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For many
years, the Fauquier County Zoning Ordinance has prohibited
development in floodplains and further required homes to be
set back 25 feet from the floodplain boundary. In all but
the RA and RC zones, the County also has allowed a developer
a 50% density credit transferable to his non-floodplain
lands. At issue, is the 50% credit. The proposed text
amendment would eliminate the transferred density credit in
all residential zoning districts.
It is important to note that his Ordinance has no impact on
allowed uses of land and this Ordinance will not affect a
lot which is otherwise buildable today; buildable lots are
grandfathered by § 2-403. Thus, for example, if the
Carberry’s (who spoke at the last public hearing) have 32
buildable lots platted, this amendment will not affect them.
Authority
for this action is found in the Virginia Code which allows
localities to regulate density and protect water quality and
further mandates that localities draw their Ordinances with
an eye toward preventing loss of life and property due to
floods.
On August
26, 2004, the Planning Commission voted to initiate the text
amendment and schedule a public hearing. On December 8,
2004, the Planning Commission held a public hearing on the
proposed text amendment and unanimously voted to forward the
text amendment to the Board of Supervisors with the
recommendation that it be adopted. On January 13, 2005, the
Board of Supervisors held a public hearing. With few
exceptions, there was wide public support for the proposal.
Nevertheless, the Board remanded this matter to the Planning
Commission for more investigation and community planning.
On January 27, 2005, the Planning Commission again initiated
a text amendment process and scheduled the public hearing
for March 31, 2005. Again, the Planning Commission
forwarded it to the Board of Supervisors with a unanimous
vote for adoption. The Board of Supervisors held a public
hearing on May 12, 2005. The public hearing was closed but
no action has been taken.
At issue is
a reduction of density - a cessation in the transfer of
density credits from unbuildable floodplains to adjacent
land. Less density usually means less impervious surface
and more vegetated land. The relationship between vegetated
land and water quantity and quality has been known for over
100 years.
In his first
Annual Message to Congress, President Theodore Roosevelt
observed:
The forests
are natural reservoirs. By restraining the streams in flood
and replenishing them in drought they make possible the use
of water otherwise wasted. They prevent the soil from
washing, and so protect the storage reservoirs from filling
up with silt. Forest conservation is therefore an essential
condition of water conservation.
With
increasing scientific sophistication, the value of
vegetation – not just trees – on water quantity and quality
increasingly is apparent. Indeed, the Chesapeake Bay
Preservation Act, adopted by the Virginia General Assembly
in 1988, is based entirely upon the precept that vegetative
buffers improve water quality. The Chesapeake Bay Local
Assistance Department (hereinafter “Bay Department”) has
developed a buffer manual that restates what Roosevelt told
the Congress 103 years ago:
The urbanization of
a watershed has several effects on the
hydrology of an
area. The development of an area alters the natural
drainage pattern as
roads and buildings are fit onto the landscape.
This also increases
the amount of impervious surface that then
amplifies the
quantity of stormwater runoff that is concentrated
before being
released into the existing drainage system. In addition
to augmenting the
runoff quantity, the concentration of water boosts
the speed at which
it travels, multiplying the scouring power in
surface streams and
rivers. Additionally, as most of the existing
natural vegetated
areas are denuded, local rises in the water table
can stress existing
deep-rooted trees.
The rapid transport
of water away from the land surface by
stormwater
conveyance systems reduces the amount of water that
seeps into the soil
and recharges the ground water system….The
recharging of the
ground water is important for maintaining wells
and supplying the
base flow waters that feed streams.
See also, Correll,
D.L., Buffer Zones and Water Quality Protection:
General Principles (1997)(“Most of the water flowing
down the channel of most streams reached the channel at some
point as ground water moving from a recharge area to the
stream.”) As noted on the Virginia Department of
Conservation and Recreation’s Stormwater Management Program
website: “Pervious surfaces, such as meadows and woodlands,
absorb and infiltrate rainfall hence generate little runoff.
Urban landscape typically covers such areas with impervious
surfaces, such as pavement and rooftops. These impervious
surfaces generate runoff every time it rains. (A typical
city block generates nine times more runoff than a woodland
area of the same size!) The quantity of runoff from these
areas quickly overwhelms natural channels and streams, often
causing channel erosion, localized flooding and property
damage.”
The Virginia
Department of Conservation and Recreation has a chart that
quantifies the relationship between runoff and impervious
surfaces. It is attached as Exhibit 2. Essentially it
shows what happens to ground recharge, evaporation and
transpiration, and runoff as the percentage of impervious
surfaces increase. As a general rule, natural groundcover
allows 10% runoff. A 10 to 20% impervious surface allows
20% runoff. With 35% to 50% impervious surface, we see 30%
runoff. Seventy five percent impervious surface yields
approximately 55% runoff.
Doug Morgan,
Fauquier County Senior Planner, spent years doing open space
calculations for single family housing in Stafford County.
Based upon his experience and training and his knowledge of
Fauquier County’s system, he estimates that the average,
conventional R-1 house in Fauquier County has a minimum lot
size of 40,000 square feet; the total amount of impervious
surface based on house, garage, sidewalk, and driveway for
the new construction is estimated less than 10% impervious.
He based this on a calculation of a 2,500 square foot house
with a 20’ x 20’ attached garage, 35’sidewalk, a 12’ x 50’
driveway, and a 10’ x 10’ shed on almost an acre lot. Using
the State’s graph, runoff doubles.
If you take
the same 40,000 square feet and re-zone it to R4, you then
have 4 times the amount of impervious surface on the same
amount of land, making the total roughly 40% (37.4%).
Runoff triples. The downstream riparian owners become the
recipients of this trebled runoff.
Culturally
accelerated runoff also alters stream patterns both up and
downstream of the point/area of entry, resulting in
adjustments to the configuration of the stream channel as it
seeks balance to accommodate this change. This will impact
existing erosion/deposition patterns with accompanying
changes to channel depth, width, and meander patterns.
Plants also
have a beneficial impact on water quality. Among other
things, they remove nutrients from stormwater. Nutrient
overloading in Virginia streams and rivers, as well as the
Chesapeake Bay, is a major problem.
However,
absorption is not the only way plants eliminate nutrients.
As noted by the Bay Department:
While an herbaceous
buffer can do significant good by
slowing surface
runoff and trapping sediment, the most significant
gains for removal
of nitrogen come from a mixed forested buffer of
woody plants. The
deep roots entering the ground water supply the
necessary carbon
and harbor bacteria in the soil for denitrification,
so nitrogen can be
permanently removed from the system. Much of
the nitrogen in a
system has entered the ground water quite a
distance away from
the surface waters. These underground aquifers
then slowly carry
the nitrogen and other contaminants to surface
waters. So, even in
an urban situation where most of the
stormwater from
adjacent properties is piped through a buffer, it still
has an important
role in pollutant removal. Woody vegetation in
these buffers can
be of significant value in removing ground water
contaminants before
they reach surface waters.
Stormwater
is also cleansed of sediments, nutrients, and toxics as a
result of particulate trapping within vegetated areas.
Correll, D.L., Buffer Zones and Water Quality Protection:
General Principles (1997).
Vegetation also retards the speed of rising streams. By
slowing current, sediments, themselves a pollutant, can
settle out and become deposited on the floodplain, rather
than fouling the water and stream bed. As noted by the Bay
Department, “When
suspended sediments settle to the bottom of the channel,
critical habitat for fish and other species may be degraded.
Benthic organisms can suffocate, depleting the food supply
for many fish, and reducing the abundance of filter-feeding
organisms that help clean the water. The turbidity also
prevents sufficient light from reaching submerged aquatic
vegetation (SAV) and benthic algae necessary as food for the
various forms of aquatic life.”
For water
quality improvement, Fauquier would ideally have wide
vegetated swaths adjacent to rivers and streams to slow and
absorb the stormwater and provide an opportunity for
percolation into the soil. As noted in the Chesapeake Bay
Local Assistant Department manual on riparian buffers: “Vegetated
riparian buffers are one of the most functionally beneficial
and biologically diverse systems….Benefits derived from
vegetated riparian buffers, especially forested buffers,
include water quality enhancement, stormwater and floodwater
management, stream bank and shoreline stabilization, water
temperature modification, wildlife habitat protection, and
absorption of airborne pollutants. These benefits can
translate into increased quality of life and real savings
for the community.”
However, one should
not become too dogmatic on the definition of buffers. The
Bay Board discusses them because they are part of their
regulatory scheme. However, all vegetated land provides
salutary benefits for stormwater quality. It is their
location and size that contributes in varying degrees to
efficiency. As subdivision occurs, the benefits of
vegetated lands are lost in piecemeal fashion. The
remaining vegetative land continues its salutary efforts
albeit with increased water to slow and more sediments and
pollutants to intercept. Alliance for the Chesapeake Bay,
Riparian Forest Buffers, Linking Land and Water (July
2004), at 9 (“Nevertheless, trees remain vital to urban
ecology. …Urban trees help reduce stormwater runoff and
encourage infiltration – intercepting falling rain,
absorbing and storing water, reducing runoff, protecting
soil from erosion, filtering pollutants, and improving air
quality.”)
Recognizing that each site is different, the Virginia
Department of Conservation nevertheless notes: “Studies
have shown that there is a significant impact on water
quality when 19% or more of a watershed is rendered
impervious….[T]his is roughly equivalent to one house for
every two acres.” DCR, Better Land Use Planning for
Coastal Virginia (November 2004).
At present,
the Commonwealth of Virginia has a Nutrient and Sediment
Reduction Strategy for the Potomac watershed, which a part
of Fauquier is in. “The …strategy…is born of the
realization that our actions on the land have a major impact
on the waters into which they drain.” Commonwealth of
Virginia, Chesapeake Bay Nutrient and Sediment Reduction
Tributary Strategy for the Shenandoah and Potomac River
Basins (April 2004) (Draft) (hereinafter “Strategy”), at 4.
The goal is to reduce pollutants from entering the waters of
the Commonwealth. The Strategy calls upon localities to
take actions to reduce non-point source pollution in their
land use decisions. The proposed text amendment is
consistent with this program to improve the Potomac River.
Virginia,
Pennsylvania, Maryland, the District of Columbia, and the
Federal Government are signatories to the Chesapeake Bay
Agreement. Pursuant to the Chesapeake Bay Agreement, the
Commonwealth of Virginia has committed to limiting sediments
and nutrients into the tributaries of the Bay by 2010.
Elimination of the floodplain credit is also consistent with
this commitment by the Commonwealth.
Because the
proposed text amendment is authorized by law and consistent
with the Commonwealth’s efforts to improve water quality and
the Chesapeake Bay, the text amendment is also consistent
with Article XI, Section 1 of the Virginia Constitution
where it is declared that the “Commonwealth's policy [is] to
protect its atmosphere, lands, and waters from pollution,
impairment, or destruction, for the benefit, enjoyment, and
general welfare of the people of the Commonwealth.”
It is
recommended that Section 2-308.4 of the Zoning Ordinance,
which addresses density calculations, be revised. The
proposed revision would affect density calculation in all
residential districts. Density calculations in the rural
districts (RA and RC) would not change and would continue to
have full density credit for land in floodplain.
The proposed
revision is:
2-308
[1-3 same]
4. In all other zoning
district categories, the maximum density shall be calculated
on the gross area of the lot except that:
A. Only fifty (50) percent
density allowance shall be calculated on that area of a lot
comprised of floodplain, quarries or existing water
bodies.
B. Only thirty (30) percent
density allowance shall be calculated on that area of a lot
comprised of slopes in excess of twenty-five (25) percent
grade.
C. Only fifty (50) percent
density allowance shall be calculated on that area of a lot
comprised of slopes in excess of fourteen (14) percent but
equal to or less than twenty-five (25) percent grade.
D. No density allowance
shall be calculated for any area of a lot in an existing
street right-of-way, floodplain, or quarry.
[5-7 same]
At the
Planning Commission’s previous public hearing, the question
was raised about the fairness of removing floodplain density
in residential districts but not from conservation and
agricultural districts; a lack of uniformity was suggested.
The
uniformity requirement is found in Virginia Code § 15.2-2282
(emphasis added): “All zoning regulations shall be uniform
for each class or kind of buildings and uses throughout each
district, but regulations in one district may differ from
those in other districts.”
For example,
there is no requirement in the law for the regulations in
Agriculture (RA) or Conservation (RC) zones to be the same
as a Residential (R-1) zone. The RA and RC zones are
designed in the Code and Comprehensive Plan to protect open
space, agriculture, silviculture, and conservation uses.
There is nothing discriminatory in having one set of
regulations for such purposes and another set of regulations
for concentrated residential development which is
principally in service districts.
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