Raphael G. Kazmann
The Federal Government's program for protection against floods began in 1917 when the Corps of Engineers initiated a levee-construction program financed on a 50-50 basis with local interests. After the Mississippi River flood of 1927 the Congress authorized the Corps to build levees on a 90-10 basis. The Federal Government provided the money and the landowners contributed land and promised to maintain the levees and to hold the Corps harmless in case of damages caused by the construction. Since then the program has expanded and now incorporates reservoirs and bank protection in addition to the levee system. In view of the floods of 1993 in the Upper Mississippi Valley, numerous levee failures and the loss of property in "protected" areas, we may legitimately draw up a bal nce sheet of expenditures vs damages and ask if the program is, on balance, beneficial.
An objective analysis must start with the data used in designing the levee system. The basic assumption is that if a historic flow and river stage are recorded then the same river stage will repeat when the same river discharge occurs. On this basis the levee system can be designed. But what if the same conditions of precipitation produce different discharges at a given point? And what if the same discharge produces a different gage height at a given point? The river system is then indeterminate and proper levee design is impossible. What does the data show, and what should we do in the future?
AAPG Search and Discovery Article #90960©1995 AAPG Southwest Section Meeting, Dallas, Texas