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Q:
WHAT IS A WATERSHED?
A:
Watersheds are nature's boundaries. They are the areas that drain
to water bodies, including lakes, rivers, estuaries, wetlands, streams,
and the surrounding landscape. Ground water recharge areas are also
considered.
Q:
WHAT WATERSHED DO I LIVE IN?
A: http://www.epa.gov/surf
Q:
WHAT IS THE "100-YEAR FLOOD"?
A:
The term "100-year flood" is misleading. It is not the flood that
will occur every 100 years. Rather, it is the flood that has a one
percent chance in a hundred of occurring each year. Thus, the 100-year
flood could occur more than once in a relatively short period of
time. In fact, it's possible for two, 100-year floods to occur in
the same week. The 100-year flood which is the standard used by
most Federal and State agencies, is used by the National Flood Insurance
Program as the standard for floodplain management and to determine
the need for flood insurance. http://www.fema.gov/nfip/readmap.htm
Q:
WHAT IS THE "500-YEAR FLOOD"?
A: The 500-year flood, like the 100-year flood is misleading.
The 500-year flood is not the flood that will occur every 500 years,
instead, it is the flood that has a .2% chance of occurring each
year. The 500-year flood, which is the standard used by most Federal
and state agencies, is used by the National Flood Insurance Program
as the standard for floodplain management and to determine the need
for flood insurance.
Flood Hazard
Mapping (http://www.fema.gov/mit/tsd/)
Q.WHAT
IS POTABLE WATER?
A:
Potable water is fresh and marginal water generally considered suitable
for human consumption.
Q:
WHAT IS OVERLAND FLOODING?
A:
A flood is the inundation of a normally dry area caused by high
flow, or overflow of water in an established watercourse, such as
a river, stream, or drainage ditch; or ponding of water at or near
the point where the rain fell. This is a duration type event with
a slower onset than flash flooding, normally greater than 6 hours.
Stormwater runoff, or overland flow, is one method of rainwater
flowing to streams or rivers. Heavy rains and rapid snowmelt can
increase this flow and can result in flooding, channel erosion and
silt buildup in waterways.
Q:
WHY DOES THE RED RIVER FLOOD?
A:
The Red River Valley was created as a lake plain, not a river valley,
according to geologists for the North Dakota Geological Survey.
It formed as the floor of Glacial Lake Agassiz about 10,000 years
ago, which is why the area is so flat. The flatness tends to exacerbate
flooding since there is only a very shallow gradient to promote
runoff of snowmelt and precipitation, slowing drainage. When a North
Dakota river overflows its banks, there is no topography to constrain
floodwaters, which may spread out over a very wide area, increasing
damage. Following the Ice Age, fine-grain sediment deposited on
the bottoms of lakes left behind by the retreating ice. This sediment
now covers much of today's Red River Valley. This sediment is relatively
impermeable to water, so runoff or precipitation doesn't soak in
very quickly. As a result, water ponds up and/or flows into the
rivers and streams, adding to flood magnitude. With an existing
high soil-moisture content, this effect is magnified.
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