31. From about 1877 the silting of the channels started to improve and trade improved again. 32. But the silting and the lack of oxygen has greatly reduced the number of trout. 33. The port silting theory has been considered but no real evidence is established at present. 34. Over the course of time, these became bogs through the natural silting up process. 35. The lake itself is increasingly silting up. 36. But heavy silting has made it hard for ocean liners to use Haiphong's harbor. 37. Seleucia Pieria, which was already fighting a losing battle against continual silting , never recovered. 38. During the early 1800s as trade was increasing, so the river was simultaneously silting up. 39. By 1908 problems with river silting and bar strandings meant that coastal shipping was avoiding Foxton. 40. Subject to silting up, it was dredged several times for the Canal's use.
