Elizabeth (UR) - Mosquitoes SUCK!

Nobody likes that pesky buzzing or those itchy bites so why dig ditches giving them more area to breed? As early as the 1760's mosquitoes have plagued the people living and visiting Florida. William Bartram, during his many travels through Florida often wrote of the sleepless nights from the troublesome mosquitoes. During the late 1800's Florida was plagued by yellow fever and said to be caused by mosquitoes.

A flier for a conference on the elimination of the disease carrying mosquito.

In the 1950's dragline ditches were dug in coastal marshland in Volusia County and all throughout Florida from the Canaveral area to north to Jacksonville. These ditches were thought to expand the areas where fish would breed and live to help control the black salt marsh mosquitoes (Aedes taeniorrynchus) and other mosquito populations by feeding on their larvae. The ditches were also dug to help with drainage. Many of the ditches are not more than 1.5 to 2.5 feet deep and are mostly a mud bottom that remains submerged during most tidal events except during low water events. Approximately 41 ditches were dug throughout the Ormond Beach area adjacent to the Tomoka River and the Tomoka River Basin.

Dragline (excavator) circa 1950s

Dragline ditches before
and after restoration

There are numerous negative effects to this ditching. The mosquitoes were inevitably given more waterway to breed in which didn't exactly help in the long run. Digging left spoils on either side of the ditch altering the flow of water in estuaries. It changed the amount of and in some cases the types of fish inhabiting the marshes and wetlands. Wetlands also provide protection during storms and these ditches diminished that. The spoils on each side of the ditches are higher than the original wetlands themselves. This allowed for non native species to invade those areas. One species that did so is the Brazilian Pepper (Schinus terebinthifolius).






In the early 2000's small grant funding was provided to the St. John's River Water Management District to begin a restoration project to fill in dragline ditches and restore wetlands to their natural habitat. They partnered with the U.S. Fish and Wildlife Service, Florida Fish and Wildlife Conservation Commission and Florida Department of Environmental Protection and Florida State Park System. As funding became available they would do small portions in different areas to restore the wetland habitat as much as possible. An Amphibious Excavator is used to dig out trees and other vegetation. This is usually left to be used as fill in certain ditches. The soil is then leveled to the original elevation of the marsh. Some areas had grasses planted whiles others were allowed to restore itself naturally. Fish, birds, crabs and plants have been seen in restoration areas where they had previously moved on due to habitat loss. Marsh grasses have grown quickly in places where the soil was reestablished. During the restoration process, turbidity in the Tomoka River was monitored due to the sediments being disturbed during back filling. Turbidity curtains were installed to at the outlets of the river to minimize impacts.

Amphibious Excavator in a restoration area

Aerial photo of the 121 Acre Restoration of  the Tomoka Marshland

Sources:

Flagler County Wetland Restoration Project – SJRWMD. (n.d.), Retrieved February 20, 2019, from 
https://www.sjrwmd.com/facts/flagler-wetland-restoration-project/

Rey, J.R., Carlson, D.B. & Brockmeyer, R.E. Wetlands Ecol Manage (2012) 20: 197, from
https://doi-org.db06.linccweb.org/10.1007/s11273-011-9235-1

City of South Daytona, Florida // Home Page, Phase 2 Dragline Ditch Project Tomoka State Park, 
Retrieved February 18, 2019, from http://www.southdaytona.org/egov/documents/13179195899818.pdf

Kathryn, Step Aboard for the Gospel of Good Health!, Retrieved February 18, 2019, from 
https://www.floridamemory.com/blog/tag/yellow-fever/