Under this alternative, management of the area will remain status quo. The area of Dyke Marsh in the vicinity of the Dyke Marsh Trail will continue to be impacted by the proliferation of social trails, trampling, and indiscriminate visitor use, and sensitive resources such as rare plants, nesting birds and wetland vegetation will continue to be adversely impacted. Flood events and erosion will continue to degrade the Dyke Marsh Trail, making it more difficult to use and more difficult to access the marsh. Since this alternative does not involve any construction, no associated construction impacts will occur.
This alternative does not include any specific actions that will enhance protection of the Chesapeake Bay, nor does it include any measures to foster the goals of the American Heritage River designation for the Potomac, including improvements to water quality, fostering environmental restoration, and enjoyment of natural, recreational, and heritage assets.
Under this alternative, there are no known impacts to any cultural resources within or near Dyke Marsh.
Under this alternative, poor access, high water, and muddy conditions will continue to limit visitor opportunities for enjoyment of Dyke Marsh. Educational opportunities for local school groups will continue to be limited for the same reasons.
The appearance of the existing entrance to Dyke Marsh will continue to degrade, as will the appearance of resources throughout the marsh.
Under this alternative, the National Park Service will continue to maintain the existing trail at approximately the same level as it does now. Occasional replacement of bank run gravel will continue to be used to maintain the Dyke Marsh Trail surface, primarily after flood events. Prime observation areas within the marsh, which are inaccessible for maintenance, will continue to degrade.
Under this alternative, the National Park
Service will construct a boardwalk structure along existing social
trails in Dyke Marsh. Since most visitors will likely choose
to use a boardwalk that is provided, trampling of rare plants
and other wetland vegetation will be reduced. Unlike the existing
network of social trails, the boardwalk will direct visitor use
off of and away from sensitive areas such as nesting bird sites
and sensitive and rare plant areas. Long-term protection of the
wetland ecosystem of Dyke Marsh and ultimately the Chesapeake
Bay will be enhanced by improvement of management of visitor
use in Dyke Marsh. An elevated boardwalk is consistent with the
designation of the Potomac as an American Heritage River, in
that it promotes enjoyment and appreciation of the natural, recreational
and heritage assets of Dyke Marsh, while educating the public
on the natural and historical features of the Potomac Basin.
Short-term, temporary impacts will occur during
the construction phase of the project. Impacts will include the
direct affects of construction such as the removal of vegetation
in the immediate corridor of the boardwalk, noise from workers
and some motorized equipment, etc. Impacts will be controlled
and minimized through appropriate construction techniques and
limitations on how the work is carried out.
Some long-term impacts will occur due to shading or loss of vegetation
directly under the approximately 6,300 square feet (967 linear
feet) boardwalk.
Long-term impacts could also result from an increase in disturbances
to nesting birds and other wildlife due to greater human use
of the area. These disturbances might be mitigated, however,
by a decrease in the amount of dispersed human use of the marsh.
The tendency of visitors to stay on the boardwalk may localize
the disturbances to only that immediate area, rather than spreading
it around unpredictably.
This alternative may not fully address the issue of social trail
proliferation since it encompasses only one portion of the area.
Although visitors will be able to view the northern sections
of the marsh from a raised platform on the boardwalk trail, there
is potential for visitors to venture off of the boardwalk to
gain physical access to the northern section of the marsh. If
this happens, it will continue to have negative impacts on wildlife
and vegetation.
Enhanced opportunities for enjoyment of the Dyke Marsh area by the proposed action may result in the Dyke Marsh Trail and subsequent boardwalk areas becoming more popular and may therefore have the potential for increase illegal pet use in the area. To mitigate this potential increase of pets off leash in the marsh and the associated adverse impacts to wildlife and wildlife habitats, the park will increase education efforts, monitor illegal pet use in the marsh and study the possibility of prohibiting all pet use in the marsh. Pets in the marsh, whether on or off leash, may disturb wildlife away from trails.
Under this alternative, there are no known impacts to cultural or archeological resources within or near Dyke Marsh. As the lands upon which this Boardwalk alternative are proposed for construction are comprised of recent fill, and the project area is remote from any National Register sites, the undertaking is believed to have no potential to effect historic properties.
This alternative will provide approximately
967 linear feet (290 meters) of elevated boardwalk in a loop
configuration through the southern portion of the marsh. Visitor
use of the area will be enhanced by improvement of access to
Dyke Marsh and by eliminating the need to slog through wet and
muddy conditions. In addition, some of the currently inaccessible
parts of the marsh will be made accessible, and interpretive
wayside exhibits will contribute to visitor enjoyment and understanding.
This alternative will not directly affect recreational opportunities
such as fishing.
The appearance of the existing entrance to Dyke Marsh will greatly improve as will the general appearance throughout the marsh.
Under this alternative, maintenance requirements will increase in order to conduct periodic inspections of the new boardwalk and maintain the structure as necessary. Sustainable design practices will be incorporated in order to ensure the structure is flood resistant and achieves its maximum useful lifetime. The structure’s physical location in the marsh will likely provide some degree of protection from flood waters and impacts from floating debris because of the surrounding wetland vegetation serving as a buffer; more than either of the other boardwalk alternatives.
Under this alternative, the National Park
Service will construct a boardwalk structure along existing social
trails in Dyke Marsh. Since most visitors will likely choose
to use a boardwalk that is provided, trampling of rare plants
and other wetland vegetation will be reduced. Unlike the existing
network of social trails, the boardwalk will direct visitor use
off of and away from sensitive areas such as nesting bird sites
and sensitive and rare plant areas. Long-term protection of the
wetland ecosystem of Dyke Marsh and ultimately the Chesapeake
Bay will be enhanced by improvement of management of visitor
use in Dyke Marsh. An elevated boardwalk is consistent with the
designation of the Potomac as an American Heritage River, in
that it promotes enjoyment and appreciation of the natural, recreational
and heritage assets of Dyke Marsh, while educating the public
on the natural and historical features of the Potomac Basin.
Short-term, temporary impacts will occur during
the construction phase of the project. Impacts will include the
direct affects of construction such as the removal of vegetation
in the immediate corridor of the boardwalk, noise from workers
and some motorized equipment, etc. Impacts will be controlled
and minimized through appropriate construction techniques and
limitations on how the work is carried out.
Some long-term impacts will occur due to shading or loss of vegetation
directly under the approximately 6,769 square feet (890 linear
feet) of boardwalk.
Long-term impacts could also result from an increase in disturbances
to nesting birds and other wildlife due to greater human use
of the area. These disturbances might be mitigated, however,
by a decrease in the amount of dispersed human use of the marsh.
The tendency of visitors to stay on the boardwalk may localize
the disturbances to only that immediate area, rather than spreading
it around unpredictably.
Because the "Y" configuration of the boardwalk design
may result in portions of each spur being visible from the other,
it is possible that some visitors may attempt to shortcut "cross-country"
between them, resulting in the development of social trails,
trampling of vegetation including rare species and disruption
of nesting birds and other wildlife.
Enhanced opportunities for enjoyment of the Dyke Marsh area by the proposed action may result in the Dyke Marsh Trail and subsequent boardwalk areas becoming more popular and may therefore have the potential for increase illegal pet use in the area. To mitigate this potential increase of pets off leash in the marsh and the associated adverse impacts to wildlife and wildlife habitats, the park will increase education efforts, monitor illegal pet use in the marsh and study the possibility of prohibiting all pet use in the marsh. Pets in the marsh, whether on or off leash, may disturb wildlife away from trails.
Under this alternative, there are no known impacts to cultural or archeological resources within or near Dyke Marsh. As the lands upon which this Boardwalk alternative are proposed for construction are comprised of recent fill, and the project area is remote from any National Register sites, the undertaking is believed to have no potential to effect historic properties.
Under this alternative visitor use of the
area will be enhanced by improvements of access to Dyke Marsh
and by eliminating the need to slog through wet and muddy conditions.
In addition, some of the currently inaccessible parts of the
marsh will be made accessible, and interpretive wayside exhibits
will contribute to visitor enjoyment and understanding.
This alternative will provide approximately 890 linear feet (270
meters) of elevated boardwalk in a "Y" configuration,
requiring visitors to walk a distance of about 1,800 feet due
to the necessity of walking out and back on each spur. Some people
might find this tedious or awkward compared with a loop trail.
This alternative will not directly affect recreational opportunities
such as fishing in the marsh.
The appearance of the existing entrance to Dyke Marsh will greatly improve as will the general appearance throughout the marsh.
Under this alternative, maintenance requirements will increase in order to conduct periodic inspections of the new boardwalk and maintain the structure as necessary. Sustainable design practices will be incorporated in order to ensure the structure is flood resistant and achieves its maximum useful lifetime. Although some degree of protection from floodwaters and impacts from floating debris, the northern spur of this structure may be more susceptible to damage from floods due to the fact that it is more exposed to the flow velocity and wave action of the river and less protected by wetland vegetation.
Under this alternative, the National Park Service will introduce a boardwalk structure along existing social trails in Dyke Marsh. Since most visitors will likely choose to use a boardwalk that is provided, trampling of rare plants and other wetland vegetation will be reduced. Unlike the existing network of social trails, the boardwalk will direct visitor use off of and away from sensitive areas such as nesting bird sites and sensitive and rare plant areas. Long-term protection of the wetland ecosystem of Dyke Marsh and ultimately the Chesapeake Bay will be enhanced by improvement of management of visitor use in Dyke Marsh. An elevated boardwalk is consistent with the designation of the Potomac as an American Heritage River, in that it promotes enjoyment and appreciation of the natural, recreational and heritage assets of Dyke Marsh, while educating the public on the natural and historical features of the Potomac Basin.
Short-term, temporary impacts will occur during the construction phase of the project. Impacts will include the direct affects of construction such as the removal of vegetation in the immediate corridor of the boardwalk, noise from workers and some motorized equipment, etc. Impacts will be controlled and minimized through appropriate construction techniques and limitations on how the work is carried out.
Some long-term impacts will occur due to shading or loss of vegetation directly under the approximately 11,200 square feet (1600 linear feet) of boardwalk.
Long-term impacts could also result from an increase in disturbances to nesting birds and other wildlife due to greater human use of the area. These disturbances might be mitigated, however, by a decrease in the amount of dispersed human use of the marsh. The tendency of visitors to stay on the boardwalk may localize the disturbances to only that immediate area, rather than spreading it around unpredictably.Enhanced opportunities for enjoyment of the Dyke Marsh area by the proposed action may result in the Dyke Marsh Trail and subsequent boardwalk areas becoming more popular and may therefore have the potential for increase illegal pet use in the area. To mitigate this potential increase of pets off leash in the marsh and the associated adverse impacts to wildlife and wildlife habitats, the park will increase education efforts, monitor illegal pet use in the marsh and study the possibility of prohibiting all pet use in the marsh. Pets in the marsh, whether on or off leash, may disturb wildlife away from trails.
Under this alternative, there are no known impacts to cultural or archeological resources within or near Dyke Marsh. As the lands upon which this Boardwalk alternative are proposed for construction are comprised of recent fill, and the project area is remote from any National Register sites, the undertaking is believed to have no potential to effect historic properties.
Impacts on Visitor Use and Visual Quality This alternative will provide approximately 1,600 feet (480 meters) of elevated boardwalk in a loop configuration. Visitor use of the area will be enhanced by improvements of the access to Dyke Marsh and by eliminating the need to slog through wet and muddy conditions. In addition, some of the currently inaccessible parts of the marsh will be made accessible, and interpretive wayside exhibits will contribute to visitor enjoyment and understanding.
This alternative will not directly affect recreational opportunities such as fishing in the marsh.The appearance of the existing entrance to Dyke Marsh will greatly improve as will the general appearance throughout the marsh.
Maintenance and Sustainability Under this alternative, maintenance requirements will increase in order to conduct periodic inspections of the new boardwalk and maintain the structure as necessary. Sustainable design practices will be incorporated in order to ensure the structure is flood resistant and achieves its maximum useful lifetime. The structure’s physical location in the marsh will likely provide the least protection from floodwaters and impacts from floating debris compared to the other boardwalk alternatives due to the fact that it is exposed to the flow velocity and wave action of the river and less protected by wetland vegetation. Although this alternative includes routes to the north of the peninsula and may experience more of these forces of nature, several respondents favored boardwalk access to northern routes in an effort to minimize impacts to sensitive species.
Under this alternative, the National Park Service will introduce a boardwalk structure along existing social trails in Dyke Marsh. The concept of this revised alternative is similar to Alternative D only it is not as large a loop and is placed to best protect sensitive species. The majority of the public responses to this EA during the open comment period recommended that a revised Alternative D be considered. Recommendations presented in the public comments were considered in developing this revised alternative.
Since most visitors will likely choose to use a boardwalk that is provided, trampling of rare plants and other wetland vegetation will be reduced. Unlike the existing network of social trails, the boardwalk will direct visitor use off of and away from sensitive areas such as nesting bird sites and sensitive and rare plant areas. Long-term protection of the wetland ecosystem of Dyke Marsh and ultimately the Chesapeake Bay will be enhanced by improvement of management of visitor use in Dyke Marsh. An elevated boardwalk is consistent with the designation of the Potomac as an American Heritage River, in that it promotes enjoyment and appreciation of the natural, recreational and heritage assets of Dyke Marsh, while educating the public on the natural and historical features of the Potomac Basin.
Short-term, temporary impacts will occur during the construction phase of the project. Impacts will include the direct affects of construction such as the removal of vegetation in the immediate corridor of the boardwalk, noise from workers and some motorized equipment, etc. Impacts will be controlled and minimized through appropriate construction techniques and limitations on how the work is carried out.
Some long-term impacts will occur due to shading or loss of vegetation directly under the approximately 7,700 square feet (1100 linear feet) of boardwalk.
Long-term impacts could also result from an increase in disturbances to nesting birds and other wildlife due to greater human use of the area. These disturbances might be mitigated, however, by a decrease in the amount of dispersed human use of the marsh. The tendency of visitors to stay on the boardwalk may localize the disturbances to only that immediate area, rather than spreading it around unpredictably.Enhanced opportunities for enjoyment of the Dyke Marsh area by the proposed action may result in the Dyke Marsh Trail and subsequent boardwalk areas becoming more popular and may therefore have the potential for increase illegal pet use in the area. To mitigate this potential increase of pets off leash in the marsh and the associated adverse impacts to wildlife and wildlife habitats, the park will increase education efforts, monitor illegal pet use in the marsh and study the possibility of prohibiting all pet use in the marsh. Pets in the marsh, whether on or off leash, may disturb wildlife away from trails.
2. Impacts on Cultural Resources Under this alternative, there are no known impacts to cultural or archeological resources within or near Dyke Marsh. As the lands upon which this Boardwalk alternative are proposed for construction are comprised of recent fill, and the project area is remote from any National Register sites, the undertaking is believed to have no potential to effect historic properties.
Impacts on Visitor Use and Visual Quality This alternative will provide approximately 1,100 linear feet (405 meters) of elevated boardwalk in a loop configuration. Visitor use of the area will be enhanced by improvements of the access to Dyke Marsh and by eliminating the need to slog through wet and muddy conditions. In addition, some of the currently inaccessible parts of the marsh will be made accessible, and interpretive wayside exhibits will contribute to visitor enjoyment and understanding. This alternative will not directly affect recreational opportunities such as fishing in the marsh.
The appearance of the existing entrance to Dyke Marsh will greatly improve as will the general appearance throughout the marsh.
Maintenance and Sustainability Under this alternative, maintenance requirements will increase in order to conduct periodic inspections of the new boardwalk and maintain the structure as necessary. Sustainable design practices will be incorporated in order to ensure the structure is flood resistant and achieves its maximum useful lifetime. The structure’s physical location in the marsh will likely provide the least protection from floodwaters and impacts from floating debris compared to the other boardwalk alternatives. Although this alternative includes routes to the north of the peninsula and may experience more of these forces of nature, several respondents favored boardwalk access to northern routes in an effort to minimize impacts to sensitive species.