Crystal_Beach_Potable_Water_Assessment_Report.pdf

Pinellas County

Potable Water Assessment Crystal Beach Drainage and Roadway Improvements – Professional Engineering Services

RFP CONTRACT NO. 21-0022-NC(PLU)

COUNTY PID NO. 003896A

April 2025

Pinellas County Crystal Beach Drainage and Roadway Improvements - Potable Water Assessment

TABLE OF CONTENTS

1.0 INTRODUCTION

ASSET INVENTORY AND CONDITION

2.1 Project Area Asset Inventory

DESIGN CRITERIA

HYDRAULIC MODELING

4.1 Fire Flow Analysis and Recommendations

4.2 Water Age Analysis and Recommendations

SUMMARY OF RECOMMENDED IMPROVEMENTS

1.0 INTRODUCTION

Pinellas County has contracted Burgess & Niple to perform a potable water assessment to determine necessary improvements and possible impacts to the existing potable water mains in the Crystal Beach neighborhood resulting from the Crystal Beach Drainage and Roadway Improvements Project. The proposed improvements are intended to be implemented concurrently with planned roadway improvements in the area.

The limits of the potable water assessment are shown in Figure 2-1. Included in this assessment is an evaluation of structural issues, water quality, hydraulic efficiency, condition assessment, and age of the existing potable water system within the project limits. In order to perform the tasks described above, the existing Pinellas County Utilities potable water hydraulic model was developed in Bentley WaterGEMS from data provided by the County GIS.

The Crystal Beach neighborhood dates back to the 1850s and consists of both old and new construction, which suggests that the existing potable water system design may not meet current standards. The resulting proposed potable water system improvements include the installation of larger diameter water mains to meet fire flow requirements as well as upgrading to current potable water main materials that meet the Pinellas County pipe material specifications. The proposed improvements will increase the water quality, fire flow safety, and integrity of the potable water main system in the Crystal Beach area.

ASSET INVENTORY AND CONDITION

The water main length in the Crystal Beach area totals approximately 4.9 miles. Almost half of the water mains within the area are 2-inches in diameter. The remaining water mains are 4-, 6- and 8-inches in diameter. Water main materials include PVC, DIP, HDPE, and unknown. The water main diameter, material, and length information was obtained from GIS and used to develop the summary tables below. The existing potable water system in the

Crystal Beach area is also shown in Figure 2-1.

2.1 PROJECT AREA ASSET INVENTORY

Table 2-1 contains pipe characteristics for the entire project area. Two-inch water mains made of PVC and unknown material comprise a vast majority of the total pipe length in the project area.

Table 2-1. Project Area Existing Pipe Diameter, Material, and Length

Diameter (in) Material Existing Pipe Length (ft)

PVC 7,028

Unknown 4,256

Total 2” Diameter 11,284

DIP 15

HDPE 356

PVC 567

Unknown 1,996

Total 4” Diameter 2,934

PVC 6,840

Unknown 26

DIP 65

Total 6" Diameter 6,931

PVC 4,198

Unknown 347

Total 8" Diameter 4,545

Subtotal Project Area 25,694

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Along S. Mayo Street , a 6-inch water main and 2-inch water main run parallel from Pennsylvania Avenue to

Tennessee Avenue. At each intersection with roads running east-west, the 6-inch water main decreases to 2-inch in GIS and increases to 6-inch on the other side of the intersection. It was confirmed by the County that these segments are drawn correctly in GIS and to include the replacement of the 2-inch segments with 6-inch diameter water main in the improvements presented in this assessment. These segments are shown in Figure 2-2, below.

Figure 2-2. 2-inch WM Segments within 6-inch WM

DESIGN CRITERIA

The proposed design criteria are based on the following standards. Where standards did not dictate design requirements, standard industry guidelines were applied.

• Pinellas County Utilities Material Specification Manual (the Manual), latest revision 2023

• Pinellas County Standard Technical Specification for Utilities and Related Construction, latest revision June

• Pinellas County fire flow requirement of 500 gpm at 20 psi residual pressure

• National Fire Protection Association (NFPA) 1 Fire Code hydrant spacing guideline of a maximum of 800 feet between hydrants for detached one and two-family dwellings such as those found within the project limits

Water age was also taken into consideration for the design criteria. Low average day demands can result in potentially harmful water age. Stagnant water causes pipe and water issues which threaten the integrity of the potable water system, making the consideration of water age important in design and hydraulic modeling. Water age above the 5 day, or 120 hour threshold, can result in pipe corrosion, low chlorine residual, discoloration of the water, and buildup of silt. To avoid these issues in low demand areas, pipe sizes are minimized as much as possible while maintaining fire flow requirements. Where issues persist, blow offs can be used to flush stagnant water from the potable water main.

The Manual states that the following pipe material shall be used for potable water mains:

• Article 6 states that PVC shall be in accordance with AWWA C900 for a diameter of 4- to 12-inches.

Dimensions include DR 14 and DR 18, with 20’, 30’, or 40’ standard joint length.

• Article 3 states HDPE shall be in accordance with AWWA C901 for 2-inch diameter service connections.

HYDRAULIC MODELING

The existing Pinellas County potable water system that was created in WaterGEMS was utilized to evaluate fire flow and water age. Fire flow and water age were evaluated using the previously created and calibrated 2020

Existing System scenarios, under maximum day and average day conditions, respectively.

4.1 FIRE FLOW ANALYSIS AND RECOMMENDATIONS

Fire flow was evaluated within the Crystal Beach area using 500 gpm (0.72 MGD) demand and 20 psi residual system pressure criteria, as established by Pinellas County. This analysis resulted in seven (7) recommended improvements. These recommendations are shown on Figure 4-1.

Recommendation FF#1: Replace 4-inch cast iron water main with 6-inch PVC water main on S. Gulf

Drive. Replacement of the 4-inch cast iron water main is recommended from S. Mayo Street along Crystal

Beach Avenue, along S. Gulf Drive, and on Georgia Avenue between S. Mayo Street and S. Gulf Drive.

Recommendation FF#2: Remove existing 2-inch water main along S. Mayo Street and relocate service connections to existing 6-inch water main. This recommendation includes abandoning the existing 2-inch water main that runs north/south along S. Mayo Street from Pennsylvania Avenue to Georgia

Avenue and relocating all service connections to the existing adjacent 6-inch water main. The 2-inch segments within the existing 6-inch water main will be replaced with 6-inch water main.

Recommendation FF#3: Install a 6-inch water main along Kentucky Avenue from Broadus Street to the east and replace the 2-inch water main along the cul-de-sac in its entirety. Install a fire hydrant at the end of Kentucky Avenue.

Recommendation FF#4: Connect existing 2-inch water main on Florida Boulevard to existing 2-inch water main on McCosh Avenue. In the southeast region of project area, there is approximately 400 feet of existing 2-inch water main that connects to the existing 8-inch water main on the west but does not connect to the existing 2-inch water main on McCosh Avenue. Install approximately 100 feet of 2-inch water main that will connect the existing 2-inch water main on Florida Boulevard to the existing 2-inch water main on McCosh Avenue.

Recommendation FF#5: Replace the existing 2-inch water mains with 6-inch PVC water main in the

Vincent Street to Broadus Street blocks on Pennsylvania Ave, Maryland Avenue, Indiana Avenue, Kentucky Avenue, and Tennessee avenue. Install fire hydrants at each of the intersections of Vincent

Street and the above-mentioned streets.

Recommendation FF#6: Install a fire hydrant at Florida Boulevard and Seaview Drive. This will ensure that hydrant spacing requirements are met.

Recommendation FF#7: Install two hydrants along Point Seaside Drive. This will ensure that hydrant spacing requirements are met.

4.2 WATER AGE ANALYSIS AND RECOMMENDATIONS

After the necessary fire flow improvements were determined as outlined above, a water age analysis was performed. Fire flow requirements typically result in larger diameter water mains resulting in an increased storage capacity within the water main. Therefore, the recommended fire flow improvements were implemented to model scenario 2020 Existing System Average Day for the water age analysis.

The water age was calculated for 5 days, or 120 hours. A water age above this threshold can result in pipe corrosion, low chlorine residual, discoloration of the water, and buildup of silt. Under average day demand, the turnover of the potable water can be low enough for issues related to water age to develop. These issues are especially prevalent in dead-end water mains that are sized to meet fire flow requirements, but average day demands remain relatively low. In these areas, blow-offs are typically installed to periodically flush the stagnant water from the main. This analysis resulted in three (3) recommended improvements. These recommendations are shown on Figure 4-1.

Recommendation WA#1: Replace 2-inch galvanized steel water main with 4-inch PVC between S.

Gulf Drive and Mayo Street on Pennsylvania Avenue, Maryland Avenue, Kentucky Avenue, and

Tennessee Avenue, as well as Indiana Avenue between Mayo Street and Vincent Street. Replace the

2-inch on Indiana Avenue east of between Broadus Street with 2-inch PVC. The new 4-inch PVC water mains will be connected to the new 6-inch water main on S. Gulf Drive, reducing water age concerns.

Recommendation WA#2: Install a 2-inch water main along Ohio Avenue and N Gulf Drive extending south to Crystal Beach Avenue.

Recommendation WA#3: Cut and cap the 6-inch line along the length of Point Seaside Drive. Tie services over to the existing 8-inch line. Replace approximately 225 LF of 6-inch water main along the cul-de-sac with 4-inch PVC. It is recommended that an automatic blow off (i.e. flushing system) is added at the dead end to provide periodic main flushing. An example of this device is the Kupferle Eclipse #9700.

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WA#2:

Install a 2-inch water main along Ohio Avenue and N Gulf Drive extending south to Crystal Beach Avenue.

Abandon in place existing 2-inch water main.

FF#3: Install a 6-inch water main along Kentucky Avenue from Broadus Street to the east, and replace the 2-inch water main along the cul-de-sac in its entirety.

Install a fire hydrant at the end of Kentucky Avenue.

FF#4:

Connect existing 2-inch water main on Florida Boulevard to existing 2-inch water main on McCosh Avenue.

FF#1:

Replace 4-inch cast iron water main with 6-inch PVC water main from S.

Mayo Street along Crystal Beach Avenue, along S.

Gulf Drive, and on Georgia Avenue between S. Mayo Street and S. Gulf Drive.

FF#5:

Replace the existing 2-inch water mains with 6-inch PVC water main in the Vincent Street to Broadus Street blocks on Pennsylvania Avenue, Maryland Avenue, Indiana Avenue, Kentucky Avenue, and Tennessee Avenue.

Install fire hydrants at each of the intersections of Vincent Street and the above mentioned streets.

FF#6:

Install fire hydrant at Florida Boulevard and Seaview Drive.

FF#2:

Remove the 2-inch water line that runs parallel to the 6-inch line on Mayo Street. Tie services over to the 6-inch line. Replace 2-inch segments within the existing 6-inch PVC water main with 6-inch PVC water main.

WA#3 & FF #7:

Cut and cap the 6-inch line along the length of Point Seaside Drive. Tie services over to the existing 8-inch line and install two hydrants. Replace approximately 225 LF of 6-inch water main with 4-inch water main along the cul-de-sac. Install a blowoff at the dead end.

WA#1:

Replace 2-inch galvanized steel water main with 4-inch PVC between Gulf Drive and Mayo Street on Pennsylvania Avenue, Maryland Avenue, Kentucky Avenue, Tennessee Avenue and Indiana Avenue between Mayo Street and Vincent Street. Replace with 2-inch PVC on Indiana Avenue between Broadus Street and Yawl Lane.

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SUMMARY OF RECOMMENDED IMPROVEMENTS

The primary drivers of the recommended improvements to the Crystal Beach neighborhood are the ability to provide adequate fire flow and minimize the potential for water age related issues. To mitigate the potential stagnant water issues in the system, water mains can be looped where feasible or blow offs can be installed to perform periodic flushing. Based on the fire flow and water age modeling results, the recommended improvements are summarized below. In addition, an engineer’s opinion of probable construction cost is provided as an attachment.

5.1.1 Project Area Improvements

Within the project area, the following improvements are recommended:

• Installation of approximately 5,540 linear feet of 6-inch water main

• Installation of approximately 2,300 linear feet of 4-inch water main

• Installation of approximately 1,500 linear feet of 2-inch water main

• Installation of nine hydrants and one automatic blow off

• Approximately 124 service connections

The total estimated cost of the water main improvements in the project area is $2,199,000.

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ATTACHMENT

ITEM DESCRIPTION UNIT UNIT PRICE QUANTITY TOTAL COST

1 Mobilization/Demobilization LS 153,800$ 1 153,800$

2 Install 6-inch PVC Water Main LF 130$ 5,540 720,200$

3 Install 4-inch PVC Water Main LF 100$ 2,300 230,000$

4 Install 2-inch PVC Water Main LF 75$ 1,500 112,500$

5 Install Hydrant EA 8,000$ 9 72,000$

6 Install Automatic Blowoff EA 4,000$ 1 4,000$

7 Connections to Existing Water Mains EA 5,000$ 29 145,000$

Service Connections

8 Service Connections 1" Short (connect to existing meter) EA 1,500$ 56 84,000$

9 Service Connections 1" Long (connect to existing meter) EA 2,500$ 68 170,000$

Subtotal $1,691,500

Contingency 30% $507,500

Estimated Construction Cost $2,199,000

CRYSTAL BEACH, FLORIDA

POTABLE WATER ASSESSMENT

ESTIMATED CONSTRUCTION COST