connector channels would replace the old ditches, which would be con- 

 nected to the system only if they are active mosquito breeding areas 

 (Figure 47). Ditches that have silted in and become revegetated would 

 be left to fill in naturally [150]. 



Figure 47. Example of approved open-marsh water management system for 

 mosquito control (left side) and the outdated grid ditching system (right 

 side) (Source: Reference 150, modified). 



"Grid 

 Ditching" 



Impoundments 



Impoundments for flooding water over a high marsh area not only 

 eliminate the flunctuating moisture conditions required for mosquito 

 breeding, but they also alter the tidal connection which ties the high 

 salt marsh to the estuary. Harmful impacts of marsh impoundments include 

 the loss of important natural areas, the retention of organic detritus 

 which is not released to the estuary, and the inability of estuarine 

 fishes to enter the impoundment for food and shelter. 



178 



