New Bridge Design TDOT
Rotherwood
Park
existing gravity flow sewer line
West
East
Lift station
Utilities Restrictions
temporary sewer line
existing sewer line
existing   water line
All the wastewater generated by City residents west of the North fork of the Holston River (e.g., Rotherwood Estates, Rotherwood Manor, Bays Cove, Allandale, etc.) flows back towards the river and is piped over the river (noted in orange) through a ductile iron pipe (see inset picture) that is built into the truss structure of the existing bridge in order to ultimately convey wastewater to the wastewater treatment plant on Industry Drive.  There is also an old abandoned waterline that would be re-activated in conjunction with the bridge construction project in order to improve water service redundancy in the west end of Kingsport.

One of the principle reasons for requesting the construction of a new bridge immediately adjacent to the existing bridge was to avoid the need to build a temporary sewer line (noted in yellow) to carry wastewater across the river when the existing bridge was torn down.  Relocating this large sewer line into the river bed would be very expensive (estimated at $500,000) and would put wastewater conveyance pipes in environmentally sensitive areas.   In addition, this option would require the construction of a large sewer lift station (similar in size to the station at the corner of Netherland Inn and Ridgefields Road) in order to push the wastewater up the hill from the river bed back up to the existing grade of the sewer lines on the east side of the bridge.

These wastewater issues were presented to TDOT as part of the City’s appeal to build a new bridge adjacent to the old bridge in order to allow the existing lines to be kept in service until the new bridge and new utility lines were constructed on the new bridge.  The TDOT design engineers agreed with the City’s concept plan.  However, as the bridge replacement project has moved forward the TDOT bridge design engineers have subsequently advised the City that no utility lines would be allowed on the new bridge.  However, in response to the City’s protests, TDOT reluctantly agreed to allow the utility lines to be located on the new bridge but they could not be placed on the same grade that they exist on the current bridge – rather TDOT would only allow the utilities to be relocated immediately beneath the new bridge decking which is 20’-30’ higher than the current lines.