2018-075 Water SupplyDate: 6/15/2018 Report No. 2018-075
INFORMAL STAFF REPORT
TO MAYOR AND CITY COUNCIL
SUBJECT:
Provide information for requests made during the June 4, 2018 City Council meeting regarding
the Water Budget and Departmental presentation and during the June 5, 2018 City Council
meeting regarding the Water Supply Planning presentation.
DISCUSSION:
Staff presented the Water Budget and Departmental presentation during the June 4, 2018 council
session and information about water supply planning during the June 5, 2018 City Council
session. During these presentation, Councilman Hudspeth asked for information about water
supply sources and pipes for both Lewisville and Ray Roberts, information concerning the Lake
Lewisville Ray Water Transmission line assessment, and specifically requested images. Images
included in this staff report include a map showing the Lake Lewisville and Lake Ray Roberts
plants with raw water line infrastructure, various images of the plants and transmission lines, and
images of the electromagnetic inspection and visual assessment of the 30 inch Lake Lewisville
Raw Water Transmission line.
With regards to water supply sources, the Lake Lewisville plant has a total capacity of 28
Million Gallons per Day (“MGD”). We produce about 35 to 40% of total Denton water demands
from this facility on an annual basis. Even though this water plant has higher capacity, there is
more energy costs to pump the water uphill from Lake Lewisville into the plant at Spencer Road
since the elevation difference is about 100 feet of vertical lift. It is important to note that these
percentages are on an annual basis. This plant will operate at a higher capacity during times of
high demand since it currently represents about 60 percent of the total system capacity. The
Lake Ray Roberts plant currently has 20 MGD capacity, and about 60 to 65% of the total Denton
water demand is produced from this plant on an annual basis. Due to elevation differences
between Lewisville and Ray Roberts, we have lower overall energy costs to use this plant and
can actually gravity feed water through the plant processes unless lake elevations are very low.
CONCLUSION:
Staff will be glad to provide any additional information upon request.
ATTACHMENT(S):
Images of plants, transmission lines, and pipe assessments
STAFF CONTACT:
Kenneth Banks.
General Manager of Utilities
(940) 349-7165
Kenneth.Banks@cityofdenton.com
Date: 6/15/2018 Report No. 2018-075
PLANT INFRASTRUCTURE:
Lewisville and Ray Roberts water plants with raw water transmission lines in red and major
infrastructure.
Date: 6/15/2018 Report No. 2018-075
Ray Roberts Plant, with the Dam and lake in the background. The intake structure is built into
the outflow of the dam
Date: 6/15/2018 Report No. 2018-075
54 inch transmission pipe during installation. This pipe conveys water from the Ray Roberts
plant to Loop 288.
Date: 6/15/2018 Report No. 2018-075
Intake Structure for the Lake Lewisville Plant near I-35 Bridge
Lake Lewisville Plant on Spencer Road
Date: 6/15/2018 Report No. 2018-075
Electrmagnetic and visual inspections of Bar Wrapped Pipe
The approach uses multiple electromagnetic detectors configured circumferentially that are
passed through pipe.
Magnetic anamolies indicate problems with broken reinforcing bars
Date: 6/15/2018 Report No. 2018-075
Pipes can then be exposed and repaired or replaced
Date: 6/15/2018 Report No. 2018-075
Video inspections via camera are conducted at the same time and can be used to detect a variety
of issues such as cracks or carbonate staining, which may indicate pipe integrity concerns.