Ecology of Red Maple Swamps in the Glaciated Northeast: A ...

Chapter 8. Values, Impacts, and
Management
hnctions sand Values of Red
Maple Swamps
As previous chapters have shown, relatively
little research has been conducted on the hydrologic,
edaphic, or ecological characteristics of red
maple swamps, despite their abundance in the
glaciated Northeast. Similarly, few publications
have directly addressed the societal values of these
swamps. Many of the functions and values currently
recognized for wetlands (e.g., Greeson et al.
1979; Richardson 1981; Adamus and Stockwell
1983; Tiner 1984; Adamus et al. 1987) are nearly
universal; that is, they are evident in a wide variety
of wetland types, regardless of dominant vegetation
or water regime. Despite the lack of documentation,
red maple swamps clearly perform
many functions that bear directly on public safety,
health, and welfare. The great abundance of red
maple swamps in the Northeast suggests that the
social significance of these functions may be great
both locally and regionally.
This section reviews the most obvious functions
and values of red maple swamps, noting documentation
where it exists, but relying on more general
information when necessary. Functions are considered
to be processes or actions that the swanlps
perform; values are the benefits of those functions
to society.
Flood Abatement
The ability to reduce the peak level of floods and
to delay the flood crest is one of the most widely
recognized functions of inland wetlands (Carter
et al. 1979; Novitzki 1979b; Tiner 1984). This function
is accomplished chiefly through (1) the storage
of surface water in wetland basins after snowmelt
and major precipitation events, and (2) the reduction
in floodflow velocity as water passes through
wetland vegetation and over the soil surface. The
social significance of the flood abatement function
is enormous, particularly if areas downstream
from major wetlands are urbanized and vulnerable
to flood damage. After a 5-year study of flood
control alternatives in the Charles River basin of
eastern Massachusetts, the U.S. Army Corps of
Engineers (1972) concluded that the least expensive,
most effective means of flood control was the
preservation of all 3,400 ha of wetlands in the
watershed as "natural valley storage areas." Many
of those wetlands are red maple swamps. By the
late 1980's, all Charles River wetlands had been
protected for flood control through either public
acquisition or easements (E W. Colrnan, U.S. Army
Corps of Engineers, Waltham, Mass., personal
communication).
The relative contribution of an individual red
maple swamp to flood abatement is heavily influenced
by its geomorphic setting and land use
within its watershed. Swamps with the greatest
potential value for flood abatement are those that
(I) are located in a well-defined basin capable of
storing floodwater, (2) have a relatively large watershed
or one that has been extensively altered
by humans, and (3) receive floodwaters directly
from an overflowing stream or lake (see Ogawa
and Male 1983 for a discussion of other factors
affecting flood abatement). Hillside seepage
swamps, for example, have relatively low floodcontrol
value compared with temporarily or seasonally
flooded basin swamps or swamps associated
with lower perennial rivers. Trees, shrubs,
and herbaceous plants growing in swamps further
aid in flood abatement by physically impeding the
flow of floodwaters. In this regard, swamps are
more effective than open water or nonpersisbnt
emergent wetlands.
Groundwater hnctions
As shown earlier, red maple swamps may be
isolated from underlying groundwater aquifers or
intimately connected to them. Swamps linked to
groundwater aquifers may be groundwater recharge
areas, groundwater discharge areas, or
both. By collecting precipitation and overland flow
and recharging the underlying groundwater sys-