Welwyn's Mimram at risk as Hertfordshire rivers show the strain
PUBLISHED: 07:38 07 May 2017
Danny Loo Photography 2017
Just when they should be at their healthiest, Hertfordshire rivers including Welwyn Hatfield's beautiful Mimram are struggling from months of dry weather, wildlife experts have warned.
After a very dry winter and early spring, the Colne, which rises in North Mymms Park, has run dry through London Colney, and while the Mimram is flowing through Welwyn and Panshanger Park, it is clearly showing the strain.
David Johnson, living rivers officer for the Herts and Middlesex Wildlife Trust, said: “We have had 50 to 70 per cent below average rainfall over the winter and the effects are now clear to see on Hertfordshire’s rivers.
“The River Mimram is noticeably lower, including at Panshanger Park, although not yet dried out anywhere. With rivers at their peak flow at this time of year, the water levels are likely to fall further as the year goes on.
“There was a drought in 2012 and it took five years for the river to recover, meaning that this latest dry spell comes just as the river was restored.
“We are concerned for wildlife, particularly as at this time of year river-dwellers are spawning. Low water levels mean that fish are threatened and have to move to downstream habitats, while less mobile organisms, like invertebrates, are unable to move, leading to their demise.
“With invertebrate populations decimated, wildlife that rely on them as a food source – such as birds and the returning fish populations when the river levels rise again, are under threat.
“Water voles will also be threatened as their habitat range will be reduced and it will be harder to escape from predation.”
Although Affinity Water says official drought conditions have not been reached yet, conservationists have begged residents to remember that domestic water use directly affects river levels.
Mr Johnson said: “Hertfordshire is a water-stressed county; with such a concentrated population, there is a high demand for water. The trust urges avoiding excessive use of water and reusing where possible.”
Some of Welwyn Hatfield’s smaller streams, for example Ellen Brook through Ellenbrook Fields and Hatfield, have completely dried.