EPA's Vessel General Permit and Small Vessel General

land-uses: rain that would normally infiltrate in forest, grassland and wetland soils falls on and
flows over impervious surfaces. That runoff is then channeled into storm sewers and released
directly into surface waters (rivers and streams), which changes the magnitude and variability of
water velocity and volume in those receiving waters.
Aquatic Nuisance Species
Aquatic nuisance species (ANS) are aquatic and terrestrial organisms, introduced into new
habitats throughout the United States and other areas of the world, that produce harmful impacts
on aquatic natural resources in these ecosystems and on the human use of these resources
(http://www.anstaskforce.gov). They are also referred to as invasive, alien, or nonindigenous
species. Introduction of these species is cited as a major threat to biodiversity, second only to
habitat loss (Wilcove et al. 1998). They have been implicated in the endangerment of 48% of the
species listed under ESA (Czech and Krausman 1997). In Hawai’i, 343 marine aquatic invasive
species have been documented. Over 250 nonindigenous species of invertebrates, algae, and
microorganisms have established themselves in the coastal marine ecosystems of California,
whose waters have been the subject of most in-depth analyses of aquatic invasions in the U.S.
More than 180 invaders have been detected and described in the Great Lakes, which are among
the best-studied freshwater systems in the world.
Climate Change
All species discussed in this Opinion are or will be threatened by the direct and indirect effects of
global climatic change. There is now widespread consensus within the scientific community that
atmospheric temperatures on earth are increasing (warming) and that these increases will
continue for at least the next several decades (IPCC 2001b). The Intergovernmental Panel on
Climate Change (IPCC) estimated that average global land and sea surface temperature has
increased by 0.6°C (± 0.2) since the mid-1800s, with most of the change occurring since 1976.
This temperature increase is greater than what would be expected given the range of natural
climatic variability recorded over the past 1,000 years (Crowley and Berner 2001). The IPCC
reviewed computer simulations of the effect of greenhouse gas emissions on observed climate
variations that have been recorded in the past and evaluated the influence of natural phenomena
such as solar and volcanic activity. Based on their review, the IPCC concluded that natural
phenomena are insufficient to explain the increasing trend in land and sea surface temperature,
and that atmospheric warming observed over the last 50 years is probably attributable to human
activities (IPCC 2001b). Climatic models estimate that global temperatures would increase
between 1.4 to 5.8°C from 1990 to 2100 if humans do nothing to reduce greenhouse gas
emissions from current levels (IPCC 2001b).
In the Northeast, annual average temperatures have increased by 2°F since 1970, with winter
temperatures increasing by up to 4°F (Karl et al. 2009). Over the same time interval, the
Northeast has experienced more days with temperatures greater than 90°F, a longer growing
season, increased heavy precipitation, more winter precipitation falling as rain than as snow,
reduced snowpack, earlier breakup of winter ice on lakes and rivers, earlier spring snowmelt
resulting in earlier peak river flows, rising sea surface temperatures and sea level.
Over the next several decades, the Northeast is expected to experience temperatures increases of
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