It is not clear when pollution first became an issue for the River Trent, but in the late 1880s, it had a thriving salmon fishery, with the river producing an annual catch of some 3,000 fish, a decade later, this had fallen to 100. The collapse of the fishery was due to the rapid population increase of the towns that developed following the Industrial Revolution. The tipping point being the introduction of piped water and a basic sewer network, which meant that effluent, which was previously stored in cesspits, was carried away through drains into the nearest brook.