Problems
Holes or gaps have to be left in the pipes to allow water to transfer from the subsoil to the pipe and these tend to block with soil or allow silt into the pipe, so blocking it or reducing the flow of water. This can be partially overcome by surrounding the pipes with gravel. However, with time even the gravel becomes choked with soil/silt, so in the latest practice, the gravel is surrounded with a geotextile material which filters out soil particles. Ideally, land drains are laid with access points so that high pressure water jetting is possible to clear silt. However, whatever the technology, all land drains have a finite life and eventually become ineffective due to the ingress of silt and/or the blocking of the surrounding filter media.
Read more about this topic: Land Drains
Famous quotes containing the word problems:
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—Hortense Odlum (1892–?)
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—Lillian Breslow Rubin (20th century)
“There is an enormous chasm between the relatively rich and powerful people who make decisions in government, business, and finance and our poorer neighbors who must depend on these decisions to alleviate the problems caused by their lack of power and influence.”
—Jimmy Carter (James Earl Carter, Jr.)