This chapter discusses methods of digging out and clearing mud, silt, ooze and rubbish from waterways and ponds that require restoration. Vegetation clearance may be required at the same time. Details on vegetation management are given in Chapter 14 – Vegetation management.
Silted ponds and other waterways have their own ecological value, and clearance should not be considered as the only course of action. Where there is the option to create new ponds nearby, a silted pond can be left to develop through its natural succession. However, often there is not the option of alternative space, and restoring the existing pond or waterway is the only way of maintaining the habitat type.
Restoration may be done for any of the following reasons:
- Diversifying habitat and improving conditions for wildlife by removing deep bottom muck, silt or dense stands of dominant vegetation.
- Preventing ecological succession due to silt buildup and invasion by reeds and scrub, where such succession is undesirable.
- Eliminating pollution caused by rubbish and toxic materials in the bottom sediments.
- Improving the flow capacity of a waterway where this is limited due to siltation or obstruction.
- Controlling the current where this has led to scouring and erosion, or silting and excess vegetation growth.
- Controlling access by people or predators to islands and other sanctuary areas.
- Improving amenity. Waterways with public access are often littered and unattractive. Rubbish clearance and other improvements for wildlife also encourage people to enjoy and look after such areas.