United States : n ,
Environmental Rrote'd tion
Agency i;
EPA832-R-93-QQ5i
September 1993
Wetland Treatment Systems;
A Case History i
The Orlando Easterly Wetlands
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A CASE HISTORY:
ORLANDO EASTERLY WETLANDS RECLAMATION PROJECT
Introduction
Wetlands have been the victim
of progress in America.
Research indicates that less
than half of the 215 million acres of
wetlands originally present in the
United States prior to settlement
remained by the mid 1970s. Much of
this loss is due to the conversion of
wetland areas into farmland.
Today, wetlands are recognized as
a valuable natural resource. They
help maintain the quality of our
environment; provide habitat for a
variety of plants and animals, including
rare and endangered species; and offer
a number of socio-economic benefits,
ranging from flood protection to
recreation opportunities.
The critical role which wetlands can
play in reclaiming valuable freshwater
resources is also recognized. Unlike the
technology of the late 1960s and 1970s,
which focused on the disposal of
wastewater effluents as quickly and
efficiently as possible (usually through
discharge into streams, lakes, or
oceans), wetlands treatment technology
involves passing wastewater effluent or
stormwater runoff through a wetland
system. By acting as a natural filter for
the pollutants that remain even in
advanced treated wastewater effluent,
wetland systems can polish the effluent
so that it can be safely returned to fresh
water sources.
One of the largest constructed
wetland treatment systems built to date
is the Orlando Easterly Wetlands
Reclamation Project. Post, Buckley,
Schuh & Jernigan, Inc. (PBS&J) served
IfallMNiiMhji*!^
as design engineers for the City of
Orlando, Florida. Background issues,
special considerations, and performance
results from this award-winning facility
are discussed next.
In operation since 1987, the
Orlando Easterly Wetlands
Reclamation Project has
demonstrated its success as
a treatment facility, reuse
project, and wildlife habitat.
Iron Bridge
Regional Water
Pollution Control
Facility
Orlando Easterly
Wetlands Project
Project Location
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PROJECT BACKGROUND
The Little Econlockhatchee (Little
Econ) is a primary tributary to
the Econlockhatchee River
(Econ), which in turn is a primary
tributary to the St. Johns River (SIR).
The SJR system drains portions of the
middle and upper east coast of Florida
to the Atlantic Ocean. Over the years,
much of the floodplain around both
the SJR and the Econ system has been
altered by drainage systems and subse-
quently converted to grazing lands for
cattle. By 1980,16 wastewater treatment
plants (WWTPs) in the eastern Orange
County area, discharged either primary
or secondary effluent to the Little Econ.
The effects of these WWTP dis-
charges on the Little Econ included
decreased dissolved oxygen levels and
the occurrence of Eichhornia crassipes
(water hyacinth), Hydrilla verticillata,
Najas guadalupensis, the duckweeds,
and Panicum spp. which at times com-
pletely covered sections of the channel
in the Econ system, and also contributed
to frequent algae blooms in Lake
Harney, a node within the SJR. (Located
about one mile downstream of the
confluence with the Econ, Lake Harney
serves as a key indicator of water quality
conditions in the Econ watershed.)
As part of a commitment to improve
water quality conditions in the Little
Econ, the City of Orlando began
construction of an advanced wastewater
treatment (AWT) plant which would
replace a number of the existing pack-
age plants. By 1980, Phase I of the
Iron Bridge Regional Water. Pollution
Control Facility (WPCF) was underway.
Permit regulations
imposed on the Iron
Bridge WPCF by the
U.S. Environmental Protection Agency
(USEPA) and the Florida Department
of Environmental Protection (FDEP)
were very stringent. Limitations for
both effluent concentrations and load-
ings were based on the Phase I flow rate
of 24 MOD. This meant that the
capacity of future expansions to
the treatment plant would be
severely limited by the allowable
effluent loading criteria in the
USEPA National Pollutant
Discharge Elimination System
(NPDES) and FDEP permits, or
the City would have to find an
alternative discharge point.
Faced with a growing popula-
tion and the need for additional waste-
water treatment capacity, the City sought
alternative effluent disposal options.
An analysis of potential options was
completed in 1984. T'he overall scope
of the study included an investigation
' of such disposal options as deep well
and aquifer injection, spray irrigation,
moving the discharge point to another
sub-basin of the SJR system, water
hyacinth treatment, and both natural
and constructed wetlands treatment.
The conclusions of this study ranked
the construction of a wetland for
effluent disposal adjacent to the flood-
plain of the SJR as the number one
alternative. Selection criteria included
economics, restoration of previously
lost wetlands, and creation of a wild-
life habitat.
The Orlando 'Easterly
Wetlands was constructed on
pasture land in an area which
had been a natural wetland
prior to human settlement
and cattle grazing.
Iron Bridge WPCF
Original Permit Conditions
BOD5
TSS
TN
TP
5 mg/L
5 mg/L
3 mg/L
1 mg/L
(1001 Ib/d)
(1001lb/d)
(600 Ib/d)
(200 Ib/d)
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SITING CONSIDERATIONS
Critical to the successful design of
the City's wetland system was
the selection of an appropriate
location. The site selected was about
1,640 acres in size and located about
two miles west of the main channel of
thb SJR. Review of historical data,
including surveys conducted in the late
1850s, indicated that much of the site
was previously part of the wetland
system adjacent to the SJR. An elab-
orate series of ditches had been used
to drain the site when it was converted
to pastureland shortly after the turn of
the century. Since this conversion, it
had been operated as a cattle ranch.
Using this site meant that more than
1,200 acres of land would be restored
to its natural wetland state.
Soil characteristics were another
important consideration in site location.
The surficial soils at the City's wetland
system are generally fine sands under-
lain by clayey soils. The depth of the
clayey soils range from the surface to
several feet below the soil surface,
and tend to restrict water movement
downward to the groundwater.
A hydraulic gradient that exists
across the site directs groundwater flows
toward the east, away from residential
wells located west of the site.
At the time the City acquired the
site, most of the on-site surface waters
were routed to a main canal that
drained to a backwater area of the SJR.
The course of the main canal bisected a
natural wetland owned by the St. Johns
River Water Management District
(SJRWMD) known as Seminole Ranch.
This canal formed part of a stormwater
management system on the SJRWMD
land that altered the natural wetland
such that transitional and upland
vegetation were invading the site.
By using the discharge waters from
the City's wetland treatment system,
wetland hydrology on about 600 acres
of the Seminole Ranch is being
restored. Today, the water discharged
from the City's wetland moves by sheet
flow through Seminole Ranch prior to
discharge into the SJR.
Existing topography was also a key
consideration in selecting the project
site. With a topographic gradient of
about 15 feet across the site, the land
slopes downward from the west to the
east. The wetland design used this
gradient to divide the site into seven-
teen cells such that the average drop
in elevation across each cell was limited
to approximately three feet. This allows
each treatment cell within the wetland
system to be operated at dry season
and wet season water depths that could
range from sheet flow to a maximum
depth of three to five feet.
Berms divide the 1,220-acre
wetland system into treatment
cells which provide additional
nutrient removal to treated
effluent passing through the site.
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PERMITTING
CONSIDERATIONS
WILDLIFE
CONSIDERATIONS
Factuating water levels are critical
:or the maintenance of desired
plant communities within wetland
treatment systems. The primary objective
in designing the City's system was to use
macrophytic communities to facilitate
additional nutrient removal for up to
20 mgd of treated effluent from the Iron
Bridge WPCF. The original permit issued
by FDEP limited flow to 8 mgd, due in
part to the untested nature of the system.
Flow increases of about 3 to 5 mgd to a
maximum of 20 mgd are being permitted
by FDEP as the system demonstrates its
ability to operate successfully at each
increase. The current system is operating
at a flow rate of 13 mgd, and the City
has received approval from FDEP to
increase flow to 16 mgd.
FDEP and USEPA did not allow the
City to use existing permit conditions
or wasteload allocations as the basis
for nutrient limitations of the wetland
discharge. This situation was largely due
to the continued degradation of water
quality conditions in Lake Harney. The
USEPA NPDES and FDEP permits
require that the wetlands' discharge
meets existing background water quality
conditions in nearby natural wetlands as
well as complies with the loadings estab-
lished under the wasteload allocation
for discharges to the Little Econ.
The City conducted a 2.5-year water
quality study in conjunction with the
SJRWMD and FDEP to estimate the
nitrogen and phosphorus limits for
the wetland's operating permits. The
nitrogen and phosphorus permit limits
generated by this study are 2.31 mg/L
and 0.2 mg/L, respectively.
A secondary objective of the
Orlando Easterly Wetlands
project was the creation of a
wildlife habitat. During the conceptual
design phase, the wildlife management
area was thought of as a function of
the wetland treatment process rather
than as a specific plan for specific
wildlife species. However, as permitting
and design proceeded, wildlife issues
shifted from simple descriptions of
potential species occurrences in the
general area of the wetland to the design
of specific habitat types. This inclusion
of areas designed as a wildlife habitat
within the City's wetland system allows
the project to serve as a valuable wildlife
refuge and opens up the site for other
uses in addition to wastewater treatment
and disposal.
Anhingas and other bird
species find the Orlando
Easterly Wetlands to be a safe
haven for raising their young.
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DEVELOPING THE WETLANDS
Approximately 1,220 acres of the
project site were developed into
the Orlando Easterly Wetlands
project. The system is divided into
seventeen cells oriented across the site
so that the first twelve cells comprise
about one-third of the total project area.
The mixed marsh includes three cells
that also comprise about one-third of
the total area. The remaining two cells
form the hardwood swamp. The cells
were defined by constructing a series of
earthen berms and were planted using
about 2.1 million aquatic wetland plants.
Vegetation originally planted in the
wetland are shown in Figure 2.
All fill material used to
construct the berms was
excavated from a borrow pit
(shown as the lake in Figure
1) located in the eastern part
of the site. The habitat poten-
tial of the lake is enhanced by
the use of an irregular shore-
line, the varied slope of the
littoral zone, the varied water
depths (e.g., the rim ditch
used to de-water the site was
left in place and now averages
up to 45 feet deep), and the
placement of construction
debris within the lake for
fisheries habitat.
The system began opera-
tion in September 1987. AWT
effluent is pumped about
17 miles from the Iron Bridge
WPCF to a three-way splitter
box at the wetland system,
after which the water flows
by gravity to the outfall structure.
Rectangular weir structures are used
to control the flow internally; two-inch
flash boards are removed or inserted
as needed. The berm design includes a
three-foot freeboard capacity for storage
of stormwater inputs. This design allows
the operators to control the flows into
and out of any given cell without influ-
encing the operation of the remaining
areas of the wetland treatment system.
The average travel time through the
Orlando Easterly Wetlands varies from
about 21 days during the dry season to
about 65 days during the rainy season.
Figure 1
N
Legend
Small Mammal Grid -123m x 123m
Lake Shoreline
© Herpetofaunal Pitfalls - 7.7m
X Fish Seining Sites
© Invertibrate Sites
•— Berm
--*• Water Flow
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WETLAND COMPONENTS
Figure 2
Orlando Easterly Wetlands
Reclamation Project
Species Planted
Red Maple (Acer rubrum)
Water hyssop (Bacopa caroliniana)
Canna (Canna flaccida)
Sawgrass (Cladium jamaicense)
Spikerush (Eleocharis cellulosa)
Pop ash (Fraxinus caroliniana)
Dahoon holly (Ilex cassine)
Blue flag (Iris hexagona)
Soft rush (Juncu s effusus)
Sweet gum (Liquidambar styraciflua)
Sweet bay (Magnolia virginica)
Stone wort (Nitella sp.)
Cow lily (Nuphar luteum)
Water lily (Nymphaea odorata)
Black gum (Nyssa sylvatica)
Maidencane (Panicum hemitomon)
Knot grass (Paspalum distichum)
Smartweed (Polygonum punctatum)
Pickerelweed (Pontederia cordata)
Pondweed (Potamogeton illinoensis)
Swamp laurel oak (Quercus laurifolia)
Arrowhead (Sagittaria graminae)
Arrowhead (Sagittaria lancifolia)
Three-square bulrush (Scripus
americanus)
Gaint bulrush (S. californicus)
Soft stem bulrush (S. valid us)
Pond cypress (Taxodium ascendens)
Bald cypress (T. distichum)
Thalia (Thalia geniculata)
Cattail (Typha domingensis)
Cattail (T. latifolia)
Tapegrass (Vallisneria americana)
Water enters the Orlando
Easterly Wetlands system
through the 12 cells that form
the deep marsh. The deep marsh cells
generally have an average depth of 3 to
3.5 feet and were planted with cattails
(Typha spp.) and bulrush (Scirpus spp.).
These areas were planned as cattail
communities at the conceptual design
stage, because the scientific literature
at the time provided more information
about using this species than any other
species for wastewater treatment.
Because cattails are potentially
capable of competitively eliminating
other native plant species and conse-
quently reducing the diversity of the
emergent plant communities in the
SIR basin, the SJRWMD voiced
concern about the formation of such a
large cattail community so near to the
SIR. In response, PBS&J designed a
large-scale in-situ experiment for the
Bulrush and Cattail
communities remove and
store most of the nutrients
from effluent entering the
wetland system.
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City to test the treatment capabilities
and competitive effects of cattail versus
bulrush communities. As a result, the
first 12 cells of the City's system are
planted with either cattails, bulrush,
or a combination of the two.
To date, the results indicate there
are subtle differences between the two
plant species relative to water quality
improvement. The bulrush cells appear
to have a slightly greater nutrient
uptake capacity than the cattail cells.
The bulrush also have proven to be
more tolerant of water level fluctua-
tions than the cattails. The deep marsh
cells are designed to take advantage of
the microbial communities associated
with the littoral zones within the cattail
and bulrush communities to remove
and store most of the nutrients entering
the wetland system.
The deep marsh cells are followed
by three mixed marsh cells. The mixed
marsh is designed as a transition point
between the water treatment aspects of
the wetland treatment system and those
associated more closely with wildlife
habitat. Approximately 30 plant species
were planted in the mixed marsh cells,
and approximately 100 other species
have become self established from the
seed bank or off-site wetlands since
system start-up.
Overall, the vegetative communities
within the mixed marsh cells provide
a very diverse habitat structure. The
mixed marsh cells act as a nutrient
polishing step to the deep marsh cells
and maintain nitrogen and phosphorus
concentrations at lower levels than
those found in the
deep marsh. An
apparent differ-
ence in the nutri-
ent removal
processes in the
deep marsh and
mixed marsh cells
is that the former
relies more on
bacterial uptake
while algae are
more dominant
in the latter.
The final
component of the
Orlando Easterly
Wetlands system
is the hardwood
swamp. This area
is specifically designed as a wildlife
habitat area. About 160,000 trees were
planted throughout the cells, intermixed
with an understory similar to that
typical of the mixed marsh. In addition,
an existing cypress (Taxodium spp.)
head was preserved, and the lake,
developed from the borrow pit, was
located within these cells. Although
the hardwood swamp cells were not
expected to play a significant role in the
nutrient uptake before system start-up,
they have since proven to produce a
net release of phosphorus back into
the water column. This release of
phosphorus can be partially attributed
to the number of rookeries located
within these cells. The nesting bird
species typically found in the rookeries
include several heron and egret species.
More than 200 animals species
use the Orlando Easterly
Wetlands as habitat today.
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MEASURING SUCCESS
In 1984, at the conclusion of the
initial study which examined
disposal alternatives, the City
established the goal of creating a
wetland treatment system that would
provide both effluent polishing and a
wildlife management area. Since
system start-up, the performance of the
Orlando Easterly Wetlands relative to
nitrogen and phosphorus uptake and
storage has been better than originally
predicted by the design (see Table 1).
The data in Table 1 show that the
Orlando Easterly Wetlands project has
consistently discharged a water quality
that is better than the permit require-
ments. The discharge has, in fact, been
statistically equal (\i < 0.05) to the water
quality conditions in the SIR, both
upstream and downstream of the
discharge point (see Table 2). These data
indicate that the system has acted to
recover a resource—fresh water—that
Table 1
TN and TP Discharge
Concentrations*
Flow TN TP ~
(mgd) (mg/L) (mg/L)
FDEP
1988
1989
1990
1991
13.00
10.00
13.33
13.28
12.90
2.31
0.84
0.92
0.93
0.80
0.200
0.095
0.076
0.090
0.087
This table compares the first four years of
compliance data for the Orlando Easterly
Wetlands project with the current FDEP permit
criteria for TN and TP discharges . Flows
shown represent influent discharges to the
wetland system.
now is being used to
hydrologically restore the
SJRWMD wetland site.
The annual perform-
ance of the system is
shown by the data in
Tables 3 and 4, with refer-
ence to Figure 1 for the
station locations. These
data indicate the system
has performed very well
for the first four years of
operation. This can be
partially attributed to the
level of commitment by
the City of Orlando to
operate the system as a
treatment process and
as a wildlife habitat area.
Operational procedures,
such as varying water depths, employed
by the project have attempted to mini-
mize nutrient releases while maximizing
the ability of the wetland treatment
system to remove and store nutrients.
The data in Table 4 also show that
phosphorus concentrations are reduced
to about 0.05 mg/L at the discharge
point from the mixed marsh.
Water quality data are only one
indication of the success of the Orlando
Easterly system. Another measure of
success is the diversity of the system
and the array of wildlife species
attracted by this diversity.
The system has demonstrated that if
properly managed, a constructed wet-
land can be used for water treatment,
water quality improvement, and diverse
wildlife habitat. In fact, data collected
to date indicate that the system may
Wetland system designers
included an operational plan
for maintaining target
communities and refuges
for forage species.
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attract more species than surrounding
natural wetlands and generally may
support a higher resident population
than similar natural habitat areas
(see Figure 3). The latter can be directly
attributed to the higher productivity
rates within the system.
The design of the Orlando Easterly
Wetlands includes the preservation of
upland areas around the site. Main-
tenance of the upland/wetland ecotone
has increased the value of the potential
habitat for wetland-dependent species.
The design also included an opera-
tional plan, i.e. managing water depths
for maintaining the hydroperiod
(optimal water depths and duration)
for targeted vegetative communities in
the system. This plan addresses proce-
dures for maintaining the refuges for
the forage species, which ultimately
will lead to stabilizing the habitat of
higher wildlife species such as birds,
alligators, and otters.
Another measure of the Orlando
wetlands success is the number of listed
species which use the site (shown in
Figure 4). To date, 145 bird species have
been observed on site and 10 of these
species are state or federally listed and
are currently utilizing the system as part
of their habitat. The sandhill crane and
Everglades kite have successfully nested
in the wetlands and fledged young
during the third and fourth years of
operation. This usage pattern of the
wildlife habitat also serves as an on-
going natural bioassay of the system,
showing that the water quality goals
have been met in full.
Table 2
Comparison of TN and TP Discharge Concentrations
with the Annual Averages of Receiving Waiters
(First Four Years)
TN (mg/L)
1988 1989 1990 1991
1988
TP (mg/L)
1989 1990 1991
HS10
SJR1
SJR5
SR
0.84
0.87
0.87
0.95
0.92
0.88
0.89
1.00
0.93
1.08
0.89
1.09
0,
1,
1,
1
.80
.05
.09
.06
0.095
0.137
0.149
0.117
0
0
0
0
.076
.074
.071
.070
0,
0,
0,
0,
.090
.098
,084
.080
0.087
0.053
0.116'
0.067
HS10 = Orlando Easterly Wetlands Reclamation Project Discharge
SJR1 = Station in the St. Johns River Upstream of HS10
SJR5 = Station in the St. Johns River Downstream of HS10
; SR, = Average Annual Cpncentratjpn for Serninple RanchJVIonitoring Stations
Comparison of T
Orlando Easterly
Station1
WP1
WPS
WP4,5
WP6
MM8
HS10
1988
4.18
1.53
1.51
1.27
0.96
0.84
Tables
N Annual Averages
' Wetlands Reclama
- (First Four Years)
Nitrogen (mg/L)
1989 1990
5.52 2.83
1.92 0.98
1 .74 1 .00
1.59 1.09
1.22 1.19
0.92 0.93
Through the
tion Project
1991
2.44
2.20
1.02
1.11
1725
0.90
Area2
0
11
16
32
67 i
100
1These stations include influent and effluent samples in addition to four internal strat.
2Area equals the percent of wetland area upstream of the listed sample station.
Table 4
Comparison of TP Annual Averages Through the
Orlando Easterly Wetlands Reclamation Project
(First Four Years)
Station1 1988
-WP1 0.572
r WPS 0.103
I WP4.5 0.102
WP6 0.106
Phosphorus (mg/L)
1989 1990
0.720 0.41
0.080 0.16
0.065 0.14
0.070 0.11
1991 Area2
0.23 0
0.37 1 1
0.12 16
0.11 32
MM8 0.091 0.050 0.05 0.06 67
HS10 0.095 0.076 0.09 0.087 100
'These stations include influent and effluent samples in addition to four internal strat.
2Area equals the percent of wetland area upstream of the listed sample station.
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COMMUNITY ACCEPTANCE
The success of the Orlando Easterly
Wetlands Reclamation Project is
attributed not only to its success
as a wastewater treatment facility and
reuse project, but also to the benefits
it offers surrounding communities.
For visitors who wish to enjoy the
beauty of Florida wildlife in a natural
habitat, a portion of the project func-
tions as a wilderness park with nature
Orlando Easterly Wetlands
Reclamation Project Costs
Land Acquisition $4,411,000
Wetlands Development
Structural 4,232,000
Vegetation 750,000
Force Main 8,491,000
Effluent Pump Station 1,982,000
Engineering 1,659,000
Total $21,525,000
Orlando Easterly Wetlands
Reclamation Project Awards
1987 PBS&J Project Excellence Award
1988 Florida Institute of Consulting
Engineers Excellence Award
ACEC Excellence in Engineering
Award
1990 FDEP Secretary's Award, Florida
Department of Environmental
Regulation
1990 State of Florida Governor's
Environmental Award
1992 Water Environment Federation
Outstanding Achievement
Award (included with other
City achievements) over the
past 10 years)
trails and seasonal camping facilities
which are open from mid-January
through September.
For area schools with environmental
educations programs, it serves as a
natural laboratory and research
facility. The result is a project which
exemplifies the current trend toward
socially responsible environmental
management.
Figure 4
Orlando Easterly
Wetlands
Reclamation Project
Observed State and
Federally Listed
Animal Species
Roseate spoonbill
Limpkin
Green-backed heron
Little blue heron
Snowy egret
Tricolored heron
Peregrine falcon
Florida sandhill crane
Woodstork
Everglades snail kite
American alligator
Eastern indigo snake
Orlando
Easterly
Wetlands
80
70-
60-
Figure 3
Comparison of Wildlife Diversity
Lake Lake Winter (BW) Resident (BW) Expected
Conway Tohopekalica Fauna
78
20 -
10
Amphibians Lizards Turtles Snakes Fishes Birds Mammals
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Acknowledgements
Numerous individuals have shared in the
efforts to create and implement the Orlando
Easterly Wetlands Reclamation Project.
Listed below are some of the key groups
and individuals:
USEPA
Robert K. Bastian
Office of Wastewater Management
Washington, D.C.
City of Orlando, FL
Bill Frederick, Mayor
Robert C. Haven, P.E.
Chief Administrative Officer
Thomas L. Lothrop, P.E.
Director, Environmental Services
Elizabeth T. Skene, P.E.
Assistant Bureau Chief, Wastewater
Alan R. Oyler, P.E.
Assistant Bureau Chief, Wastewater
William P. Allman
Manager, Iron Bridge WPCF
FDEP
Alex Alexander, P.E.
Disrtrict Director, Central District
Carlos Rivero deAguilar, P.E.
Program Administrator for Water Facilities
Christianne Ferraro, P.E.
Program Manager for Domestic Waste
James Hulbert
En vironmental Administrator
PBS&J
Phillip E. Searcy, P.E.
Senior Executive Vice President
JoAnn Jackson, P.E.
Project Engineer
Seth B. Blitch
Project Biologist
John S. Shearer, P.E.
Director of Environmental Services
Prepared by Post, Buckley, Schuh
& Jernigan, Inc.
1560 Orange Ave.,
Suite 700
Winter Park, FL 32789
(407) 647-7275
Editors:
Jon C Dyer, P.E.
Kathe Jackson
EPA Project Officer:
Robert K. Bastian
Photo courtesy of Seth Blitch
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