Sediment discharge from dredging

Sediment discharge from dredging

02. Flow regulations

General description

Many human activities (e.g. farming, forestry, road construction) can cause erosion in catchment areas that often cause sediment runoff. Mining operations directly or through escapes in their settling ponds often produce sediment discharges to the river. Also, directly dredging operations on rivers release suspended sediment into the water column by agitation of the bed and by discharging overflow slurries. There are four reasons for undertaking dredging works: flood alleviation, land drainage improvement, navigation and gravel and sand mining. In all cases the effect is to increase the river channel capacity and thus its ability to convey water.

Effect/Impact on (including literature citations)

• HYMO (general and specified per HYMO element)
• physico - chemical parameters
• Biota (general and specified per Biological quality elements)

Case studies where this pressure is present

• Vääräjoki_-_Niskakoski
• KUIVAJOKI

Possible restoration, rehabilitation and mitigation measures

• Improve continuity of sediment transport
• Trap sediments
• Reduce impact of dredging
• Reduce undesired sediment input
• Reduce erosion
• Remove sediments