Q
NONPOINT SOURCE SUCCESS STORY
Horim
Wetland Restoration Project Increases Dissolved Oxygen Levels in
Alligator Creek
Waterbody Improved
Water quality impacts from nutrient loading and polluted runoff
from both point and nonpoint sources led the Florida Department
of Environmental Protection (DEP) to add Alligator Creek to Florida's 1998 Clean Water Act (CWA)
section 303(d) list of impaired waters for exceedances of the historical minimum dissolved oxygen
(DO) impairment threshold. In response, project partners implemented numerous nonpoint source
pollution management strategies, including the construction of Kapok Park, a local neighborhood
park that provides habitat for a variety of wildlife and enhances water quality, flood control and
channel stabilization. Improved DO measurements in Alligator Creek show that the project has had a
positive impact on water quality.
Problem
Alligator Creek is in the Group 1 Tampa Bay watershed
in central Pinellas County in Clearwater, Florida.
Alligator Creek flows into Alligator Lake and then into
Tampa Bay (Figure 1). The entire reach of Alligator
Creek is roughly 4 miles long and falls within WBiD
1574. Alligator Creek is a Class lil fresh waterbody
designated for recreation and the propagation and
maintenance of healthy, well-balanced fish and
wildlife populations. The predominant land uses in the
Alligator Creek watershed are 83 percent urban/built
up (of which 48 percent is residential and 52 percent is
commercial), as well as transportation, communication
and utilities (6 percent).
Portions of the creek are highly modified and engi-
neered, which has altered the natural flow of water
within the creek and caused the DO concentrations to
fall below the state's applicable water quality standard
for Class III waterbodies. As a result, in 1998, DEP
placed Alligator Creek on the state's CWA section
303(d) list for DO impairment. Point sources in the
Alligator Creek watershed include one domestic waste-
water treatment facility; nonpoint sources of pollution
include septic systems and surface water runoff.
Story Highlights
In 2003, the City of Clearwater's Kapok Wetland and
Fioodplain Restoration Project received CWA sec-
tion 319(h) funding. Kapok Park was designed and
Figure 1. Alligator Creek is on Florida's Gulf Coast.
constructed to address nonpoint source pollution
impacting Alligator Creek and provide benefits such
as wetland restoration, flood control, water quality
improvement and recreational opportunities. Project
work was conducted in 2005-2009 and restored the
fioodplain function to a 37-acre urbanized tract of land.
The pollutant load reductions included 23,850.7 pounds
per year (Ibs/yr) of total suspended solids, 291.8 Ibs/yr
of total phosphorus, 644.3 Ibs/yr of total nitrogen and
10,622.3 Ibs/yr of biological oxygen demand.
The project included construction of 19.4 acres of
herbaceous and forested wetiands to absorb nutri-
ents, enhance water quality and reduce pollutant
loading downstream to Alligator Lake and Old Tampa
Alligator Greek-:WBID 1574

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Bay. Reducing these pollutants contributed to the
improvement of the DO levels in Alligator Lake. The
project is located in what was previously the Kapok
Mobile Home Park, where most homes were within
the 25-year floodplain and approximately one-third of
the 200 structures were within the 10-year floodplain.
The restored wetland and upland areas also provide
essential habitat for wildlife, including many threat-
ened and endangered species (Figure 2). Interpretive
signs were installed at the site to educate the public
about the benefits of the project.
Results
Thanks to the efforts of many stakeholders and the
completion of the Kapok project, the DO concentra-
tions in Alligator Creek have increased (Figure 3).
Data were collected at two long-term monitoring
stations (21FLPDEM14-10 and 21FLPDEM14-11).
The exceedance ratio decreased from 48/90 before
and during the project (1999-2009) to 13/59 in the
post-project timeframe (2009-2013). DO values
also show improvement: minimum values increased
from 0.8833 milligrams per liter (mg/L) to 2.2 mg/L,
while maximum values increased from 8.9 mg/L to
9.59 mg/L. it is important to note that the mean
DO value increased from 4.898 mg/L in 1999-2009
(below the 5.0 mg/L state DO standard threshold) to
6.136 mg/L in 2009-2013 (above the DO standard
threshold). These changes in the DO measurements
demonstrate that the project has had a positive impact
on water quality in Alligator Creek. The increase in DO
Figure 2. Kapok Wetland and Floodplain Restoration
Project area in 2004 (left: pre-project) and in 2009
(right: post-project).
concentrations can be attributed to the removal of
immediately adjacent structures and the restoration of
a natural wetland area that established a more natural
flow regime.
Partners and Funding
The Kapok Wetland and Floodplain Restoration
Project was funded through the City of Clearwater
($5,150,541), Southwest Florida Water Management
District-SWIM Trust Fund ($1,089,082), Pinellas-
Anclote River Basin Board of the Southwest Florida
Water Management District ($726,064) and CWA
section 319(h) funding ($490,625). Pinellas County has
also implemented multiple environmental education
campaigns, including Be Floridian, and has partnered
with University of Florida's IFAS Extension offices.
Long Term Dissolved Oxygen (mg/L) Data for WBID 1574
Figure 3. Long-term dissolved oxygen data for Alligator Creek (1999-2013).
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U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA 841-F-20-0Q1FF
December 2020
For additional information contact:
Amanda Peck
Florida Department of Environmental Protection
850-245-2952 • Amanda.Peck@dep.state.fl.us
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