High water table

[kechha2060]

What are best practices that need to considered for a roadway, storm sewers, water line project that will be designed and constructed in a high water table location? The water table is like 4' below the existing grade.

Thanks

 

[Ron]

High groundwater can impact the design, construction and maintenance of each of those.

Pavement:
Groundwater within about 18 inches of a flexible pavement base material will can reduce the structural life of the pavement. The design should accommodate groundwater level control through fill, underdrains, swales or a combination of these. Rigid pavement is less sensitive to high groundwater but is still affected if the subbase support to the concrete is compromised.

Storm sewers:
The most significant problems here are construction (getting the piping in place) and sealing the joints and intersections with manholes, etc. Water and sand infiltration at joints causes downstream problems of lowered capacity and silting/sand buildup

Water line:
Groundwater has little effect on water lines as long as you can get them constructed. Dewatering might be required. If the piping is affected by corrosion, then the groundwater can be an issue...otherwise not so much.

 

[beej67]

When looking at dewatering in sandy or silty soils, make sure you take a hard look at the possible ill effects of temporarily reducing the water table to get your utilities in, particularly to adjacent properties with water features.

Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com

 

[cvg]

also bear in mind if you dewater, you will generally need a permit for both temporary and permanent measures.

floatation of pipes and manholes can occur both during installation or after construction if not properly anchored.

 

[GoldDredger]

That ought to be enough to answer the homework questions.