Slough of Despond?
As we were contemplating exploring the Slough Arm it started raining and blowing a gale so we decided to continue to Bull's Bridge where the Paddington Arm leaves the main line. Through this horizontal precipitation we spied a plastic launch in difficulties. On hailing the unfortunate sailors we were informed that their engine had stopped working so we towed them round to their marina mooring.
The almost dead straight five mile arm from Cowley Peachey to Slough was one of the last canals to be built in England . In 1882 the railways were making an impact on transport economics throughout the land. However it did survive for a while, taking bricks into London for the building boom and bringing back domestic waste. This was not, I believe, the reason many locals refer to Slough as The Dump. This is more likely to have originated after WW1 when many of the military vehicles were brought to what is now the Trading Estate for disposal.
The town has been immortalised by John Betjeman (in the 1930s) and, more recently, by Rickey Gervaise. Which will be the more enduring depiction we will have to wait to see.
May I remind you of John Betjeman's contribution?

Slough

Come, friendly bombs, and fall on Slough

It isn't fit for humans now,

There isn't grass to graze a cow

Swarm over, Death!

Come, bombs, and blow to smithereens

Those air-conditioned, bright canteens,

Tinned fruit, tinned meat, tinned milk, tinned beans

Tinned minds, tinned breath.

Mess up the mess they call a town --

A house for ninety-seven down

And once a week for half-a-crown

For twenty years,

And get that man with double chin

Who'll always cheat and always win,

Who washes his repulsive skin

In women's tears,

And smash his desk of polished oak

And smash his hands so used to stroke

And stop his boring dirty joke

And make him yell.

But spare the bald young clerks who add

The profits of the stinking cad;

It's not their fault that they are mad,

They've tasted Hell.

It's not their fault they do not know

The birdsong from the radio,

It's not their fault they often go

To Maidenhead

And talk of sports and makes of cars

In various bogus Tudor bars

And daren't look up and see the stars

But belch instead.

In labour-saving homes, with care

Their wives frizz out peroxide hair

And dry it in synthetic air

And paint their nails.

Come, friendly bombs, and fall on Slough

To get it ready for the plough.

The cabbages are coming now;

The earth exhales.

John Betjeman