Infiltration and inflow: Difference between revisions

Revision as of 01:24, 3 January 2011

Revision as of 14:50, 24 March 2011

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[[Groundwater]] entering sanitary sewers through defective pipe joints and broken pipes is called ''infiltration''.<ref name="king">King, James J. ''The Environmental Dictionary'' (1995) John Wiley & Sons ISBN 0-471-11995-4 p.335</ref> Pipes may leak because of careless installation; or they may be damaged after installation by differential ground movement, heavy vehicle traffic on roadways above the sewer, careless construction practices in nearby trenches, or degradation of the sewer pipe materials. In general, volume of leakage will increase over time.

Infiltration will occur where local groundwater elevation is higher than the sewer pipepippe. Gravel bedding materials in sewer pipe trenches act as a [[French drain]]. Groundwater flows parallel to the sewer until it reaches the area of damaged pipe. In areas of low groundwater, sewage may exfiltrate into groundwater from a leaking sewer.<ref name="eddy">Metcalf & Eddy ''Wastewater Engineering'' (1972) McGraw-Hill pp.39-44</ref>

==Inflow==