Revegetation of open water areas appears to be occurring in the southeast corner of the plan 

 area. Turbidity has decreased and submerged aquatic vegetation has increased in the open water 

 areas. More waterfowi (10%; 2,295 versus 2,562) and alligators (3.8%; 81 versus 78) were recorded 

 in 1987 compared to 1986. 



In summary, the management area may have produced some positive results in the 2 years since 

 implementation: (1) increased abundance and diversity of submerged aquatic vegetation, (2) 

 revegetation of small areas surrounding islands in the southeast portion of the plan, (3) more 

 stabilized water levels and turbidity inside the plan area than outside, and (4) a slight increase in 

 waterfowl and alligator abundance. 



INTRODUCTION 



The area included in the Tenneco LaTerre (TLT) mitigation bank is about 2,828 ha. It is 

 located in Terrebonne Parish, LA, and is within hydrologic unit 5. The entire area was a fresh 

 marsh as shown in the 1963 Terrebonne Parish Soil Survey. In 1953, the marsh in this area was 

 vegetated primarily by Paille fine (Panicum hemitomon). As of 1982, about 1,333 ha had been 

 converted to intermediate/brackish marsh and large open water areas-unproductive from a wildlife 

 standpoint (Figure 1). 



Significant deterioration in the area began around 1962 with the opening of the Houma 

 Navigation Canal which provides a direct avenue of saltwater to the area via the Falgout Canal. 

 In 1984, Hurricane Hilda hit the area, bringing in saltwater. The Pipeline Canal, with solid levees 

 on both sides, was constructed east to west across the property, cutting off all freshwater recharge 

 from the Marmande Canal. Other oil or gas exploration canals excavated into the area aggravated 

 the situation by providing additional corridors for saltwater intrusion. All of these factors plus 

 subsidence have had a detrimental effect on the area. 



An attempt is being made to stop and reverse the deterioration of this marsh. A marsh 

 management plan was developed by TLT with the guidance and approval of the Soil Conservation 

 Service (SCS), the U.S. Fish and Wildlife Service (USFWS), U.S. National Marine Fisheries Service 

 (USNMF), and the Louisiana Department of Natural Resources (DNR). 



A Memorandum of Agreement (MOA) was implemented between TLT and the above agencies 

 to establish a mitigation bank of fish and wildlife habitat units gained, resulting from habitat 

 improvements in the management area. These habitat units could then be used to mitigate habitat 

 units lost because of oil and/or gas exploration projects conducted by Tenneco and other 

 companies. 



The MOA states that the area will be intensively managed for at least 25 years by installing, 

 operating, and maintaining a series of water control structures and levees for the purpose of 

 increasing freshwater and sediment inflow, improving water circulation, and reducing saltwater 

 intrusion. 



More specifically, the objectives of the plan are to enhance the area for wildlife, waterfowl, and 

 marine organisms and control erosion by doing the following: 



1. Control saltwater intrusion into fresh and intermediate marshes. 



2. Stabilize water levels within the management area. 



320 



