1987-003 - Laserfiche WebLink

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term maintenance of the circulation channels may become desirable both to insure viability of the Open Marsh Water Management mosquito control system and functional viability of the rehabilitated and created marsh. Because the circulation channels will be initially modified by a floating vacuum dredge, they will continue to be accessible by small barge mounted equipment. Numerous access points will continue to be available through golf fairways that lie between upland roadways and the circulation channels. The equipment to be used for circulation channel maintenance will be a form of the jet spray system which combines suction dredging with detritus knives and a spray system which can be accurately directed to adjacent marsh areas. The value of dredge material used as top dressing for marsh restoration is well appreciated. As pointed out by Daiber (1986),"While the tidal accumulation of sediments can influence the plant species composition, the deposition of spoil on the marsh surface can have a profound influence on the well- being of the marsh vegetation." This periodic "top dressing" has been accomplished using the jet spray equipment with authenticated positive results. The jet spray equipment was developed in Florida and is currently available from Aztec Development Co., P.O. Box 3348, Orlando, Florida 32802, 305;849-6420. They have considerable references and independent write ups on their various activities which they would be happy to §hare. The only other maintenance that may become necessary would involve the radial ditches. that would be used to connect any small isolated mosquito breeding depressions that may be discovered after system rehabilitation. Because of the system geometry, however, we do not expect such ditching to become necessary. If they are found to be necessary, their maintenance for mangrove removal will be covered by the same program as mentioned for the circulation channels. If major maintenance is required in the long run, the jet spray system would not be effective because of the narrowness if the radial ditches. If the radial ditches become necessary, they will be cut using a rotary ditcher which also br•oadcaststhe material thinly over the adjacent marshes. This equipment is designed to cause minimum marsh disturbance being built on large low pressure tire support that will actually support the vehicle in open water. This same rotary ditcher can be used for rotary ditch maintenance for detritus and vegetation removal if it becomes necessary. Again, access will be across the golf course areas and the ditcher can be floated through the circulation channels to the radial ditch sites -without damage to the intervening marsh areas. It is a condition of the DER permit that permit modifications will be requested and approved prior to any additional mosquito control efforts. As in the past it will be possible to accomplish any additional ditching (if found to be necessary) by hand labor to reduce any adverse impacts on the high marsh.