22 



in 20 years to 3 out of every 4 years. Similar findings were reported 

 by Clark and Benforado (1981) and Roelle et al . (1987). 



In general, the average duration of a flood event by site ranged 

 from 3 months to longer than 5 months for the Zone 2-3 boundary, from 

 3 weeks to greater than 2 months for the Zone 3-4 boundary, from 1 week 

 to 1 month for the Zone 4-5 boundary, and from less than 1 day to 

 10 days for the Zone 5-6 boundary (Table 3) . 



As an example, a hydrograph of site 3 at Steele Bayou (Appendix C) 

 for 20 years of data shows that flooding conditions vary greatly from 

 one season to another and from one year to another. Also, flooding 

 during the growing season usually occurs during early spring and is 

 usually continuous with the nongrowing season flooding. Flooding rarely 

 occurs late in the growing season. Unusual events such as the 1973 

 flood can greatly affect the calculated value of average events. For 

 example, if the data for 1973 were excluded, the average duration per 

 flood event at site 3 is reduced to 37 days, 25 days, 9 days and less 

 than 1 day, from 143, 30, 14, and 6 days, for Zone boundaries 2 through 

 5, respectively (Table 4). Such an event has an especially large effect 

 on average duration even over a 20-year period, especially in the higher 

 zones . 



Vegetation Data 



Vegetation data were collected at each of the 55 hydrologically 

 defined zones for the 17 study sites (Appendix D) . Eleven stands were 

 sampled in Zone 2, 15 stands in Zone 3, 14 stands in Zone 4, 4 stands in 

 Zone 5, and 11 stands in Zone 6. The total possible number of stands 



