Looking after the River Test at Mottisfont

A path beside the river at Mottisfont, Hampshire

The famous River Test flows through our grounds. It has shaped the estate through the centuries, binding the history of the house and its people to the landscape. The crystal-clear waters provide vital habitats for many species.

The River Test is a fantastic example of a chalk stream - one of only around 200 in the world. The water filters through the surrounding chalk landscape before entering the river through springs. This gives it pure, clean water that maintains relatively stable temperatures and flow rates.

Providing that they are well managed, chalk streams provide habitats for a huge variety of species. To tend the river the stretches of river that surround the estate we have a specialist River Keeper, the only role of its kind within the National Trust.

Our River Keeper during weed cut season
Mottisfont's River Keeper Neil Swift cutting weed in the River Test
Our River Keeper during weed cut season

On the banks we allow lush marginal fringes to grow, providing habitats for all manner of insects, small mammals and even reptiles such as grass snakes, slow worms and common lizards. Branches from bankside trees and bushes hang low over the water providing shade and cover for fish and a resting spot for the many species of birds that live around the water.

In the river itself, areas of clean gravel provide ideal spawning habitat for trout, salmon and grayling. Whilst the river weed must be cut during the summer months, we leave plenty to ensure the young fish a have safe place to hide. Both the gravel and weed are also habitat for many of the species of river fly, such caddis and mayfly, which in turn provide food for the fish.

The results of the work we do are clear to see both on the banks and in the river; otters, water voles, kingfishers, grebes and the rare southern damselfly all thrive here. Numbers of juvenile salmon have increased dramatically, alongside a stable population of wild brown trout and at least 11 other freshwater fish species from tiny minnows and bullheads to huge pike.