Mongomery design guidelines for creating aquatic habitats ... · British Waterways Design...

Design Guidelines for CreatingAquatic Habitats

WWT Wetlands Advisory ServiceReport toBritish Waterways

WWT Wetlands Advisory ServiceWildfowl & Wetlands TrustSlimbridgeGlos.GL2 7BT

December 2003

WWTWetlands Advisory Service

British Waterways Design Guidelines for Creating Aquatic HabitatsDecember 2003

Contents

Contents

Figures

Tables

1. INTRODUCTION

2. METHODS

3. SPECIES HABITAT REQUIREMENTS

Design considerations

Design solutions

Summary of species habitat requirements

Identification of different species Groups

Design considerations and solutions for identified species Groups

4. GENERIC DESIGN GUIDELINES

Environmental design considerations

Political design considerations

General design considerations

Oxygenation and role of water flow

Pumping to produce required flow

Silt traps and nutrient control

Liners

Consideration of a lock by-wash system to provide water flow

Designing out waterbirds

Tree planting and its role in shading aquatic macrophytes

Outline recommendations for public access

Minimising erosion from scour and wave action

Attenuation of succession

5. CONCLUSIONS/DISCUSSION

6. REFERENCES

APPENDIX I. LITERATURE REVIEWED



Figures

Figure 1 – Concept design one.

Figure 2 – Concept design two.

Figure 3 – Concept design three.

Figure 4 – Concept design four.

Figure 5 – Concept design five.

Tables

Table 1 - Target plant species.

Table 2 – Species habitat requirements, design considerations and design solutions

Table 3 - Species habitat requirements summary

Table 4 – Species Group 1





Table 9 – Design consideration and solutions of Species Group 1



1. INTRODUCTION

1.1 The Wetlands Advisory Service (WAS) was commissioned by British Waterways in October 2003to investigate and provide best practice design principles for creating wetland habitats toprimarily support a number of notable aquatic macrophytes and emergent plants species. BritishWaterways aim to create new habitat for aquatic and emergent plants as part of the MontgomeryCanal Conservation Management Strategy.

1.2 No sites have been yet been identified by British Waterways for the creation of these aquatichabitats. Therefore, the design considerations, solutions and concept designs discussed in thisreport are not site specific and have been designed to suit a range of sites. A full environmentalsurvey and site specific detailed design should precede any habitat creation works.

1.3 The design principles were collated from a literature review, consultation with Nigel Willby,Liverpool University, and from the practical experiences of the staff of the Wildfowl & WetlandTrust and The Wetlands Advisory Service.

1.4 The objectives of this report were to collate best practice design principles for creating aquatichabitats that would be suitable to support self sustaining populations of the species listed inTable 1, draw up generic concept designs and provide detailed specifications for certain aspectsof these designs, as specified by British Waterways.

1.5 The notable species described in Table 1 occur in the Montgomery Canal and would naturallyoccur in the sheltered backwaters of lowland streams and rivers. Much of this habitat has beenlost through drainage and pollution. As a consequence, these aquatic macrophytes are ofconservation importance. This aquatic and emergent assemblage have been granted nationalprotection through the Welsh stretch of the Montgomery Canal, designated as a Site of SpecialScientific Interest (SSSI), which is also designated a Special Area of Conservation for theinternationally important Floating Water Plantain Luronium natans, under the European Speciesand Habitats Directive (1994).

Table 1 - Target plant species.

Aquatic macrophyes Emergent species

Floating Water Plantain Luronium natans Narrow-leaved WaterPlantain

Alisma lanceolatum

Grass-wrack Pondweed Potamogetoncompressus

Flowering rush Butomus umbellatus

White Stemmed or Long-stalked Pondweed

Potamogetonpraelongus

Lesser Pond Sedge Carex acutiformis

Flat-stalked Pondweed Potamogeton friesii Cyperus sedge Carex pseudocyperus

Red Pondweed Potamogeton alpinus Tubular Water-dropwort Oenanthe fistulosa

Frogbit Hydrocharis morsus-ranae

Celery-leaved buttercup Ranunculus sceleratus

1.6 Ideally, the best practice for maintaining a healthy population of these notable species would beto continue with the present management of the Montgomery Canal. In the event that theMontgomery Canal is restored for boat traffic and increased recreational use, with theconsequential loss of aquatic habitat that presently supports these species, then these guidelinesprovide best practice in creating habitat that aims to support these species. There is no guarantee



that these species will establish or persist in newly created habitats. Their habitat requirementsare specific and there are information gaps and generalities. This report will need to beconsidered by the ‘Partnership’ before sites are selected. Carefully consideration needs to begiven to site selection. Some sites may be considered to be inappropriate for restoration and assuch mitigation through habitat creation may not be appropriate for these sites.

2. METHODS

2.1 This report was undertaken by collating information from a range of published and unpublishedsources (see Appendix 1) and from the practical experience of staff at the Wildfowl andWetlands Trust (WWT), Wetlands Advisory Service (WAS) and consultation with Dr. NigelWillby. Nigel Willby has extensive experienced of the habitat requirements of these aquaticspecies and is in the process of writing a detailed report on the habitat requirements of thesespecies for British Waterways, on which he has been consulted for this report. The specieshabitat requirements detailed in this report should be checked against the final completed reportby Willby.

2.2 In order to produce design guidelines for suitable habitats for the target species, it was firstnecessary to identify the habitat requirements for each species. From these requirements, a set offactors that need to be considered within a design for these species, termed ‘designconsiderations’, were identified. Practical design solutions to these ‘design considerations’ couldthen be identified.

2.3 The information was evaluated in order to generate concept habitat designs that could support asmany of the target species as possible. This would maximise the potential of the habitat tosupport a wide diversity of aquatic and marginal species. Species with similar requirements weregrouped. The grouping was undertaken by summarising the habitat requirements for all targetspecies and identifying which species possess very similar requirements, then by identifyingwhich species and species groups have different requirements but whose habitat design featuresfor which could be combined within one habitat. Concept designs were drawn up for eachspecies group or compatible species groups.

2.4 The target species have been referred to by their scientific names throughout this report, as theyare most commonly used for Pondweeds. It also avoids confusion, as some Pondweeds areknown by more than one common name.

3. SPECIES HABITAT REQUIREMENTS

3.1 Table 2 provides information on the habitat requirements for each of the notable plant species interms of flow, water chemistry, water quality, land form, ground profile, substrate and ecology.The habitat requirements have been identified from a number of sources, including Rodwell(2000), Haslam et al. (1982), British Waterways (2001), a number of web references and personalcommunication with Nigel Willby.

Design considerations3.2 The species habitat requirements would need to be considered in the design of a wetland habitat

for these species. Therefore, the ‘design considerations’ have been identified from theserequirements and are also listed in Table 2. These may or may not be a constraint to designing a



suitable habitat, depending on the conditions of the land selected for habitat creation and abilityto maintain the desired conditions.

Design solutions

3.3 The most appropriate solutions to designing a habitat to address the ‘design considerations’ arealso listed in Table 2. Further details on the design solutions are given in Section 4.

3.4 Design considerations underlined are high priority, as that species is particularly sensitive to thatrequirement. Those in italics are of lower priority, as the species will tolerate some variationfrom the specified requirement. Those in black are of moderate priority and are essential if thespecies is to thrive but they could tolerate a modest amount of variation from the specifiedrequirement.

Table 2 – Species habitat requirements, design considerations and design solutions

Luronium natansSpecies habitatrequirements

Designconsiderations

Design solutions

Flow: moderate toslow, benefits fromscouring

Water chemistry:pH 6.0-8.0 butknown to tolerate awider pH range

Water quality: Clearwater. Intolerant ofsedimentation wouldblock light tosubmerged plants.

Water quality:Low potential risk ofpollution events,such as grey waterfrom boats,agricultural run-off,and fuel spills etc.Water quality: oligo-eutrophic but will nottolerate build up oforganic matter

Maintain moderateto slow flows withsome scouring.

Maintain pH around6.0-8.0

Maintain lowturbidity

Minimise risk ofpollution

Ensure waters donot becomehypereutrophic.

§ Control flow rate by meanders (with moderately low sinuosity to avoidslack water), cross-sectional area, profile and gradient across site.

§ Emergent vegetation across inlet will reduce flows, so keep mostlyclear.

§ Source suitable inflow to maintain flows.§ By-wash can be incorporated into design to maintain flows and

accommodate some scouring flows.

§ If catchment soils are acidic consider alternative sites or liming§ If hydrological inputs to the system are not extremely acidic or basic

and due to pollution, tackle at source or with a suitably designedreedbed or other emergent fringing vegetation. If diffuse, create bufferstrips.

§ If habitat is created by flooding land, as opposed to excavation, insurewater pH post inundation not extremely acidic or basic by identifyingappropriate sites during initial surveys and utilising areas withappropriate water chemistry.

§ If risk of input altering pH beyond limits of tolerance, then look toproduce hydrologically isolated habitats of the right water chemistry,although this may compromise the habitats contribution towards themetapopulation.

§ Minimise potential for erosion. Where erosion might be an issue, usebank stabilization by planting and profiling.

§ Silt traps may be necessary. Settling pools and reedbeds can also beused.

§ Control fishing and fish stocks, as introduced fish increase turbidity.§ Exclusion of cattle to minimise bank erosion§ Use a substrate of fine gravels to reduce turbidity.

§ Create refuges or hydrologically isolated habitats.§ Tackle at source or with a reedbed or other emergent fringing

vegetation.§ If diffuse, create buffer strips.§ Maintain flow and turnover rates.§ Soils used for pond liners will affect water quality.

§ Minimise the build up of organic matter by harvesting biomass latesummer.

§ Trees should be planted away from edge to prevent build up of leaflitter.

§ Treatment of algal growth with barley straw.§ Steep banks to reduce build up of organic matter.§ Ensure all hydrological inputs are not hypereutrophic; if so tackle at

source or with a reedbed or other emergent fringing vegetation.§ If diffuse, create buffer strips.§ As hypertrophic water become anoxic, aerate water by maintaining



Landform: Severalhydrologicallyconnected waterbodies in closeproximity, such aslakes, ponds, canals,scrapes, streams

Ground profile:shallow margins forsexual reproduction,deeper areas forvegetativereproduction

Substrate: sand,sand and gravel, silt,peat.

Ecology: Lowinterspecificcompetition

Ecology: Lowgrazing pressure

Ecology:Good lightpenetration, noshading

Create severalhydrologicallyconnected waterbodies in closeproximity

Provide shallowmargins anddeeper pools.

Provide andmaintain asubstrate of sand,sand and gravel,silt or peat.

Ensure attenuationof succession

Minimise grazing bywater birds.

Minimise shadingof the open waterhabitat.

flows by pumping, profiling or by by-wash.§ Reduce the deposition of organic sediment by maintaining flows by

pumping or profiling.§ Control wildfowl i.e. limit build up of faeces, by designing a site

unattractive to feeding and roosting birds§ Depth- deeper water bodies less susceptible to eutrophication.

§ Ensure interconnectivity of habitats§ Ensure permanent pools with drawdown zones§ Ensure mosaic of different land forms§ Ensure delivery of water§ Ensure there are several water bodies in close proximity to support the

metapopulation, which is more important than the size of individualwater body

§ Create permanent pools with gently sloping banks (<1:2). One side ofthe ponds could have steeper banks.

§ Pools would need to have deeper areas to 2m large enough to supportself sustaining populations

§ Excavation in existing ground§ Low risk of erosion of margins and deep pools by creating appropriate

degree of slope for substrate.§ Prevent infill of deep pools by sedimentation by using silt traps and

dredging§ Create variation in gradients and depths

§ Ensure liners are covered with the appropriate substrate.§ Ensure bank gradient is such that it has the ability to retain material in-

situ§ Silt traps may be necessary to reduce sedimentation of sands and

gravels. Settling pools and reedbeds can also be used.§ Where sands and gravels used minimise deposition by maintaining

flows or trapping silts

§ Ensure some substrates dry out by creating ephemeral pools§ Design to allow for wave action with open stretches of water, with tall

vegetation down wind of the prevailing wind§ Scouring - will occur where streams enter the ponds or can be created

using the lock by-wash§ Create deeper pools have less light and limit establishment of other

vegetation§ Cut and removal of vegetation§ Dredging§ Prevent nutrient enrichment with buffer zones, reed fringes, harvesting

biota, treat pollution at source etc. (see water quality).§ Treatment of algal growth with barley straw.

§ Reduce the attraction of the site to water birds by planting trees andemergent vegetation appropriately to disrupt sight lines, keeping openwater bodies small or narrow. Avoid use of islands

§ Protect establishing vegetation using fencing

§ Minimise shading by planting trees away from water edge.

Potamogeton compressusSpecies habitatrequirements


Design solutions

Flow: slow, lessturbulent stretcheswhere wave action isminimal. Can toleratemoderate flows bylock by-wash (hascompetitiveadvantage)

Maintain slow tomoderate flows andminimise waveaction.


§ Emergent vegetation across inlet will reduce flows.§ Source suitable inflow to maintain flows.§ By-wash can be incorporated into design to maintain flows.§ Minimise wave action by minimising length of fetch, plant shelter beds

up wind of the prevailing wind, create shallow bank gradients



Water chemistry:calcareous

Water quality: clearwater, as turbidwater would blocklight to submergedplants.

Water quality:Low potential risk ofpollution events,such as grey waterfrom boats,agricultural run-off,and fuel spills etc.

Water quality:mesotrophic, willtolerate build up oforganic matter

Landform:permanent ponds,canals, ditches,streams, oxbows,middle and lowerreaches of limestonerivers

Ground profile:shallow watermargins and deeppools around 2mdeep

Substrate: fineorganic to mineral,usually on limestone,alluvium or fen peat.


Maintaincalcareous water

Maintain lowturbidity, minimiseerosion

Minimise risk ofpollution, especiallydiffuse

Insure waters donot becomehypereutrophic.

Create severalpermanent openwater bodies

Maintain shallowmargins and deeppools around 2mdeep

Create andmaintain asubstrate of fineorganic to mineralsoils.


§ If catchment soils are acidic consider alternative sites or liming§ If hydrological inputs to the system are not extremely acidic or basic

and due to pollution tackle at source or with a suitably designedreedbed or other emergent fringing vegetation. If diffuse, create bufferstrips.

§ If habitat is created by flooding land, as opposed to excavation, insurewater post inundation is calcareous by utilising areas with appropriatewater chemistry.

§ If risk of input altering pH beyond limits of tolerance then look toproduce hydrologically isolated habitats of the right water chemistry,although this may compromise the habitats contribution towards themetapopulation.



§ Control fishing and fish stocks, as introduced fish increase turbidity.§ Exclusion of cattle to minimise bank erosion


vegetation.§ If diffuse, create buffer strips.§ Maintain flow and turnover rates.§ Soils used for pond liners will affect water quality. Could use gravels

over clay to reduce turbidity.

§ Treatment of algal growth with barley straw.§ Ensure all hydrological inputs are not hypereutrophic; if so tackle at

source or with a reedbed or other emergent fringing vegetation.§ If diffuse, create buffer strips.§ As hypertrophic water become anoxic, aerate water by maintain flows

by pumping or profiling.§ Control wildfowl i.e. limit build up of faeces, by designing a site

unattractive to roosting birds§ Depth- deeper water bodies less susceptible to eutrophication.

§ Ensure interconnectivity of habitats§ Ensure permanency of water levels§ Ensure mosaic of different land forms§ Ensure delivery of water



degree of slope for substrate.§ Create variation in gradients and depths


situ§ Silt traps may be necessary to reduce sedimentation. Settling pools

and reedbeds can also be used.

§ Create deeper pools have less light and limit establishment of othervegetation

§ Cut and removal of emergent vegetation§ Planting of over hanging trees shades out competitive plants§ Dredging§ Prevent nutrient enrichment with buffer zones, reed fringes, harvesting

biota, treat pollution at source etc. (see water quality).§ Appropriate control of non-native species§ Treatment of algal growth with barley straw.§ Moderate flows provide unsuitable conditions for many competitive

species




Ecology:Require shading byvegetation (notturbidity)

Minimise grazing bywater birds,livestock andrabbits

Ensure someshading of theopen water habitat

§ Reduce the attraction of the site to water birds by planting trees andemergent vegetation appropriately to disrupt sight lines, keeping openwater bodies small or narrow.


§ Planting trees appropriately along one margin/bank, around a shelteredbay to provide organic-rich sediment.

Potamogeton praelongusSpecies habitatrequirements


Design solutions

Flow: gently flowing.Restricted to lessturbulent stretcheswhere wave action isminimal.

Water chemistry:pH 7-8.5, circumneutral to base-rich

Water quality: clearwater, as turbidwater andsedimentation wouldblock light tosubmerged plants.

Water quality: Lowpotential risk ofpollution events,such as grey waterfrom boats,agricultural run-off,fuel spills etc.

Water quality:mesotrophic can onlywithstand a modestamount ofeutrophication

Landform: lakes,dykes, canals,

Maintain slow flowsand minimiseerosion

Maintain pH 7-8.5,circum neutral tobase-rich



Ensure waters donot becomehypereutrophic

Create several




§ If catchment soils are very acidic consider alternative sites or liming§ If hydrological inputs to the system are not extremely acidic or basic

and due to pollution tackle at source or with a suitably designedreedbed or other emergent fringing vegetation. If diffuse, create bufferstrips.





§ Control fishing and fish stocks, as introduced fish increase turbidity.§ Exclusion of cattle to minimise bank erosion§ Could use fine gravels over clay to reduce turbidity






by pumping or profiling.§ Reduce the deposition of organic sediment by maintaining flows by

pumping or profiling.§ Control waterfowl i.e. limit build up of faeces, by designing a site





streams

Ground profile:between 1-6m deep(pools ideally around3m below surfacewhere it is clear andstill)

Substrate: fine tomedium, mineral toorganic, usually onlimestone, alluvium orfen peat. Fine gravelsimportant to maintainanchorage



Ecology:Good to fairly lowlight conditions

hydrologicallyconnected waterbodies

Maintain deeppools of 3m indepth and variationin depth within thewater body

Create andmaintain asubstrate of finegravels and also offine to mediumorganic to mineralsoils.


Minimise grazing bywater birds,livestock andrabbits

Minimise shadingof the open waterhabitat


§ Pools would need to have deeper areas around 3m deep and largeenough to support self sustaining populations


degree of slope for substrate.§ Prevent infill of deep pools by sedimentation by using silt traps§ Create variation in gradients and depths



and reedbeds can also be used.§ By-wash can be important in maintaining course gravels


§ Cut and removal of vegetation§ Avoid dredging as this species has over-wintering rhizomes§ Prevent nutrient enrichment with buffer zones, reed fringes, harvesting

biota, treat pollution at source etc. (see water quality).§ Appropriate control of non-native species§ Treatment of algal growth with barley straw.



§ Minimise shading by planting only a few trees along water edge,manage to prevent further shading.

Potamogeton friesiiSpecies habitatrequirements


Design solutions

Flow: still to gentlyflowing with minimalwave action

Water chemistry:pH 7-8.5, circumneutral to base-rich

Water quality: clearwater, as turbidwater and

Maintain still toslow flows andminimise waveaction.

Maintain pH 7-8.5,circum neutral tobase-rich


§ Control flow rate by meanders (with a moderately high sinuosity tocreate some slack water), cross-sectional area, profile and gradientacross site.

§ Emergent vegetation across inlet will reduce flows.§ Source suitable inflow to maintain flows.§ Minimise wave action by minimising length of fetch, plant shelter beds

up wind of the prevailing wind, create shallow bank gradients andsheltered end bayments

§ If catchment soils are very acidic consider alternative sites or liming§ If hydrological inputs to the system are not extremely acidic or basic

and due to pollution, tackle at source or with a suitably designedreedbed or other emergent fringing vegetation. If diffuse, create bufferstrips.




§ Silt traps may be necessary - settling pools and reedbeds .



sedimentation wouldblock light tosubmerged plants.

Water quality:Low potential risk ofpollution events,such as grey waterfrom boats,agricultural run-off,fuel spills etc.

Water quality: meso-eutrotrophic, canonly withstand amodest amount ofeutrophication

Landform: lakes,dykes, canals, ponds

Ground profile: inwater up to 2 to 3mdeep

Substrate: fine,mineral to organic.





Ensure waters aremeso-eutrophicand do not becomehypereutrophic

Create severalhydrologicallyconnected waterbodies

Maintain deeppools of 2-3m indepth and variationin depth within thewater body

Create andmaintain asubstrate of fineorganic to mineralsoils.


Minimise grazing bywater birds,livestock

Minimise shadingof the open waterhabitat





§ Minimise the build up of organic matter by harvesting emergentvegetation.


§ Treatment of algal growth with barley straw.§ Create some steep banks to reduce build up of organic matter.§ Ensure all hydrological inputs are not hypereutrophic; if so tackle at







§ Pools would need to have deeper areas to 3m large enough tosupport self sustaining populations








§ Cut and removal of vegetation§ Dredging§ Prevent nutrient enrichment with buffer zones, reed fringes, harvesting







Potamogeton alpinusSpecies habitatrequirements


Design solutions

Slow: to gentlyflowing. Tolerant ofspate

Water chemistry:wide ranging butgenerally pH neutralto base-poor



Water quality:Mesotrophic, canonly withstand amodest amount ofeutrophication

Landform: streams,ditches, canals,ponds

Ground profile:Shallow margins to1m deep

Substrate: fine tocoarse, mineral toorganic. Often on

Maintain slow togentle flows.

Maintain pH neutralto base-poor



Ensure waters aremesotrophic with alow risk of nutrientenrichment


Maintain shallowmargins to 1m deep

Create and maintaina substrate of fineorganic to mineralsoils with bare rock


§ Emergent vegetation across inlet will reduce flows.§ Source suitable inflow to maintain flows.§ By-wash can be incorporated into design to maintain flows.

§ If catchment soils are base-rich consider alternative sites§ If hydrological inputs to the system are basic and due to pollution,

tackle at source or with a suitably designed reedbed or otheremergent fringing vegetation. If diffuse, create buffer strips.

§ If habitat is created by flooding land, as opposed to excavation, insurewater pH post inundation not basic by identifying appropriate sitesduring initial surveys and utilising areas with appropriate waterchemistry.








§ Minimise the build up of organic matter by harvesting biota.§ Trees should be planted away from edge to prevent build up of leaf

litter.§ Treatment of algal growth with barley straw.§ Create some steep banks to reduce build up of organic matter.§ Ensure all hydrological inputs are not eutrophic or cause nutrient

enrichment; if so tackle at source or with a reedbed or other emergentfringing vegetation.

§ If diffuse, create buffer strips.§ As hypertrophic water become anoxic, aerate water by maintain flows





§ Create water bodies with gently sloping banks (<1:2). One side of theponds could have steeper banks or a bench as ~1m deep.


degree of slope for substrate.§ Create variation in gradients and depth to ensure required gradient is

created





hard rock.




surfaces.



Minimise shading ofthe open waterhabitat

and reedbeds can also be used.§ As this species tolerates modest spate, planting downstream of the

by-wash maybe effective


§ Cut and removal of vegetation§ Dredging§ Prevent nutrient enrichment with buffer zones, reed fringes, harvesting

biota, treat pollution at source etc. (see water quality).§ Appropriate control of non-native species§ Treatment of algal growth with barley straw.§ Identify/design inflows to allow possibility of spate, where other

species would not have such a competitive advantage




Hydrocharis morsus-ranaeSpecies habitatrequirements


Design solutions

Flow: Standing

Water chemistry:neutral to base-rich

Water quality: clearwater, intolerant ofturbid water


Water quality:mesotrophic toeutrophic, usuallymesotrophic and

Maintain areas ofstanding water.

Maintain neutral tobase-rich water



Ensure waters aremostly meso-eutrophic and do

§ Control flow rate by meanders (with moderately high sinuosity tocreate slack water), cross-sectional area, profile and gradient acrosssite.

§ Emergent vegetation across inlet will reduce flows.§ Source suitable inflow to maintain flows.

§ If catchment soils are not neutral to base-rich, consider alternativesites or liming

§ If hydrological inputs to the system are acidic and due to pollution,tackle at source or with a suitably designed reedbed or otheremergent fringing vegetation. If diffuse, create buffer strips.

§ If habitat is created by flooding land, as opposed to excavation,insure water pH post inundation is not acidic by identifyingappropriate sites during initial surveys and utilising areas withappropriate water chemistry.









litter.§ Treatment of algal growth with barley straw.



free of build up oforganic matter

Landform: open orclosed dykes andponds, disused andlittle used canals

Ground profile:along the openwater transitiondown to <1m belowwater surface

Substrate: clay, siltmineral substrates,sometimes throughpeat

Ecology: Lowinterspecificcompetition-regular disturbanceis essential topreventsuccessionaladvancemacrophytes oremergents,



not becomehypereutrophic


Maintain shallowmargins down to1m below watersurface

Create and maintaina substrate of clay,silt, mineral or peatysoils.



Minimise shading ofthe open waterhabitat

§ Create some steep banks to reduce build up of organic matter.§ Ensure all hydrological inputs are not hypereutrophic; if so tackle at





§ Ensure interconnectivity of habitats§ Ensure permanency of water and fluctuating water levels§ Ensure mosaic of different land forms§ Ensure delivery of water

§ Create water bodies with gently sloping banks (<1:2). One side ofthe water bodies could have steeper banks.

§ Excavation in existing ground§ Low risk of erosion of margins and deep pools by creating

appropriate degree of slope for substrate.§ Create variation in gradients and depths

§ Ensure liners are covered with the appropriate substrate.§ Ensure bank gradient is such that it has the ability to retain material

in-situ§ Silt traps may be necessary to reduce sedimentation. Settling pools


§ Cut and removal of vegetation§ Dredging§ Prevent nutrient enrichment with buffer zones, reed fringes,

harvesting biota, treat pollution at source etc. (see water quality).§ Appropriate control of non-native species§ Treatment of algal growth with barley straw.

§ Reduce the attraction of the site to water birds by planting trees andemergent vegetation appropriately to disrupt sight lines, keepingopen water bodies small or narrow.



Alisma lanceolatumSpecies habitatrequirements


Design solutions

Flow: Still tomoderate

Water level: +60 to-20cm from groundlevel

Maintain moderateto still flows.

Maintain water levelof +60 to-20cm from groundlevel

§ Control flow rate by meanders (with a moderately high sinuosity tocreate some areas with slack water), cross-sectional area, profileand gradient across site.


§ Excavation and profiling§ If site too dry due to drop in topographic height, use weirs, sluices or

bunds to hold water up§ Source suitable inflow to maintain water levels. By-wash could be

used.




Water quality:mesotrophic toeutrophic

Landform: mud andopen water, such asponds, lakes, canalsand streams

Ground profile:open water transitiondown to 0.75mbelow water surface

Substrate: clay andsilt of low tomoderate organiccontent

Ecology: Attenuationof succession andlow rates ofcompetition withvigorously growingnative emergentspecies




Ensure waters aremostly meso-eutrophic and donot becomehypereutrophic

Provide muddybanks to openwater bodies

Maintain shallowmargins down to0.75m below watersurface

Ensure a substrateof clay or silty soilsof low to moderateorganic content.

Minimisesuccession andcompetition tomaintain someopen water habitat


Minimise shadingof the margins ofthe open waterhabitat






litter.§ Treatment of algal growth with barley straw.§ Create some steep banks to reduce build up of organic matter.§ Ensure all hydrological inputs are not hypereutrophic; if so tackle at

source or with a reedbed or other emergent fringing vegetation.§ If diffuse, create buffer strips.§ As hypertrophic water become anoxic, aerate water by maintain

flows by pumping or profiling.§ Reduce the deposition of organic sediment by maintaining flows by




§ Create water bodies with gently sloping banks (<1:2) or shelvesdown to 0.75m below water level.

§ Excavation in existing ground§ Low risk of erosion of margins by creating appropriate degree of

slope for substrate.§ Create variation in gradients and depths, with some steeply sloping

banks to restrict other species




§ Cut and removal of dominant species§ Dredging§ Prevent nutrient enrichment with buffer zones, reed fringes,







Butomus umbellatusSpecies habitatrequirements


Design solutions

Flow: still to slow




Landform: muddymargins andshallows of openwater, such asponds, lakes,ditches, canals andstreams

Ground profile:,margins andshallows down to 1m

Substrate:especially on clay,also silt and gravelwith low organiccontent

Ecology: Attenuationof succession andlow rates ofcompetition withvigorously growingnative emergent

Maintain still toslow flows.

Maintain water levelof between +100to -30cm fromground level


Ensure waters areeutrophic and donot becomehypereutrophic


Maintain shallowmargins down to1m below watersurface

Ensure a substrateof clay, silt andgravels with loworganic content.

Minimisesuccession andcompetition




bunds to hold water up§ Source suitable inflow to maintain water levels. By-wash could be used.

§ If catchment soils are not neutral to base-rich consider, alternative sitesor liming

§ If hydrological inputs to the system are acidic and due to pollution,tackle at source or with a suitably designed reedbed or other emergentfringing vegetation. If diffuse, create buffer strips.

§ If habitat is created by flooding land, as opposed to excavation, insurewater pH post inundation is not acidic by identifying appropriate sitesduring initial surveys and utilising areas with appropriate waterchemistry.




source or with a reedbed or other emergent fringing vegetation.§ If diffuse, create buffer strips.§ As hypertrophic water become anoxic, aerate water by maintain flows by

pumping or profiling.§ Reduce the deposition of organic sediment by maintaining flows by




§ Create water bodies with gently sloping banks (<1:2) down to 1mbelow water level.

§ Excavation in existing ground§ Low risk of erosion of margins by creating appropriate degree of slope

for substrate.§ Create variation in gradients and depths


situ§ Silt traps may be necessary to reduce sedimentation. Settling pools and

reedbeds can also be used.

§ Cut and removal of dominant marginal species§ Dredging§ Prevent nutrient enrichment with buffer zones, reed fringes, harvesting











Carex acutiformisSpecies habitatrequirements


Design solutions

Flow: Still to veryslow

Water level: +50 to -40cm from groundlevel



Landform: marginsof open water, suchas ponds, ditches,canals and rivers

Ground profile:margins to 50cm

Maintain still to veryslow flows.

Maintain water levelof between 50 to -40cm




Maintain shallowmargins down to50cm below water





used.












§ Create water bodies with gently sloping banks (<1:2) down to 50cmbelow water level.


slope for substrate.



below water surface

Substrate:especially on clay,also silt and gravel

Ecology: Requiressome undisturbed,unmanaged areas,where it candominate



surface

Ensure a substrateof clay or silt andgravels.

Provide someundisturbed,unmanaged areas



§ Create variation in gradients and depths


in-situ§ Silt traps may be necessary to reduce sedimentation of sands and

gravels. Settling pools and reedbeds can also be used.


harvesting biota, treat pollution at source etc. (see water quality).§ Appropriate control of non-native species§ Treatment of algal growth with barley straw.§ Restrict access for livestock§ Maintain some shallow, undisturbed habitat


§ Protect establishing vegetation using fencing§ Minimise shading by planting trees away from water edge.

Carex pseudocyperusSpecies habitatrequirements


Design solutions

Flow: still to slow


Water chemistry:base-rich



Maintain water levelof +30 to -60cm fromground level

Maintain base-richwater






used.

§ If catchment soils are not base-rich, consider alternative sites orliming









Landform: openwater swamps, oftenalong the sides ofslow-flowing dykesand in ponds,oxbows and derelictcanals.

Ground profile:margins to 30cmdeep

Substrate: clay, silt

Ecology: Requiressome undisturbed,unmanaged areas,where it candominate


Ecology:Partial or no shading

Provide muddybanks to openwater bodies andswamps

Maintain shallowmargins down to30cm below watersurface

Ensure a substrateof clay or silt.

Provide someundisturbed,unmanaged areas


Partial and noshading of themargins of theopen water habitat







slope for substrate.§ Create variation in gradients and depths





harvesting biota, treat pollution at source etc. (see water quality).§ Appropriate control of non-native species§ Treatment of algal growth with barley straw.§ Restrict access for livestock§ Maintain some shallow, undisturbed habitat




Oenanthe fistulosaSpecies habitatrequirements


Design solutions

Flow: still to slow

Water level: +30 to-30cm, benefits fromseasonal fluctuationsin water level



Maintain water levelof between +30 to-30cm from groundlevel






used.§ Create profiling and identify appropriate water sources such that

some open water margins are exposed during summer low waterlevels


§ If hydrological inputs to the system are acidic and due to pollution,tackle at source or with a suitably designed reedbed or other



Water quality:mostly eutrophic

Landform: marshes,pond edges andcanals

Ground profile:,shallow watermargins to 30cmdeep

Substrate: finemineral soils of claysand silts

Ecology: Attenuationof succession andlow rates ofcompetition withvigorously growingnative and non-nativespecies

Ecology: requiresopen, grazed, muddyareas

Ecology:Good light, minimalshading

Ensure waters aremostly eutrophicand do not becomehypereutrophic

Provide very gentlysloping banks toopen water bodiesand marshes


Ensure a substrateof fine clay and silt.


Create bare mud


emergent fringing vegetation. If diffuse, create buffer strips.§ If habitat is created by flooding land, as opposed to excavation,

insure water pH post inundation is not acidic by identifyingappropriate sites during initial surveys and utilising areas withappropriate water chemistry.







unattractive to roosting birds

§ Ensure sloping banks leading to open water§ Ensure high soil moisture and periodic inundation§ Ensure delivery of water





in-situ§ Settling pools and reedbeds can also be used.

§ Cut and removal of vegetation§ Prevent nutrient enrichment with buffer zones, reed fringes,

harvesting biota, treat pollution at source etc. (see water quality).§ Appropriate control of non-native species

§ Trampling of margins by stock


Ranunculus sceleratusSpecies habitatrequirements


Design solutions

Flow: Still to slowflow, fluctuatingwater levels


§ Control flow rate by meanders (with moderately high sinuosity tocreate some slack water), cross-sectional area, profile and gradientacross site.

§ Emergent vegetation across inlet will reduce flows.§ Source suitable inflow to maintain flows.



Water level: +30 to -60cm from groundlevel



Landform: marshes,pond and canalbanks, poachedditches, disturbedmuddy watermargins

Ground profile:shallow water muddymargins to 30cmdeep

Substrate: finemineral soils of claysand silts


Ecology: requiresconditions createdby grazing

Ecology:Good light noshading

Maintain water levelof +30 to-60cm from groundlevel


Ensure waters aremostly eutrophicand do not becomehypereutrophic

Provide gentlysloping banks toopen water bodiesand marshes


Ensure a substrateof fine clay and silt.


Grazing bylivestock


§ By-wash can be incorporated into design to maintain flows.



used.


§ If hydrological inputs to the system are acidic and due to pollutiontackle at source or with a suitably designed reedbed or otheremergent fringing vegetation. If diffuse, create buffer strips.






flows by pumping or profiling.§ Control wildfowl i.e. limit build up of faeces, by designing a site


§ Ensure fluctuating water levels and exposure of wet mud§ Ensure mosaic of different land forms§ Ensure delivery of water





in-situ§ Silt traps may be necessary to reduce sedimentation.



§ Graze by livestock and encourage poaching to create open mudhabitat




Summary of species habitat requirements

3.5 A habitat could be designed for one particular species, providing design solutions for each of thespecies specific habitat requirements. However, many of the target species have similarrequirements and one design could provide suitable habitat to support several of the targetspecies, increasing biodiversity within a wetland. Table 3 summarises the species habitatrequirements for all the target species in order to identify which have similar requirements. Forexample, a habitat designed to have a suite of particular habitat requirements, such as still to slowflows and mesotrophic water, could potentially support 7 of the 12 species.

3.6 When all species habitat requirements are considered, further analysis has enabled the groupingof species with the same habitat requirements (Tables 4 to 8). These species shown in shadedcolumns are within the same group. In Table 3 habitat requirements underlined are high priorityas that species is particularly sensitive to that requirement. Those in italics are not essential; thespecies will tolerate some variation from the specified requirement.



Table 3 - Species habitat requirements summary

Plant species

Habitatrequirements

Luroniumnatans

(1)

Potamo-getoncompressus

(2)

Potamo-getonpraelongus

(3)

Potamo-getonfriesii

(4)

Potamo-getonalpinus

(5)

Hydrocharismorsus-ranae

(6)

Alismalanceolatum

(7)

Butomusumbellatus

(8)

Carexacutiformis

(9)

Carexpseudo-cyperus

(10)

Oenanthefistulosa

(11)

Ranunculussceleratus

(12)Flow Slow to

moderateSlow tomoderate.Wave actionminimal

SlowWave actionminimal.

Still to slow.Wave actionminimal

Slow.Tolerant ofspate

Still Still tomoderate

Still to slow Still to veryslow

Still to slow Still to slow Still to slow.

Water level 0 to +200cm 0 to +200cm 0 to +300cm 0 to +300cm 0 to +300 0 to +50cm +60 to-20cm

+100 to-30cm

+50 to-40cm

+30 to-60cm andseasonalfluctuations

+30 to-30cm

+30 to-60cmToleratesfluctuatingwater levels

Waterchemistry

pH 6.0-8.0 Base-rich pH 7-8.5,c.neutral tobase-rich

pH 7-8.5c.neutral tobase-rich

Generallyneutral tobase-poor

Neutral tobase-rich.

Neutral tobase-rich

Neutral tobase-rich.

Neutral tobase-rich

Base-rich Neutral tobase-rich

Neutral tobase-rich

Water quality(turbidity)

Clear, lowrates ofsediment-ation

Clear, lowrates ofsediment-ation &turbidity





Unknown Unknown Unknown Unknown No No

Water quality(pollution)

Low potentialrisk ofpollution






Unknown Unknown Unknown Unknown Unknown Unknown

Water quality(nutrientstatus)

oligo-eutrophic.Free of buildup of organicmatter

Meso-trophic Meso-trophic Meso-eutrophic,can onlywithstandmodesteutrophica-tion

Mesotrophiccan onlywithstandmodesteutrophica-tion

Meso-eutrophicFree of buildup of organicmatter

Meso-eutrophic toeutrophic.Low tomoderateorganiccontent

Meso-trophicto eutrophicLow organiccontent

Mostlyeutrophic

Meso-trophicto eutrophic



Plant species Luroniumnatans

Potamo-geton

Potamo-geton

Potamo-geton

Potamo-geton

Hydrocharismorsus-

Alismalanceolatum

Butomusumbellatus

Carexacutiformis

Carexpseudo-

Oenanthefistulosa




Habitatrequirements (1)

compressus

(2)

praelongus

(3)

friesii

(4)

alpinus

(5)

ranae

(6) (7) (8) (9)

cyperus

(10) (11) (12)Land form Hydrologicall

y connected& in closeproximity, -ponds,lakes,canals,scrapes,streams

Permanentponds,canals,ditches,streams,oxbows

Lakes, dykes,canals,streams

Ponds, lakes,dykes,canals,

Ponds,canals,ditches,streams

Open orclosed dykesand ponds,disused andlittle usedcanals

Muddymargins andopen water-ponds, lakes,canals andstreams

Muddymargins &shallows ofopen water-ponds,lakes,canals,streams &ditches

Margins ofopen water,such asponds,ditches,canals andrivers,streams

Open waterswamps,margins ofslow-flowingdykes,ponds,oxbows andderelictcanals.

MuddymarginsPond & canaledges,streams,marshes

Muddy watermarginsPond, ditch &canal edges,marshes

Groundprofile

Shallowmargins,deep poolsc.200cm,drawdownzones

Shallowmargins,deeper poolsto 200cm

Deep wateraround300cmbelowsurface)

Deep water200-300cmdeep

Shallowmargins to100cm deep

Shallowmarginsdown to100cmbelow watersurface

Shallowmarginsdown to100cmbelow watersurface

Shallowmarginsdown to<100cmbelow watersurface

Shallowmargins to50cm belowwatersurface

Shallowmargins to30cm belowwatersurface

Shallowwatermargins to30cm belowwatersurface

V. gentlyslopingbanks to30cm belowwatersurface

Substrate Sand, sandand gravel,silt, peat.

Fine mineralto organic,usually onlimestone,alluvium orfen peat.

Fine to med.mineral toorganic, finegravels.,limestone,alluvium orfen peat

Fine mineralto organic.

Fine tocoarse,mineral toorganic.

Mineralsubstrates,clay, siltsometimesthrough peat

Clay and siltof low tomoderateorganiccontent

Clay, silt andgravel withlow organiccontent

Especially onclay, also siltand gravel

Clay, silt Fine mineralsoils of claysand silts

Fine mineralsoils of claysand silts

Ecology(competition)

Attenuatesuccessionand low ratesofinterspecificcompetition

Low rates ofinterspecificcompetition





AttenuatesuccessionMaintainopen waterhabitat


Requiressomeundisturbed,unmanagedareas whereit candominate

Requiressomeundisturbed,unmanagedareas whereit candominate



Ecology(grazing)

Low grazingpressure

Low grazingpressure

Low grazingpressure

Low grazingpressure

Low grazingpressure

Low grazingpressure

Low grazingpressure

Low grazingpressure

Low grazingpressure

Low grazingpressure

Requiresopen,grazed,muddymargins

Requiresopen,grazed,muddymargins

Ecology(shading)

Good lightpenetration,no shading

Requiresshading as itreducescompetition

Good tofairly low,someshading







Partial or noshading





Identification of different species Groups3.7 Table 4 shows that the emergent plant species have similar requirements. They all tolerate these

habitat requirements although some species have a wider tolerance to deviations from thesehabitat requirements, for example; all but Carex pseudocyperus also tolerate water that is pH neutral;C. pseudocyperus and Ranunculus sceleratus can also tolerate water levels that drop to 30cm belowground surface. Therefore, ideally, a habitat to support this species group would have a mosaicof ground profiles, such that the water level would lie between +30 and -30cm relative to groundlevel, with some areas permanently inundated to at least +100cm and some areas where depth towater table would be 60cm. It would be possible for a site with neutral water chemistry tosupport 6 of these species, as shown in Table 5.

3.8 Table 6 demonstrates that Luronium natans and Potamogeton compressus have very similar habitatrequirements, they only differ in that P. compressus tolerates shade and has a competitiveadvantage in tree shaded sites and is also tolerant of a build up of organic matter, whereas L.natans requires unshaded sites and does not tolerate a build up in organic matter, it also requiresgravels to maintain anchorage. Therefore, a habitat could support both species if it were partshaded with local gravel beds.

3.9 Table 7 shows that Luronium natans, Potamogeton compressus, P. praelongus and P. friesii have similarrequirements. They all tolerate these habitat requirements although some species have apreference for alternative habitat features and are likely to have a competitive advantage if thesefeatures were present. For example: L. natans, P.compressus grow well in accelerated flows, wherecompetition is reduced; as well as being able to grow in slow flows. P.compressus and P.praelongus,also tolerate some shading, giving them a competitive advantage, as well as being able to growwith no shade. P. praelongus and L. natans are also known to grow well on gravels (Pers. comm.Nigel Willby, 2003). P. praelongus requires gravel substrates to maintain anchorage but will toleratesilt and peat. Therefore, ideally, a habitat to support this species group would have slow andmoderately flowing areas, each with part shade and a slower flowing area would have part gravelsubstrate.

3.10 The only species that has a specific requirement for neutral to base-poor water is Potamogetonalpinus but otherwise it has similar requirements to the other species of Potamogeton. It is unlikelythat hydrologically connected water bodies could range from base-poor to base-rich, so thisspecies has not been grouped with the other species. Creating a habitat for this species could alsoprovide habitat for other aquatic macrphytes typical of pristine base-poor wetlands, such asLuronium natans, Bog Pondweed P. polygonifolius and Blunt-leaved Pondweed P. obtusifolius, and awide range of emergent species, such as Bulbous Rush Juncus bulbosus, Soft Rush J. effuses andBottle sedge Carex rostrata. (It is not known if these particular species are naturally occurring onthe Montgomery Canal).




Plant species

Habitatrequirements

Luroniumnatans

(1)

Potamo-getoncompressus (2)

Potamo-getonpraelongus (3)

Potamo-getonfriesii (4)

Potamo-getonalpinus (5)

Hydrocharismorsus-ranae (6)

Alismalanceolatum

(7)

Butomusumbellatus

(8)

Carexacutiformis

(9)

Carexpseudo-cyperus (10)

Oenanthefistulosa

(11)


(12)Flow: still to slow No No Yes Yes Yes Yes (still) Yes Yes Yes Yes Yes YesWater level:+30 to -30cm,(+100 to-60)

No No No No No Yes (but>0cm)

Yes Yes Yes Yes Yes Yes


Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes

Water quality:clear, lowsedimentation

Yes Yes Yes Yes Yes Yes - - - - - -

Water quality lowrisk of pollution


Water qualitymeso-eutrophic

Yes No No Yes No Yes Yes Yes Yes Yes Yes Yes

Low organicmatter

Yes No (toleratesbuild up oforganicmatter)

No (toleratesbuild up oforganicmatter)

Yes Yes Yes Yes Yes Yes No (toleratesbuild up oforganicmatter)

Yes Yes

Land form: ponds,lakes, canals

Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes

Ground profile:shallow marginsto +100 to -60cm

Yes Yes Yes Yes Yes Yes Yes (requiremuddymargins)

Yes (requiremuddymargins)

Yes Yes Yes (requiremuddymargins)


Substrate: Siltand clay

No No No No No Yes Yes Yes Yes Yes Yes Yes

Ecology: lowcompetition

Yes Yes Yes Yes Yes Yes Yes Yes Yes (alsoundisturbed&unmanaged)

Yes (alsoundisturbed&unmanaged)

Yes Yes

Ecology: lowgrazing pressure

Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No (requirespoachedmargins)

No (requirespoachedmargins)

Ecology goodlight, no shading

Yes Yes (but alsorequiresshade)

Yes (but alsorequiresshade)

Yes Yes Yes Yes Yes Yes Yes(toleratesshading)

Yes Yes




Plant species

Habitatrequirements

Luroniumnatans

(1)






Alismalanceolatum

(7)

Butomusumbellatus

(8)

Carexacutiformis

(9)


Oenanthefistulosa

(11)


(12)Flow: still to slow No No Yes Yes Yes Yes (still) Yes Yes Yes Yes Yes YesWater level:+30 to -30cm,(+100 to-60)

No No No No No Yes (but>0cm)

Yes Yes Yes Yes Yes Yes

Water chemistry:neutral

Yes No Yes Yes Yes Yes Yes Yes Yes No Yes Yes





Water qualitymeso-eutrophic

Yes No No Yes No Yes Yes Yes Yes Yes Yes Yes

Low organicmatter

Yes No (toleratesbuild up oforganicmatter)

No (toleratesbuild up oforganicmatter)

Yes Yes Yes Yes Yes Yes No (toleratesbuild up oforganicmatter)

Yes Yes



Ground profile:shallow marginsto +100 to -60cm

Yes Yes Yes Yes Yes Yes Yes (requiremuddymargins)


Yes Yes Yes (requiremuddymargins)


Substrate: Siltand clay

No No No No No Yes Yes Yes Yes Yes Yes Yes

Ecology: lowcompetition

Yes Yes Yes Yes Yes Yes Yes Yes Yes (alsoundisturbed&unmanaged)

Yes (alsoundisturbed&unmanaged)

Yes Yes

Ecology: lowgrazing pressure

Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No (requirespoachedmargins)

No (requirespoachedmargins)


Yes Yes (but alsorequiresshade)

Yes (but alsorequiresshade)

Yes Yes Yes Yes Yes Yes Yes(toleratesshading)

Yes Yes




Plant species

Habitatrequirements

Luroniumnatans

(1)






Alismalanceolatum

(7)

Butomusumbellatus

(8)

Carexacutiformis

(9)


Oenanthefistulosa

(11)


(12)Flow: moderate Yes Yes No No No (tolerates

spate)No Yes No No No No No

Water level: 0 to+300cm

Yes Yes Yes Yes Yes Yes No No No No No No







Water qualitymesotrophic

Yes Yes Yes Yes Yes Yes (loworganicmatter)

Yes Yes (loworganicmatter)

Yes Yes Yes Yes

Low organicmatter

Yes No (toleratesbuild up)

No (toleratesbuild up)

Yes Yes Yes Yes Yes Yes No (toleratesbuild up)

Yes Yes



Ground profile:shallow marginsand deep pools


Substrate: finemineral toorganic, silt

Yes (alsorequiresfine gravel

Yes Yes (but alsorequires finegravels)


Yes (but alsoclay)

No No No No No No

Ecology: Lowcompetition

Yes Yes Yes Yes Yes Yes Yes Yes Yes(undisturbed &unmanaged)

Yes(undisturbed& unmanaged)

Yes Yes

Ecology lowgrazing pressure

Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No(requirespoachedareas)

No (requirespoachedareas)


Yes No, requiresshade

No, requiresshade

Yes Yes Yes Yes Yes Yes Yes, buttoleratesshade

Yes Yes




Plant species

Habitatrequirements

Luroniumnatans

(1)






Alismalanceolatum

(7)

Butomusumbellatus

(8)

Carexacutiformis

(9)


Oenanthefistulosa

(11)


(12)Flow: slow Yes (also

requiresmoderateflows)

Yes (but alsorequiresmoderateflows)

Yes Yes Yes (but alsotolerant ofspate)

No Yes Yes Yes Yes Yes Yes










Yes Yes Yes Yes Yes Yes Yes Yes) Yes Yes Yes Yes

Low organicmatter

Yes No (toleratesbuild up)

No (toleratesbuild up)

Yes Yes Yes Yes Yes Yes No (toleratesbuild up)

Yes Yes






Yes (alsorequiresfine gravel



Yes (but alsoclay)

No No No No No No


Yes Yes Yes Yes Yes Yes Yes Yes Yes(undisturbedunmanaged)

Yes(undisturbedunmanaged)

Yes Yes


Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No (requirespoachedareas)




No, requiresshade


Yes Yes




Plant species

Habitatrequirements

Luroniumnatans

(1)






Alismalanceolatum

(7)

Butomusumbellatus

(8)

Carexacutiformis

(9)


Oenanthefistulosa

(11)


(12)Flow: slow Yes (but

alsorequiresmoderateflows)

Yes (but alsorequiresmoderateflows)

Yes Yes Yes (but alsotolerant ofspate)

No Yes Yes Yes Yes Yes Yes



Water chemistry:neutral to base-poor

No No No No Yes No No No No No No No






Yes (loworganicmatter)

Yes Yes Yes Yes Yes (loworganicmatter)

Yes Yes (loworganicmatter)

Yes Yes Yes Yes






Yes (alsofinegravels)



Yes (but alsoclay)

No No No No No No


Yes Yes Yes Yes Yes Yes Yes Yes Yes(undisturbed &unmanaged)

Yes(undisturbed&unmanaged)

Yes Yes


Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No (requirespoachedareas)




No, requiresshade


Yes Yes



Design considerations and solutions for identified species Groups3.11 For each ‘species Group’ the habitat requirements, design considerations and design solutions

have been given in Tables 9 to 14. These tables synthesis a information provided in earlier tables.Using these design principles it is possible to design suitable habitats for each species Group.

Table 9 – Design consideration and solutions of Species Group 1

Species Group 1: Hydrocharis morsus-ranae, Alisma lanceolatum, Botomus umbellatus, Carex acutiformis, Carexpseudocyperus, Oenanthe fistulosa, Ranunculus sceleratus

Species habitatrequirements


Design solutions

Flow: Still and slow

Water level: +30 to -30cm from groundlevel, some areasto+100cm, others to60cm




Water quality:mesotrophic

Maintain still andslow flows.

Maintain water levelof +30 to -30cmfrom ground level,some areas+100cm, others60cm

Maintain base-richwater



Ensure waters aremesotrophic anddo not becomehypereutrophic

§ Control flow rate by meanders (with a moderately high sinuosity tocreate slack water), cross-sectional area, profile and gradient acrosssite.

§ Emergent vegetation across inlet will reduce flows.§ Source suitable inflow to maintain flows.§ By-wash can be incorporated into design to maintain slow flows.

§ Excavation and profiling to provide a mosaic of different levels§ If site too dry due to drop in topographic height, use weirs, sluices or


used.

§ If catchment soils are not base-rich consider alternative sites orliming

§ If hydrological inputs to the system are not base-rich and due topollution, tackle at source or with a suitably designed reedbed orother emergent fringing vegetation. If diffuse, create buffer strips.

§ If a habitat is created by flooding land, as opposed to excavation,insure water pH post inundation is base-rich by identifyingappropriate sites during initial surveys and utilising areas withappropriate water chemistry.



§ Silt traps may be necessary. Settling pools and reedbeds can alsobe used.




§ Minimise the build up of organic matter by harvesting emergentvegetation in late August.









Landform: muddymargins and shallowopen water such asponds, lakes, canals,streams

Ground profile:open water transitiondown to 100cmbelow water surface

Substrate: clay andsilt substrates





Maintain shallowmargins down to100cm belowwater surface

Ensure a substrateof clay or silty soils.




§ Depth- deeper water bodies less susceptible to eutrophication.

§ Ensure interconnectivity of habitats§ Ensure fluctuating water levels to expose muddy margins§ Ensure mosaic of different land forms§ Ensure delivery of water

§ Create water bodies with gently sloping banks (<1:2) down to100cm below water level.


slope for substrate.§ Create variation in gradients and depths. A. lanceolatum also

requires some steeply sloping banks to restrict other species.





harvesting biota, treat pollution at source etc. (see water quality).§ Appropriate control of non-native species§ Treatment of algal growth with barley straw.§ Restrict access for livestock but allow poaching in some areas to

attenuate succession§ Maintain some shallow undisturbed habitat


§ Protect establishing vegetation using fencing§ Fence off some areas to exclude livestock§ Only allow grazing in certain areas in late summer, with occasional

cattle drink (this will increase turbidity and sedimentation, sohydrologically isolate these habitats or use emergent fringes or silttraps downstream.


Species Group 2: Hydrocharis morsus-ranae, Alisma lanceolatum, Botomus umbellatus, Carex acutiformis,Oenanthe fistulosa, Ranunculus sceleratus



Design solutions



Flow: Still and slow

Water level: +30 to -30cm from groundlevel, some areasto+100cm, others to60cm

Water chemistry:neutral




Landform: muddymargins and shallowopen water such asponds, lakes, canals,streams

Ground profile:

Maintain still andslow flows.

Maintain water levelof +30 to -30cmfrom ground level,some areas+100cm, others60cm

Maintain neutral



Ensure waters aremesotrophic anddo not becomehypereutrophic


§ Control flow rate by meanders (with a moderately high sinuosity tocreate slack water), cross-sectional area, profile and gradient acrosssite.

§ Emergent vegetation across inlet will reduce flows.§ Source suitable inflow to maintain flows.§ By-wash can be incorporated into design to maintain slow flows.

§ Excavation and profiling to provide a mosaic of different levels§ If site too dry due to drop in topographic height, use weirs, sluices or


used.

§ If catchment soils are not circum neutral consider alternative sites orliming

§ If hydrological inputs to the system are not circum neutral and due topollution, tackle at source or with a suitably designed reedbed orother emergent fringing vegetation. If diffuse, create buffer strips.

§ If a habitat is created by flooding land, as opposed to excavation,insure water pH post inundation is circum neutral by identifyingappropriate sites during initial surveys and utilising areas withappropriate water chemistry.



§ Silt traps may be necessary. Settling pools and reedbeds can alsobe used.




§ Minimise the build up of organic matter by harvesting emergentvegetation in late August.







§ Ensure interconnectivity of habitats§ Ensure fluctuating water levels to expose muddy margins§ Ensure mosaic of different land forms§ Ensure delivery of water

§ Create water bodies with gently sloping banks (<1:2) down to100cm below water level.

§ Excavation in existing ground



open water transitiondown to 100cmbelow water surface

Substrate: clay andsilt substrates




Maintain shallowmargins down to100cm belowwater surface

Ensure a substrateof clay or silty soils.




§ Low risk of erosion of margins by creating appropriate degree ofslope for substrate.

§ Create variation in gradients and depths. A. lanceolatum alsorequires some steeply sloping banks to restrict other species.





harvesting biota, treat pollution at source etc. (see water quality).§ Appropriate control of non-native species§ Treatment of algal growth with barley straw.§ Restrict access for livestock but allow poaching in some areas to

attenuate succession§ Maintain some shallow undisturbed habitat


§ Protect establishing vegetation using fencing§ Fence off some areas to exclude livestock§ Only allow grazing in certain areas in late summer, with occasional

cattle drink (this will increase turbidity and sedimentation, sohydrologically isolate these habitats or use emergent fringes or silttraps downstream.


Species Group 3: Luronium natans and Potamogeton compressus



Design solutions

Flow: moderate toslow, benefits fromscouring

Water chemistry:Base-rich

Water quality: Clearwater. Intolerant of

Maintain moderateto slow flows withsome scouring.

Maintain base-richwater chemistry



§ Emergent vegetation across inlet will reduce flows, so keep mostlyclear.

§ Source suitable inflow to maintain flows.§ By-wash can be incorporated into design to maintain flows and

accommodate some scouring flows.§ Minimise wave action by minimising length of fetch, plant shelter beds


§ If catchment soils are not base-rich consider alternative sites or liming§ If hydrological inputs to the system are not base-rich and due to

pollution, tackle at source or with a suitably designed reedbed or otheremergent fringing vegetation. If diffuse, create buffer strips.

§ If habitat is created by flooding land, as opposed to excavation, insurewater pH post inundation is base-rich by identifying appropriate sitesduring initial surveys and utilising areas with appropriate waterchemistry.

§ If risk of input altering pH beyond limits of tolerance then look toproduce hydrologically isolated habitats of the right water chemistry,although this may compromise the habitats contribution towards themetapopulation and the species ability to colonise naturally.



§ Control fishing and fish stocks, as introduced fish increase turbidity.



sedimentation wouldblock light tosubmerged plants.


Water quality:mesotrophic, L.natans will nottolerate build up oforganic matter but P.compressus will



Substrate: fine andmedium, organic tomineral- sand, sandand fine gravel, silt,peat.



Ensure waters donot becomehypereutrophic.,minimise build upof organic matter incertain areas

Create severalhydrologicallyconnectedpermanent openwater bodies inclose proximity

Provide shallowmargins anddeeper pools to2m.

Provide andmaintain asubstrate of fineand medium,organic to mineral-sand, sand and finegravel, silt, peat.


§ Exclusion of cattle to minimise bank erosion§ Use a substrate of fine gravels to reduce turbidity

§ Create refuges or hydrologically isolated habitats (but the speciesability to colonise naturally and their contribution towards themetapopulation may be compromised.

§ Tackle at source or with a reedbed or other emergent fringingvegetation.

§ If diffuse, create buffer strips.§ Maintain flow and turnover rates.§ Soils used for pond liners will affect water quality. Could use gravels


§ Minimise the build up of organic matter by harvesting emergentvegetation in late summer.

§ Trees should be planted away from edge to prevent build up of leaflitter in some areas, plant around sheltered bays in other areas.



by pumping or profiling.§ Reduce the deposition of organic sediment in some areas by

maintaining flows by pumping or profiling.§ Control wildfowl i.e. limit build up of faeces, by designing a site


§ Ensure interconnectivity of habitats§ Ensure permanent open water with drawdown zones§ Ensure mosaic of different land forms§ Ensure delivery of water§ Ensure there are several water bodies in close proximity to support the

metapopulation, (more important than the size of individual water body)

§ Create permanent water bodies with gently sloping banks (<1:2). Oneside could have steeper banks.

§ Pools would need to have deeper areas to 2m large enough to supportself sustaining populations









vegetation down wind of the prevailing wind and limiting number ofislands

§ Scouring - will occur where streams enter the ponds or can be createdusing the lock by-wash


§ Cut and removal of emergent vegetation§ In some areas plant tress to reduce competition by shading for P.

compresses§ Dredging§ Prevent nutrient enrichment with buffer zones, reed fringes, harvesting




Ecology:no shading for L.natans and shadingfor P. compressus

Minimise grazing bywater birds andlivestock.

Minimise shadingof the open waterhabitat in someareas, ensureshading in otherareas.

biota, treat pollution at source etc. (see water quality).§ Treatment of algal growth with barley straw.§ Moderate flows provide unsuitable conditions for many competitive

species.


§ Protect establishing vegetation using fencing§ Fence off to exclude livestock

§ Minimise shading by planting trees away from water edge in someareas, and in other areas create shading by plant trees along watermargins.

Species Group 4: Luronium natans, P. compressus, P. praelongus and P. friesii



Design solutions

Flow: gently flowingwhere wave action isminimal (although L.natans benefits fromscouring)

Water chemistry:Base-rich

Water quality: Clearwater. Intolerant ofsedimentation wouldblock light tosubmerged plants.



Maintain slow flowsand minimiseerosion, createsome areas withscouring

Maintain base-richwater chemistry



Ensure waters do



up wind of the prevailing wind, create shallow bank gradients andincorporate spits and islands

§ If catchment soils are not base-rich consider alternative sites or liming§ If hydrological inputs to the system are not base-rich and due to

pollution, tackle at source or with a suitably designed reedbed or otheremergent fringing vegetation. If diffuse, create buffer strips.

§ If habitat is created by flooding land, as opposed to excavation, insurewater pH post inundation is basic by identifying appropriate sitesduring initial surveys and utilising areas with appropriate waterchemistry.

§ If risk of input altering pH beyond limits of tolerance then look toproduce hydrologically isolated habitats of the right water chemistry,although this may compromise the habitats contribution towards themetapopulation and the species ability to colonise naturally.



§ Control fishing and fish stocks, as introduced fish increase turbidity.§ Exclusion of cattle to minimise bank erosion§ Use a substrate of fine gravels to reduce turbidity

§ Create refuges or hydrologically isolated habitats (but the speciesability to colonise naturally and their contribution towards themetapopulation may be compromised).

§ Tackle at source or with a reedbed or other emergent fringingvegetation.

§ If diffuse, create buffer strips.§ Maintain flow and turnover rates.§ Soils used for pond liners will affect water quality. Could use gravels


§ Reduce the deposition of organic sediment in some areas bymaintaining flows by pumping or profiling.

§ Minimise the build up of organic matter by harvesting emergentvegetation in late summer.

§ Trees should be planted away from edge to prevent build up of leaf



L. natans will nottolerate build up oforganic matter but P.compressus and Ppraelongus will



Substrate: fine andmedium, organic tomineral- sand, sandand fine gravels , silt,peat.



Ecology:no shading for L.natans & P. friessiand shading for P.

not becomehypereutrophic,minimise build upof organic matter incertain areas

Create severalhydrologicallyconnectedpermanent openwater bodies inclose proximity

Provide shallowmargins anddeeper pools of 2to 3m deep.

Provide andmaintain asubstrate of fineand medium,organic to mineral-sand, sand andgravel, silt, peat.


Minimise grazing bywater birds.

Minimise shadingof the open waterhabitat in some

litter in some areas, plant around sheltered bays in other areas.§ Treatment of algal growth with barley straw.§ Create some steep banks to reduce build up of organic matter.§ Ensure all hydrological inputs are not hypereutrophic; if so tackle at




§ Ensure interconnectivity of habitats§ Ensure permanent open water with drawdown zones§ Ensure mosaic of different land forms§ Ensure delivery of water§ Ensure there are several water bodies in close proximity to support the

metapopulation, (more important than the size of individual water body)

§ Create permanent water bodies with gently sloping banks (<1:2). Oneside could have steeper banks.

§ Pools would need to have deeper areas of 2 to3m, large enough tosupport self sustaining populations









vegetation down wind of the prevailing wind and limiting number ofislands

§ Scouring - will occur where streams enter the ponds or can be createdusing the lock by-wash


§ Cut and removal of emergent vegetation§ In some areas plant tress to reduce competition by shading for P.

compresses§ Dredging in some areas but as P. friesii is intolerant of dredging leave

some areas undredged§ Prevent nutrient enrichment with buffer zones, reed fringes, harvesting

biota, treat pollution at source etc. (see water quality).§ Treatment of algal growth with barley straw.§ Moderate flows provide unsuitable conditions for many competitive

species.


§ Protect establishing vegetation using fencing§ Fence off to exclude livestock

§ Minimise shading by planting trees away from water edge in someareas, and in other areas create shading by plant trees along watermargins.



compressus & P.Praelongus

areas, ensureshading in otherareas.

Species Group 5: Potamogeton alpinus



Design solutions

Slow: to gentlyflowing. Tolerant ofspate

Water chemistry:wide ranging butgenerally pH neutralto base-poor



Water quality:Mesotrophic, canonly withstand amodest amount ofeutrophication

Landform: streams,ditches, canals,ponds

Ground profile:Shallow margins to1m deep

Maintain slow to gentleflows.

Maintain pH neutral tobase-poor

Maintain low turbidity


Ensure waters aremesotrophic with a lowrisk of nutrientenrichment


Maintain shallowmargins to 1m deep

§ Control flow rate by meanders (with moderately low sinuosity toavoid slack water), cross-sectional area, profile and gradientacross site.


§ If catchment soils are base-rich consider alternative sites§ If hydrological inputs to the system are basic and due to

pollution, tackle at source or with a suitably designed reedbed orother emergent fringing vegetation. If diffuse, create buffer strips.

§ If habitat is created by flooding land, as opposed to excavation,insure water pH post inundation not basic by identifyingappropriate sites during initial surveys and utilising areas withappropriate water chemistry.

§ If risk of input altering pH beyond limits of tolerance then look toproduce hydrologically isolated habitats of the right waterchemistry, although this may compromise the habitatscontribution towards the metapopulation.

§ Minimise potential for erosion. Where erosion might be an issue,use bank stabilization by planting and profiling.

§ Silt traps may be necessary. Settling pools and reedbeds canalso be used.

§ Control fishing and fish stocks, as introduced fish increaseturbidity.

§ Exclusion of cattle to minimise bank erosion


vegetation.§ If diffuse, create buffer strips.§ Maintain flow and turnover rates.§ Soils used for pond liners will affect water quality. Could use

gravels over clay to reduce turbidity.

§ Minimise the build up of organic matter by harvesting biota.§ Trees should be planted away from edge to prevent build up of

leaf litter.§ Treatment of algal growth with barley straw.§ Create some steep banks to reduce build up of organic matter.§ Ensure all hydrological inputs are not eutrophic or cause nutrient

enrichment; if so tackle at source or with a reedbed or otheremergent fringing vegetation.

§ If diffuse, create buffer strips.§ As hypertrophic water become anoxic, aerate water by maintain

flows by pumping or profiling.§ Reduce the deposition of organic sediment by maintaining flows




§ Create water bodies with gently sloping banks (<1:2). One sideof the ponds could have steeper banks or a bench as ~1m deep.

§ Excavation in existing ground§ Low risk of erosion of margins and deep pools by creating



Substrate: fine tocoarse, mineral toorganic. Often onhard rock.




Create and maintain asubstrate of fineorganic to mineral soilswith bare rocksurfaces.

Ensure attenuation ofsuccession

Minimise grazing bywater birds, livestock

Minimise shading of theopen water habitat

appropriate degree of slope for substrate.§ Create variation in gradients and depth to ensure required

gradient is created

§ Ensure liners are covered with the appropriate substrate.§ Ensure bank gradient is such that it has the ability to retain

material in-situ§ Silt traps may be necessary to reduce sedimentation. Settling

pools and reedbeds can also be used.§ As this species tolerates modest spate, planting downstream of

the by-wash maybe effective

§ Create deeper pools have less light and limit establishment ofother vegetation


harvesting biota, treat pollution at source etc. (see water quality).§ Appropriate control of non-native species§ Treatment of algal growth with barley straw.§ Identify/design inflows to allow possibility of spate, where other

species would not have such a competitive advantage

§ Reduce the attraction of the site to water birds by planting treesand emergent vegetation appropriately to disrupt sight lines,keeping open water bodies small or narrow.



4. GENERIC DESIGN GUIDELINES

Environmental design considerations

4.1 It is possible to design a habitat to support any one species Group. However due to the habitatrequirements of the Groups, the objective of increasing biodiversity and maximising thepotential of the wetland habitat, the design solutions for certain species Groups have beencombined to produce a habitat mosaic.

4.2 Figures 1 to 5 provide illustrative representations of generic concept designs which providesuitable habitat conditions for the five species Groups, and hence all the notable species. Whilstthese provide an illustrative representation of habitat requirements for the notable species, it isrecommended that site specific detailed engineering drawings would need to be produced beforeconstruction. These could only be generated once appropriate sites have been identified.

4.3 The emergent and aquatic macrophytes species Groups, Groups 1 and 6 differ in requirementsfor flow rate, nutrient requirement, water depth and substrate but it is possible to create a habitatmosaic that is likely to be suitable to support both groups.

4.4 Group 1 requires still to slow flows, where as Group 6 requires slow to moderate flows. It ispossible to create hydrologically connected water bodies with different flow rates by using thedesign solutions outlined in Table 9, such as creating some stretches with meanders of low



sinuosity for faster flows and other with high sinuosity, which would create slack water. Thesefeatures could be created in two hydrologically connected, parallel channels for example.Seasonally inundated shallow depressions, like side channels, or oxbows could also be created offthe main open water channel to create still to sluggish flows. Incidentally, flow decreases towardsthe shallower open water margins due to drag from the substrate. So, the flow at the margins willnaturally be slower than through the centre or deepest section of the water body.

4.5 Both Group 1 and 6 tolerate mesotrophic water, although Group 1 prefers meso-eutrophic. Theopen water would need to be mesotrophic, however, inputs to wetland habitat from overlandrun-off, seepage through substrates and from streams and ditches could be eutrophic if anemergent fringe was planted around the water body, which would lock up nutrients in theirbiomass and so decrease the nutrient status of the water flowing into the water body. A reedbedwould act in the same way. It is therefore, likely to be possible to create meso-eutrophicconditions for emergent species whist maintaining mesotrophic conditions for the aquatic plants.

4.6 Group 1 requires shallow margins and deep pools, whereas Group 6 requires shallow margins.Variation in water depth can be created through ground profiling, such that channels to 3m deepfor the aquatic species have shallow margins for the emergent species.

4.7 Group 1 requires silt and clay substrates, whereas Group 4 requires silt and peat substrates.Varying substrate is more complicated in terms of construction but would be possible. Pondliners of different material can be used in different locations. For example, fine gravels could beused in areas of moderate flow, by the lock by-wash for instance, for Luronium. natans andPotamogeton praelongus. The channel bed could be fine organic or mineral soils suitable for all theaquatic macrophytes and the banks puddle clay suitable for the emergent plants. If it provesnecessary to excavate areas of peat, it would be possible to reuse this material to locally line areasof the newly created habitats.

Political design considerations

4.8 Whilst the generic concept designs provide suitable environmental conditions for the species,there are also a number of political considerations which need addressing. British Waterwayshave identified (British Waterways, 2003) certain features or issues to be addressed in the habitatdesigns. These should not compromise the sites ability to support the notable species. It may,therefore, not be possible to include all of the following prescriptions within a design at aparticular location or that some locations may not be suitable.

• Minimising excavation• Incorporating excavated material into the design by storing on site for bunds or

screening.• Access for management• Minimising management intervention• Habitat size to be as wide as possible• Access by foot paths

4.9 The issues concerning the above are described for each of the concept designs in Figures 1 to 5.

General design considerations4.10 Figures 1 to 5 provide generic concept design solutions for a range of scenarios. The following

information applies to the majority of the concept designs. This general design informationneeds to be considered when implementing specific design.



4.11 The Environment Agency should be contacted regarding any plans to alter a water course.Permission would need to be sought from the appropriate statutory body and land owner priorto any construction works. A Local Planning Authority will also need to be contacted to makesure there are no planning implications.

4.12 The concept designs (Figures 1-5) are only likely to support the target species with appropriatemanagement. The following points include a brief guide to management practices that are likelyto be required and are generic to all the concept designs.

Oxygenation and role of water flow4.13 Many of the groups require a degree of flow to maintain oxygenated conditions and to reduce

the risk of algae blooms. A range of generic measures can be applied, most of which arerepresented in Figures 1 to 5. The presence of emergent vegetation across a flowing inlet couldreduce flows, therefore by manipulating the gradient it could be possible to regain flow ratedownstream.

4.14 By sourcing suitable inflow locations, where prevailing flows currently provide the appropriateconditions it should be possible to maintain flows in the created habitats. By-wash could also beincorporated into design to maintain flows and accommodate some scouring flows where this isdesired. The Wern Aqueduct Reserve utilises by-wash to provide enhanced flow. This has beenconsidered to be important for the survival of Potamogeton praelongus (Pers. comm. Nigel Willby,2003).

4.15 Where flows may be too great, methods can be adopted to reduce flow rates. Bed-check weirscould be installed within the channels to reduce the gradient of the bed by introducing a series ofsmall (300m) steps, which have been successful at Maghull Brook, Merseyside (Gilbert andAnderson, 1998). They would also oxygenate the water improving overall environmental qualitybenefiting aquatic plants.

4.16 It is possible to control and manipulate flow rate by utilising an appropriately designed channel.Consideration needs to be given to the detail design of meanders, cross-sectional area, bankprofile and gradient to ensure that the appropriate flow conditions prevail.

4.17 Meanders should have a moderately low sinuosity as Luronium natans does not tolerate thesluggish flows created by highly sinuous channels. By-wash is a potentially important way tocreate moderate flows. In certain locks in Manchester P. compressus grows well where flow isenhanced, possibly as a result of reduced competition (Pers. comm. Nigel Willby, 2003). Flowscan also be manipulated by creating deeper and narrower channels.

4.18 The use of aeration pumps could provide additional benefit for slower flowing water to reducethe BOD but would not compensate for lack of flow. Certain species actually require a flow ofwater.

Pumping to produce required flow4.19 The site selection process should seek to identify sites where water delivery can be provided

under gravity in a sustainable manner, rather than having to utilise a pumped option. Where noalternative exists other than pumping, then a sustainable solution, utilising wind or solar powershould be considered.

4.20 A single 9m wind pump with 2.5m diameter blades, when appropriately sited with access to agood undisturbed fetch, can deliver up to 80m3/day. This translates to a discharge of0.0093m3/s. To provide suitable flows more than one wind pump may be required.



4.21 Solar powered pump technology is evolving all the time. Both direct drive and battery operatedsystems exist. The power generated depends on the number of photovoltaic cells or panels andthe degree of incoming solar radiation (insolation). More power can be added by increasing thenumber of panels. A simple 1 horsepower (hp) pump with three 50-watt panels could provide aslittle as 10m3/day (0.00017m3/s). However a 3hp pump with an array of 60 panels could deliverin excess of 5000m3/day (0.0579m3/s).

4.22 The ability of a solar powered pump to deliver water also depends on distance through whichwater needs to be lifted as well as the distance over which pumping is required. Additionally theefficiency of the pump will also determine the water delivery rate.

4.23 If a pumped water supply is the only option then careful consideration needs to be given to thechoice of pump and its associated energy source. If a sustainable option is not possible, mainselectric can be utilised to drive a pump.

Optimum size4.24 The maximum wide of the channel depends on the discharge rate, water quality and grazing.

Ultimately it is restricted by grazing. A water body becomes more attractive to waterfowl thewider it is. It will be impossible to exclude some species, like Coot and Mallards that will graze asite regardless of the width of the water body, however, if wider than around 30m it could attractlarge number of geese that would result in heavy grazing pressure. Previous evidence of suitablechannel widths for reserves created along canals Newbold (2003) considers a through-flow ofwater with a gradient of one loch depth over 250m between inflow and outflow to be optimumfor channels of 6-20m wide, as is the case for Wern Reserve, Montgomery Canal (Newbold,2003). The designs have been based on these principles. There is no empirical evidence to datafor the exact discharge rates required by the aquatic species or the discharge rates for site thatcurrently support these species, so it is not possible at this stage to state the potential maximumwidth a channel could be created. This research needs to be undertaken.

Silt traps and nutrient control4.25 Nutrient enrichment and sedimentation pose a threat to all aquatic plants. Some species have a

direct intolerance, other are indirectly affected by competition from more aggressively growingor tolerant species. Newbold (2003) investigated the benefits of planting up the inflow to a waterbody from a study of reserves along Montgomery Canal. Emergent plants and aquaticmacrophytes lock up nutrients in their biomass and so improve water quality. They also act totrap sediments entering the system.

4.26 To suppress nutrient inputs to the aquatic environment, vegetation needs to be cut and removedannually in August, before it decays in September. Newbold (2003) considers cutting only 25%of the cover across an inflow to be optimum, as this ensures that vegetation can still removesediments during winter periods. At the Wern Reserve, Montgomery Canal, a stand of Reed-grass Glyceria spp. established across the inflow of the first pond and first meander was found tobe successful at nutrient removal and trapping sediments (Newbold, 2003).

4.27 Silt traps slow the flow resulting in silt settling out when the flow is less than 0.2m/s. Silt trapsare best located just below the inflow. They need to be cleaned out regularly to preventsediments going back into suspension, so should be designed to make dredging simple by, forexample, providing a concrete approach for machinery access. Ideally, there should be areas todump silt located close to the trap (Merrit, 1994).

4.28 Where nutrient rich water is delivered to the Canal then attempts should be made to manage thisissue at source through sensitive and appropriate land management. Where this is not possible,consideration should be given to using reedbeds or buffer zones to improve water quality, priorto entry to the canal system. It is essential that the location and siting of such features is given



careful consideration. In the case of reedbeds it is important that sufficient land area is availableto provide necessary retention times to reduce nutrient levels.

Liners4.29 Wherever possible, it is most cost-effective to excavate into existing material of low hydraulic

conductivities (preferably less than 10-4m/day), such as massive clays and use these asimpermeable barriers. In locations where the substrate possesses a permeability which wouldpreclude the retention of water, such as sands and gravels and potentially peat, then the createdhabitats should be lined.

4.30 A range of materials are available for lining. A good review of options is provided in Merritt(1994). When considering a liner it is important to remember that the option selected could havean influence on the character of the wetland created. For instance, liners will dictate thepermeability and consequently the rate of water movement; they will provide a medium withinwhich benthic fauna can live; they can provide a source of nutrients for, and a medium in which,plants can live; and they can influence the water quality of the overlying water body.

4.31 The most commonly used impermeable liners are excavated clay, flexible synthetic liners,bentonite and concrete. Each has there own merits depending on the function it has to serve. Inthe context of creating habitats for the notable species associated with the Montgomery Canalpreference should be given to using clay excavated locally. Consideration needs to be given tothe nature of the clay, the degree to which other materials such as sand and silt may be present,the haulage distance and route required to bring the material on to site, the ability to stockpilematerial on site, any levels of potential contamination and the volume required.

4.32 A clay liner should be applied in layers of no more than 300mm thickness. Ideally each layershould be approximately 150mm thick. Up to 500mm is usually required for a clay liner. Eachlayer must be compacted (puddled) mechanically to ensure that an impermeable seal is formed.The clay should be slightly moist when applied; working in very wet or very dry conditionsshould be avoided. Consideration should be given to the type of planting proposed and thethickness of the liner to ensure that plant roots do not puncture the clay seal. A final dressing canbe applied to the clay to provide the appropriate substrate for the chosen species Group. Forinstance, gravel or silt may be applied to the finished clay surface to satisfy the species-specificrequirements.

4.33 Over peat substrates a range of alternatives exist. It is possible to excavate then compact peatover limited areas. Therefore if relatively impermeable bunds need to be created, it is possible tokey into undisturbed peat at depth then back fill and compact excavated peat. This should bedone to a level of compaction using the appropriate machinery such as a sheep’s foot roller.

4.34 Over wider areas it may prove more difficult to generate a guaranteed impermeable barrierthrough the use of peat. Depending on the depth and type of peat, it can be possible overrelatively shallow deposits with a low degree of decomposition to lay a clay liner as describedabove. However, over areas of deep well decomposed soft peat an artificial liner may be moreappropriate.

4.35 There are conservation and archaeological concerns regarding excavation, disturbance andremoval of peat deposits. The selection of locations underlain by peat should take these factorsinto account.

4.36 Other liners, such as bentonite, synthetic materials or concrete could be used, however theselection of one of these medium should undergo careful consideration in order to assess theirinfluence on delivering the appropriate habitat conditions for the notable species. Bentoniteliners can form very effective impermeable seals but, due to their relatively narrow thickness, canbe punctured by the roots of deep-rooted plants. Therefore a bentonite liner should be covered



with sufficient depth of soil (ideally of low or appropriate nutrient status) to reduce the risk ofpuncture. Synthetic, butyl of HDPE liners suffer from similar problems as bentonite liners andin addition may not provide an impermeable seal indefinitely, potentially resulting in a futuredegradation of the habitat.

Consideration of a lock by-wash system to provide water flow4.37 In some locations the flow provided by the Canal could be supplemented by water delivered

from a lock by-wash system. Careful consideration needs to be applied to the location of anyinflow pipes or channels from lock by-wash as the ephemeral and flashy nature of the flow couldcontribute to local scouring and erosion and may create flow conditions unsuitable for some ofthe target species.

4.38 Where lock by-wash is considered it may also be necessary to provide a degree of protectionfrom bed erosion by using fine gravel substrates, which are tolerated by Potamogeton praelongus aslong as the flow did not produce turbulent conditions. Similarly bank protection may benecessary through green techniques such as using hazel faggots or coir matting. It isrecommended that willow species are not used as these could result in unwanted shading of thechannel.

Designing out waterbirds4.39 Waterbirds are integral components of canal and wetland ecosystems. Whilst measures can be

advocated and implemented, it is impossible to exclude all waterbirds. A range of options areavailable to make sites less attractive to waterbirds. Similarly a range of measures can beimplemented to reduce the impact birds may have on the vegetation, especially in the sensitiveestablishment phase.

4.40 It is currently thought that it is possible to make an area permanently unattractive to somespecies of waterbird through appropriate habitat management (Allan, 1999). Many species ofwaterbird, especially geese, require unrestricted 360 degree views to remain alert to potentialpredators. Any obstruction can reduce their feeling of safety and therefore reduce the site’sattractiveness. Similarly, many species of waterbird feel vulnerable if they cannot see a clear viewof water. Discouraging waterbirds by utilising this behaviour can be achieved through habitatmodification and management such as:

• barrier planting i.e. establishing dense areas of emergent and terrestrial vegetationaround areas of large open water to restrict the birds’ view of the water;

• planting of trees and tall shrubs close to waterbodies to deter species that prefer ashallow angle to fly out of waterbodies e.g. swans and some geese;

• consider planting vegetation that is not palatable to waterbirds e.g. ivy and manyshrub species thus discouraging feeding waterbirds;

• ensure any areas of grassland around the sites are kept long to reduce theattractiveness of the area for feeding for swans, geese and some ducks such asWigeon;

• Smaller or linear water bodies are less attractive, especially if no wider than 30m.

4.41 The above measures should make the sites less attractive to swans, geese and some ducks such asWigeon. However, other species of waterbird, including Teal, Mallard and Moorhen are unlikelyto be excluded as they are undeterred by small, enclosed waterbodies. It is therefore extremelyimportant to ensure a range of measures are implemented to reduce the impact of waterbirds onthe vegetation, especially during the establishment period.

4.42 The main ways in which waterbirds can impact newly establishing aquatic and emergentvegetation are through grazing and trampling. Both issues can be addressed by preventing



waterbirds gaining access to sensitive areas through the erection of temporary, orange plasticfencing 0.3-1 metre high around the newly planted areas. This fencing may have to remain forseveral years until the new planting is strongly established. Submerged aquatic vegetation shouldalso be protected during establishment, particularly from diving and dabbling duck, by the use ofwire cages. Any fencing or cages must be of an approved design that would not present a risk towildlife.

4.43 Scaring techniques may also be a useful tool, although these are often only effective as short termdeterrents. Options include visual scarers, such as flags or flutter tapes, acoustic options such asgas cannons and scaring by the presence of human beings. The most effective method has beenfound to be a ‘Scary man’, which is a red, man shaped balloon that inflates for 30 seconds every30mins. Also, if adjacent grassland floods in winter this will increase the overall size of the waterbody, making it more attractive. Water levels could be controlled to minimise flooding over largeareas of adjacent land.

4.44 Past experience suggests it is unlikely that any one single management technique will be fullyeffective in excluding waterbirds. It is always recommended that an integrated managementstrategy is adopted which should incorporate several techniques. Even then it should berecognised that any waterbody is likely to attract some species of waterbird and it is impossible toever completely exclude waterbirds from a wetland system.

Tree planting and its role in shading aquatic macrophytes4.45 Trees are required to provide the shaded conditions necessary for Potamogeton compressus and P.

praelongus. Shading of the open water margins should be minimised as all other target species areintolerant of shade. Trees could be planted around the outside of some meanders i.e. along onebank only and for short stretches. Alternatively, some sites could be part shaded for P. compressusand P. Praelongus and other sites left entirely unshaded, although a few trees could be plantedacross the site, but 1.5 times tree height away from the water margins to break up bird flightpaths but so as not to shade the open water.

4.46 Shading from trees or tall emergent vegetation limits light to aquatic macrophytes and therefore,limits their growth. Over-hanging trees also cause a build up of leaf litter in the water body,increasing nutrients and resulting in anoxic sediments, which would hinder the survival of thenotable aquatic macrophytes. Therefore, trees should be planted at least one tree height awayfrom the edge of the water body. Newbold (2003) considers no more than 25% of the edgeshould support trees if the management objective is for aquatic plants and that 25% of emergentvegetation should be removed annually. This should be undertaken in August from one side ofthe bank at a time and should be cut on rotation. Encroaching scrub should be manuallyremoved or controlled through water level management. If grazing by livestock is used tomanage adjacent grassland vegetation fencing, such as temporary fencing, would be necessary toprevent access to the emergent vegetation and open water channels to prevent poaching, grazingand increase in turbidity. It would be possible to allow access to certain pools as Oenanthe fistulosaand Ranunculus sceleratus require poached open water margins.

Outline recommendations for public access4.47 The public need to be managed as an integral part of the habitats to be created. In some areas it

will be desirable to exclude the public. In such locations consideration should be given to the useof dense bramble and scrub planting or the use of ditches as wet fences to discourage access.

4.48 In locations where public access is to be allowed it is recommended that access should becontrolled and restricted to well marked and defined pathways. Interpretation should beprovided to inform and educate the public so as to assist in persuading the public to remain ondesignated pathways. Signage should also identify the potential risk to the habitats imposed byangling, uncontrolled dogs and the feeding of waterbirds.



Minimising erosion from scour and wave action4.49 The key principle behind the control of bed scour and bank erosion is the need to reduce the

energy available to generate wave action. This can be achieved through several techniques.

4.50 By creating water bodies which are relatively enclosed and do not have an extensive fetch theopportunity for waves to develop is reduced. Therefore, careful consideration is required whenconfiguring the distribution of waterbodies and their orientation with regard to the prevailingwind direction. Ideally, sites should be linear with perpendicular cross winds or screening can beused to intercept winds.

4.51 Careful tree planting to create shelter banks can also be used to reduce wind speed and toeffectively truncate the fetch. The use of tree planting as shelter should only be used if otherpotentially detrimental effects trees may have on overall habitat quality are adequatelyconsidered.

4.52 Bank profiles can be manipulated to provide shallow gradients allowing wave energy to bedissipated before reaching banks. The creation of undulating bed profiles and small ‘reef’ areas infront of banks can also dissipate wave energy.

4.53 The use of planting should also be considered, not just in terms of providing the target habitats,but also to provide bank and shoreline protection and stabilisation. The provision of a robustemergent fringe can reduce greatly the erosional impact on banks.

4.54 As discussed above, the use of ‘green engineering’ techniques could also be considered whereerosional problems are anticipated. The use of willow and alder are not recommended unlesstrees are essential to the habitat design. The potentially deleterious impact shading may have onthe notable species needs to be considered prior to using such bank protection techniques.Alternative solutions could involve the use of hazel hurdles or faggots which are back-filled andplanted, or coir rolls or matting which could also provide additional habitat.

4.55 To prevent bed scour the use of gravels could be considered to provide a degree of armouring.Locations should not be selected where bank or bed scour could be severe. However, if noalternatives exist then the use of harder engineering techniques such as gabions or rip-rap couldbe considered.

Attenuation of succession4.56 Dredging and chain cutting the vegetation has proven to be particularly successful management

for Potamogeton compresses along sections of the River Trent. Management also includes thedragging of a chain over the vegetation (Pers. comm. Nigel Willby, 2003). These techniquescould be used along some sections to attenuate succession and provide habitat for poorlycompetitive species.

4.57 Suppression of succession can be created and managed by: the drying out of the substrate(creating ephemeral pools); scouring (will occur where streams enter the ponds); depth (deeperpools have less light and limit establishment of other vegetation, therefore create pools to 3mdeep), cutting and removal of vegetation (annually after August), dredging (once every 3-5 years),prevention of nutrient enrichment (buffer zones of a minimum of 10m, reed fringes, ensuresource has low risk from pollution, treat at source, minimise waterbird numbers, thereforefaeces, by planting trees and keeping open water bodies small or narrow.

Invasive species4.58 The problems associated with invasive species should be considered when planting up a site and

during immediate aftercare and long-term management. The main seven six highly invasive, non-native aquatic plants to look out for are Canadian Pondweed Elodea Canadensis, New Zealand



Pigmyweed or Australian Swamp Stonecrop Crassula helmsii (it has been sold under the namesTillaea recurva and Tillaea helmsii), Floating Pennywort Hydrocotyle vulgaris, Parrots FeatherMyriophyllum aquaticum, Water Fern (similar to Azolla. caroliniana), Japanese Knotweed Polygonumcuspidatum and Indian Balsam Impatiens glandulifera.. Three of these species are widely availablefrom garden centres. Their rapid growth causes concern to gardeners who often dump excessmaterial in the nearest pond. They also may be present as small specimens accompanying nativeplants from nurseries, and so great care must be taken when purchasing any aquatic plants.

4.59 If left unchecked, the occurrence of any of these plants on a water body will result in a mat ofsurface vegetation which prevents light reaching the water, resulting in the death of native plants.As the dead material decomposes, the water then becomes depleted of oxygen. Native wildlife isunable to survive in such conditions. The current best practice for controlling these species aregiven in Appendix 1.

4.60 The sites are designed to minimise the risk of algal blooms. If algae becomes a problem it can beremoved in several ways. Filamentous algae can be removed by raking or using a dragline to clearthe pond, but this offers only temporary control. Addition of barley straw to the pond can alsohelp to control algal growth but it must be organically grown. It releases compounds that controlalgal growth. Barley straw should be introduced into the water in March and will be effective for6 months, so treat again in July and placed loose or broken up in shallow water or floated nearthe surface. One bale should clear approximately 0.1ha of algae for about 6 months. To preventfurther algal growth, the source of nutrient enrichment must be identified and stopped.

5. CONCLUSIONS/DISCUSSION

5.1 The aquatic and emergent plant assemblages occurring through the Welsh stretch of theMontgomery Canal have been granted national protection. There is also a Special Area ofConservation for the internationally important Floating Water Plantain Luronium natans, underthe European Species and Habitats Directive (1994).

5.2 Whilst every attempt should be made to conserve the plant species in situ, where plans for therestoration of the canal for boat traffic exist, the design principles contained within this reportshould be applied.

5.3 The assessment has identified the habitat requirements and constraints for the notable species.Generic, non-site specific, concept designs have been produced to demonstrate possible designsolutions. Whilst these are intended to be illustrative, with appropriate site selection andunderstanding of existing environmental conditions the principles enshrined in these conceptdesigns should transfer to detail designs.



6. REFERENCES

ALLEN, J. (1999). The Management Problems Caused by Canada Geese. A Guide to BestPractice. DETR.

BRIGGS, J.D. (1989) British Waterways Board Montgomery Canal Ecological Survey ReservesReport 1985-88. Environmental Scientist Gloucester.

GILBERT, O.L. & ANDERSON, P. (1998) Habitat Creation and Repair. Oxford UniversityPress.

HASLAM, S., SINKER, C. & WOLSELEY, P. (1995) British Water Plants. The Field StudiesCouncil, Shrewsbury.

LANSDOWN, R.V. & WADE, P.M. (2001) Floating Water-plantain (Luronium natans). EnglishNature, Peterborough.

LEES, S. (2003) Montgomery Canal Conservation Management Strategy Working Draft.Montgomery Canal Partnership.

LEES, S. (2003) Montgomery Canal Ecology and Conservation: Resolving Potential Conflictswith Navigation. Montgomery Canal Partnership.

MERRIT, A. (1994) Wetlands, Industry & Wildlife. The Wildfowl & Wetlands Trust.

NEWBOLD, C. (2003) The Montgomery Canal Reserves A Macrophyte Survey.

OVE ARUP & PARTNERS (1986) The Montgomery Canal Offline Aquatic Reserves Vol.1Main Report . OVE ARUP & PARTNERS, Manchester.

OVE ARUP & PARTNERS (1986) The Montgomery Canal Offline Aquatic Reserves Vol.2Details of the reserves. OVE ARUP & PARTNERS, Manchester.

RODWELL, J.S. (2000) British Plant Communities Vol. 4. The University of Cambridge.

ROSE, F. (1991) The Wild Flower Key. Penguin Group, London.

THORNE, C.R., HEY, R.D. & NEWSON, M.D. (19970 Applied Fluvial Geomorphology forRiver Engineering and Management. John Wiley & Sons, Chichester.

WARD, D., HOLMES, N. & JOSE, P. (1995) The New Rivers & Wildlife Handbook. The RoyalSociety for the Protection of Birds, Bedfordshire.



FIGURES

Figure 1 – Concept design one.

Figure 2 – Concept design two.

Figure 3 – Concept design three.

Figure 4 – Concept design four.

Figure 5 – Concept design five.



APPENDIX I. Invasive species

This advice note describes six highly invasive, non-native aquatic plants, and possible methods ofcontrol. Three of these species are widely available from garden centres. Their rapid growth causesconcern to gardeners who often dump excess material in the nearest pond. They also may be presentas small specimens accompanying native plants from nurseries, and so great care must be taken whenpurchasing any aquatic plants.

The plants are New Zealand Pigmyweed, Canadian Pondweed, Floating Pennywort, Parrots Feather,Water Fern, Japanese Knotweed and Indian Balsam. If left unchecked, the occurrence of any ofthese plants on a water body will result in a mat of surface vegetation which prevents light reachingthe water, resulting in the death of native plants. As the dead material decomposes, the water thenbecomes depleted of oxygen. Native wildlife is unable to survive in such conditions.

A mat of Crassula

New Zealand Pigmyweed has been recorded in over 10,000 water bodies in the UK, and the numberof sites appears to be doubling every two years. The spread of these plants is now so rapid, that theyare destined to be a major problem for all wetland managers in the future, with more and more timeand money allocated to their control. It is estimated that £3 million is now required to control NewZealand Pigmyweed and a further £3 million to control floating pennywort in the UK.

The seriousness of the situation is made worse by the fact that New Zealand Pigmyweed, as far as weknow, has never been successfully eradicated from any water body, without the deliberate destructionof that water body.

Because these plants are now so common in garden ponds, it is essential that no aquatic material isaccepted from the public, including amphibian spawn. It is also essential that garden pondequipment is not brought onto the site.

Unfortunately, waterbird eat New Zealand Pigmyweed readily, and may defecate viable material,which makes it even more important that these plants are dealt with as soon as they are discoveredIn dealing with these plants, there are two issues to resolve:

1 - Identification of the plants



2 - Successful controlIdentification

It is essential that all personnel, from managers to volunteers, know what to look for. The followingsections describe each of these plants in detail, and colour copies of this advice note should beavailable to all personnel working on site.

General Control

It is essential that, with the exception of Water Fern, no attempt should be made to control theseplants by hand or other mechanical methods. The smallest fragments of these plants will re-grow,and so mechanical disturbance simply spreads the problem further.

Removal of Water Fern by hand is ineffective anyway, due to the rapid growth of the plant.Herbicide application is the normal method of control.

Factors to consider when applying herbicides:

1 - An extra NPTC module is needed to apply herbicide over or in water.It’s another part of PA6, and should be a day course, costing under £100.00

2 - The Food and Environment Protection Act 1985 requires approval from the EnvironmentAgency to use herbicides on water if the water body is on line (connected to other waterbodies, still or flowing).

3 - Within 5 to 10 years, there will be an EU ban on all residual herbicides for aquatic use. We will be left only with contact herbicides such as glyphosate.

4 - Glyphosate is far more effective if used out of water, so the infested water body should be drained wherever practical, until control is complete. Obviously, these plants are also far less vigorous out of water.

5. It is essential that you seek advice before using any of these methods. Guidelines andrecommendations differ for each plant and must be followed.

6. A waste license is required to remove Japanese knotweed to a waste disposal facility. Allwaste materials, including weeds, are subject to the Duty of Care and must only betransferred to, and carried by, registered waste carriers. (EA website)



New Zealand Pigmyweed

New Zealand Pigmyweed or Australian Swamp Stonecrop, and just to confuse things further, it hasbeen sold under the names Tillaea recurva and Tillaea helmsii since 1911 as an oxygenating aquatic fromnurseries and garden centres.

New Zealand Pigmyweed, note the collar where the leaves attach the stem

New Zealand Pigmyweed is a succulent aquatic from Tasmania. It has a creeping growth form, whichproduces roots from the nodes. It has the ability to reproduce rapidly by vegetative means resultingin dense mats of vegetation. The stems have pairs of unstalked opposite leaves (4-20 mm). Wherethe leaves join the stem there is a collar about 1 mm high. This is a distinctive characteristicwhich allows the plant to be distinguished from other plants such as starworts. Flowers appear in theemergent growth only. They are stalked from the base of the leaves, are solitary, and have four whiteor pink petals, with white filaments and black anthers, appearing between July and September. It is awell rooted plant and can grow in up to 3m of clear water, or damp ground well above the waterlevel. It grows throughout the year, with no dormant period.

New Zealand Pigmyweed has the ability to colonise a variety of different habitats and occurs in bothacid and alkaline waters. It is now known from over 10,000 Water bodies in the UK. The number ofinfested sites appears to be doubling every two years. The smallest stem fragments of this plant strikein moist conditions. It is known to have been transferred on people's boots. It is thought hat noviable seeds have been produced in the UK, but this needs further examination.

Waterbirds eat New Zealand Pigmyweed readily, and it is highly likely that the green material is viableafter digestion by waterfowl. This of course means that waterbirds may spread New ZealandPigmyweed to new sites.



Looking down on New Zealand Pigmyweed

Control

New Zealand Pigmyweed is shade tolerant for long periods. It is also tolerant of frost, low levels ofsalinity, and able to withstand dessication. The best time to treat New Zealand Pigmyweed is duringthe winter, as it is one of a few plants still productive, non-target plants will not be affected and it iseasy to see any re-growth. However, you will probably not have the luxury of flexible timing, if youare to ensure that the plant does not get out of control, or spread to other areas. Higher water levelsin winter may also be a problem for control.

HerbicidesNew Zealand Pigmyweed is only susceptible to herbicides containing Glyphosate and Diquat.“Midstream” is a viscous gel formation of Diquat, originally for use in flowing water, but it can alsobe used for spot treatment in still water. The sticky nature of the gel means that it penetrates theplant more efficiently than other herbicides. If the growth is a dense mat, then diquat application willnot penetrate the lower layers, and so many applications may be necessary. After first treatment, sideshoots may break off, and so a second treatment, should be carried out no more than 3 weeks afterthe first. Ponds in Hampshire which have undergone heavy Diquat treatment have been monitoredfor adverse effects upon wildlife. There have been no fish kills and invertebrate life appears to behealthy. Once a die off has been achieved, the decaying material must be removed and disposed ofsafely, to prevent oxygen depletion of the water.

It is recommended to use Glyphosate only on dry emergent stems. Glyphosate is therefore the bestoption for New Zealand Pigmyweed growing on banks. This does however, require high dosagerates. All of an infestation should be treated in a single event.

Covering with black plasticThis starves the plant of light, and should be done for a minimum of six months, preferably for ayear. A problem with this method, is that when thick mats start to decay, the resulting gas can lift thesheet, and so it must be properly secured. This is the only suitable method if you are to protect otheraquatic species within hydrologically linked habitats.



Integrated approachEffective control with Glyphosate may be more efficient if the water body can be drained. Thismakes it easier to cover any re-growth with black material / bin lids etc.

Sites where New Zealand Pigmyweed control has been undertaken should be monitored regularly forat least 5 years, as complete eradication has yet to be achieved.

Canadian Pondweed

Canadian pondweed is an introduced species which can quickly ‘take over’ in ponds. It is difficult toeradicate since broken stems re-root easily. Canadian pondweed can be controlled by raking in springbefore plants are developed. It responds to the same treatments as New Zealand Pigmy weed and isbest treated by covering in winter provided the covers can be secured.



Floating Pennywort

Floating Pennywort is a native of North America. It was first brought to Britain in the 1980's by theaquatic nursery trade. It has now been found on over 80 sites, mostly in Essex, Sussex, South Walesand Devon.

Floating Pennywort leaf

Floating pennywort can sometimes be found for sale posing as our native Marsh Pennywort(Hydrocotyle vulgaris). There should be no confusion as the alien leaves average 10cm in diameter(18cm max), and have indented edges. Marsh pennywort is almost disc shaped, with leaves of only 2– 5 cm in diameter.

Mat of Floating PennywortFloating Pennywort roots in the shallow margins of slow-flowing water bodies, and forms denseinterwoven mats of vegetation which can quickly cover the water surface. In Britain, growth hasbeen observed at 20 cm per day! It is tolerant of salinity, shade, and some aquatic herbicides.

The leaves are emergent, rising on stalks from the horizontally growing stem. Both the stem and theleaf stalks are fleshy. Leaves may rise to 40 cm above the water surface and the interwoven mat of



roots and stems to 50 cm below water surface. One square metre of pennywort can weigh a huge 75kg.

Reproduction is vegetative, and the plant is capable of forming extensive mats from the smallest rootfragment, although introduction by seed may be possible.

In the UK, maximum growth is during late summer. It over winters in the margins and on banks asa much flatter and smaller plant.

Control

Mechanical removal can be useful in preparation for chemical treatment. However, withoutthorough removal of all cut material the inevitable spread of the plant will be exacerbated.

Applications of Reglone (Diquat) as a surface spray at a dilution rate of 1 in 4 are effective atcontrolling both submerged and emergent tissue. This is an application rate of 50 litres per hectare.This is equivalent to the dose rate for submerged plants. The 3 l/ha label rate is ineffective againstboth emergent and submerged tissue and higher doses have to be applied.

Small leaves under the main canopy will be shaded from the herbicide. It is therefore essential toplan a follow-up treatment in any chemical control programme which allows spot treatment about 2to 4 weeks after the first herbicide application.

Small plants whose leaves lie at, or below, the water surface will have to be physically removed, aswater flowing over the leaves will negate the efficacy of the herbicide.

Decomposition of the plant material is often slow, and may take as long as six weeks in slow flowingwater bodies.

NB - Floating Pennywort is resistant to Casoron G, Glyphosate and other slow acting herbicides.



Parrots Feather

Parrot's Feather is a member of the water-milfoil family, from the Amazon River. It appears toprefer warmer, milder climates and has spread quickly via plant fragments through waterways anddrainage systems. Because of its appearance and ease of cultivation, parrot's feather has been usedextensively as a popular water garden plant, and is continually promoted as such in the media,including many web sites on the internet..

Parrots feather. Note the tiny white flowers on the leaf axils

Parrots Feather with roots Mat of Parrots Feather



The bright green emergent stems can protrude up to 50cm above the water surface, giving theappearance of a miniature coniferous plantation. The submerged leaves are limp and quicklydecompose. Adventitious roots form at the leaf nodes. When rooted on the bank, stems can extendhorizontally for many metres over the water surface. The tiny white flowers are borne in the axils ofthe leaves, and only 0.2-0.4mm. When disturbed, the stem will break into small fragments, which canrapidly regenerate into viable plants.

Growth is rapid, and large ponds may be covered in a single year. Parrots feather has not beenobserved producing seed in the British Isles, but reproduces by fragments breaking from the parentplant and being moved by water currents. They may grow free floating for a period before rooting insediment. It has the ability to over winter in the British Isles either by surviving under the freezingzone or buried in mud where it is protected from severe frosts.

The plant is also able to tolerate shading, and many months of drought. It has been recorded on thedry bank of a council tip in West Cornwall, and causes a particular problem in the south west wherethe lack of severe frosts fail to control its growth.

Control

Control with herbicides is difficult due to the waxy cuticle that requires a surfactant for penetration.Surfactants, however, are harmful to most aquatic organisms. The most successful herbicides includedichlobenil (Casoron G) and Diquat (Reglone). Diquat can be applied as a surface spray toemergent vegetation after June or as a sub-surface treatment earlier in the season. The water bodyshould be monitored and any re-growth should be spot treated as necessary.



Water Fern

Water Fern is a native of western North America. It is very similar to A. caroliniana, which is fromeastern North America. Detailed examination is required to separate them.

Water Fern is a small free floating aquatic fern. The plants are up to 2.5 cm long, ovate withnumerous small overlapping leaves that conceal a branching horizontal stem. The single un-branched roots hang down and are up to 5 cm in length.

The leaves are green during the summer, but take on a red colouration when the leaves becomestressed, usually towards autumn. Water Fern grows vegetatively, and from spores, which are themethod of over wintering.

Water Fern leaves

Water Fern mats, when green and red



Water Fern does well in water with high phosphate, zinc and magnesium and obtains nitrogenthrough a symbiotic relationship with the cyanobacteria Anabaena azollae, which inhabits the leavesjust under the dorsal surface. Anabaena fixes atmospheric nitrogen and converts it to ammonia,which is absorbed by Water Fern.

Water Fern does not do well in the larger water bodies, and this is attributed to wave action. Mats ofWater Fern are also a serious health and safety risk, as they have the appearance of dry land.

Control

Removal with a boom is in-effective due to the rapid growth rate of the plant. Removal with asuction pump is undertaken by some operators, but complete eradication is almost impossible,particularly if there are dense margins, such as reeds. If the plant has spored, the operation will needto be repeated.

Glyphosate can be used to control Water Fern. However, spraying Glyphosate in the water willinevitably kill other native aquatic plants. Diquat used from above is in-effective.

Water Fern is very susceptible to Asulam (Asulox), which is commonly used for bracken control (anddocks). Asulam is not approved for use in water, but is approved for use near surface waters. Thereare no known effects upon other aquatic life.

At WWT London Wetland Centre, and many other sites, Water Fern is infested with a non-nativespecies of weevil, Stenopelmus rufinasus. This is a small weevil, about 2mm long, with a yellow stripedback, and is totally dependant upon Water Fern for all stages in its life cycle. The weevil is fromArgentina, and adults can disperse a distance of up to 5 km. The larvae are aquatic, and thousandsper square metre were found in infested pools at WWT London Wetland Centre. The larvae are upto 10mm in length with yellowish / brownish bodies and black heads. Pupae are described as blackblobs. Control of Water Fern in South Africa by the introduction of the weevil has been extremelyeffective. The interaction between the weevil and Water Fern is stochastic. High reproductive andfeeding rates cause rapid and extensive damage to the mats, causing them to sink, leaving no residualWater Fern. The weevil population then undergoes massive larval mortality with the sinking mat,and adult weevils disperse to find a new Water Fern mat. High numbers of adults on a mat, alsoencourage dispersal.

The Water Fern spores under stress, and consequently re-appears each spring. The weevils then haveto re-colonise an infested site. This results in a lagg phase of biological control each year.Unfortunately, this lagg phase occurs during the critical spring growth and breeding period foraquatic life. It would also be better, if the Water Fern was consumed before it got a chance to spore.It is consequently important to attempt to keep adults and larvae of the weevil over the winterperiod, (in a state of diapause if possible) so that they may be inoculated back onto Water Fern assoon as it appears in spring.

To facilitate this, centres with a Water Fern problem, should attempt to keep a pure stock of WaterFern (weevil free) so that farmed weevils can be fed through the winter. Obtaining a pure batch ofWater Fern has been difficult to date, and will probably involve careful removal of larvae, pupae andadults from a collected sample. If given enough light, a small weevil free sample should multiplyrapidly.



Japanese knotweed and Indian Balsam

Likely the best means of control for Japanese Knotweed and Indian Balsam is through repetitive cuttingof the stems near the soil surface with the addition of spot application of a systemic biodegradableherbicide like glyphosate (e.g. Roundup, etc.) If no herbicide is applied, the act of cutting the stems nearthe ground during the early to mid part of the growing season results in depleting the food reservesstored in the rhizomes that are necessary to produce new aerial shoots. Several cuttings would likely berequired during a single season followed by a similar treatment the following and perhaps subsequentyears until no new shoots appear. The application of glyphosate by painting the cut stems with theherbicide is likely to be more effective and a more rapid means of eliminating the underground portionsof the plant. Glyphosate can also be sprayed on the entire plant, taking appropriate precautions inapplying the herbicide for personal health reasons and also to minimize spraying other desirable plants.Glyphosate is a non-selective herbicide. If plants are sprayed, the best time is late in the year when leavestend to conduct nutrients to the rhizome as part of the build-up of food reserves to support growth thefollowing year. Such general spraying is not recommended in nature reserves where other species may beimpacted and because of the likelihood that repeated applications may be required. (National trust website)

The cheapest and most environmentally-friendly method of controlling Japanese Knotweed is to mow,cut or pull regularly; every two weeks throughout the growing season. This will kill plants after two orthree years. Alternatively apply Roundup in May and again in late summer or spring of the followingyear. Old fragments that re-grow may need spot treatment.

Giant hogweedAny Giant Hogweed Heracleum mantegazzianum that appears should be controlled - as well as beinginvasive it is highly poisonous. If, when looking at a hogweed-type plant, there is any uncertainty aboutwhether it is Giant Hogweed or ordinary Hogweed then it is almost certainly ordinary Hogweed. GiantHogweed is unmistakable.

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