Keeping drainage in good working order is one of the most important parts of greenway management. Drains, ditches, ponds and soakaways keep your path free of standing water and protect them from run-off. They also provide an opportunity to create a wildlife habitat.
The principles of Sustainable Drainage Systems (SuDS) can be applied to existing and new drainage to help reduce possible negative impacts such as runoff or downstream flooding. Drain clearance should be planned as part of the annual cycle of maintenance activities and catch pits should be regularly checked and cleared of any silt and debris that builds up, otherwise they can lead to blocked pipes and flooding.
Always be aware of the potential hazards of working near water including waterborne diseases such as leptospirosis.
Areas of standing water can become stagnant and polluted, attract biting insects or pose a potential hazard to path users. Appropriate management to encourage beneficial water plants and wildlife will help keep a waterbody clean and make it an attractive feature.
In order to keep open ditches clear while also protecting wildlife:
- work only from one bank
- maintain the existing water level wherever possible
- leave parts of the ditch undisturbed each time you clear vegetation or de-silt the ditch; only do what is needed (not the entire feature)
- try to create bends or rough areas to reduce flow rates, avoid straight clear channels with smooth bottoms
- manage the ditch in an upstream direction to enable wildlife to recolonize disturbed areas more easily
- leave aquatic vegetation taken from the ditch on the bankside for a couple of hours to allow wildlife to escape back to the ditch
- do not leave vegetation on the bankside in the long-term as it will rot and pollute the water.
Ponds can support legally protected species such as great crested newts and this restricts what management can take place. Where non-native invasive species occur management can easily spread seeds or eggs exacerbating the problem and potentially posing legal issues.
It may be simpler and more beneficial to create new ponds and scrapes and increase the diversity of water bodies in an area, rather than clearing out existing ponds.
Current Pollution Prevention Guidelines should be adhered to for all work around watercourses to prevent pollution (including muddy run-off) from maintenance work. Refer to chapter 2 in our Greenway management handbook (pdf 6MB) for more information.
Vegetation clearance can sometimes be beneficial around water courses to allow sunlight to reach the water and facilitate the growth of aquatic vegetation.
However this should only be undertaken on the advice of an ecologist who has been to the site and assessed the habitat, as existing vegetation along watercourses can also be valuable and support protected and notable wildlife.