rrc@therrc.co.uk 01234 752979 www.therrc.co.uk

People and Process-Based River

Management: Restoring River Processes;

Natural Flood Management; Healthy

Catchments

16TH ANNUAL NETWORK CONFERENCE

The RRC would like to thank the sponsors of the RRC Annual Conference 2015 who support discounted places

Tweet us using

#RRC2015

Ballymoney Riverside Park Restoration ‘Boating lake to salmonid channel in three months’

Dr. Gareth Greer - DARD Rivers Agency John Kane – DCAL Inland Fisheries

Overview of presentation

Background to project, where and why

Who was involved? (Partnership working)

What was done and how

Ballymoney River catchment, 88 Km²

Lower Bann

Riverside Park – 40 acre Parkland and Ballymoney River

River widened and weir constructed early 1970s Boating lake formed Over time transformed into duck pond Sedimentation of ‘pond’ raised local concerns about ‘eyesore’

Project development: • Local discussions between council / fisheries / drainage staff • Realisation that opportunity existed to restore and enhance area • Initial proposal put to council to return channel back to its natural width / gradient • Project sold on basis of cost savings against dredging (≤£250k), plus WFD compliance and habitat creation

Partnership working

Three groups involved:

Ballymoney Council – Site owner, & funder of wetland

and amenity works

DCAL Inland Fisheries – Fishery owner and funder of

river channel rehabilitation (NASCO)

Rivers Agency – Principal contractor and contributor of

benefit-in-kind plant & labour

Proposed layout

Design and Construction Issues

• Flood risk

• Flow management

• Sediment management

Flow & sediment management

Requirement not to release significant volumes of silt

Coffer dam and Bypass channel created

Flow Bypass: • Reduced sediment mobilisation • Allowed channel construction ‘in the dry’ • Maintained fish passage during migration period

• Tributary of the Lower River Bann, the main outlet of Lough Neagh to the Sea •It is small salmonid stream supporting a healthy stock of brown trout . Historically salmon where virtually wiped, however with enhancement measures and some co-ordinated restocking, a small but improving run of Salmon have re-established to the point where there is a small rod catch (released) each year • Salmonid in-river habitat is grade 2 spawning and 1 to 2 nursery •Geology is basalt bed rock, most of the water supply is runoff, however there is some aquifer supply from springs running along a fault •The catchment substrata mainly gleyed soils and some peat. Most of the catchment is intensive grassland agriculture, supporting the dairy industry, in some areas the river suffers from diffusive eutrophication •pH fluctuates from 6.5 during times of high run off to 8 in low water conditions, indicative of the inclusion of ground water •Fishing rights are controlled by the Department of Culture Arts and Leisure Northern Ireland.

Overview of the Ballymoney river system

Ballymoney River Fish Species

Species Distribution

Atlantic salmon Localised to suitable habitat

Brown trout Widespread

Stickleback Widespread

Minnow Widespread

Eel Widespread

Roach Localised Lower section

Perch Localised Lower section

Flounder Localised Lower section

In stream salmonid habitat sequence

Groyne to constrict water course and increase velocity to create scare

Pool 1+ m to provide depth and cover for 2+ adults

Spawning gravel 20mm to 80mm Ø 250 mm gravel depth Velocity 0.2 to 0.7 m³/sec Ova and 0+ fry

Nursery cobbles and boulders, 100 mm to 400 mm Ø For bed structure and cover for 1+ parr

Nursery habitat requires riffle with thalwegs and stone breaking the surface to create an undulating river bed

Ballymoney river – Enhancement Works

• Breckagh Burn – 2009

– 100m of vortex Weirs/fencing/Lunkers

– Focus on salmonid enhancement

• Ballymoney Park – 2014 - 2015

– Removal of ponded area

– 250m of Habitat units

– Broader environmental focus

Ballymoney River – Recent Enhancement Works

Ballymoney Park

Breckagh Burn

Enhancement Site

1 km Control Site

Breckagh Burn fully quantitive Electric Fishing

0

10

20

30

40

50

60

0+trout 1+trout 2+trout 3++trout

De

nsi

ty (

no

. 10

0 m

-2)

Control Site

Control Before

Control After (1 y)

0

10

20

30

40

50

60

0+trout 1+trout 2+trout 3++trout

De

nsi

ty (

no

. 10

0 m

-2)

Enhancement Site

Expt Before

Expt After (1 y)

Park weir removal

•The removal of the impounding weir at the outlet of the pond improved fish passage, flow dynamics and increased the bed gradient for habitat construction

• It created a 400mm of fall over the site, which was the limiting factor in the method of habitat construction used

Trillick

House

River

Ballym

oney

(Presb)

Church

Presbyterian

First

Trinity Church

Tk (covd)

Playground

SP

Mry

Slpg

FB

Foot Bridge

Issues

Car Park

(covd)Tks

SP

Pond

Hall

Gospel

Car Park

Hall

Hall

Hall

Hall

ESS

Hall

Posts

Manse

Hall

41.7

BM 41.71

39.6

42.6

44.5

Posts

MP 53

Pond

Car Park

Shelter

FB

Foot

Bridge

Subway

Shelter

BM 40.42

MP 1/4

Car Park

Playing Field

LB

B a l

l y m

o n

e y

A l l W e a t h e r P i t c h

P l a y i n g F i e l d s

Bridge

All Weather Playing Field

Ballymoney park, river restoration fishery plan John Kane April 2014

Lunkers = bank protection with subsurface overhangs

Out line of new water course; length 250 m x average width 5 m

Nursery Cobble 100 mm to 300 mm round wash stone

Low level deflector groyne with pool and banks protection

Spawning gravel 20 mm to 80 mm round washed stone

Up stream horse shoe groyne

Pools => 1 m depth A

A

B

B

Existing bed level

Groyne max height from bed level 300mm

Pool Depth, min 1000 mm

Spawning bed consisting of gravel max height from bed level 250 mm

Nursery bed consisting of round stone/ cobble mat max height from bed level 300 mm

Approximate distances

15m 10 m 15 m 6m

Sectional view A - B of habitat unit and Lunkers, Ballymoney river 2014 (not to scale)

A

Low flow water level

Lunkers of rock armour 500 mm to 1000m built to create overhang

Banks side soil and vegetation

8m

A

Flow

Sectional view C-C of deflector groyne , Ballymoney river 2014 (not to scale)

B B

Existing bed level

Low flow water level

Banks side soil and vegetation

1/3 1/3 1/3

Rock Armour bank protection to prevent pond silt escapement

Height of the deflector groyne from the existing bed level =0.300 m

The low level river flow to flow within the restricted channel

River channel divided into thirds 2/3 defector groyne, 1/3 open channel to depth of existing invert

5.0m Approximate distances

Deflector groynes were used due to the limitations of the bed gradient over the site

Coffer dam removed once basic channel reformed. New river banks prevented silt from the old pond entering into the newly constructed channel

New river corridor

Non linier, undulating watercourse. No straight lines in nature! New channel ready for habitat sequences within the river wetted area

Site prepared

Lunker construction

Concrete span roof

Foundation and walls

Clay dam removed bank dressed and faced

Lunker construction

0.750 m

2 m 8 m

Double spans can also be used where the site allows

Opposing Deflector groynes 2/3 constricted 1/3 open channel

Pools

Lunkers The holding water

Velocity directed into the lunker to prevent silting up

Spawning area

Gravel is 20mm to 80 mm Ø washed round stone with an even aggregate across the size range planted to a depth of 250 mm The constriction of the groyne and pool directly up stream create a velocity of 0.2 to 0.7 m³/sec to allow sufficient water penetration to ensure survival of ova / alevins through incubation period

The nursery area

Riffle, with bed structure of random stoning 100 mm to 300 mm Ø, plenty of broken water and fast flow through thalwegs between stone Aim to achieve 2:1 nursery to spawning ratio, to improve the overall carrying capacity of the site

Going Forward – Establish emergent and bank side flora to stabilise and buffer river corridor Continued monitoring of fish stocks by fully quantitative electro-fishing survey

Hydroseeding

Native wetland species sown with biodegradable mulch

Ideal for poor ground conditions

Holds seed in place

Ideal environment for germination

Gives seed a ‘head-start’ against weed species

April 2015 Wetland construction post channel works

Scheme costs

Weir removal/ Approx. 200m of channel & habitat construction including gravel / cobble

£50,629

Wetland landscaping/paths/other works

£59,895

Hydro-seeding/planting/ 1 yr establishment and maintenance visits

(approx) £29,500

Total (approx.) £140,024

Thanks to: Rachel Bain - Ballymoney Council Richard Kennedy - AFBI

Claire Corr, Kieran Mullan, Ruth Anderson (all Rivers Agency)

and you for listening!