At a glance it could have been flowing milk.

So much time, money and effort has gone into cleaning up our waterways. And they certainly needed some cleaning up from the ravages of generations gone by.

Just 40 years ago the Calder and some of its tributaries regularly changed colour, depending who was discharging waste into it.

Since then the system has been cleaned to such an extent it now supports a rich divergance of wildlife from heron and kingfishers to trout and grayling.

Where once the smell of detergent would have bowled people over, now the riverbanks and walkways are full of walkers and people taking in the view over a picnic.

The Environment Agency was quick on the scene and believes there was little, if any, ecological damage. This time.

Samples of the water will tell the truth when analysed.

It is encouraging that members of the public were so vigilant in this instance.

The battle against pollution and polluters is ongoing.

In the interests of the environment it is up to every one of us to keep our eyes wide open.