The Canal and River Trust says it will invest an extra £2 million in Gloucester Docks.
The funding doubles the forthcoming dredging budget to £4 million.
Work is due to begin on 5 October and aims to increase navigation depths, support boaters and help waterside businesses.
The Trust says exceptional conditions this year, including prolonged dry weather, low river flows and high tides, have led to more silt being carried into the docks from the River Severn.
It will also explore further measures to reduce future silt entering the docks and improve long-term resilience.
Regional director Ben Cottam says the Trust understands local frustration and remains committed to Gloucester Docks as it marks its bicentenary.