Natural England - Teesmouth: history

Teesmouth: history

For thousands of years, the sea swept across the Tees Estuary, washing the shoreline at high tide and exposing mudflats and sand bars as it ebbed.

Local people, eager to find more land to farm, built defensive banks against the tides, changing the currents and the flow. Gradually, the ground became solid, lost its saltiness and became fit for agriculture.

Areas still covered by the sea at the highest tides developed as saltmarshes which were used by medieval monks to graze sheep, whose thick fleeces they then sold across Europe.

Outside the old sea defences, sand formed dunes, and today this process continues, with sand blown against the sea walls stabilising as grasses begin to take hold.

In medieval times the area was also important for its salt, which was extracted by boiling sea water until the liquid evaporated, leaving the precious salt crystals behind. The ash from fuel used in the process was left on Seaton Common, and now forms an historic landscape of grass-covered mounds.

Pollution in the estuary was heaviest during the nineteenth and twentieth centuries, and wildlife only just hung on. But with the clean-up of industry during the latter half of the last century, it gradually began to move back in.

Natural England and its predecessors first became involved with the site in 1966, when Seal Sands and Seaton Dunes and Common first became Sites of Special Scientific Interest.

While the area continues to be highly industrialised, Natural England manages the area to minimize pollution threats, maintain the quality of the site's habitats and reduce disturbance to wildlife.

If left alone, some areas manage themselves, while others need human intervention to help them thrive. At North Gare, Natural England is introducing carefully controlled grazing, so that many flowering plants can survive without being swamped by strong-growing grasses. And on Seal Sands, a ten hectare area has been excavated to recreate more of the now scarce intertidal mud.