Open space preservation usually happens at the local level, where resident concerns about rising property taxes drive efforts to manage the need for constant increases in future years.

In Prince William, as growth pressures continue and the amount of vacant land rapidly declines, land values are increasing dramatically. Local communities face hard choices and a shortened timeframe.

One important property worth saving is Merrimac Farm, in Nokesville along Cedar Run. Owned by the late Dean McDowell, one of Prince William's most vocal supporters of open space preservation, Merrimac Farm has been struggling toward a long-term conservation outcome for several years.

It is a valuable property to protect from a community perspective. With a total of 300 acres, Merrimac Farm includes 115 acres of wetlands and one mile of frontage along Cedar Run, which flows into the Occoquan Reservoir. Both waterways are included on Virginia's 2004 Dirty Water list.

Merrimac Farm provides critical watershed management functions that help prevent additional pollution from reaching our public drinking water supply.

Besides its significant location along Cedar Run, Merrimac Farm connects more than 22,000 acres at Quantico Marine Corps Base with the 300 acre protected Cedar Run wetland mitigation bank (154 acres of created, restored and enhanced wetlands, 52 acres of preserved wetlands and 102 acres of preserved upland buffers).

Preservation of Merrimac Farm would maximize the wildlife and watershed values of all three properties, and creates an opportunity where local communities could achieve superior returns on preservation investments.

Dean McDowell managed his farm for birds and other wildlife. Merrimac Farm's diverse and high-quality wetland habitats support a variety of wildlife. Last January, we were surprised to see an immature Cormorant, generally viewed along the Potomac River shoreline, sunning itself on a tree that had toppled into the pond, where one end has been extended into a wetland.

During a walk in January, 2004, we heard many cricket frogs at the pond. We also saw green frogs, chorus frogs and spring peepers as we walked through wetland areas on our way to Cedar Run. It was heartening to casually observe many different species of frogs, which are akin to 'canaries in the coal mine.' Their porous skin makes frogs especially susceptible to changes in the environment. Frogs are among the first to suffer the consequences of pollution, wetland destruction, impacts from nonnative species and increased UV radiation.

Merrimac Farm is home to one of Northern Virginia's largest communities of Bluebells. On April 15, the banks of Cedar Run at Merrimac Farm were blanketed with a carpet of bluebells that went on for nearly one mile.

Merrimac Farm is home to American bitterns, herons, quail, turkeys and many other bird species. The wetlands provide valuable nesting grounds for ducks and other waterfowl, and forest species that rely on vernal pools to reproduce.

Merrimac Farm's high quality habitats are important to wildlife and people.

Nearly 100 acres of wetlands buffer a one mile stretch of Cedar Run within Merrimac Farm. This area, protected by about 200 acres of upland buffer, provides critical habitat to a diversity of wildlife. The wetland areas are an important source of water and food for mammals and breeding grounds for a variety of wildlife.

In addition, Merrimac Farm's high quality wetlands protect Cedar Run and the Occoquan Reservoir from the negative impacts of new and existing development within the watershed.

Prince William's rapid development has resulted in small remaining pieces of ecosystems so isolated that some plant and animal populations can no longer survive.

Choices about open space preservation are decided by Prince William communities. Merrimac Farm is one opportunity where the benefits of open space preservation are especially meaningful. A conservation outcome for Merrimac Farm is not certain. As efforts continue to move forward, Prince William communities have the opportunity to influence what happens at Merrimac Farm and throughout west Prince William.

The McDowell land presents a unique and valuable opportunity to protect water quality in the headwaters of the Occoquan Reservoir, protect critical wildlife habitat in a rapidly suburbanizing area, secure high quality public land for passive recreation within Northern Virginia , and honor the late Col. McDowell's wishes for the land.

Preservation of Merrimac Farm would be an exciting first for Prince William, where open space planning remains noticeably absent from land use choices. Citizens interested in open space preservation and public wildlife watching opportunities are encouraged to contact the Prince William Conservation Alliance at alliance(at)pwconserve.org for information on how to help.