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:
“It’s so easy during those first few months to think that the problems will never end. You feel as if your son will never sleep through the night, will always spit up food after eating, and will never learn to smile—even though you don’t know any adults or even older children who still act this way.”
—Lawrence Kutner (20th century)
“The truth of the thoughts that are here set forth seems to me unassailable and definitive. I therefore believe myself to have found, on all essential points, the final solution of the problems. And if I am not mistaken in this belief, then the second thing in which the value of this work consists is that it shows how little is achieved when these problems are solved.”
—Ludwig Wittgenstein (1889–1951)
“Men decide far more problems by hate, love, lust, rage, sorrow, joy, hope, fear, illusion, or some other inward emotion than by reality, authority, any legal standard, judicial precedent, or statute.”
—Marcus Tullius Cicero (106–43 B.C.)