Exhibit 1 - Agenda Information SheetCity of Denton
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AGENDA INFORMATION SHEET
DEPARTMENT: Procurement & Compliance
CFO: Antonio Puente, Jr.
DATE: March 3, 2020
SUBJECT
Consider adoption of an ordinance ratifying the expenditure of funds by the City Manager and the
Purchasing agent for the emergency purchases for the State School Interceptor sewer line failure and the
Hickory Creek forcemain break in accordance with Texas Local Government Code 252.022, which provides
that procurement of commodities and services made to preserve or protect the public health or safety of the
municipality’s residents is exempt from competitive bidding, and if over $50,000 shall be awarded by the
governing body; and providing an effective date (File 6917 – State School failure expenditure of
$260,709.20 and Hickory Creek forcemain break expenditure of $71,245.49). The Public Utilities Board
recommends approval (6 - 0).
INFORMATION/BACKGROUND
This ordinance ratifying emergency purchases includes response to two separate failures within the same
section of the wastewater collection system (1) The State School Interceptor, and (2) the Hickory Creek
Forcemain.
STATE SCHOOL INTERCEPTOR
The State School Interceptor begins near the State Assisted Living Center and carries the majority of the
flow coming into the Pecan Creek Water Reclamation Facility. A portion of this line runs along Pecan
Creek east of the landfill and water reclamation facility
Pecan Creek Emergency and Immediate Response
Monday October 1, 2018 at 1:30PM, Watershed Protection staff located a slope failure which caused a
sewer interceptor failure along Pecan Creek near the Pecan Creek Water Reclamation Plant (PCWRP). The
discovery was made during a field investigation initiated due to a reported fish kill in Pecan Creek.
The creek bank along Pecan Creek suffered a severe slope failure caused by heavy rainfall. Denton received
approximately 12 inches of rain in September 2018, compared with an average of approximately 3 inches.
A single rainfall event accounted for over 7 inches of rain in 2 days.
Approximately 1,800 feet south of the PCRWP, a large section of the stream bank collapsed into the creek,
along with a 21-inch diameter sewer interceptor. Utilities staff were on site by 2:00PM and immediately
began work to stabilize the slope and stop the overflow. Water distribution and wastewater collection staff
were able to place a plug in the line at a manhole upstream of the failure, successfully bypassing the flow
to a parallel 24-inch diameter line at 11:30PM. Staff performed non-stop earthwork activities to prevent
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any further slope failure in the area, completing temporary stabilization at approximately 2:00PM Tuesday.
Wastewater collection staff remained on site 24-hours a day to monitor the status/condition of the plug, to
prevent it from becoming dislodged from the pipe, and to observe any further erosion by water flow in the
creek.
The day the failure was discovered, Utilities Administration enlisted the services of 3rd party civil and
structural engineers to assist with design and recommendations for both temporary and permanent stream
bank stabilization. Geotechnical borings were completed the day after the failure was discovered and were
led by a geotechnical engineer.
Design and Implementation of Repairs
Wastewater Collection and Water Distribution Crews stabilized the creek bank slope and repaired the failed
section of the 21-inch diameter wastewater interceptor.
Concurrent with the repair work, staff negotiated a professional services contract with CP&Y, Inc. for
design of a re-routed 1,000-feet segment of the State School Interceptor lines in the vicinity of break at
Pecan Creek, and a separate contract for design of stabilization of the stream bank.
Outcome of Interceptor Replacement Design
The Engineer’s Opinion of Probable Construction Cost was $375,000.00, comparable to staff estimates.
Bids were received from 3 Contractors; the low bid was $563,380.00. As this far exceeded the expectations
of the project team, all bids were rejected.
Outcome of Stream Bank Repair and Design
Periodic monitoring of the repaired creek bank slope revealed that the repairs have remained stable for over
12 months, during which time, several significant rainfall events have occurred. Limited preliminary stream
bank repair design and surveying work was completed during this monitoring period. The Professional
Services Contract for streambank repair design was closed prior to completion.
HICKORY CREEK FORCE MAIN
The Hickory Creek Lift Station is at the end of the Hickory Creek Interceptor sewer and pumps all
wastewater flows from the Hickory Creek sewer basin through a 24-inch diameter 12,000 plus feet long
pressure force main to the State School Interceptor, a gravity sewer line located near Denton State School.
Hickory Creek Force Main Emergency and Immediate Response
On December 13, plant staff were alerted to a No. 1 Pump VFD Failure alarm from the Hickory Creek
Lift Station. An attempt was made to start Pump No. 1, at which point it was discovered that the VFD
would not start. Pump No. 2 was started to continue pumping operation. There was no overflow reported
with this alarm.
A short time later, Utilities Dispatch received a call reporting sewer spilling onto the ground along
Thoroughbred Trail. Plant staff immediately drove to the area and found a break in the force main within
an easement through private property, close to a resident’s home. Staff prepared a plan of action that
included shutting down the lift station so that the overflow could be diverted to a less populous area
reducing the chances of human contact. Collections staff mobilized equipment and exposed the break in
the force main and called in welders to repair the break in the 24-inch force main.
A bypass pump vendor was called to bring in bypass pumps to pump from the Hickory Creek Lift Station
to the Upper Trinity Lift Station on Old Alton Rd. Bypass pumping was performed for approximately 24
hours during the repair.
Implementation of Repairs
Wastewater Collection enlisted the services of a specialty pipe repair contractor, as the necessary work is
beyond the capabilities of in-house crews. The repair required specialized welding and protection.
Impacts to private property were mitigated.
Follow-up Investigation
Our internal investigation of the events that happened shows no indication that the VFD failure and the
break in the force main are tied together. There is no indication that the ram check on the No. 1 pump
malfunctioned when the VFD failed. The ram check still operated the way it was intended to operate and
it regulated the shutting of the check valve. This regulated slow closing of the check valve is designed to
alleviate any surge pressures in the 24 inch pressure main. Further evidence of this is that the pump
packing was not pushed out as it would be if the check valve had slammed.
DME was contacted to see if there were any power disruptions in the area and none were observed from
DME. No other alarms were generated at the lift station.
Since the break occurred on the far end of the force main, it does not appear that there would be sufficient
surge pressure that far from the pump station that would cause the pipe failure. Given the evidence that the
check valves did not slam, it appears that the joint where the pipe failed had some defect that just presented
itself at the optimal time. When the pipe was exposed for repair, besides the joint where the hole in the pipe
occurred, rest of the pipe was observed to be in good condition and not affected by surge pressure.
PRIOR ACTION/REVIEW (Council, Boards, Commissions)
Issued an Informal Staff Report for the Pecan Creek failure on October 5, 2018.
On February 24, 2020, the Public Utilities Board (PUB) recommended this item to the City Council for
consideration.
RECOMMENDATION
Staff recommends the approval of expenditures for the emergency purchases for the State School
Interceptor sewer line failure and the Hickory Creek forcemain break.
ESTIMATED SCHEDULE OF PROJECT
Project complete.
FISCAL INFORMATION
The project was funded using unallocated funds placed in Account 640389541. A total of $331,954.73
was expended.
State School Interceptor sewer line failure expenditures $260,709.20
o Barco Pump - $116,327
o CP & Y Inc - $38,070.80
o Mid-West Hose & Specialty Inc - $89,101.77
o Redi-Mix Concrete - $1,160
o Sunbelt Rentals - $16,049.67
Hickory Creek forcemain break expenditures $71,245.49
o Ferguson Waterworks - $2,727.88
o Graybar Electric Company - $16,958.88
o Rangeline Pipeline Services, LLC. - $13,695.71
o Sunbelt Rentals - $27,288.16
o Titan Fence and Supply Co - $10,574.86
EXHIBITS
Exhibit 1: Agenda Information Sheet
Exhibit 2: Declaration of Emergency – State School Interceptor
Exhibit 3: Declaration of Emergency – Hickory Creek Forcemain Break
Exhibit 4: Ordinance
Respectfully submitted:
Lori Hewell
Purchasing Manager
For information concerning this acquisition, contact: Frank Pugsley, 940-349-8086.
Legal point of contact: Mack Reinwand at 940-349-8333.