HOBE-ST. LUCIE CONSERVANCEY DISTRICT
2015 Facility Evaluation Report – Phase I

Prepared by:
Higgins Engineering, Inc.

July 24, 2015

07-18.7

Table of Contents

Introduction	1
Surface Water Irrigation System	2
St. Lucie Irrigation Pump Station	2
Kanner Highway Culvert	4
Pasture Pump Station	5
Irrigation Culverts	7
Ground Water Irrigation System	8
Unit 1	9
Unit 2	9
Unit 3	9
Balance of the District	10
Unit Number 1	11
Outfall Canal 1 - OC-1	12
The 72” Culvert for water from State Lands	13
Unit Number 1 Outfall Structure	13
Unit Number 2	15
Turnpike Canal	15
Unit Number 2 Outfall Canal – OC-2	15
Culvert Interconnect between Unit 2 and Unit 3	15
Unit Number 2 Outfall Structure	16
New Culvert Crossing SE corner of Balance of the District	17
Canal Crossings 2, 3 and the Cypress Creek Structure	19
Unit Number 3	22
Unit Number 3 Outfall Canal	22
Unit Number 3 Outfall Structure	23
Unit 3 Interconnect IC1	24
Findings and Recommendations	24
Estimated Maintenance Cost Table	26

Introduction

On April 24th, 2013, this office was requested by the Hobe-St. Lucie Conservancy District (the District) to perform a review of the current condition of the Water Control Facilities for Units 1, 2, 3, and the “Balance of the District” under its jurisdiction and provide an evaluation of their current condition. The District further requested that the review be a two phased approach. Phase I will include water control facilities located in Unit 1, 2, and 3, and Phase II will include the “Balance of the District.”

Based on the review of these facilities, the general conditions of the canals were found to be good with aquatic weeds absent or at least less prevalent upstream than the downstream portions of the canal.

The St Lucie intake structure was found to be in good condition, however the intermediate “pasture pump” facility was found to be in fair to poor condition and is in need of attention. Shortly after this field visit the pumps were refurbished. The other irrigation canal IC-1 was found to be in good condition with some side slope erosion. Two of the three outfall structures were in good condition but the third, the outfall structure for Unit 2 “Cypress Creek Structure”, which was constructed in the 1960’s needed to be repaired, replaced, or removed.

The District files did not seem to be complete with several pipes and structures, either mentioned only in general terms or not reflected at all on the facility report or maps.

This specific issue was a concern during the 2004 hurricane season when several downstream blockages impacted District facilities and restricted flows. These structures continue to be a potential restriction in storm water discharges and a future maintenance concern.

After evaluating the necessary repairs and replacement costs, it estimated that the District can be expected to expend approximately $100,000 in the next five years.

To summarize, this office believes the following to be the major areas for the District to focus on.
Address the erosion around the St. Lucie Irrigation Pump Station outfall before damage is done to the infrastructure.
Address the leak at the Unit Number 3 Outfall Structure.
Continue an aggressive aquatic weed control program. St. Lucie Canal to Unit 2 (IC 2)

Surface Water Irrigation System
The canal IC 2, as designated on the District facility maps, provides irrigation water to a portion of the District. It draws water from the St. Lucie Canal, discharging to the west side of Unit 2.

St. Lucie Irrigation Pump Station
The intake structure is located on the St. Lucie Canal approximately 6 miles west of the Florida Turnpike and north of the Kanner Highway. The pump station consists of two 25,000 gallon per minute vertically mounted axial flow pumps with 150-horsepower electric motors. Drive shafts and gear heads connect the pumps with the motors. Pump operation  is controlled by floats and timers. Timers are used to take advantage of off-peak electrical power rates. These motors and pumps were installed in their current configuration approximately 17 years ago. At that time the existing steel sheet pile fore-bay was  improved with the installation of concrete walls. In 2013 both pumps were refurbished. A sound barrier wall was added facing the canal. The resulting structure is in good condition and would be expected to serve the District at least 15 more years into the future.
The motors are in good condition and should have an expected life of greater than 15 years. Both pumps were recently refurbished in 2013.
The pump house, a concrete block building with a removable roof, appears to be in good condition. The entire facility is enclosed in a 6 foot chain link fence which is also in good condition with the exception of the corrosion where it comes into contact with the concrete. Additional supports have been welded on to the fence to provide structural strength. In the future the fence posts will likely need replacement. It is recommended the posts be properly treated anywhere they come in contact with concrete. The only areas that

may be subject to improper access is from the St. Lucie Canal. As a result, The District may wish to consider adding additional security and warning measures to the structure on the portion facing the Canal.
St. Lucie Irrigation Pump Station

Recommended Maintenance:
Erosion around headwalls of pump discharge needs to be addressed (Short Term).

The fencing around the intake structure which was contacting the cement corroded near the contact point. A short term repair has been made by welding braces to the fencing. At this

time the repair is holding up fine, but should be watched for additional corrosion. Fencing should be budgeted for replacement (Mid to Long Term).

Flap gates in stilling well were replaced this year. A grease fitting was installed that will allow for the flap gates to be greased from the stilling well opening. Before greasing, the flap gate hinges required a maintenance person to go into the stilling well which is time consuming and challenging.

Kanner Highway Culvert
During a freeze that occurred in the past both pumps were running and water reportedly was observed flowing over the road. With the refurbishment of the pumps it can be expected that the pumps will be pumping closer to their design flow rates. A HEC-RAS and S2DMM analysis was performed which showed the two 42” Culverts and the Irrigation Canal (IC-2) are capable of providing conveyance for both pumps turned on. Regular maintenance is required.
The channel itself is in relatively good condition, and while some nuisance species were observed, it does not appear to impede the flow of the channel. The entire Channel recently was mechanically cleaned. Regular maintenance is required.