20100147 Ver 1_More Info Received_20100512

10- C)149
Evans, Mechwart, Hambleton & Tilton, Inc.
Engineers, Surveyors, Planners, Scientists
May 7, 2010 8
Ms. Emily Jernigan 14AY 1 0 2010
U.S. Army Corps of Engineers
Wilmington District - Washington Field Office DE'R-WATER G"JALITy
P.O. Box 1000 YVEXkND$ AW STOR;IIYrATER V MCFi
Washington, NC 27889-1000
Subject: The Province at Greenville Response to Public Comments - SAW-2010-00257
Dear Emily,
Below please find responses to public comments for The Province at Greenville permit application
located in the City of Greenville, Pitt County, North Carolina. The comments have been
summarized from the Pamlico-Tar River Foundation letter dated March 24, 2010 and three
scientific papers cited below.
Comment 1 - The applicant has failed to demonstrate the wetland impacts have been avoided
to the maximum extent practicable and that there are no other practicable alternatives available.
Response 1 - The applicant researched and examined many other sites prior to choosing the
current location for this project. The three factors needed to make this project viable included:
1) The site needed to be within walking distance of East Carolina University;
2) The site needed to be 12-15 acres or have other properties available that could be
assembled to meet the acreage needs;
3) The site needed to be priced within the budget.
Five total sites were considered; however, the current site was the only one that had all three
factors and will make the project viable. Two sites near Reade Circle and South Evans Street met
the distance requirements; however, did not have enough acreage or other available parcels and
were too expensive ($1 million per acre) to make the project viable. The middle school site at
South Elm Street and East 14th Street met the distance and acreage requirements; however it was
being sold for the cost of constructing a new middle school ($15 million), which did not fit within
the budget. The fourth site, near West 10th Street and South Washington Street was close
enough and priced appropriately; however, was located within the Historic Tobacco District in
which existing buildings cannot be demolished. Additionally, the site itself was too small, and no
adjoining properties were available. As a result, the West 10th Street site did not meet the
requirements for the project. The fifth site considered is the current location, which was close
enough, priced appropriately, and had adjoining parcels available to assemble the required
acreage. Additionally, multifamily-residential zoning already exists at the site and the project is
supported by the City of Greenville and East Carolina University. Seven parcels were combined
to create the current site. All of the other adjoining property owners were contacted in hopes that
more parcels could be acquired to lessen/avoid wetland impacts; however, a deal could not be
struck for any additional property adjoining the current site. Some parcels were priced out of the
budget, others were not for sale, and others had tenants in rental contracts past the date
demolition needs to start. The additional small properties to the west that were acquired have
allowed the entire site plan to be shifted to the west, there by lessening wetland impacts.
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U.S. Army Corps of Engineers May 7, 2010
The Province at Greenville - Response to Public Comments
Wetland impacts were avoided and minimized to the greatest extent practicable while designing
the project through multiple strategies. The resourceful site layout accomplishes minimized
wetland impacts without lowering the economic feasibility of the site. The efficient, square with
an open center building design allows for four buildings to be connected, which results in a
reduced footprint without lowering the square footage available for living space. The open
center/courtyard of the buildings also allows the layout to save land space by moving the
recreation areas to the center of the buildings, rather than taking up other property.
Parking has also been efficiently designed by including compact car only areas and areas that
allow roommates to double park/park each other in. Shifting parking into buffer areas was
examined to lessen wetland impacts; however, the floodway of Green Mill Run extends through
buffer. Placing parking within the buffer would cause more impacts to the floodway and
floodplain, therefore the idea was not carried through. The number of parking spaces in this off-
campus student housing development has been reduced from the developer's preferred 1 space
per resident to 0.86 spaces per resident. As stated in the comments dated February 2010 from
the City of Greenville and North Carolina Department of Transportation (NCDOT) after their
review of the preliminary development plans, "The provisions of 0.75 parking stall per bed is un-
realistically low. Suggest parking of 1 per bed plus visitor spaces." The proposed 0.86 spaces
per resident design has split the difference between the City of Greenville code of 0.75 spaces
per resident and the developer and NCDOT request of 1:1.
To further reduce wetland impacts, a 0.61 acre levy along the eastern bank of Green Mill Run is
being removed to decrease the amount of wetland excavation needed to bring the site out of the
Green Mill Run floodplain. The excavation is necessary to bring the site out of the 100 year
floodplain and floodway, which will result in improvements to the downstream water quality by
removing a significant portion of the site, including a section of the parking lot, trash bins,
buildings, and cars, from the floodplain/floodwaters of Green Mill Run. This will remove trash,
debris, oils, and other fluids from the water as well as cease structural damage from occurring to
the buildings. (See Comment 4 for a more detailed discussion on the Green Mill Run floodplain.)
Another impact reducing feature is the 400 foot long retaining wall that has been designed for
the northeastern boundary of the development. This $300,000 wall decreases grading and
buffer impacts by approximately 30-40 feet (0.14 acre) along the entire length of proposed
wall to slope from the parking lot elevation of 33 feet (outside the floodplain) down to the buffer
and stream at 23 feet (within the floodplain and floodway). If the wall were not used, the
grading activities would increase buffer impacts and floodplain/floodway impacts, which would
cause at least 0.14 acre more wetland excavation. To comply with Americans with Disabilities Act
(ADA) requirements for connections to the existing roadways and sidewalks around the site, the
main elevation of the site needs to be maintained at 33 feet.
Comment 2 - We believe that the proposed fill and excavation of the onsite wetlands will
remove or degrade some of the existing uses of the wetland including:
a. Storm and flood water storage and retention and the moderation of extreme water level
fluctuations,
b. Groundwater recharge,
c. Filtration of storage of sediments, nutrients, toxic substances, or other pollutants,
d. Habitat for the propagation of resident wetland-dependent aquatic organisms,
e. Habitat for the propagation of resident wetland-dependent wildlife species
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U.S. Army Corps of Engineers May 7, 2010
The Province at Greenville - Response to Public Comments
Response 2 - The project proposes fill and excavation of the onsite wetlands; however, it is not
believed that the actions will remove or degrade some of the existing wetland uses as described
below:
a. The project will not substantially alter the ability of the wetland to assist in the moderation
of extreme water fluctuations. A portion of the water storage capacity lost by the
proposed 0.44 acre wetland fill will be replaced by the excavation of the 0.61 acre levy
along the stream and by the proposed 0.50 acre excavation within the wetland. Although
the 0.85 acre stormwater wetland is not being built for mitigation, it will also help to
moderate extreme water level fluctuations and provide added water storage capacity
and retention. More information on the storm and flood water storage and retention is
discussed below in Response 3.
b. The current amount of groundwater recharge provided by the wetland is unknown,
however, there will only be a net loss of approximately 0.44 acre of wetland on the site.
The 0.85 acre stormwater wetland (although not being created for mitigation) and 0.61
acre of levy removal will help to lessen the amount of groundwater recharge lost by the
wetland fill.
c. After construction, the undisturbed 1.53 acres of wetland, wetland excavation areas, 0.85
acre constructed stormwater wetland (not mitigation for wetland impacts), and levy
removal area will all be near the same elevation of 25 feet above sea level. After
construction, the latter three areas have the potential to return and/or become wetland
habitat. The removal of the levy will ensure that the area receives water from the stream
and stays wet, which will reinforce the establishment of wetland plant species. The natural
movement of the plants from the existing wetland and post construction plantings will
facilitate the reestablishment of wetland habitat in the 25 foot elevation areas. Although
exact numbers are not available, these new areas will provide filtration and storage of
sediments, nutrients, toxic substances, or other pollutants that are currently being provided
by the existing wetland.
d. Habitat for the propagation of resident wetland-dependent aquatic organisms will be
supported by the areas discussed in Response 2c. There are no documented rare,
threatened, or endangered species for this area.
e. Habitat for the propagation of resident wetland-dependent wildlife species will be
supported by the areas discussed in Response 2c. There are no documented rare,
threatened, or endangered species for this area.
Comment 3 - The proposed project will cause a loss of floodplain storage and increase the
impervious surface on the site which will further degrade the stream system and cause potential
impacts to downstream property owners.
Response 3 - The Province at Greenville project includes fill of both floodplain fringe and
floodway to raise the site out of the floodplain and floodway. To do this, a permit is required
from the City of Greenville, the State of North Carolina Department of Emergency Management
(NCDEM), and Federal Emergency Management Agency (FEMA). To mitigate for the fill, the levy
along the western bank of Green Mill Run will be removed to restore connection of the stream to
its floodplain. Excavation will include removal of 0.5 to 2 feet of soil, depending on levy height,
from the approximately 0.61 acre levy, which not only restores the stream connection to the
floodplain in that area, but also minimizes wetland impacts. Additionally, 0.50 acre of existing
wetland will be excavated an average of 2 feet, depending on existing elevation and the
proposed elevations after construction. Without the fill, wetland excavation, and levy removal, a
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U.S. Army Corps of Engineers May 7, 2010
The Province at Greenville - Response to Public Comments
large portion of the site would remain in the floodplain and floodway, which would render the
project unviable.
The detailed hydraulic study, which has already been completed, shows that after the site has
been constructed as proposed, the increase in floodplain elevation caused by the fill and
excavation will only be 0.27 feet (3.24 inches) maximum within the project area. The increase
dissipates to 0.25 feet (3 inches) at the 14th Street Bridge and continues to decrease south of 14th
Street. There are no increases in floodplain elevation downstream of the project. The study also
shows that after the site has been constructed, the increase in floodway elevation caused by the
fill and excavation will only be 0.04 feet (0.48 inches) maximum within the project area. The
increase dissipates to 0.00 feet (0 inches) downstream of the 141h Street Bridge.
The project will increase impervious area on the site by 14%; however, the stormwater from the
existing 46% impervious areas currently flows into Green Mill Run without treatment for water
quality and without limitations on the amount of water flowing into the stream during storm
events. The proposed project is obligated to meet all of the requirements of the Tar-Pamlico
Stormwater Rule, which requires a 30% reduction in nitrogen loading, no increase in phosphorus
loading, 85% Total Suspended Solids (TSS) removal, and peak stormwater flow from the site to
remain equal or less than current conditions. A constructed stormwater 0.85 acre wetland (not
mitigation for the wetland impacts) is proposed to treat the runoff for water quality and limit the
amount released into the stream. The wetland will ensure that the reduction in nutrient levels and
removal of TSS will occur before the water is discharged to Green Mill Run. In addition to the
nutrient removal, the wetland will limit the amount of water allowed into Green Mill Run during
and after storm events. By slowing down and limiting the amount of water being discharged into
the stream, flood elevations and erosion downstream may be lowered. This treatment and
limitation on water release rates will not only be provided for The Province site, but also for the
stormwater generated from adjacent properties that flows through the site and into the stream.
When all these stormwater treatment and retention factors are combined, it is our opinion that the
proposed development will improve water quality and the downstream system compared to the
existing site.
Comment 4 - If the purpose of the wetland fill, cut, and stream bank excavation is to allow for
additional stormwater treatment, the use of wetlands as treatment systems is prohibited, as stated
in the 11/19/07 U.S. Environmental Protection Agency (USEPA) letter.
Response 4 - No area of stream bank excavation is proposed and no impacts will occur below
the Ordinary High Water Mark of Green Mill Run. A 0.61 acre levy along the eastern stream
bank is proposed to be excavated for flood storage, along with 0.50 acre of wetland, and are
both discussed in detail within Response 3.
Wetland fill of 0.44 acre will increase the usable space on the site and will be mitigated for by
payment into the Ecosystem Enhancement Program (EEP) In-Lieu Fee Program, along with the 0.50
acre of wetland excavation. Once the existing wetland has been impacted by fill and mitigated
for, a 0.85 acre engineered stormwater wetland (not a mitigation wetland) will be constructed for
treatment of stormwater on the site. The constructed wetland will not connect to the existing
wetland, but will have an outlet directly into Green Mill Run in compliance with the Tar-Pamlico
Stormwater Rule. The existing wetland, considered a water of the U.S., will not be used for
stormwater treatment. The constructed stormwater wetland, not considered a water of the U.S.,
will only be used for stormwater treatment and will not be used as mitigation for wetland impacts.
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U.S. Army Corps of Engineers May 7, 2010
The Province at Greenville - Response to Public Comments
Mitigation for the total 0.94 acre of wetland impact will be handled through payment into the
EEP In-Lieu Fee Program
Comment 5 - While we recognize the importance of reconnecting stream systems to their
floodplains, the 400-450 feet of stream bank cut, along with riparian wetland fill with no
additional stormwater control measures proposed on-site or upstream will not provide an overall
environmental benefit.
Response 5 - The proposed project is obligated to meet all of the requirements of the Tar-
Pamlico Stormwater Rule. To do this, a constructed stormwater wetland (not mitigation for the
wetland impacts) is proposed to treat the runoff for water quality and limit the amount released
into the stream, which is discussed in detail in Response 3. This treatment and limitation on water
release rates will not only be provided for The Province site, but also for the stormwater
generated from adjacent properties that flows through the site and into the stream. When all
these stormwater treatment and retention factors are combined, it is our opinion that the
proposed development will improve water quality and the downstream system. Other
environmental benefits are discussed in Response 2.
Comment 6 -The resulting mitigation will most likely occur outside the Green Mill Run Watershed
Response 6 - The wetland mitigation will be handled through payment into the EEP In-Lieu Fee
Program and because of this, the exact location of the mitigation wetland is not known. Based on
site constraints, onsite mitigation would make the project unviable and was therefore not
proposed. A local mitigation bank was the first choice researched; however, there are no
operating banks within the watershed. If a mitigation bank were available in the regional or
local watershed, it would have been used.
Comment 7 - Stream Channel Enlargement Response to Urban Land Cover in Small Coastal Palin
Watersheds, North Carolina. Lecce, Saban, O'Driscoll. 2009. The study says that:
a. Greater watershed impervious area resulted in greater bankfull discharges,
b. Channel incision in low order streams is a response to urbanization,
c. Urban streams contained significantly more gravel and less sand than rural channels,
d. Urban channel incision reduced the interactions between urban streams and riparian
vegetation.
e. The urban incision response has resulted in streams being cut off from their floodplains,
reducing the sediment-trapping and water quality functions of floodplains.
Response 7 - The Province project is within an existing urban environment and is a
redevelopment project that will demolish current structures and pavement to construct a new
residential complex.
a. The project will increase impervious area on the site by 14%; however, will be in
compliance with Tar-Pamlico Stormwater Rule, which requires control of the peak
stormwater flow from the site to remain equal or less than current conditions. By
implementing these controls, the bankfull discharge should not increase due to the
proposed project. More information on stormwater is in included under Response 3.
b. Green Mill Creek is a 3rd order urban stream that does not appear to be incised on the
site. The stream is currently and will continue to be connected to its floodplain and
floodway now and after the proposed development is constructed. The removal of the
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U.S. Army Corps of Engineers May 7, 2010
The Province at Greenville - Response to Public Comments
0.61 acre levy proposed by the project will increase the connection of the stream to its
floodplain and lessen any incision that may be present.
c. The stream substrate will not be impacted by the proposed development.
d. The stream currently floods out of its banks and interacts with the riparian vegetation. The
removal of the 0.61 acre levy proposed by the project will increase the connection of the
stream to its riparian vegetation. The stream will continue to overtop its banks once
construction of the new development is completed.
e. The stream is currently, and will continue to be connected to its floodplain and floodway
after the project is constructed. The removal of the 0.61 acre levy proposed by the
project will increase the connection of the stream to its floodplain. The proposed project
will not impact the sediment-trapping or water quality functions of the floodplains.
Comment 8 - Urban Land Use, Channel Incision, and Water Table Decline Along Coastal Plain
Streams, North Carolina. Hardison, O'Driscoll, DeLoatch, Howard, Brinson. 2009. The study says
that:
a. Urban streams generally displayed higher peak flows, lower base flows, and decreased
lag times compared with the more rural systems.
b. Channels that drained watersheds with greater degrees of imperviousness were more
incised.
c. Urban streams showed greater groundwater depths, greater annual range in ground-
water depth, and a distinct summer low and winter/spring high period, which was
subdued for the rural systems.
d. Stream riparian zones are drying in response to incision and related upstream urban land
use.
e. The overbank flooding is highly reduced along incised urban channels, which can reduce
the extent of the floodplain surface and the residence time of floodwaters in the riparian
zones more than other settings where floodplain widths then to be smaller and overbank
events less frequent.
Response 8 - The Province project is within an existing urban environment and is a
redevelopment project that will demolish current structures and pavement to construct new.
a. The project will be in compliance with Tar-Pamlico Stormwater Rule, which requires control
of the peak stormwater flow from the site to remain equal or less than current conditions.
By implementing these controls, the peak flows, base flows and lag times will not increase
due to the proposed project. More information on stormwater is in included under
Response 3.
b. The total impervious area within the watershed is not known; however the project will only
increase impervious area on the site by 14%. To ensure compliance with Tar-Pamlico
Stormwater Rule, the peak stormwater flow from the site will remain equal or less than
current conditions, thereby not increasing the amount of stormwater from impervious
surfaces reaching the stream. More information on stormwater is in included under
Response 3. The stream is currently and will continue to be connected to its floodplain and
floodway now and after the proposed development. The removal of the 0.61 acre levy
proposed by the project will increase the connection of the stream to its floodplain. By
implementing these measures the proposed project should not promote the stream to
become incised.
c. The current amount of groundwater recharge provided by the site is unknown; however,
there will only be a net loss of approximately 0.44 acre of wetland on the site. The 0.85
acre stormwater wetland (although not being created for mitigation) and 0.61 acre of
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U.S. Army Corps of Engineers May 7, 2010
The Province at Greenville - Response to Public Comments
levy removal will help to lessen the amount of groundwater recharge lost by the
redevelopment of the site and wetland fill. After construction, the undisturbed 1.53 acres
of wetland, wetland excavation areas, and levy removal area will all have the potential
to return and/or become wetland habitat and assist with groundwater recharge. The
0.85 acre stormwater wetland will also assist with groundwater recharge.
d. After construction, the undisturbed 1.53 acres of wetland, wetland excavation areas, and
levy removal area have the potential to return and/or become wetland habitat. The
removal of the levy will ensure that the area receives water from the stream and stays
wet and will also reinforce the establishment of wetland plant species. The floodplain on
this urban site is anticipated to remain wet.
e. The stream is currently and will continue to be connected to its floodplain and floodway
now and after the proposed development. The removal of the 0.61 acre levy proposed
by the project will increase the connection of the stream to its floodplain. The undisturbed
1.53 acres of wetland, wetland excavation areas, and levy removal area have the
potential to return and/or become wetland habitat, which should not change the residence
time of floodwaters in the riparian zone from the current conditions on the site.
Comment 9 - Effects of Urbanization on the Ecological Condition of Small Streams in the Inner
Coastal Plain of North Carolina. Hardison, Brinson. 2008. The study says that:
a. Urban streams in this region display dramatic increases in stormwater runoff, lower
baseflows, and decreased channel densities, which is related to the degree of watershed
imperviousness.
b. Floodplains in urban areas were drier than less urbanized floodplains.
c. The lower water tables observed in urban areas results from a combination of channel
incision that drains adjacent riparian zones and decreased infiltration within urban areas.
d. Total suspended sediments, water temperature, and ammonium in streams increase with an
increase in total impervious area.
e. Urban stream systems are heterogeneous and highly variable with regard to nutrient and
sediment sources and vegetation cover.
Response 9 - The Province project is within an existing urban environment and is a
redevelopment project that will demolish current structures and pavement to construct new.
a. The project will increase impervious area on the site by 14%; however, will be in
compliance with Tar-Pamlico Stormwater Rule, which requires control of the peak
stormwater flow from the site to remain equal or less than current conditions. By
implementing these controls, the stormwater runoff, baseflow levels, and channel densities
should not altered due to the proposed project. More information on stormwater is
included under Response 3.
b. After construction, the undisturbed 1.53 acres of wetland, wetland excavation areas, and
levy removal area have the potential to return and/or become wetland habitat. The
removal of the levy will ensure that the area receives water from the stream and stays
wet and will also reinforce the establishment of wetland plant species. The floodplain on
this urban site is anticipated to remain wet.
c. The current amount of water infiltration provided by the site is unknown, however, there
will only be a net loss of approximately 0.44 acre of wetland on the site. The 0.85 acre
stormwater wetland (although not being created for mitigation) and 0.61 acre of levy
removal will help to lessen the amount of groundwater recharge lost by the
redevelopment of the site and wetland fill. After construction, the undisturbed 1.53 acres
of wetland, wetland excavation areas, and levy removal area will all have the potential
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U.S. Army Corps of Engineers May 7, 2010
The Province at Greenville - Response to Public Comments
to return and/or become wetland habitat and assist with groundwater recharge. As
explained in Response 9b, the floodplain on this urban site is anticipated to remain wet
and connected with the stream after the proposed development.
d. The project will increase impervious area on the site by 14%; however, will be in
compliance with Tar-Pamlico Stormwater Rule, which requires a 30% reduction in nitrogen
loading, no increase in phosphorus loading, 85% Total Suspended Solids (TSS) removal
and that peak stormwater flows from the site will remain equal or less than current
conditions, thereby not increasing the amount of stormwater from impervious surfaces
reaching the stream. A 0.85 acre constructed stormwater wetland (not mitigation for the
wetland impacts) is proposed to treat the runoff for water quality and limit the amount
released into the stream. The wetland will ensure that the reduction in nutrient levels,
including ammonium, removal of TSS, and reduction in water temperature will occur before
the water is discharged to Green Mill Run. This treatment and limitation on water release
rates will not only be provided for The Province site, but also for the stormwater
generated from adjacent properties that flows through the site and into the stream. When
all these stormwater treatment and retention factors are combined, it is our opinion that
the proposed development will improve water quality and the downstream system. More
information on stormwater is in included under Response 3.
e. The nutrient and sediment sources on the site will be remain equal or less than current
conditions after treatment by the stormwater wetland (no mitigation for the wetland
impacts) More information on stormwater is in included under Response 3 and Response
9d. The majority of the vegetation cover along the stream on the site is forested and will
not be disturbed during construction. Areas that will be disturbed will be replanted with
native species.
If you have any questions regarding the application or comment responses, please feel free to
contact me at 614-775-4515.
Sincerely,
EMH&T
c
!p r
Robert F. Milligan
Director, Environmental Department
Copies: Ian McMillan, NCDENR
Dave Tyndall, Edwards Communities Development Company
Chris Mann, EMH&T
Doug Turney, EMH&T
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