Open Marsh Water Management
History: Open Marsh Water Management (OMWM) was originally developed in New Jersey as an environmentally sensitive alternative to grid ditching salt marshes and has been used in the Mid Atlantic States for many years. A three year study of OMWM began in 1982 in a collaborative effort between mosquito control, the Town of Rowley Massachusetts, the Manomet Bird Observatory, and the Massachusetts Audubon Society. Based on the principles established in New Jersey and the Mid Atlantic States, the Standards for Open Marsh Water Management were developed specific to the needs of the salt marshes of New England.
Objective: The objective abate mosquito population, reduce the need for insecticides, enhance the tidal food web and restore previously ditched, altered or degraded salt marshes.
Principle: OMWM is a site specific management technique that uses existing
features of a salt marsh to create or enhance ponds, pools and pans to serve as
reservoirs for mosquito eating fish and habitat for water fowl and wading shore
birds and provides access for the fish to mosquito breeding areas by creating or
enhancing radial connectors.
Standards: OMWM is done in strict accordance to the standards for OMWM. The standards are a step by step procedure that is followed to implement OMWM projects.
Sites are monitored before work is done and established criteria must be met. The standards define the types of alteration which are acceptable. Sites are monitored for two years after work is completed.
Site Plan: After a site is monitored and criteria is met, this data is analyzed and alterations are designed on site and a plan is developed. The site plan is an aerial photograph with a transparent overlay depicting alterations.
Alterations: Designed alterations are implemented by highly specialist, environmentally sensitive, low ground pressure equipment.
Restoration: It is estimated that 3,000. miles of grid ditch were excavated by hand in Essex County between 1929 and 1934. These ditches severely altered and degraded salt marshes. The demonstrates ability of OMWM to restore salt marsh and manage Phragmites growth has led to partnerships with numerous Federal, State and private groups to restore coastal salt marshes.
2009 03 23 UPDATE:
OMWM has been an important component of the Districts IPM strategy to manage salt marsh mosquitoes for 25 years. During this time hundreds of OMWM projects have been successfully completed resulting in an incremental reduction in the number of acres aerial larvicided and a dramatic reduction in adulticiding / truck spraying for adult mosquitoes. While the District continues to strongly support the concept and implementation of OMWM, our permit has expired and despite a two year effort to renew the permit, it has been denied. Therefore we are unable to implement any OMWM projects for the foreseeable future. While the District is actively working to resolve this matter we are also reviewing the fiscal realities of continuing to implement OMWM. Extensive permitting procedures and increased site monitoring and project implementation protocol will significantly increase operational costs. These considerations may ultimately make OMWM cost prohibitive.
Selective Salt Marsh Ditch Maintenance: In lieu of OMWM, and to insure that the significant gains achieved through OMWM are not lost, the District will implement a selective salt marsh ditch maintenance program. The District will investigate potential sites for opportunities to implement selective salt marsh ditch maintenance. Sites will be considered based upon surveillance data obtained through the District's aerial larviciding program: known mosquito larval habitat. Areas of greatest distance from aerial larviciding landing zones (to minimize operational costs) and areas which are difficult to treat due to physical site characteristics will be given priority.
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