2020-080 Farris Road SewerDate: September 4, 2020 Report No. 2020-080
INFORMAL STAFF REPORT
TO MAYOR AND CITY COUNCIL
SUBJECT:
On Sunday August 30, 2020 a resident of unincorporated Denton County and customer of the Oak Bend
Homeowners Water Supply Company (OBHWSC) wrote to Council to express their concern regarding a
proposed wastewater collection line along Farris Road. The resident noted that the OBHWSC wells are
located approximately 100 feet from the proposed wastewater line. The resident requested clarification
regarding why the Farris Road alignment was being proposed by the developer, while other alternatives
appear to be available.
DISCUSSION:
It should be noted prior to beginning this discussion that the Utility is in the preliminary design phase for
the Clear Creek Wastewater Lift Station, located north of Hartlee Field Road. This lift station will ultimately
handle the wastewater from the developments in question, with anticipated completion in 2023. The flow
contributions from the development would cease when the lift station is placed into operation.
The OBHWSC owns and operates two (2) water wells and a distribution system to provide potable water
to their residents. The residents are presumed to have individual septic systems.
The resident had a conversation with Mr. Stephen Belknap, P.E., Denton County Development Services
Engineer, where the resident understood that the City of Denton was preparing to install a wastewater
collection line along Farris Road, from Grant Parkway, north to Hartlee Field Road.
The developer of the proposed “Hartlee Field Ranch” development has been working with the Utilities
Department to provide options for access to adequate water and wastewater utility service. In accordance
with the Denton Development Code and Water and Wastewater Design Criteria Manual, the City will not
construct any extensions for the developer. If the development is approved, the wastewater infrastructure
in question would be wholly paid for and constructed by the Developer and dedicated to the City upon final
inspection and acceptance. The City has design review and inspection authority over any such infrastructure
and must inform the County that the City shall assume operations and maintenance of any developer
constructed infrastructure, once inspected and accepted by the City.
Connection Options
The developer approached the City requesting confirmation of their proposed water and wastewater utility
connection points, which initially included wastewater discharge to the collection system near Long Road
and Sherman Drive/FM 428. This plan would constitute pumping wastewater out of one drainage basin
(Clear Creek Basin) to another (Cooper Creek Basin). Sewer basins are generally divided by ground
elevation/topography, as wastewater generally flows by gravity to the treatment facility. Because the
wastewater collection system is designed and constructed using flow projections for a particular basin,
pumping from one to another is sometimes unfeasible due to capacity issues, which is the case with the
collection system near Long Road and Sherman Drive/FM 428. The developer went as far as placing a flow
metering device in the collection system near this location to verify the city-provided data.
Date: September 4, 2020 Report No. 2020-080
The collection system line at the intersection of Grant Parkway and Farris Road currently has adequate
capacity to accommodate flow from the initial phases of development along Hartlee Field Road.
As noted above, when the Clear Creek Lift Station is complete, all sewer flows north of Hartlee Field Road
are intended to be handled by the Clear Creek Lift Station, pumping the wastewater south to the treatment
plant.
The Utility and Developer discussed three (3) potential options:
1. Discharge to the collection system on Long Road – Insufficient capacity
2. Discharge to the collection system on Farris Road – Sufficient capacity, interim solution pursued
by developer
3. Discharge to the collection system on Cooper Creek Road – Insufficient capacity
Oak Bend Homeowners Water Supply Wells
The Texas Water Development Board database indicates that the OBHWSC owns two water wells, one
screened between 616 to 626 feet and 630 to 656 feet below ground surface. The second well is screened
between 1067 to 1088 feet and 1115 to 1136 feet below ground surface.
From a geologic standpoint, well No. 1 appears to draw water from the Paluxy Formation, based on its
depth of 616 to 656 feet, and well No. 2 draws water from the Twin Mountain Formation, based upon notes
on the well report, both components of the Trinity Aquifer. The Trinity Aquifer is separated from the surface
by the Woodbine Aquifer and several hundred feet of low permeability formations consisting of clay, shale,
limestone and marl. Contamination of the Trinity Aquifer form local septic systems, or wastewater
collection mains by infiltration is not possible.
The Texas Commission on Environmental Quality (TCEQ) rules (30 TAC §290.40(c)) require minimum
separation distances between water wells and certain wastewater infrastructure:
50-feet – Tile or concrete sanitary sewer, sewerage appurtenance, septic tank, storm sewer, or
cemetery.
150-feet – septic tank perforated drain field, areas irrigated by low-dosage, low angle spray on-site
sewage facilities, absorption bed, evapotranspiration bed, improperly constructed water well, or
underground petroleum and chemical storage tank or liquid transmission pipeline.
The TCEQ also requires minimum separation distances between water distribution lines and wastewater
infrastructure (30 TAC §217.53(d)). This minimum distance is 9-feet in all cases, without additional
construction methods and materials (Figure: 30 TAC §217.53(d)(3)).
In no case would the City permit the construction of wastewater infrastructure in violation of these
provisions. The City does not permit the construction of wastewater gravity mains using tile (clay) or
concrete pipe. PVC wastewater pipe is the current City standard in the size anticipated here.
Date: September 4, 2020 Report No. 2020-080
Development Area Map
Water Well Area Map
Date: September 4, 2020 Report No. 2020-080
STAFF CONTACT:
Date: September 4, 2020 Report No. 2020-080
Frank Pugsley
Director of Water and Wastewater Utilities
940-349-8086
REQUESTOR:
Multiple Council Members
PARTICIPATING DEPARTMENTS:
Water Utilities
STAFF TIME TO COMPLETE:
4 man-hours