52
THE COUNTY’S NATURAL ENVIRONMENT
PLANNING ISSUE
There are 2,600 structures
and various types of
infrastructure in county
floodplains that may be
subject to future damage. To
minimize future damage,
existing structures should be
removed or floodproofed and
future floodplain development
needs to be limited.
What’s New
•
The impact of flooding in Montgomery County has
been considerable over the past 30 years, resulting in
several fatalities, over $120 million in property losses,
and damage to key transportation and utility
infrastructure.
•
Floodplain maps, generally known as the Flood
Insurance Rate Maps (FIRMs), were updated in 2012
by the Federal Emergency Management Agency
(FEMA). These maps, available online, delineate
three zones: floodways which carry the bulk of the
floodwaters; areas with a 1% chance of being flooded
in a year; and floodplains with a 0.2% chance of being
inundated in a year.
•
All of the municipalities in the county have
developed floodplain ordinances to limit
development within floodplain areas. As a result of
newly adopted FIRMs for the county, each
municipality will be required to update their
floodplain regulations.
•
A model flood plain ordinance was prepared by the
Montgomery County Planning Commission.
Geology
Climate
Hydrology
Floodplains
Air Quality
Steep Slopes
Soils
Wetlands
Woodlands
Wildlife
Natural Areas Inventory
Floodplains
Floodplains include land bordering streams and rivers that
are inundated periodically. The characteristic soil and
vegetation of a floodplain are influenced by floods.
Protection of the floodway, the portion of the floodplain
closest to the water course, is critical since changes to it
could impede floodwaters, increasing the height and
destructive ability of floods. Protection of the remainder of
the floodplain is important to reduce injuries and property
loss. The regulated floodplain in the county is an area along
a stream or river with a 1% chance of being inundated in a
given year. This area comprises 21,311 acres, representing
about 7% of the county.
P
reserving floodplain areas in their natural state is the surest
way to prevent flood disasters, including fatalities and
property loss. Structures or improvements within the
floodplain will be flooded—it is just of a matter of when.
Flood elevated or flood proofed structures may reduce
property loss and reduce fatalities and injuries, but will not
address all of the impacts of a flood. With current
development in the county, it would be impossible to return
all floodplains to natural conditions. Now, over 2,600
structures exist in areas of the county that have a 1%
probability of being flooded in any given year.
Additionally, floodplains contain various infrastructure
which need to be located along streams and rivers.
Various hazard mitigation strategies to reduce flood impact
include flood warning systems, drainage system
management, land use management, building code
enforcement, the removal of flood prone structures, more
effective stormwater management, floodproofing and
elevation, floodplain management through ordinances,
developing flood control structures, natural resource
protection, and public information programs. Though there
are no federal laws preventing floodplain development,
municipalities can restrict floodplain development through
local floodplain ordinances. Montgomery County’s Hazard
Mitigation Plan Amendment 2012 identifies flooding as the
county’s most significant overall hazard.
Floodplains used for planning are those lands that have a 1%
annual chance of being inundated.
Flooding in the Port Indian community in West Norriton Township is a
common occurrence.
