Ballachulish Community Hydropower Scheme +44 (0)141 222 4500 F +44 (0)141 221 2048 W Ballachulish Community Hydropower Scheme River Laroch Feasibility Study 335086///001/A 4 June 2014

Ballachulish Community Hydropower Scheme

River Laroch Feasibility Study

June 2014

Ballachulish & Glencoe Community Company

335086 001 A

PIMS/SNI/GLA/335086/REP/INT

4 June 2014





June 2014

Ballachulish & Glencoe Community Company

Mott MacDonald, 1 Atlantic Quay, Broomielaw, Glasgow G2 8JB, United Kingdom

T +44 (0)141 222 4500 F +44 (0)141 221 2048 W www.mottmac.com

Ballachulish Community Hydropower Scheme River Laroch Feasibility Study

335086///001/A 4 June 2014 PIMS/SNI/GLA/335086/REP/INT

Revision Date Originator Checker Approver Description Standard

A 30/05/2014 A Davitti C Cload D MacDonald First Draft

Issue and revision record

This document is issued for the party which commissioned it and for specific purposes connected with the above-captioned project only. It should not be relied upon by any other party or used for any other purpose.

We accept no responsibility for the consequences of this document being relied upon by any other party, or being used for any other purpose, or containing any error or omission which is due to an error or omission in data supplied to us by other parties.

This document contains confidential information and proprietary intellectual property. It should not be shown to other parties without consent from us and from the party which commissioned it.



Chapter Title Page

1 Introduction 1

1.1 Study Location _____________________________________________________________________ 1 1.2 Land Ownership ____________________________________________________________________ 2 1.3 Study Methodology __________________________________________________________________ 2

2 Potential Scheme Options 3

2.1 Discussion of scheme options _________________________________________________________ 3 2.2 Options identified ___________________________________________________________________ 4 2.2.1 Option 1 __________________________________________________________________________ 4 2.2.2 Option 2 __________________________________________________________________________ 6 2.2.3 Option 3 __________________________________________________________________________ 6

3 Engineering Assessment 8

3.1 Energy Potential Calculation __________________________________________________________ 8 3.2 Available Flow _____________________________________________________________________ 8 3.3 Critical Evaluation of LFE _____________________________________________________________ 9 3.4 Indicative Annual Revenue ____________________________________________________________ 9 3.5 Engineering Constraints _____________________________________________________________ 10 3.5.1 Access __________________________________________________________________________ 10 3.5.2 Scottish Water abstraction ___________________________________________________________ 11 3.5.3 Pipeline alignment _________________________________________________________________ 11 3.5.4 Grid connection ___________________________________________________________________ 12 3.6 Capital Costs _____________________________________________________________________ 13 3.7 Financial Analysis __________________________________________________________________ 14

4 Environmental Considerations 15

4.1 Approach to the Ecological Study ______________________________________________________ 15 4.2 Desk Study _______________________________________________________________________ 15 4.3 Desk Study Findings________________________________________________________________ 16 4.3.1 Statutory and Non-Statutory Designated Sites ____________________________________________ 16 4.3.2 Protected and Notable Species _______________________________________________________ 16 4.3.3 Invasive Species __________________________________________________________________ 17 4.4 Site Walk-Over Observations _________________________________________________________ 17 4.4.1 Terrestrial Ecology _________________________________________________________________ 17 4.4.2 Aquatic Ecology ___________________________________________________________________ 18 4.5 Potential Ecological Constraints _______________________________________________________ 18 4.5.1 Otters ___________________________________________________________________________ 18 4.5.2 Badgers _________________________________________________________________________ 18 4.5.3 Bats ____________________________________________________________________________ 18 4.5.4 Breeding Birds ____________________________________________________________________ 19 4.6 Recommendations for Further Survey Work _____________________________________________ 19

5 Conclusion and Recommendations 20

Contents



5.1 Conclusions ______________________________________________________________________ 20 5.2 Recommendations for Further Work____________________________________________________ 20 Appendix A. Flow Estimate for the River Laroch ____________________________________________________ 22 A.1 Low Flows Enterprise FDC ___________________________________________________________ 22


i 335086///001/A 4 June 2014 PIMS/SNI/GLA/335086/REP/INT



1

Ballachulish & Glencoe Community Company (B&GCC) expressed interest to

investigate the potential to develop hydro-power on the River Laroch, to the South

of the village of Ballachulish. The objectives are to provide a sustainable source

of electricity and revenue for the Community Company.

Mott MacDonald Ltd (MML) was commissioned to assess the

hydropower potential on the River Laroch watercourse, including initial

environmental, hydrological and economic analyses. The purpose of

this report is to further quantify the resource, scope options, identify

potential engineering and environmental constraints and provide outline

costs.

1.1 Study Location

The River Laroch catchment is located to the South of the village of

Ballachulish, approximately 17km south west of Fort William, draining

northwards into Loch Leven, which in turn connects to Loch Linnhe.

The River Laroch is approximately 7km long; it is a typical fast-flowing

Highland watercourse with a river bed mainly comprised of rocks and

boulders, and a step-pool morphology. The river network is essentially

a single channel, which drains the slopes of the surrounding peaks (i.e.

Sgorr Bhan, Sgorr Dhearg and Sgorr a’ Choise), and joined by several

minor tributaries.

The catchment is typical of upland catchments on the west coast of

Scotland, with a high Standard Average Annual Rainfall (SAAR) of

3007mm (Institute of Hydrology, 1999) and steep gradient. The

majority of the land cover of the catchment is mountain heath and bog,

with some areas of grassland and woodland (LCM 2000 dataset, CEH

website). There are no lochs present in the catchment to impact

runoff. The underlying geology of the catchment consists of low

permeability bedrock, which will result in a ‘flashy’ response to rainfall

events (BGS Hydrogeology Summary, CEH website). This means that

during rainfall events, runoff from the catchment will be fast, resulting in

a hydrograph which displays sharp peaks and short, steep recession

periods.

1 Introduction

Figure 1.1: River Laroch (upper

catchment)



2

The land use in the catchment has a distinct contrast between the

upper and lower altitude areas. In the upper catchment (Figure 1.1) the

ground is blanket bog and wet heath which supports very low levels of

grazing.

In the lower catchment, to the east of the watercourse, the land use is

commercial forestry of mature age and planted very densely even along

the watercourses. This area, owned by the Forestry Commission of

Scotland (FCS), appears heavily modified, with the presence of a

disused Scottish Water Treatment Plant and intake structures, an

Archery Centre, slate quarries and a network of tracks and paths

popular amongst walkers.

1.2 Land Ownership

According to the OS maps available, the land located to the East side of

the lower catchment area belongs to FCS. The West side of the River

Laroch and the upper catchment are in private ownership. The River

Laroch and the existing fences are assumed to be ownership

boundaries, however they need to be confirmed.

As discussed with B&GCC, MML recommends that land ownership

should be investigated further. It is anticipated that any future

development is subject to agreement between the interested parties.

1.3 Study Methodology

A calculation of hydroelectric energy potential has been undertaken,

based on average rainfall and local topography from OS maps.

Indicative average annual revenue has been assessed, taking into

account the Government’s Feed-in Tariffs (FITs). High level capital

costs have been estimated, allowing a simple payback period to be

calculated in years.

The practicability of construction for each intake option, approximate

pipeline route, and powerhouse location has been assessed by desk

study and a site walkover carried out on 2nd

May 2014.



3

2.1 Discussion of scheme options

The options considered are shown in Figure 2.1 below, with key

parameters given in Table 2-1. For all potential schemes, the

infrastructure would be located on the eastern bank of the River Laroch.

The grid references and elevations of the elements were obtained

during the site visit with a handheld GPS and will need to be confirmed

by topographic survey.

Figure 2.1: Map of Scheme Options Considered

Source: OS OpenData: contains Ordnance Survey data © Crown copyright and database right 2010

2 Potential Scheme Options



4

Table 2-1: Key details of scheme options considered

Option Infrastructure National Grid Reference

Elevation Gross Head

Pipeline length

Max Power Output

Total Annual Energy Yield

Option 1 Intake NN 0810 5629 115m AOD 41m 950m 100 kW 399 MWh

Powerhouse NN 0820 5719 74m AOD

Option 2 Intake NN 0810 5629 115m AOD 66m 1350m 313 kW 964 MWh


Option 3 Intake NN 0693 5478 243m AOD 128m 2100m - -


2.2 Options identified

Three potential options were identified by MML personnel during the

site visit, as described below.

It should be noted that further survey and design work (as well as

costings) will be required to confirm the preferred options. The

information provided in this Feasibility Report should be considered as

preliminary to facilitate the discussion between B&GCC and MML in

order to determine the preferred option to develop further.

2.2.1 Option 1

The proposed intake for Option 1 would be located at NN 0810 5629,

approximately 350m upstream of the confluence between River Laroch

and its eastern tributary Allt Socaich, at an elevation of approximately

115m AOD. This section (Figure 2.2) is the highest point within the FCS

boundary suitable for an intake location, as the topography of the river

upstream of this section consists of steep banks difficult to access.



5

Figure 2.2: Option 1 and 2 – Intake location.

The penstock would lie below ground on the east bank of the river, in

the strip of land between the access track and the watercourse. It is

anticipated that tree felling would be required to allow for the excavation

and laying of the pipeline.

Due to the presence of trees and difficult ground cover, the pipe route

was not surveyed in detail during the site visit, and it should be

considered preliminary until further studies are carried out.

The proposed powerhouse is located at NN 0820 5719, within the

ground adjacent to the watercourse and to the west of the disused

Scottish Water Treatment Plant.

Option 1 would benefit from having the infrastructure entirely on FCS

land and a relatively short pipeline, however the limited available Gross

Head (41m) would limit the available Power Output.

Flow and Head available make a Francis turbine appropriate for this

option, although alternative turbines might be suitable.

As an alternative powerhouse location, it may be possible to utilise the

existing Scottish Water Treatment Plant (Figure 2.3) to house the

Mechanical and Electrical equipment, however this would further

Figure 2.3: Ballachulish Water

Treatment Plant (disused).



6

reduce the available head, as the Plant is located at a higher elevation

from the River Laroch.

2.2.2 Option 2

Option 2 has the same proposed intake location as Option 1.

However the proposed powerhouse would be located further

downstream on open ground (NN 0815 5758). This lower location

would require a longer pressure pipeline (and increased capital cost),

however this is compensated by a 50% increase of available Gross

Head and by the proximity to Grid Connection.

Similarly to Option 1, the penstock would be located on the east bank of

the river, in the strip between the access track and the watercourse. It is

anticipated that tree felling would be required to allow for the excavation

and laying of the pipeline.

Due to the presence of trees and difficult ground cover, the pipe route

was not surveyed in detail during the site visit, and it should be

considered preliminary until further studies are carried out.

Option 2 would benefit from having the infrastructure entirely on FCS

land.

Flow and Head available make a Turgo turbine appropriate for this

option, although alternative turbines might be suitable.

2.2.3 Option 3

Option 3 would have an intake located within the higher catchment of

the River Laroch, in order to maximise the elevation available. A

suitable intake location has been identified at NN 0693 5478 (Figure

2.5), upstream of a long river stretch with the watercourse lying in a

gorge.

The Powerhouse would be located at NN 0810 5629 (at approximately

the same location of the Intake for Options 1 and 2), with a buried

pipeline on the eastern bank and an available Gross Head of over

120m.

However, the benefits of the increased elevation would be outweighed

by a series of negative aspects, including:

Figure 2.4: Option 2 –

Powerhouse location.



7

Reduction in catchment area and available flow;

The length of pipeline (approximately 2km) would make the

financial assessment of the development unviable;

Distance to Grid Connection;

The infrastructure would be located on a more environmentally

sensitive area;

The infrastructure would be almost entirely located within private

ownership;

It would be very difficult to access, construct and route a pipeline in

the sections below the intake, due to the steep topography of the

gorge.

Following the above considerations and in agreement with B&GCC,

Option 3 has been discarded and will not be considered further.

Figure 2.5: Option 3 – Intake location.



8

3.1 Energy Potential Calculation

The energy potential of a hydropower scheme is a function of flow

(which depends on catchment area and rainfall) and the height through

which the water drops from the intake to the turbine or tailrace (known

as head).

As a first estimate for river flow, MML has used the data obtained

through Low Flows Enterprise (see Section 3.2). The head was

estimated using the elevations gathered during the site visit using a

handheld GPS. Both flow and head will be confirmed following

additional studies (i.e. topographic survey and, if required, flow

monitoring).

Standard values for efficiency and losses within the system have been

used to calculate annual energy generation. All schemes are assumed

to be ‘run-of-river’, that is no water storage.

3.2 Available Flow

SEPA has adopted the Low Flows Enterprise (LFE) software developed

by Wallingford Hydro Solutions as their initial point of reference for

evaluation of any abstraction licence application. This software utilises

data series from SEPA’s long term gauging stations selected for the

similarity of their hydrological characteristics.

The flow-duration curve (FDC) for the River Laroch used in this report

has been obtained through LFE software, and shown in Appendix A.

A more accurate FDC for the river could be developed through further

hydrological analysis. This may be required in due course by SEPA for

licensing under the Controlled Activities (Scotland) Regulations (CAR).

Improved confidence in the river flow patterns would improve certainty

in the predicted financial return of the scheme, and allow the turbine to

be sized more accurately to make best use of the available resource.

For small hydropower schemes, SEPA may also require a direct

measurement of low flow in the river to inform their determination of an

appropriate ‘hands off’ compensation flow that must be maintained in

the river.

This would require continuous flow monitoring equipment to be

installed for a period of 6 to 12 months. This would be calibrated by a

3 Engineering Assessment



9

programme of spot flow measurements on the River Laroch, and linked

to an analogue catchment with a long gauged record. While flow

monitoring is not necessarily required for SEPA, it would further

improve confidence in river flows, which may be useful for potential

scheme funders.

3.3 Critical Evaluation of LFE

To improve confidence in the energy and financial calculations

undertaken using the LFE FDC estimate, a critical evaluation of the

data has been undertaken.

LFE is used to derive a FDC for the catchment in the absence of

gauged data. LFE uses a pooling group approach to derive the

catchment FDC estimate. This involves screening long term gauging

stations from the existing hydrometric network to identify which stations

have similar catchment characteristics to the catchment site, and using

data from each gauging station derives the FDC estimate. Comparing

the pooling group gauges to the target site allows an assessment of the

quality of the LFE FDC estimate and improves confidence that it is

providing a reasonable assessment of flows for the target catchment.

Table A.1 in Appendix A presents a comparison of pertinent catchment

characteristics between the River Laroch catchment and each of the

gauged catchments included in the pooling group. Each of the

characteristics is scored and colour coded as per the scoring matrix

presented in Table A.2 where green is a favourable comparison and red

is a poor comparison. The scoring is based on a SEPA scoring

mechanism which has been adopted as a standard for assessing LFE

FDC estimates.

A commentary on the compatibility of each of the characteristics of the

pooling group catchments is given in Appendix A.

The pooling group generally shows a good comparison with the

characteristics of the target catchment and therefore the LFE FDC is

thought to represent flows in the target catchment well. It is noted that

the low flow end of the LFE FDC may overestimate flows slightly.

3.4 Indicative Annual Revenue

The Feed-in Tariff (FIT) scheme is intended to encourage the uptake of

small-scale low carbon technologies up to 5MW, through tariff

payments made on both generation and export of renewable energy.



10

The revenue can be broken down into two main components:

1. Generation Tariff

This is a fixed payment by the FIT Licencee (Registered Feed-in

Tariff Licenced Supplier) to the Generator for every kWh generated

by the installation. This rate varies based on the installed capacity

of any given scheme (Table 3-1), and is applicable for the 20-year

tariff lifetime. Note that these rates are subject to annual degression,

of which the future scale is unknown. Assuming that the hydro

scheme on the River Laroch will be pre-accredited by December

2015, in this report the revenue has been estimated assuming a

10% degression applying to the current tariff.

Table 3-1: Hydropower Feed-in Tariffs

Scheme Rating Present Generation

Tariff (p/kWh)

Future Generation Tariff (p/kWh) assuming 10%

degression

≤15 kW 21.12 19.01

15 - 100 kW 19.72 17.75

100 kW - 500 kW 15.59 14.03

500 kW – 2 MW 12.18 10.96

2 MW – 5 MW 3.32 2.99

Source: Ofgem, Feed-in Tariff Scheme: Tariff Table 1 April 2014 - 31 March

2015 Non-PV Only

2. Export Tariff

A payment to the Generator for every kWh exported to the

transmission or distribution network. The price for the export of

electricity is negotiated on the open market, however at present a

minimum of 4.77 p/kWh is guaranteed and this figure has been used

in this assessment, as this is not expected to decrease in future.

A combined rate of 22.52p/kWh (or £225.20/MWh) has therefore been

assumed for Option 1, and 18.8p/kWh (or £188/MWh) for Option 2.

3.5 Engineering Constraints

3.5.1 Access

The preferred intake site will require access for routine inspection and

screen clearing. This could comprise a defined access track or a quad

Figure 3.1: Forest Road.



11

bike/Argocat route. Temporary access will also be required along the

pipeline route during construction.

For Options 1 and 2 the proposed powerhouse sites are located on the

eastern bank of the River Laroch within the FCS land. These locations

benefit from an existing Forest Road (Figure 3.1) which runs parallel to

the watercourse, minimising the need for additional access to the

powerhouse. Access agreements may be required with affected

landowners.

3.5.2 Scottish Water abstraction

Ballachulish Water Treatment Works (Scottish Water) historically

abstracted raw water from the Allt Socaich, with a maximum abstraction

of 110 m3/day. MML is aware that in 2006 Scottish Water requested an

increase in their abstraction from the Allt Socaich to 400m3/day,

following the loss of their additional intake on the River Laroch, and this

was acceptable to SEPA.

However, B&GCC have advised that the abstraction on the Allt Socaich

(Figure 3.2), and associated Water Treatment Plant, are currently

disused.

The evaluation contained in this report does not take into account a

possible additional intake for the hydro scheme on the Allt Socaich,

which could potentially increase the energy yield of the hydro

development.

It is recommended that Scottish Water, and Scottish Water’s

Redundant Assets Disposal Team, should be contacted with regard to

the use and sale of these assets.

3.5.3 Pipeline alignment

No detailed assessment of the pipeline alignment has been undertaken

to date. From the initial site walkover, no insurmountable pipeline

installation problems were identified, however dense ground cover

obscured large areas (Figure 3.3).

It has been noted that there are several side tributaries (Allt Socaich

and other minor drainage ditches) intersecting the potential pipeline

route. This would require further study with regard to suitable crossing

solutions (i.e. culverts or bridges).

Figure 3.2: Scottish Water

abstraction on the Allt Socaich

(disused).



12

Further pipeline route investigation and a topographical survey are

strongly recommended.

Figure 3.3: Tree cover between Forest Road and River Laroch.

3.5.4 Grid connection

It has been assumed that the powerhouse can be connected to the

electrical grid at an existing pole in close proximity to the FCS fence

(Figure 3.4), which belongs to the local 11kV (three phase) line. This

will need to be confirmed with the Distribution Network Operator.

Given the close proximity to the potential grid connection point, it is

assumed that no high voltage transmission would be required for the

proposed powerhouse location. However, this will need to be verified by

Scottish & Southern Energy (SSE).

Figure 3.5 shows the location of the potential connection pole (also

shown in Figure 3.4) in relation to the sites selected for the

Powerhouse.

Figure 3.4 - Potential

Grid Connection pole.



13

Figure 3.5 - Proposed connection to Ballachulish grid network.

3.6 Capital Costs

Indicative capital costs for the schemes have been assessed using

construction rates based on recent experience from other small

hydropower schemes in Scotland and observations made during our

site walkover.

An allowance of 25% has been included in the build-up of capital cost to

cover preliminaries and contingencies, based on our experience of the

construction of similar schemes.

Pipe Costs

Conservative pipe cost assumptions have been made based on

average rates obtained for recent similar schemes.



14

M&E Costs

Costs for the turbine, generator, and other associated mechanical and

electrical plant are also based on recent similar schemes. Quotes

should be sought from suppliers once the preferred option is selected.

Table 3-2 shows indicative capital costs of Option 1 and Option 2.These

costs will be subject to change as the design develops and further

information becomes available.

Table 3-2: Indicative Capital costs of options considered

Item Option 1 Cost (£)

Option 2 Cost (£)

Development 35,000 45,000

Civil Cost 450,000 600,000

Mechanical and Electrical 250,000 350,000

Grid Connection 100,000 180,000

Design and Project Management

(10% of subtotal) 83,500 117,500

Preliminaries and Contingency

(25% of subtotal) 229,625 323,125

Total CAPEX 1,148,125 1,615,625

3.7 Financial Analysis

Predicted average annual revenue for each option has been calculated

as discussed in Section 3.4. Capital cost estimates (CAPEX) for each

option are as given in Table 3-2.

A simple payback period in years has also been calculated (Table 3-3),

based on capital cost divided by annual revenue. No consideration has

been given to running costs or discounting future expenditure at this

stage.

Table 3-3: Financial details of options considered

Scheme Number / Intake Location Option 1 Option 2

Max Power Output 100 kW 313 kW

Total Annual Energy Yield 399 MWh 964 MWh

Unit Rate 225.2 £/MWh 188 £/MWh

Annual Revenue £89,950 £181,364

CAPEX £1,148,125 £1,615,625

Indicative payback 12.76 years 8.91 years



15

4.1 Approach to the Ecological Study

The ecological assessment comprises two components:

Desk-based study consisting of a review of available online literature and resources from relevant organisations and regulatory bodies.

Site Walkover which aimed to identify potential ecological features (including habitats and protected species) which could be impacted upon by the design of the hydro scheme.

4.2 Desk Study

A desk study was conducted to evaluate the nature conservation

importance of land within and surrounding the proposed hydro scheme

site. This comprised a search for statutory designated sites, protected

species records and local and national priority habitats and species.

Information was sought from a variety of sources including:

Scottish Natural Heritage (SNH)1 designated site database

Joint Nature Conservation Committee’s (JNCC)2;and,

The British Trust for Ornithology (BTO).

A search was conducted for the presence of any statutory designated

conservation sites within close proximity to the proposed hydro power

scheme including:

Internationally designated sites including Ramsar sites, Special

Protection Areas (SPAs), and Special Areas of Conservation

(SACs);

Nationally Designated Sites including Sites of Special Scientific

Interest (SSSIs) and National Nature Reserves (NNRs); and,

Local Nature Reserves (LNRs).

A 10 km radius was applied around the proposed scheme to assess where any development could possibly impact upon a designated area. Where appropriate this was extended to areas within the Zone of Impact (ZOI) for water catchments i.e. sites downstream.

1 http://www.snh.org.uk/

2 http://www.jncc.gov.uk/

4 Environmental Considerations



16

4.3 Desk Study Findings

4.3.1 Statutory and Non-Statutory Designated Sites

Glen Etive and Glen Fyne Special Protection Area (SPA) qualifies

under Article 4.1 of EC Directive 2009/147 (The Birds Directive) by

regularly supporting a population of European importance of the Annex

1 listed species Golden eagle (Aquila chrysaetos), supporting 19 active

territories in 2003, more than 4.2% of the GB population.

The proposed scheme Options 1 and 2 are within 1km of the SPA

boundary, and therefore are close enough to require consideration for

this protected site.

The proximity of the SPA is however unlikely to form a constraint to the

hydro scheme. The proposed development will be discrete to its

location, any potential impacts will be localised and consequently will

have no impact upon the qualifying feature of this site. Consultation with

the relevant bodies will be undertaken to confirm that there are no

nesting golden eagle or other ‘Schedule 1;’ raptor species with the Zone

of Influence (ZoI) of the scheme.

4.3.2 Protected and Notable Species

An initial search of online data has identified records of protected,

relevant or important species occurring within the national grid squares

NN05, within which the proposed hydro scheme is located. These

include several protected mammal species:

European otter (Lutra lutra);

Eurasian badger (Meles meles);

Pine martin (Martes martes);

Eurasian red squirrel (Sciurus vulgaris);

Mountain hare (Lepus timidus).

It must be noted that SNH or SEPA may hold information regarding

populations of the mammal species noted above, not available to Mott

MacDonald without undertaking consultation. It is possible that such

statutory agencies would need assurance that these protected species

are not impacted upon, and require that detailed surveys to be carried

out.

Other protected or notable species identified during the desk study

included:



17

Numerous breeding bird species including Schedule 1 listed

species and BoCC3 Red listed species;

Reptiles and amphibians including slowworm (Anguis fragilis) ) and

adder (Vipera berus );

Fish species including brown trout (Salmo trutta) and European eel

(Anguilla Anguilla).

4.3.3 Invasive Species

4.3.3.1 American Signal Crayfish (Pacifastacus leniusculus)

The highly invasive American Signal Crayfish was identified at a pond

in Ballachulish Quarry in July 20114. However, following a coordinated

effort from SEPA, SNH, The Highland Council and Lochaber Fisheries

Trust, the species was successfully eradicated. The River Laroch was

monitored, due to its close proximity to the infected pond (<400 metres)

and was confirmed to be free of this invasive species. This species is

therefore unlikely to form a constraint to the proposed scheme.

4.4 Site Walk-Over Observations

4.4.1 Terrestrial Ecology

The land use in the catchment has a distinct contrast between the

upper and lower altitude areas. Habitats surrounding the upper

catchments comprise of a mosaic of wet/dry heath and blanket bog, but

is dominated by large open expanses of dry heath, dominated by ling

(Calluna vulgaris), with scattered areas of silver birch trees (Betula

pendula).

Habitats in lower areas comprise of commercial forestry, with a more

semi-natural fringe containing silver and downy birch, rowan (Sorbus

aucuparia), and hazel (Corylus avellana),along the eastern banks of the

River Laroch.

3

4 Biocide Treatment of the Ballachulish Quarry Ponds to Eeradicate American Signal

Crayfish. Final Project Report. Lochaber Fisheries Trust . (2012)



18

4.4.2 Aquatic Ecology

A detailed assessment of the aquatic ecology of the River Laroch has

yet to be conducted. During the walk-over, no areas of suitable

spawning grade substrates were observed which would be required to

support breeding migratory fish species such as Atlantic salmon (Salmo

salar) or sea trout (Salmo trutta trutta). A number of potentially

impassable obstacles were observed, which further support the

assessment that the river is unlikely to be an important salmonid river.

4.5 Potential Ecological Constraints

4.5.1 Otters

Terrestrial and riparian habitats of the River Laroch and tributaries are

suitable for otters, although no indicative field signs of otter were

observed during the ecological walkover of the site. Evidence is

available to suggest the presence of otters in the wider area, including

protected otter holts. An otter survey is therefore proposed as part of

the ecological survey strategy, to inform relevant mitigation

requirements.

4.5.2 Badgers

Although no indicative field signs of badgers were observed during the

ecological walkover, surrounding habitats are considered suitable and

evidence is available to suggest their presence in the wider area. A

badger survey along the route of the pipeline is proposed as part of the

ecological survey strategy to inform relevant mitigation measures.

4.5.3 Bats

A number of bat species, including Pipistrelle (Pipistrellus spp.) are

confirmed as being as being present within <10km, however further

scoping of the site will be required to fully establish the importance of

the area to local bat populations. The absence of mature woodland and

specific suitable habitat features within the zone of potential impact

would mean bats are unlikely to form a potential constraint to the

scheme.



19

4.5.4 Breeding Birds

BTO records confirm the presence of Schedule 1 species such as

Golden eagle, Hen harrier (Circus cyaneus) and Merlin (Falco

columbarius) in the wider area. Given the presence of typical upland

habitats, there is potential for ground nesting bird species to nest at the

time when works are being conducted. These could form constraints

during the construction phase such as delays during the period in which

birds are nesting.

4.6 Recommendations for Further Survey Work

On instruction to progress with development of the scheme, Mott

MacDonald’s initial action will be to undertake consultation as part of a

screening stage. This would provide the relevant agencies such as

SEPA and SNH with an opportunity to highlight any potential concerns

they have. As mentioned these organisations, who have regional offices

and local knowledge of the site and wider area, may possess

information (through records and anecdotal evidence) regarding the

presence of protected and notable species, as well as the distribution of

sensitive habitats. Concerns that they may have, other than those

listed within this report, would be highlighted by such an exercise

The following ecological surveys are expected to be a requirement to

form a baseline for the Laroch hydro power scheme environmental

assessment.

Phase 1 habitat survey with habitat mapping,

Protected Mammal Survey (including otter, badger, pine martin, red

squirrel);

Aquatic ecology surveys.

Surveys which may be requested by statutory consultees may include

the following:

River Habitat/Fish habitat surveys;

Bird surveys;

Detailed NVC vegetation surveys;

Invertebrate surveys (aquatic and terrestrial);

Rare Bryophyte survey.



20

5.1 Conclusions

From currently available information, our initial walkover and desktop

assessment of potential, two options of a small hydropower scheme on

the River Laroch appear technically and economically feasible.

Option 1 (100kW) is estimated to produce an Annual Average Energy

Production of approximately 400 MWh. Assuming a 10% degression in

the current Feed-in-Tariffs (for the sub 100kW tariff banding), the

scheme has the potential to generate an annual income of around

£90,000.

Option 2 (313kW) would benefit from a lower Powerhouse location: its

estimated Annual Average Energy Production is approximately 965

MWh. Assuming a 10% degression in the current Feed-in-Tariffs (for

the sub 500kW tariff banding), the scheme has the potential to generate

an annual income of around £180,000.

There is potential to increase output and revenue by utilising flow from

Allt Socaich, a side tributary of the River Laroch.

The initial environmental desk study has not identified any significant

environmental constraints to the project, however further consultation

with stakeholders, and environmental survey work will be required as

the project progresses.

There is the potential for protected species (including otters, badgers,

pine martens and bats) to be present in the development area. It could

be a constraint to the development if they are found to be present,

requiring appropriate mitigation.

It should be noted that scheme development is dependent upon

resolving all necessary licences and permissions, and the scheme

viability should be rechecked at key stages through the development

process, or as key events occur.

5.2 Recommendations for Further Work

To progress the project we recommend discussion within B&GCC in

order to choose the preferred option to develop further, and to proceed

with the activities included in the Stage 2 of our Proposal.

This includes:

Investigation of grid capacity availability with the Network Operator,

through an application for Grid Connection.

Liaison with SEPA and submit a CAR screening document.

5 Conclusion and Recommendations



21

Review of environmental, ecological and archaeological constraints

and carry out initial consultation (Screening Report) with the local

Planning Authority (the Highland Council) to establish the likely

response to planning consultation.

Consultation with landowners that might be affected by the proposed

development.

As the summer months are usually the optimum time to undertake

the ecological surveys, mobilisation of these is also advisable.



22

A.1 Low Flows Enterprise FDC

Figure A.1: LFE catchment FDC Estimate

Source: Wallingford Hydrosolutions Ltd.

Percentile Flow (m³/s)

Q5 1.725

Q10 1.187

Q20 0.715

Q30 0.459

Q40 0.302

Q50 0.202

Q60 0.136

Q70 0.093

Q80 0.062

Q90 0.037

Q95 0.027

Q98 0.018

Q99 0.014

Appendix A. Flow Estimate for the River Laroch


23 335086///001/A 4 June 2014 PIMS/SNI/GLA/335086/REP/INT

Table A.1: LFE Critical Evaluation

Station Name River

Station No. Easting Northing

Catchment Area (km²) Proximity

SAAR (mm)

BFIHOST(SCOT) BFIHOST

Q95/Qmean (%) Land Cover

Underlying Geology

Target River

Laroch N/A 208104 756291 5.61 N/A 3007 0.258 0.359

5.86

Woodland: 5 %

Arable / horticultural: 0.0 %

Grassland: 20 %

Mountain / Heath / Bog: 75 %

Urban Extent: 0.0 %

Low perm. Bedrock: 100.0 %

Succoth Eas a Ghaill

89009 220649 726481 10.2 32.34 3094 0.285 0.384 4.60

Woodland: 39.1 %


Grassland: 34.7 %

Mountain / Heath / Bog: 31.8 %

Urban Extent: 0.0 %


Inverlochy Lochy 89005 219692 727471 47.1 31.06 2946 0.258 0.366 7.10

Woodland: 34.9 %


Grassland: 26.1 %


Urban Extent: 0.0 %


Glen Strae Strae 89004 215033 729930 36.6 27.26 2772 0.256 0.362 5.19

Woodland: 6.5 %


Grassland: 61.0 %


Urban Extent: 0.0 %

Low perm. Bedrock

100%

Victoria Bridge

Linne nam

Beathach 89002 227189 742153 49.9 23.75 2905 0.295 0.384 5.16

Woodland: 7.3 %


Grassland: 49.4 %


Urban Extent: 0.0 %



24 335086///001/A 4 June 2014 PIMS/SNI/GLA/335086/REP/INT

Station Name River

Station No. Easting Northing

Catchment Area (km²) Proximity

SAAR (mm)

BFIHOST(SCOT) BFIHOST

Q95/Qmean (%) Land Cover

Underlying Geology

Glen Orchy

Orchy 89003 224259 731917 252.8 29.24 2724 0.264 0.359 7.07

Woodland: 11.0 %


Grassland: 39.7 %


Urban Extent: 0.0 %


Table A.2: LFE Critical Evaluation Scoring Criteria

Feature Scoring Criteria

Catchment Area Catchment Area score (a multiplicative factor of the target, generally*):

Area : < 5= green, 5-10 = yellow, 10-100 = orange, > 100 = red

(This is a multiplicative factor of the target)

e.g. target area is 5 and analogue is 30 then score is 6, yellow.

* In the unusual event that the analogue area is smaller than the target area then the score would be less than one and hence green. In this case take the factor of the analogue area and score that instead.

Proximity Distance/proximity score (arithmetic difference from target in km):

Distance: < 25km = green, 25 - 50km = yellow, 50 - 150km = orange, > 150km = red

SAAR SAAR 6190 score (difference from target):

SAAR : <200 = green, 200-400 = yellow, 400-800 = orange, >800 = red

BFIHOST SCOT BFI HOST (SCOT) score (arithmetic difference from target): *AUTOMATIC SCORING*

BFI HOST (SCOT): < 0.05 = green, 0.05 – 0.1 = yellow, 0.1 – 0.15 = orange, > 0.15 = red

BFIHOST AS BFIHOST(SCOT)

Q95/QMean Q95 / Qmean score (% difference from target):

Q95 / Qmean score: < 0.75%= green, 0.75 - 2% = yellow, 2 - 5% = orange, > 5% = red

Land Cover Assessed on a case by case basis due to multiple variables

Underlying Geology Assessed on a case by case basis due to multiple variables



25

Review of Pooling Group Comparison

Catchment Area

The target catchment has a small catchment area, which is not

regularly replicated in the existing hydrometric network and hence all

the gauges in the pooling group have a larger catchment area than the

target catchment. Despite this the comparison is considered

reasonable.

Proximity

The hydrometric network is relatively dense in the area surrounding

Ballachulish and therefore all five of the pooled gauges are located

within 35km of the target catchment. All catchments will be subject to

similar climatic conditions as the target catchment which is important

given the west to east rainfall gradient for Scotland.

SAAR

The pooling group Standard Average Annual Rainfall (SAAR) values

show a favourable comparison to the target catchment, with three good

scores and two moderate/good scores. This is important as the target

catchment lies in a high rainfall area, with all pooled gauges also

receiving high rainfall.

BFIHOSTSCOT / BFIHOST

The pooled base flows show a good comparison score, and will

replicate the base flows of the target catchment well.

Q95/Qmean Ratio

The Q95/Qmean ratio comparison is favourable, though the gauges at

Inverlochy (7.10%) and Glen Orchy (7.07%) both show a slightly higher

ratio than may be expected given the location and characteristics of the

target catchment. The LFE FDC returns a ratio of 5.86% which is

reasonable, but shows the LFE FDC estimate may be overestimating

low flows slightly.

Land Cover



26

The pooling group gauging stations have larger catchment areas than

the target site and therefore show an increased diversity in their land

cover types. The comparison is still regarded to be moderately good,

with all the pooling group catchments showing a reasonable percentage

of mountain, heath, bog and grassland cover. It is noted that the

gauged catchments at Succoth and Inverlochy have over 30%

woodland coverage which will have an impact on catchment runoff and

the gauged FDC at these locations. Despite the woodland coverage

there is no clear impact on the LFE FDC estimate that can be attributed

to it.

Underlying Geology

All pooling group catchments show low permeability bedrock covering

their entirety as per the target catchment. Permeability controls how

the catchment reacts to rainfall, and therefore as all catchments show

the same permeability as the target catchment, the LFE FDC will

replicate response to rainfall well. This is linked to base flow and

explains the close comparison in the base flow category.

Conclusions

The pooling group generally shows a good comparison with the

characteristics of the target catchment and therefore the LFE FDC is

thought to represent flows in the target catchment well. It is noted that

due to the higher Q95/Qmean ratios at Inverlochy and Glen Orchy the

low flow end of the LFE FDC may overestimate flows slightly.

Documents

Ballachulish Community Hydropower Scheme +44 (0)141 222 4500 F +44 (0)141 221 2048 W Ballachulish Community Hydropower Scheme River Laroch Feasibility Study 335086///001/A 4 June 2014