Chapter II — Species of Special Concern 



die-off response during its November 1996 annual 

 meeting. Results of that review and related planning 

 recommendations were provided to the Service on 31 

 December 1996, and in April 1997 the Service 

 completed a manatee die-off contingency plan outlin- 

 ing responsibilities and needed actions by the Service, 

 the state, and others in the event of another major 

 manatee die-off. 



To provide necessary details concerning operational 

 response needs, particularly those for which the state 

 was responsible, the Florida Department of Environ- 

 mental Protection contracted early in 1997 for a more 

 detailed plan to guide its response efforts. As de- 

 scribed in its previous annual report, the Commission 

 commented on the state's draft plan by letter of 29 

 October 1997 noting that it was thorough and well 

 done. With further changes to address comments by 

 the Commission and others, the state transmitted its 

 plan to the Service on 26 December 1997 requesting 

 that it be appended to the Service's plan. 



The Service replied on 23 January 1998 noting that 

 merging the two plans was an excellent idea and that 

 it would revise and update the plan to do so, while 

 working with the state to resolve any discrepancies or 

 ambiguities that might exist with regard to agency 

 responsibilities. In November 1998 the Service 

 provided copies of the final plan to key officials in the 

 Florida Department of Environmental Protection and 

 other agencies and groups. The revised plan reflects 

 information and guidance contained in the two plans 

 as well as advice and provisions set forth in the 

 "National Contingency Plan for Response to Unusual 

 Marine Mammal Mortality Events" completed in 1996 

 to provide a general framework for marine mammal 

 die-off responses. As of the end of 1998 the Service 

 and the state were arranging a planning meeting early 

 in 1999 to discuss steps that should be taken in 

 advance of any future manatee die-off response needs. 



Flood Gates and Navigation Locks 



After vessel collisions, the largest source of 

 manatee mortality is entrapment in closing flood gates 

 and navigation locks used to control water flow along 

 Florida's extensive network of drainage canals and 

 inland waterways. Since 1974 more than 150 mana- 

 tees have been killed in these structures, most of 



which are owned and operated by the South Florida 

 Water Management District or the Army Corps of 

 Engineers. To prevent this mortality, the two agen- 

 cies began working cooperatively in 1992 to design a 

 device, similar to an elevator door, that would auto- 

 matically and immediately reverse the operation of a 

 closing door if anything became caught in it. The 

 District assumed responsibility for designing and 

 testing mechanisms for flood gates, and the Corps 

 took the lead for developing and testing a mechanism 

 for navigation locks. 



Flood gates open and close by raising and lowering 

 a single door. As an initial approach for these struc- 

 tures, District engineers designed a mechanical 

 plunger device to be installed along the edge of a gate 

 door. If the plungers were depressed by the pressure 

 of a trapped object caught beneath a closing door, the 

 gate closing immediately reversed direction. Because 

 of fouling by marine growth and clogging by debris, 

 the devices proved difficult to maintain. Therefore, 

 in 1994 the District began to investigate the possibility 

 of using strips of piezoelectric film along the edge of 

 gate doors, rather than mechanical plungers, to trigger 

 gate reversals. The film, a tough plastic material that 

 converts mechanical pressure into electric current, has 

 no moving parts, and preliminary tests indicated that 

 the new device would be an effective, low-mainte- 

 nance solution. A prototype was therefore developed 

 and installed for the first time on two of four gates at 

 a flood control structure in Dade County in July 1997. 



Based on the promising result of preliminary 

 testing, the Army Corps of Engineers developed a 

 two-part plan to contract for the installation of new 

 devices at 20 flood-control structures and seven 

 navigation locks. It estimated the cost to carry out 

 this work at $2.7 million. As noted in its 1997 annual 

 report, the Commission commented to the Corps on 

 the plan on 15 September 1997 urging that contractual 

 arrangements be based on standardized designs 

 developed as quickly as possible and with the benefit 

 of any additional design modifications as may be 

 indicated by further testing. 



Based on successful operations at the two gates 

 retrofitted in 1997, the District proceeded to install its 

 new device on the two remaining gates at that struc- 

 ture and at three additional flood-control structures. 



103 



