19th July 2023

The discharge of untreated sewage into the nation’s river network from treatment works has caused widespread concern.

The problem has become significantly worse in recent years, and unfortunately it directly affects the rivers in the Colne Valley Regional Park.

We were deeply disturbed by the findings of a recent study carried out in the Watford area that detected an astonishing 267 micropollutants in samples of river water, some of which are hazardous to the environment and to humans. You can read more about it here.

Further investigation is urgently needed both locally and nationally to give us all a better understanding of what this really means, but in the meantime it seems obvious that our relationship with our rivers needs to be considerably more cautious.

The River Misbourne, for example, is one of the key attractions of Denham Country Park and the events we organise for children there are always extremely popular.

Attempts to find definitive practical advice from the authorities on safely enjoying our rivers have so far been unsuccessful – at the time of writing it appears there are no clear guidelines or reassurances to the public on the risks to human health caused by repeated raw sewage discharges.

In the absence of official advice, the Colne Valley Regional Park’s managing agents, Groundwork South have reviewed and updated risk assessments for all activities hosted at our visitor centre in Denham Country Park.

We certainly don’t want to cause unnecessary alarm among our many visitors, but it is only fair that we should remind members of the public that the water in local rivers like the Misbourne and Colne may well not be as clean as they might expect.

The River Misbourne is a chalk stream, so beautiful on the surface.

We urge visitors to keep an eye on the special Thames Water map which carries notifications of any raw sewage discharges

We recently had to change arrangements for a local school’s river-dipping event in the Misbourne because the sewage treatment works upriver at Gerrards Cross had been discharging just days before the session was due to take place.

This was the only responsible thing we could do, but the children were very disappointed that they couldn’t go into the river. They did, however, understand the reasons why and ended up greatly enjoying the alternative learning activities we provided for them instead. The class decided it will write to Thames Water, and we greatly look forward to seeing a copy of their letter.

We are asking all those who have taken part in river-dipping sessions to wash their hands thoroughly afterwards with soap and clean water, particularly if they intend having anything to eat or drink in the café, and to try not to splash one another while in the river itself.

We want everyone to get the maximum enjoyment from our beautiful rivers and countryside and, together with landowners and partners, will be keeping a close eye on developments to ensure you can continue to do that in safety.