set the box on a layer of free draining gravel or sand and backfill with granular material. provide a cover which fits tightly and a gasket or seal to prevent water from coming in the top
Alternatively if your soil is not free draining you can construct a base slab with a sump in one corner big enough to accept a small submersible pump. Say 300mm x 300mm by 300mm deep.
I once put a system of underground conduit with manholes that was in a heavy clay soil.
We simply put sump pits in each manhole and ran a 50 mm PVC with a heat trace line from manhole to manhole. The seepage was pumped through 4 manholes before we got close to an existing drain.
Rick Kitson MBA P.Eng
Construction Project Management
From conception to completion
