safely passing through the spillway on its way southeast toward Gavin’s Point Dam, Sioux City, Iowa, and the lower valley.  The white and green water moves fast atop the smooth concrete surface of the spillway.  Two high concrete walls on either side of the spillway keep the river water from moving sideways.  The linear flow of water in the spillway is in such contrast to the movement of water through the lower valley.  There the Missouri appears dirty and undirected.  It slops over farmland, burrows under levees, and knocks over trailer houses.  Here at Fort Randall Dam, the Army still looks like it’s in control of the situation.  In the spillway, the river is moving where the Army wants it.  But the Army’s control begins to diminish at the foot of the dam.  Just off the end of the spillway, the Missouri is eroding its banks and knocking trees into the channel.We think of reservoirs as lakes or lengths of river that have been tamed through technology.  But today, Lake Francis Case, the reservoir behind Fort Randall Dam, looked anything but docile.  Fierce winds swept in off the plains to the southwest and whipped the water into tall white caps.  Three- and four-foot high waves slammed down on the reservoir’s eastern shoreline.  Not a single fishing boat cruised the lake.  This afternoon, the river did not allow anyone to ride its serpentine back.  At the Snake Creek Recreation Area west of Platte, South Dakota, wave action recently undermined bluffs along the eastern shore.  Dark, rain-soaked slabs of earth have peeled off the hills and crashed into the reservoir below.  The Army refers to this phenomenon as “slumping.”  Slumping puts silt into the reservoir and reduces its storage capacity.  Since the start of the Great Flood, the Missouri has been tearing away at the reservoir’s sides.  The Missouri within the reservoir, in a manner similar to the Missouri through the navigation channel, resists containment.