Today, Harrington Nature Reserve is one of Workington's best wildlife and community sites. What is now the reservoir has always been a damp place with water playing an important role in developing the many 'wetland' habitats that remain today. Being largely unsuitable for growing crops or building houses upon, many of the surviving habitats have either been left alone or responded to subtle changes, for example animal grazing or occasional felling and cutting. This legacy of minimal intervention has created habitats that are largely semi-natural and of very high nature conservation value.
The reservoir in its present state was built by a Mr Bairds in 1863, a Scotsman working for the nearby iron works in the village of Harrington. Damming the water at this relatively high point above the village of Harrington ensured water would be readily available to further production of iron and be used for cooling iron making equipment
Unfortunately, just one year after the first dam was constructed, major flooding at Belle View cottages and at Mr Kendals brewery, both located just downstream from the dam, meant the dam had to be rebuilt. The final shipment of 'pig iron' left the iron works in 1928 on the cargo ship Girasol on its way towards Swansea.
The reservoir, although created exclusively for the iron industry was still undoubtedly an important wetland habitat. It's likely that
much of the land surrounding the reservoir was used for grazing and Ordinance Survey maps of the time show that there were few houses
in the area, certainly not on the scale of the present day Brierydale and Salterbeck housing estate. The present day willows were not
planted until quite recently so it's likely that the area was quite open and consisted of marsh and fen vegetation.
In 1993, Allerdale District Council, as it was then known, declared the site a Local Nature Reserve, effectively giving the site legal protection and committing itself to protecting the special features that make the reserve so important for local people and visitors alike.