AN EVALUATION OF THE TENNECO LATERRE 

 MITIGATION BANK MANAGEMENT PLAN 



Richard Simmering 



Billy Craft 



USDA Soil Conservation Service 



3737 Government Street 



Alexandria, LA 71302 



John Woodard 

 Tenneco LaTerre 



P. O. Box 208 

 Houma, LA 70361 



Darryl Clark 



Coastal Management Division 



Louisiana Department of 



Natural Resources 



P. O. Box 44887 



Baton Rouge, LA 70804-9386 



ABSTRACT 



The 2,828 ha Tenneco LaTerre mitigation bank plan consists of brackish, intermediate, and fresh 

 marshes, bottomland hardwood forests, and wax myrtle scrub-shrub habitat. The plan was 

 implemented in 1985 and has been monitored by an interagency team in addition to the U.S. Soil 

 Conservation Service and Coastal Management Division of the Louisiana Department of Natural 

 Resources. 



The planned structural components consist of three wooden fixed-crest weirs, one double 

 variable-crested flap-gated weir, spoil bank maintenance, a low level levee, and gaps in existing 

 pipeline canal spoil banks for freshwater introduction. The plan goal is marsh restoration through 

 a reduction of abnormal tidal flows and water level drawdowns. 



The plan has been monitored by transect at 22 stations for percentage of vegetative cover. 

 Tenneco LaTerre has recorded water levels at one station and salinity at 1 1 stations at a frequency 

 of every 4-5 days since implementation. Marsh:water ratios, trapping and hunting data, and 

 vegetative prevalence indexes were also recorded. 



The results of the 1986 monitoring indicated that the average salinities rose 0.6 ppt and water 

 levels rose 0.06 cm inside the managed area compared to those values measured outside. Turbidity 

 was reduced and submerged aquatic vegetation increased in abundance and diversity. 



The 1987 evaluation results also indicated that average water levels were slightly higher inside 

 (mean=24.84 cm) than outside (mean=22.15 cm) the plan area. Stations outside the plan area 

 showed greater water fluctuations (10.63 cm versus 4.83 cm). Salinities averaged 21% higher 

 outside (1.22 ppt) compared to values recorded inside (1.01 ppt). Average salinities were 1.0 ppt 

 in 1987 compared to 4.2 ppt in 1986 at the same station. 



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