One reason why a lot of rivers dry up is due to abstraction by man
rather than natural processes.
As far as the levels of streams and rivers, here in the UK, they don't
seem to have dropped measurably and in many cases have been the cause
of significant flooding in recent years. This is because our
watercourses are dependent on the annual variation in rainfall, and
not the presence of ice upon the landscape that disappeared nearly
10,000 years ago.
On 10/15/15, John Wood <[log in to unmask]> wrote:
>>On 10/15/15, Constantinos Ragazas
>> <[log in to unmask]> wrote:
> "Unlikely"? I would argue "more likely". Since the closer in time we
> are to the glacier great melt, the more meltwater we have to be
> drained from the surface. The glaciers at their maximum were said to
> have been 2 miles thick! (not my estimate!). That is a lot of water!
> But, Kostas, when the Rhosyfelin quarry was being used the glaciers
> and their meltwater had long gone!
> But we don't need to go that far back to recognize water levels of
> rivers and lakes have declined over the years. In my own lifetime I
> have seen some rivers and streams in the countryside of my youth
> nearly dry up. And we can also see the water levels drop if we look at
> current river banks. Where the higher water volumes carved and eroded
> vertical layers of sediments tens of meters thick. I have seen these
> too in the countryside of my youth. And of course you must have too.
> Are you saying that we are rivers our still carrying water from the
> last glaciation, and this meltwater has just got less and less over
> the time? In this country most of our river water comes from rain, it
> falls out of the skies, though looking at pictures of your formative
> homeland you probably never had that there, so an alternative such as
> glaciation might be more appealing.