United States
               Environmental Protection
                     Office of Water (WH-556F),
                     Office of Wetlands, Oceans,
                     and Watersheds (A-104 F)
                       March 1993
              WETLANDS  FACT SHEET #3
               Consequences of Wetland

               Loss and Degradation
    The lost or degradation of wetland* can lead to serious consequences, including increased
    flooding; species decline, extinction or  deformity; and decline in water quality.  The
    following ait* few examples oftkeconseauences of wetlands loss and degradation*






        I I I I  I I I I I I I I

      Populations of mallard and northern pin-
tail ducks in North America have declined since
1955 (see graph
above). The loss
and degradation
of wetlands is one
of  the  major
causes for the de-
cline in certain
waterfowl popu-
lations.  For ex-
ample, in the US.
prairies in 1990,
mallard   duck
reached   their
lowest recorded
number.   The
well-being of wa-
terfowl popula-
tions is tied directly to the status and abundance
of wetland habitats. Waterfowl populations
have reached record lows in recent years. Sim-
ply said, as wetlands go, so go waterfowl.


       Wetlands in the  Kesterson National
Wildlife Refuge in California's Central Valley
weredegradedafter being continuously flooded
with agricultural irrigation return flow waters
that contained high concentrations of selenium.
Large-mouth and striped bass and catfish dis-
appeared from Kesterson National Wildlife Ref-
uge in 1982. In the spring of 1983, eggs from
water birds at the site hatched less frequently
and had more deformities in the embryos. Cost
estimates for the refuge cleanup and restoration
of its wetlands now exceed $5 billion.
    Decline in Duck Populations: 1955 -1991
    Source Office of Migratory Bird Management Population
    ' ii mm i m Section, USFWS

      Based on a study comparing parts of the
Charles River in Massachusetts with and with-
                      out wetlands, it was
                      determined that the
                      loss of 8,422 acres of
                      wetlands within the
                      Charles River Basin
                      would have pro-
                      duced an annual
                      flood damage  of
                      over $17  million.
                      For this reason, the
                      US Army Corps of
                      Engineers elected to
                      preserve wetlands
                      rather than  con-
                      struct  extensive
                      flood control facili-
                      ties for this portion
                      of the Charles River
near Boston.


      Forested riparian (streamside) wetlands
play an important role in reducing nutrient
loading into water bodies such as the Chesa-
peake Bay. In one study, a riparian forest in a
predominantly agricultural watershed was
shown to remove approximately 80% of the
phosphorus and 89% of the nitrogen from the
water before entering a tributary of the Chesa-
peake Bay. Destruction of wetlands that reduce
the amount of nutrients entering the Bay would
lead to an increase of undesirable weed growth
and algae blooms.  When these algal blooms
decompose, large amounts of oxygen are used
up, depriving fish and other aquatic organisms
of the oxygen needed for survival. Algal blooms
are a major cause of fish kills.
     For more information, contact the EPA Wetlands Hotline at 1-800-832-7828
* contractor operated