pemberton creek

117 Pages·2004·51.41 MB·English

by  Hillsborough County

PEMBERTON CREEK/
BAKER CANAL AREA

STORMWATER MANAGEMENT
MASTER PLAN

Prepared for the
Hillsborough County Board of County Commissioners

By

Public Works Department/Engineering Division
Stormwater Management Section
September, 2002

Daniel A. Kleman..........................................................County Administrator
Patricia Bean..................................................... Deputy County Administrator
Bernardo Garcia........................................................Director of Public Works
Robert R. Gordon, P.E...........................................................County Engineer
Eduardo J. Tapia, P.E ......................................................................... Manager
TABLE OF CONTENTS

PEMBERTON-BAKER AREA
WATERSHED MANAGEMENT PLAN

TABLE OF CONTENTS

List Of Figures
List Of Tables
List Of Exhibits
List Of Appendices

EXECUTIVE SUMMARY

CHAPTER 1 INTRODUCTION

1.1 Overview............................................................................................................. 1-1
1.2 Purpose and Scope.............................................................................................. 1-5
1.2.1 Flood Control Level of Service.............................................................. 1-5
1.2.2 Water Quality Treatment Level of Service............................................. 1-6
1.3 Project Organization........................................................................................... 1-6

CHAPTER 2 WATERSHED DESCRIPTION

2.1 Overview............................................................................................................. 2-1
2.2 Climate................................................................................................................ 2-4
2.3 Soils.................................................................................................................... 2-5
2.4 Physiography And Hydrology............................................................................ 2-9
2.5 Geology And Hydrogeology............................................................................. 2-10
2.5.1 Surficial Aquifer................................................................................... 2-11
2.5.2 Semi-confining Zone.............................................................................2-13
2.5.3 Upper Floridan Aquifer.........................................................................2-13
2.6 Existing And Future Land Use..........................................................................2-14
2.6.1 Existing Land Uses................................................................................2-14
2.6.2 Future Land Uses...................................................................................2-20

Pemberton-Baker Area Watershed Management Plan TOC - i
TABLE OF CONTENTS

Chapter 3 Major Conveyance Systems

3.1 Existing Conveyance Systems.........................................................................................3-1
3.2 The Flint Creek System...................................................................................................3-1
3.3 The Campbell Branch System.........................................................................................3-1
3.4 The Antioch Branch System............................................................................................3-1
3.5 The Baker Creek System.................................................................................................3-2
3.6 The Pemberton Creek System.........................................................................................3-2
3.7 The Baker Canal System.................................................................................................3-2

Chapter 4 Hydraulic/Hydrologic Model Methodology

4.1 General Methodology And Database Development............................................4-1
4.2 Hydrology............................................................................................................4-1
4.2.1 SCS-CN Method......................................................................................4-1
4.2.2 SCS Dimensionless Hydrograph............................................................4-10
4.2.3 Model Implementation...........................................................................4-11
4.2.4 Rainfall Depth........................................................................................4-12
4.2.5 Soil Data, Land Use And SCS-CN Number Determination..................4-13
4.2.5.1 Soil Data..................................................................................4-13
4.2.5.2 Land Use..................................................................................4-13
4.2.5.3 Run-Off Curve Numbers..........................................................4-14
4.2.6 Time Of Concentration..........................................................................4-14

4.3 Hydraulics..........................................................................................................4-15
4.3.1 Major Modification................................................................................4-15
4.3.2 Boundary / Initial Conditions................................................................4-18
4.3.3 Overflow Weirs......................................................................................4-18
4.3.4 Roughness Coefficients.........................................................................4-19
4.3.5 Numerical Instability.............................................................................4-19

Chapter 5 Hydraulic/Hydrologic Model Calibration And Verification

5.1 Boundary Conditions...........................................................................................5-1
5.2 Data Collection....................................................................................................5-1
5.3 Existing Conditions Model Calibration...............................................................5-6
5.4 Existing Conditions Model Verification..............................................................5-9
5.5 Summary............................................................................................................5-15

Pemberton-Baker Area Watershed Management Plan TOC - ii
TABLE OF CONTENTS

Chapter 6 Existing Conditions Flood Level Of Service

6.1 Introduction..........................................................................................................6-1
6.1.1 Standard Design Storm Events................................................................6-1
6.1.2 Existing Conditions Model Simulation Results.......................................6-2
6.2 Baker Canal ......................................................................................................6-2

6.3 Pemberton Creek..................................................................................................6-7

6.4 Campbel Branch.................................................................................................6-13

6.5 Antioch Branch..................................................................................................6-17

6.6 Flood Control Level Of Service Definitions......................................................6-21
6.7 Level Of Service Analysis / Methodology........................................................6-21
6.7.1 Establishment Of Landmark Elevations................................................6-23
6.7.2 Comparison Of Computed Results And Landmark Elevations.............6-23

6.8 Level of Service Designations...........................................................................6-23
6.8.1 Baker Canal............................................................................................6-24

6.8.2 Pemberton Creek....................................................................................6-26

6.8.3 Campbell Branch...................................................................................6-28

6.8.4 Antioch Branch......................................................................................6-29

Pemberton-Baker Area Watershed Management Plan TOC - iii
LIST OF FIGURES

PEMBERTON-BAKER AREA
WATERSHED MANAGEMENT PLAN

LIST OF FIGURES

FIGURE # TITLE PAGE

1-1 Project Location Map...........................................................................................1-2

2-1 Watershed Water feature Map.............................................................................2-2
2-2 Subbasin Delineation Map...................................................................................2-3
2-3 Topographic Map.................................................................................................2-4
2-4 Soil Classification By Type.................................................................................2-7
2-5 Soil Classification By Hydrologic Group............................................................2-8
2-6 Representative Hydrologic Cross Section.........................................................2-12
2-7 1995 SWFWMD Land Use / Land Cover Map.................................................2-15
2-8 Property Appraiser Office Existing Land Use Map...........................................2-16
2-10 Planning Commission Generalized Future Land Use Map (2015)....................2-17

3-1 Major Conveyance Systems.................................................................................3-4

4-1 Definition Of Unit Hydrograph.........................................................................4-11

5-1 Gage Station Location Map.................................................................................5-3
5-2 Rainfall Distribution of September 26 & 27, 1997 Event...................................5-4
5-6 Comparison of Water Levels in Baker Canal
(Muck Pond Road, September 26 & 27, 1997 Event)......................................5-7
5-7 Comparison of Water Levels in Pemberton Creek
(McIntosh Road, September 26 & 27, 1997 Event)..........................................5-8
5-8 Comparison of Discharges in Pemberton Creek
(McIntosh Road, September 26 & 27, 1997 Event)..........................................5-8
5-9 Comparison of Water Levels in Flint Creek
(Kelso Road, September 26 & 27, 1997 Event)................................................5-9

Pemberton-Baker Area Watershed Management Plan LOF - i
LIST OF FIGURES

6-1 Flood Control Level Of Service Diagram........................................End Of Chapter
6-2 2.33 yr/24 hr Level Of Service Map................................................End Of Chapter
6-3 5 yr/24 hr Level Of Service Map.....................................................End Of Chapter
6-4 10 yr/24 hr Level Of Service Map...................................................End Of Chapter
6-5 25 yr/24 hr Level Of Service Map...................................................End Of Chapter
6-6 Flooding Complaint Map.................................................................End Of Chapter

Pemberton-Baker Area Watershed Management Plan LOF - ii
INTRODUCTION

This Stormwater Management Master Plan (SMMP) for the Pemberton Creek/Baker Canal
Area (PBA) reports the results of a watershed study; which includes Pemberton Creek, Baker Creek,
Baker Canal, Campbell Branch, Antioch Branch, Flint Creek and Lake Thonotosassa. The project
was conducted by the Stormwater Management Section of the Engineering Division/Department of
Public Works. It makes use of a previous Floodplain Analysis ("existing conditions") that was
partially funded by the Hillsborough River Basin Board of the Southwest Florida Water
Management District (SWFWMD). This SMMP establishes the existing level of service (LOS) for
stormwater facilities as described in the Stormwater Element of the Hillsborough County
Comprehensive Plan (Future of Hillsborough). It also identifies deficiencies in existing
infrastructure and recommends improvements for increasing the level-of-service provided. A water
quality assessment is included in an accompanying report titled, "Pemberton Creek Environmental
Conditions Report (1998)", as required by the National Pollution Discharge Elimination System
(NPDES) permit issued to Hillsborough County on September 9, 1995 (effective January 1, 1996).

1.1 General Description

The PBA watershed lies in the northeastern portion of Hillsborough County, and
encompasses approximately 65 square miles as shown in Figure 1.1. The project area is generally
bordered on the east by the City of Plant City, on the west by Kingsway Road, on the north by U.S.
Highway 301 and on the south by the CSX Railroad line near S.R. 60 in Brandon. The PBA
watershed contains six (6) major stormwater conveyance systems and one (1) outfall. These
conveyance systems are:

1) The Flint Creek System
2) The Campbell Branch System
3) The Antioch Branch System
4) The Baker Creek System
5) The Pemberton Creek System
6) The Baker Canal System

Flint Creek is a tributary to the Hillsborough River which is used as a water supply source by
the City of Tampa. The Hillsborough River outfalls to Tampa Bay. Flint Creek drains Lake
Thonotosassa; the Lake is the receiving body for the other portions of the watershed including
Pemberton Creek and Baker Canal.

Pemberton Creek-Baker Canal Area Watershed Management Plan 1-1
CHAPTER ONE Introduction

1.2 Purpose

The purpose of this project is to assess level of protection or level of service provided by the
existing infrastructure and to identify improvements to increase that flooding level-of-service. The
target level-of-service for major stormwater conveyance facilities is the protection of roads and
property from substantial flooding during a 25-year storm (a storm with a 4-percent chance of
occurrence during any one year). Due to existing development in basins, it is not always feasible to
attain the 25-year level-of-service. Also, flood levels are in some cases controlled by natural
systems that cannot be modified without extreme cost and/or environmental damage. This report
identifies deficiencies in the existing stormwater management system and improvements needed to
achieve an increased level of service.

1.3 Scope

The scope of this plan includes the establishment of the existing conditions for the PBA
stormwater management infrastructure in terms of computed water surface elevations and computed
flows. A computer model of the physical characteristics of the stormwater conveyance/storage
system has been developed to determine these existing conditions for the 3-year, 5-year, 10-year, 25-
year and 100-year design storms. Survey data was acquired, and computer mapping performed to
provide inputs for the computer model. The model was calibrated to available existing hydrologic
data.

The results of the existing conditions modeling were then evaluated to identify the locations
and extent of flooding problems. Those flooding problems for which a history of actual flooding
could be documented have been given priority. Public funding for deficiencies associated with the
flooding of County roadways during the design event (25-year) have been prioritized above those
associated with site flooding of private property. Potential solutions were formulated and then tested
on the calibrated computer model. The most effective of the alternative solutions have been
identified and recommended in this report. Water quality needs were considered in the selection of
recommended alternatives. Planning-level cost estimates have also been developed for the proposed
solutions. Implementation priorities have also been suggested.

Based on the 1998 PBA Masterplan report, there are four areas of focus for recommended
improvements in the proposed condition. The majority of these improvements have been
implemented. These improvements include structural upgrades and non-structural improvements. All
of these efforts will lead to achievement of the Level of Service (LOS), Level B in the Pemberton
Creek/Baker Canal Area.

Pemberton Creek-Baker Canal Area Watershed Management Plan 1-1
CHAPTER ONE Introduction

1.3 Background

The 1998 Stormwater Management Master Plan (SMMP) for the Pemberton Creek-Baker
Canal Area (PBA) utilized a combination of various studies prior to the 1991-1992 Pemberton
Creek-Baker Flood Analysis Study. The 1991 Pemberton/Baker Creek Hydraulic Analysis Greiner
study for the flooding of I-4 utilized the U.S. Army Corps of Engineers HEC-2 model information
for Baker Canal. The 1991 Gee and Jensen HEC-2 data was utilized for the Campbell Branch and
Pemberton Creek . Furthermor, the CDM Extran model for the Plant City portion was incorporated
for the headwaters of Pemberton Creek. All of these studies were sources for the 1998 Hillsborough
County’s PBA SMMP study and was prepared for the Southwest Florida Water Management
District (SWFWMD) and Hillsborough County. The County used the RUNOFF block of the EPA
Stormwater Management Model (SWMM) to compute peak discharge values. The U.S. Army Corps
of Engineers HEC-2 model were used to compute flood elevations within the Pemberton Creek and
Baker Canal channel system. The enclosed report is an 2002 update by the Hillsborough County
Stormwater Section using a Federal Emergency Management Agency approved version SWMM
modified by the County staff, HCSWMM4.31B respectively.

The Federal Emergency Management Agency (FEMA) has published three versions of the
Flood Insurance Rate Maps (FIRM) for the PBA watershed. The first was in 1984, and there were
subsequent revisions in 1989 and 1992. Many of the existing conditions peak discharge values
reported in the various reports are also shown in the FEMA Flood Insurance Study (1992).

Since the completion of the 1993 Flood Analysis, and 1998 Hillsborough County Pemberton
Creek-Baker Canal Stormwater Management Master Plan, most of the recommended improvements
listed in both studies have been implemented. All these completed drainage construction projects
have been included in the current existing conditions portion of this report.

The modeling effort reported herein is based partially on the data used by County staff in
1998 and partially on additional data that was not available at the time of the previous studies. It is
also based on a hydrodynamic modeling technology that computes discharge and water surface
elevation as a function of simulated time.

Pemberton Creek-Baker Canal Area Watershed Management Plan 1-3