Stream-Front Wall

Location

Knoxville, TN

Total Wall Area

321 square feet

Maximum Height

5.3 feet

Challenge

This residential retaining wall is located along a stream in the owner’s backyard. While typically less than a foot deep, this stream can rise to a depth over four feet of fast rushing water in heavy rain events. Existing walls were failing along the stream as they were undermined by the fast moving water. Construction along a stream can be challenging due to working within tight time constraints to avoid elevated water levels. Traditional stone footings can not be utilized due to long term scouring concerns from the flowing water. Drainage is also a concern as these walls need to be able to discharge water quickly to avoid a buildup of hydrostatic pressure behind the wall.

Solution

The wall construction was observed and recommendations were made by Dean Engineering and Design to combat the conditions caused by the stream. A concrete leveling pad was utilized to remove the concern of scouring by the stream. A solid core retaining wall unit was selected to allow for quicker construction. Typically walls are built 24 inches at a time then backfilled. By using a solid unit, the wall could be constructed to full height and backfilled at the end so that the stream would not have to be diverted for as long. Additional drainage was incorporated in the wall and free draining aggregate was specified to ensure the wall could discharge water as quickly as the stream levels recede.