BLUFF EROSION OF A MISSISSIPPI RIVER MEANDER AT PORT HUDSON,LOUISIANA |
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| Authors: | Richard H Kesel Robert H Baumann |
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| Institution: | Louisiana State University , Baton Rouge |
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| Abstract: | The rate of bluff erosion has been monitored and related processes examined on a Mississippi River meander bend at Port Hudson, Louisiana, from 1971 to mid-1980. The erosion data were analyzed using a stepwise multiple regression analysis to determine the conditions controlling the amount and distribution of bluff erosion. The results indicate a pattern of decreasing bluff erosion that is attributed to downstream migration of the zone of maximum basal scour. Bluff retreat in the period of active basal undercutting (1971 to mid-1975) was 18.9m/year and in the following period of decreased basal scour activity (mid-1975 to mid-1980) was 6.8m/year. Approximately, 61% of the erosion was associated with rising river levels. The data also indicated that 66% of the erosion occurred at bankfull discharge stage or above. Conditions that produce bluff erosion were found to vary between the two eriosion periods and also as river levels rose or fell in each of the periods. During the actively undercutting period, precipitation rate and amount of river rise explained 94% of the bank erosion that occurred as river levels rose. During the falling river phase, days above bankfull stage and amount of river fall accounted for 99% of the bluff erosion. In the period of decreased basal scour, precipitation rate and maximum river stage accounted for 94% of the bluff erosion related to rising river levels, while the erosion during falling river levels could be only tentatively correlated to precipitation rate and factors associated with drawdown. Changes in slope processes as the result of decreased basal scour were also examined. |
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| Keywords: | WET-Health landuse/landcover sustainability hydrology geomorphology vegetation |
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