Delta Development Distributary Water coming down a river hits the ocean; gradient goes to zero Sediment is deposited; channel eventually fills River jump its banks and takes a new course Process repeats Very common in deltas
Sediment Load - fine particles are moved in suspension, never touching the ground (suspended load) - silt & clay giving the water a muddy look - coarse particles are moved by traction along the stream bed, jumping along (bed load) - move by saltation: short leaps as a strong current picks them up and moves them a short distance. - 7-10% of the total sediment load, on average. - abrasion between particles causing them to wear, smoothing them and forming round pebbles and stones. - also wears away the stream channel along the sides and bottom of the channel. - dissolved materials are carried along in solution (dissolved load) - invisible chemical ions
Flooded River Levees occur when active deposition takes place along the banks of an older river when it is in a flood. Each time this happens the banks get higher forming a natural levee -- a barrier to future flooding.
“IOWA'S BEACHES WILL STAY OPEN THIS YEAR.EVEN IF THEY *ARE* POLLUTED WITH FECAL BACTERIA.THE IOWA DEPARTMENT OF NATURAL RESOURCES SAYS THE BEACHES AT STATE PARKS ARE TOO POPULAR AND VALUABLE TO IOWANS TO CLOSE THEM WHEN THERE ISN'T CLEAR EVIDENCE OF A HEALTH RISK.LAST YEAR, EMERSON BAY IN LAKE OKOBOJI WAS ONE OF SEVERAL BEACHES CLOSED.THE D-N-R SAYS THIS YEAR THE STATE WILL POST WARNING SIGNS INSTEAD.WORKERS WILL BASE THEIR FINDINGS ONLY ON TESTS FOR FECAL COLIFORM BACTERIA.LAST YEAR, THE STATE CONSIDERED THREE DIFFERENT BACTERIAS.THE D-N-R SAYS IT CONSULTED HEALTH OFFICIALS BEFORE DECIDING THAT USING THREE WAS CONFUSING AND CUMBERSOME.” KMEG News: Storm Lake, IA