Case Study - Copper Hill

This multi-family property was experiencing water seeping over a sidewalk and across a portion of the parking lot. One tenant had already fallen and injured herself. The source of the water was subsurface flow that was being exposed as it migrated to the lower elevations where the walkway and parking area were located.

This photo was taken just as our project was getting underway. Water can be seen seeping out from under the sidewalk. Notice that stakes are being placed along what will be the trench. Information is written on each stake to allow for the trench depth to be measured from each stake. This insures the correct slope of the pipe. Drainage Case Study - Copper Hill 1
The design calls for intercepting the subsurface flow before it can be exposed. This will require that a trench will be excavated on uphill side of the walkway. Immediately after beginning the excavation, water can be observed in the trench. Drainage Case Study - Copper Hill 2
After the trench excavation is complete, the water is already beginning to flow through the trench rather than across the concrete. The system is already doing its job.

In this photo, you can see the fabric used to line the trench and the perforated pipe placed in the bottom. Not shown is the gravel that will be used to backfill the trench to near the top. The theory is that water will flow across the trench and fall through the spaces between the gravel aggregate to the bottom of the trench. It will then enter the pipe through the holes in the pipe and then flow with the slope of the pipe to the discharge point. 

Drainage Case Study - Copper Hill 3
After the trench is backfilled with gravel, the fabric is folded over on top of the trench, totally enclosing the system. This helps to keep dirt from getting into the gravel and slowing the flow of water through the gravel. Native soil can then be placed on top and new grass can be planted. With a little water on the sod, this area will look as good as new , and no more “slippin’ and slidin’” for residents. Drainage Case Study - Copper Hill 4