Water Conservation and Central Control

Focused Project

Project Overview

Along Florida's Treasure Coast you'll find the beautiful city of Port St. Lucie. Formed in 1988, Port St. Lucie's current population is over 150,000 residents and covers approximately 114 square miles.

Figure 1: Regional Aerial

The City of Port St. Lucie Public Works Department, part of the Environmental Services Division, is charged with maintaining all road and canal rights-of-way (60 miles) within the City, in addition to all drainage rights-of-way (158 miles) and miscellaneous special areas (200 acres).

Figure 2: Median Plantings

Figure 3: Becker Road Sign

Beginning in the year 2000, the City of Port St. Lucie Public Works Deptartment contracted with Masuen Consulting, LLC to assist with their irrigation needs. Since then, Masuen Consulting has worked methodically to increase the quality of new irrigation installations, control system efficiencies, and manage systems through central control to provide only the water truly needed. This work included a complete analysis of water usage, irrigation audits, inspections, permitting assistance, new city codes and specifications, and public educational courses. Masuen Consulting guided the conversion of all older public works irrigation systems to central control and now monitors the Rain Bird Maxicom system. Based on the success of implementing the central control conversion, the City asked Masuen Consulting for guidance on where to invest in new, more efficient pump stations and when to explore the use of alternate water sources.

Figure 4: Percolation Testing

Figure 5: Pump and Controls Enclosure

The overall cumulative result has been remarkable as suggested by the award of a Water SIP grant in 2008 from the local water management district, South Florida Water Management District (SFWMD). Subsequently, in 2010 Masuen Consulting petitioned SFWMD for a variance from the standard ’2 days per week’ watering schedule. No such variances had been awarded previously by SFWMD. A variance would allow the weather and soil moisture sensor based control system to operate to its maximum capability. In 2011, SFWMD granted the City of Port St. Lucie this variance. Here is a general guideline of Masuen Consulting's involvement with the City:

2000: The City of Port St. Lucie contracted with Masuen to assist with irrigation water use issues
2000 through 2010: Masuen worked methodically to increase the efficiency of existing irrigation systems, and bring existing systems ‘on‐line’ through central control.
2008: South Florida Water Management District (SFWMD) awarded Port St. Lucie a Water SIP grant
2010: Upon Masuen petition, SFWMD granted Port St. Lucie their only current variance of ‘day per week’ watering!
2011: Masuen currently manages all sites using Rain Bird Maxicom computerized central control. In the City we have pioneered the use of both soil moisture sensors with weather stations (ET) to develop irrigation schedules, an industry leading development.

In 2010, the City of Port St Lucie used only 36% of its allocated annual water. Prior to Masuen’s management annual water use usually exceeded this allotment.

The System

Statistics

1 central control computer tied to an online Workstation
Online Workstation presenting graphic interpretations of all information and issuing alerts
47 Controllers
878 Zones
22 Rain cans
19 primarypump stations
4 recharge pump stations
15 metered (reclaimed or potable) sources
14 soil moisture sensors

Energy Savings

Since the City of Port St. Lucie currently uses only 36% of their allocated water they also use only 36% of the energy they would use if they were pumping 100% of the allocated water (It is common to hear complaints that allocations are not sufficient.) Research indicates that it costs approximately $6.00 to pump 1000 gallons. The energy costs at 100% allocation would be $231,141.40 per year. Since only 36% of allocated water is being used, this drastically increases energy savings as well. The City of Port St. Lucie saves an estimated $145,000 per year in energy costs alone.

38,521,900 gallons of water were allocated to PSL in 2007
It takes @5 Kw (7 HP) to pump 100 gpm of water at 80 psi, in 1 hour it will use 300 Kwh and pump 6000 gallons of water
Average Cost per Kwh = $.12 (U.S. Energy Information Administration)
Energy Cost per 1000 gallons pumped: $6.00
Energy Cost at 100% allocation: $231,131.40
The average permit holder exceeds their allocation
PSL Public Works uses @ 36% per year
$231,131.40 * .36 = $83,207.30
$147,924.10 Saved in Energy alone per year

Time Savings

Since Port St. Lucie’s sites are centrally controlled by a Maxicom system, this cuts back on man power required to manage the sites. Thus, lowering costs associated with city owned vehicles, gas, number of employees required to maintain the sites, and overall time involved with field adjusting irrigation controllers and inspecting zones. The City of Port St. Lucie saves an estimated $140,000 per year in time associated savings!

In the words of our client:

“Before Masuen, our water use exceeded our annual allotment from the water district. Today with Masuen’s management we use only 36% of our allotment. Due to Masuen’s knowledge and direction, Port St. Lucie is recognized as a leader in water conservation within the State of Florida. I recommend Masuen Consulting to anyone whose true interest is water conservation. If they helped us they can help you, too.”

John Dunton

Director Environmental Services

Port St. Lucie Public Works