1、The expanding waters would leave fertile silt all along the banks of the river,making the area farming land noce the river had subsided angai.
2、It can also be caused by tsunamis,large waves in the ocean triggered by a shift in the Earth's crust.
3、When the land is saturated-that is ,has soaked up all the water it can-any more water that accumulates must flow as runoff.
4、feeling the pinch of food prices and monthly mortgage payments.
喷涌而出的水会将肥沃的淤泥带到河岸每处角落，使得河岸周围的农田沉淀。。。（后面这句太难了还是你打错了）
2、It can also be caused by tsunamis,（which is 修饰tsunamis）后置定语从句large waves in the ocean triggered by a shift in the Earth's crust.
这也可能是由于海啸造成的，海啸是那种由于地球地壳的移动而造成海洋上巨大的波浪。
3、When the land is saturated-that is ,has soaked up all the water it can-any more water that accumulates must flow as runoff.（这句话要结合前面的内容理解翻译，不能断章取义）
当土地被浸泡，那就是泥土吸够他所能吸的水再也不能吸取后，积累在泥土里的水就会形成一条径流而流出。
4、feeling the pinch of food prices and monthly mortgage payments.（这应该是定语或状语从句，结合前面那句理解）
由于食物价格和每月房贷的偿还感到手头拮据。