Why manage ditches? - EverySite

1 Why manage ditches ? The ditch networks in river valleys have beenestablished over the centuries linked with traditionalagricultural practices. Today they contribute to theunique landscape character of the area. ditches are important habitats for aquatic plants,animals, insects and birds. For example, well-managedditches provide feeding sites for wildfowl and groundnesting birds, and habitat for water voles and otters. An efficient and maintained ditch system helps drainthe land in times of high flows, whilst retaining waterduring periods of drought. Maintaining water levels and flows enables ditches tofunction as wet fences and provides drinking waterfor livestock. Regular management prevents ditches silting up andthe banks becoming scrub covered.

2 Financial benefits may be achieved because ditchmanagement can contribute towards premium tierpayments under agri-environment ditches to function efficiently they require regularmaintenance so a little-and-often approach is morecost-effective and ecologically sound. If ditches havebecome redundant, more substantial restoration isneeded. Best practice techniques apply to both routinemaintenance and the restoration of ditches , forexample: When vegetation clearing or de-silting, leave parts of the ditch undisturbed to ensure some refuge habitat is kept, enabling wildlife to re-colonise areas disturbed through management. manage ditches in an upstream direction, to help wildlife return to the disturbed length downstream. Work from one bank only, avoiding damage to the working bank by careful operation of a machine that is appropriate to the channel size.

3 Maintenance or restoration should aim to keep the existing water level - there should be no need to excavate below the present ditch bed level. Ditch management in late summer/early autumn avoids disturbance to wildlife whilst access is generally easier because of the drier ground conditions. If removing aquatic vegetation, leave cut material adjacent to the watercourse for several hours so wildlife can return to the water. But avoid leaving large amounts of decomposing weed on the banks because the liquor could pollute the water (keep livestock away from dredgings that might contain poisonous plants such as Hemlock, Hemlock-water-dropwort or iris). manage banks sympathetically, preferably by light grazing rather than mowing. Herbicides should not be used to control plants within the channel or on the banks, as they can be extremely damaging to for wildlife - best practice ditchesis a win - winsituation!

4 Enhancing ditches for wildlife ditches that are deep and steep-sided are not livestock or wildlife-friendly,ways to enhance your ditch system are illustrated the ditch network on a rotational basis, to ensuresome areas of wetland habitat are kept undisturbed on a 5-6 year rotation (15-20% per year).Restore over 2-3 ditchbanks to gentlegradients(maximum 45degrees) toprovide shallowwater fringesfor aquaticplants <450 Leave one bank and channelmargin intact throughout, orleave blocks of ditch habitatundisturbed (approximately8-10m).If spoil is not removed thenspread thinly on adjacent land,at least 2m from the may include harrowingand topping for weed shallow watershelves (berms) to increasediversity and maintain thecapacity of the not deepen beyond the original profile.

5 Ideallysummer water levels should be no less than 300mmbelow mean field producing or adding to a raisedspoil bank (levee), previously createdthrough repeated de-silting can be removed at intervals (orentirely) to re-connect the ditch to theflood suitable, material from levees canbe placed back in the channel: to raise the bed level. to act as a water control. mechanism. to retain water in the ditch during dry 2/3 Fences cause banks to scrub up. This increases bank maintenance. is environmentally poor because it shades the channel inhibiting aquatic plant growth. Conflicts with breeding wader fenced banks: if fences cannot be removed, thenmechanical management is desirable. Top or flail (one bank each year), latesummer or autumn, raising the cutterbar to the highest appropriate stockingdensity and suitablyprofiled banks, fences areunnecessary.

6 Livestockgrazing will prevent scruband coarser vegetationbecoming landClear scrub to maintainan open landscape forbreeding waders, butretain broadleaved trees,like pollard willows,where there are noconflicts with shallow scallopeddrinking bays for livestock. Thishelps limit erosion and increaseshabitat shallow scrapes inecologically-poor areas of thefield. These provide feedingsites for breeding waders andover-wintering birds like thelinkage betweenditches helps wildlifeto disperse orrecolonise throughoutthe not fill in wetlandfeatures with spoil fromditch Pollution prevention:Ditch work will result in siltrelease. Silt can cause damage to river life, for example,by smothering clean gravels used for fish spawning;affecting plant growth and insect life.

7 Water containingsilt loads should never be allowed to flow directly into astream or river, this can be controlled with simplepollution prevention measures. Securing straw bales orsuitable geotextile material at the downstream end of adrain during de-silting will help filter out much of the siltand prevent it flowing into adjacent rivers. These can beremoved when the silty water has settled. Spoil disposal:In areas liable to flood, the EnvironmentAgency recommend that spoil arising from de-siltingworks is removed to prevent the creation of raised bankswhich could obstruct flood flows. Water voles: The water vole is the UK s most rapidlydeclining mammal species. They favour wetland habitatssuch as rivers, ditches canals and ponds particularly withdense fringing vegetation like reeds, rushes and typically construct burrow systems within the banksor in the absence of suitable bank habitat, may createnests in tussocky vegetation.

8 If water vole burrows arepresent within ditch systems every effort should be madeto conserve and enhance this habitat. Indeed, under theWildlife and Countryside Act 1981, it is anoffence to damage, destroy or obstructaccess to water vole burrows or disturbwater voles whilst they are using sucha place. If in any doubt, please seekadvice from English Nature. Archaeology:The presence ofearthworks or former sluices, bridgesor weirs may indicate historic watermeadow archaeologicalinformation can beobtained from thesesites, revealing theevolution and operationof old water potential for wetlandarchaeology to bepresent should be aconsideration if significantditch restoration works areintended - be aware that you mayneed to seek the guidance of your local CountyArchaeologist.

9 Recreation:Care needs to be taken to ensure thatpublic footpaths and bridleways within floodplains arenot adversely affected through ditch managementworks. Please plan your work to ensure minimumdisruption. What should I do now?Before proceeding with ditch management involving de-silting works you may need the approval of theEnvironment Agency and English Nature. It is thereforerecommended that you first make contact with theTechnical Team (Fisheries, Recreation and Biodiversity) atyour Environment Agency Area office (see back page),who will guide you to the most appropriate contactdepending upon local circumstances. The Agency can alsoprovide guidance, for example in relation to the creationof livestock drinking bays or otter National Helpline(08459) 33 55 Nature National Office(01733) specific advice on capital grants for restorationprograms within agri-environmental schemes contact yourlocal DEFRA office, or the DEFRA National to considerREGIONAL OFFICEE nvironment AgencySouth West RegionManley HouseKestrel WayExeter EX2 7 LQTel: 01392 444 000 Fax: 01392 444 238 CORNWALL AREA OFFICEE nvironment AgencySir John Moore HouseVictoria SquareBodmin PL31 1 EBTel: 01208 78301 Fax: 01208 78321 NORTH WESSEX AREA OFFICEE nvironment AgencyRivers HouseEast QuayBridgwater TA6 4 YSTel: 01278 457 333 Fax.

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