Broads Authority to dredge Heigham Sound

Following the Broads Authority’s successful project dredging Candle Dyke, near Martham, last year and the re-creation of a trial island at Duck Broad, work is due to start later this month on increasing water depths in Heigham Sound. The narrow section between Duck Broad and Meadow Dyke has the highest priority in the Authority’s Sediment Management Strategy. It has silted up to a depth of 90cms in places and local boat owners have been pushing hard for it to be dredged for several years. The work, subject to approval by Natural England, will start in  the quieter, early part of the season moving into Heigham Sound at the beginning of the main boating season. Water temperatures early in the year are low, which should help reduce anglers’ concerns about an algal bloom. Using the tried and tested experience gained from last year’s successful dredging project, water quality will be carefully monitored to check the levels of Prymnesium parvum algae, which, if they bloom, can prove toxic to fish. The Broads Authority will take samples from four locations around Heigham Sound on a weekly basis to check Prymnesium counts and a joint fish rescue plan is in place.  The Environment Agency also carries out Prymnesium monitoring on a monthly basis throughout the year. Rob Rogers, Head of Construction and Facilities at the Broads Authority, said: “We would like to reassure anglers that every precaution is being taken to prevent a Prymnesium outbreak. It is not the Prymnesium season and the water is very cold at the moment. We dredged all the way through a very warm summer last year, when the water was 26ºC, and counts remained well below the trigger levels.“Prymnesium is a naturally occurring alga which is always present in the Upper Thurne. Our intervention level in the event of an increase in Prymnesium is lower than that set by the Environment Agency and we would stop dredging before there is a bloom. We will schedule a meeting with local anglers in the near future when we will be trying to alleviate their concerns.”