General Comments:

Many of the impoundments in this area are located within the Merritt Island National Wildlife Refuge. There are several unimpounded marshes in the area, particularly in Volusia County, and several impounded marshes remain open all year with mosquito control accomplished via OMWM.

The MINWR presently operates under the mandate of providing habitat and food for migratory birds and waterfowl. As such, management of many of these impoundments revolve around production of food plants and provision of suitable resting and foraging habitat for these birds; however, more emphasis on "ecosystem management" is probably forthcoming. A fall/winter drawdown schedule, alternating with years when impoundments are left open is the most common technique utilized presently for migratory bird management. However, management versatility is critical for achieving the stated goals. Refuge managers need the flexibility to alter the management of individual or groups of impoundments to cope with unpredictable weather conditions, and to maintain suitable habitat quality in these marshes.

Two factors presently limit the efficient management of many of the refuge impoundments: 1) Insufficient pumping capabilities, and 2) shortage of personnel to operate pumps and culvert gates. In the MLMA, the first problem could be resolved by installing a 36-inch pump in impoundment T-27A, which could be used to control water levels in close to 4,000 acres of impounded marshes. With pumping capabilities and additional field technicians, many of these impoundments could be opened sooner and/or closed later, thus maximizing the time where effective marsh-lagoon interchange is maintained. Obtaining funding for purchase and installation of said pump is important for this area, and for the lagoon as a whole.

Management of many of the MINWR impoundments under a fall/winter drawdown schedule limits the connections between marshes in this area and the lagoon, both in a temporal and a spatial sense. However, the management strategy for many of these impoundments includes periodic year-round opening, which should be staggered among sites so that some impoundments are open at any given time. Nevertheless, every effort should be made to maintain the marsh-lagoon connection in the remaining marshes in the area. Fortunately, many of the Volusia County impoundments can be managed under an OMWM strategy. These, together with the unimpounded marshes in the area, offer the best opportunities for balanced management.

Impoundment C-8. - This impoundment is breached with rotary ditches and should be left as is.

Impoundment D-2. - This impoundment receives a great deal of runoff from the uplands and is a good candidate for use as a stormwater retention area. The four existing culverts could be closed during high runoff periods, and/or riser boards installed to control discharge into the lagoon.

Impoundment D-12N. - This is an isolated insular impoundment whose main water input is from rainfall and groundwater. As a result there is a proliferation of cattails and duckweed. This marsh could be best managed as an OMWM system with breached dikes. Prescribed burning may be necessary to eliminate some of the unwanted vegetation.

Impoundment D-12S. - This marsh can be kept open all year if more ditches are constructed to eliminate mosquito breeding.

Impoundments V1 to V5. - These relatively isolated and shallow impoundments are prolific mosquito producers. Additional ditches and internal culverts are needed to improve water circulation, minimize drainage, and to maintain and disperse larvivorous fish. Water circulation may also be improved with external culverts, but the shallow topography and a lack of natural conduits for water to the marsh interior severely limit the locations where the latter would be effective. With the above modifications, the impoundments can be left open all year.

Impoundment T-45. - This impoundment can also be left open all year if more ditches are added for mosquito control.

Impoundments T-44 to T-38. - This and the next group of impoundments form the core of the migratory bird/waterfowl management sites for this area. As such, management of these impoundments should consist of a mix of fall/winter drawdown, and open year round, with variations as needed for exotic control, sediment oxidation, etc. As mentioned in the general comments, flexibility is the key for successful management of these impoundments; specific schedules and timetables will have to be determined on a year-by-year basis, depending upon water levels, weather, marsh conditions, etc. Impoundment T-39S has been permitted for breaching by NASA, and others could conceivably also be breached in the future. More culverts are needed in the non- breached impoundments in this block for efficient water management.

Impoundments T-33C to T-27A. - Management as above. A high priority for this group is the installation of a pump to allow efficient manipulation of water levels. One large (36-inch) pump installed at impoundment T-27A would allow proper control of water levels in the whole series of impoundments from T-27A to T-29B. Additional internal culverts (one 36-inch culvert each) connecting T-33A, T-33B, T-29A, and T-29B would extend the coverage of the pump to the T-33 group thus allowing proper management of 3,932.5 acres (1,573 ha) of prime overwintering habitat. In addition, pump installation will probably result in a longer open period for these marshes because managers will not have to depend upon tidal and rainfall trapping for flooding the area. Installation of the pump and culverts is considered one of the highest priorities on a lagoon-wide basis.