A significant area of industrial activity within the catchment is Montrose Port which lies at the mouth of the River South Esk. Montrose was the first port in Scotland to develop a support base for the off-shore oil industry, and today the port provides support and services to both oil and renewable energy industries. The main cargo traffic using the port includes vessels transporting forestry products such as pulp and timber; fertiliser; and agricultural products including grain. Businesses based in or near Montrose Port include those producing pharmaceuticals, cement and fertiliser. With so many businesses in operation and in close proximity to the estuary, there is an increased risk of pollution arising from oil spills, manufacturing waste and ballast.

Biannually, sediment which has accumulated in the narrow channel leading into the port is dredged and deposited in Montrose Bay. Whilst dredging ensures continual navigation through the estuary, sediment will inevitably be released into the wider area. Silt can become suspended in the water and reduce oxygen levels.

Dredging is a regulated activity and as such a licence must be applied for from SEPA and an Environmental Impact Assessment (EIA) carried out, before it can take place. When a licence is issued it includes several conditions, such as the need to use a less environmentally destructive dredging method, only carrying out works during stable weather conditions and not during the salmonid breeding period.