glyn rhonwy pumped storage development consent order · glyn rhonwy pumped storage development...

Glyn Rhonwy Pumped Storage Development Consent Order

Deadline 3 – Excess Water Management Strategy

PINS Reference EN010072

Document Nos. SPH_GREX_DCOD3_04

Authors SPH/AECOM/GVA/BS

Revision Date Description

0 27th April 2016 Issued

Prepared by: Walter Robison .......................... Checked by: Dylan Huws Senior Engineer Associate Director

Approved by: Catherine AndersonAssociate Director

Glyn Rhonwy Pumped Storage – Excess Water Management Strategy

RevNo

Comments Checkedby

Approvedby

Date

0 Issued for DCO Deadline 3 DH CA Apr 2016

1 Tanfield, Edinburgh, EH3 5DATelephone: 0131 301 8600 Website: http://www.aecom.com

Job No 60484860 m001.004 April 2016

This document has been prepared by AECOM Limited for the sole use of our client (the “Client”) and inaccordance with generally accepted consultancy principles, the budget for fees and the terms of referenceagreed between AECOM Limited and the Client. Any information provided by third parties and referred toherein has not been checked or verified by AECOM Limited, unless otherwise expressly stated in thedocument. No third party may rely upon this document without the prior and express written agreement ofAECOM Limited.

Glyn Rhonwy PumpedStorage

Excess Water Management Strategy

TABLE OF CONTENTS

1 Introduction .................................................................................................................. 11.1 Introduction............................................................................................................. 11.2 the Development .................................................................................................... 11.3 Basic operation....................................................................................................... 21.4 Discharge locations ................................................................................................ 31.5 Abstraction location ................................................................................................ 4

2 Excess water management .......................................................................................... 52.1 Excess Water Management ................................................................................... 52.2 release of + excess water ....................................................................................... 52.3 abstraction for - excess water................................................................................. 62.4 Reservoir safety features and incidental release of water ...................................... 62.5 Environmental Management Systems .................................................................... 8

Appendix A: Drawings & Figures ..................................................................................... 10



Snowdonia Pumped Hydro Ltd. 1

1.1 INTRODUCTION

1.1.1 Optimum operation of the Development requires a constant volume of water within its closed

reservoir system. Rainfall on the reservoirs can cause additional or “excess water” within the system.

Whilst the reservoirs are designed to cope safely with the most severe rainfall that is expected to

occur, efficient operation of the Development is maintained by the management of excess water.

1.1.2 This Outline Excess Water Management Strategy is intended to set out the principles by which the

water within the Development is managed. This document sets out the strategy only; at the time of

writing the Development has not been subject to detailed design therefore a full operational algorithm

with precise values of each hydraulic element cannot be given. This strategy therefore cannot go into

detail on precise water levels, flows rates and volumes involved with specific movement of water

within the system.

1.1.3 For the background to the abstraction and discharge rates, together with the environmental and flood

risk appraisals, reference should be made to the Environmental Permitting applications to Natural

Resources Wales (NRW) and their supporting documentation.

1.2 THE DEVELOPMENT

1.2.1 The Development at Glyn Rhonwy comprises a pumped storage hydro-electric scheme situated

within a series of disused slate quarries. The quarry system has been numbered from Q1 in the west

to Q8 in the east, which can be seen in Figure 2 in Appendix A. The quarries used in the

Development are:

· Quarry 1 (Q1) – Chwarel Fawr; Headpond

· Quarry 6 (Q6) – Glyn Rhonwy; Tailpond

1.2.2 The Development comprises of the following permanent features:

· Headpond reservoir (Q1), its dam, access shaft and spillway infrastructure to the Nant Y Betws;

· Tailpond reservoir (Q6), its dam, access shaft and spillway infrastructure to Llyn Padarn;

· Pumping station in close proximity to Llyn Padarn;

· Power house at Glyn Rhonwy Industrial Estate Platform 5 (south of Q6) with underground

turbine hall housing pump turbines;

· Penstock (connecting Q1 to the power house); and

· Tailrace (connecting the power house to Q6).

1INTRODUCTION




1.2.3 A schematic representation of the scheme is presented on Drawing SHT-10-ZN00-Z-001 in

Appendix A showing the hydraulic connections between the system components and the

environment.

1.3 BASIC OPERATION

1.3.1 A pumped-storage system essentially consists of two reservoirs, upper and lower (Headpond and

Tailpond). Inputs are the natural hydrology of the area; watercourses that flow into the reservoirs and

direct rainfall. Outputs (losses) are evaporation, controlled release (e.g. compensation flow),

uncontrolled release (e.g. flow over a spillway) and infiltration/seepage losses from the reservoirs;

infiltration and seepage are usually negligible relative to any incoming watercourse. Water flowing

from the upper reservoir drives turbines to generate power. The water is collected in the lower

reservoir and is later pumped back to the upper reservoir.

1.3.2 If there is more water in the reservoir system than required there is said to be positive excess water.

If there is less water in the reservoir system than required then there is said to be negative excess

water.

· If over time Rainfall > Losses (evaporation / infiltration): Positive (+) Excess Water is to be

released to Llyn Padarn

· If over time Rainfall < Losses (evaporation / infiltration): the scheme will be in a state of

Negative (-) Excess Water, and the closed system will require to be topped-up.

1.3.3 Both positive and negative excess water can have an impact on the optimum operation of the

Development, therefore a means and strategy for managing excess water on a day to day, week to

week basis is required.

1.3.4 The water input and outputs applicable to the scheme are summarised in Table 1 below:

Table 1 – Glyn Rhonwy Pumped Storage Scheme, excess water factors

Input (incoming water) Applicability to scheme

Watercourse None

Rainfall Direct rainfall on reservoir surfaces

Output (water losses) Applicability to scheme

Evaporation Evaporation from open water bodies (reservoirs)

Controlled release (e.g. compensationflow) No compensation flow or other required outflow

Uncontrolled release (e.g. flow over aspillway) None planned

Infiltration/seepage losses Unknown at this stage; reservoirs will be designed tominimise these losses.

1.3.5 In a pure pumped-storage scheme, isolated from the wider environment, the total volume of water in

the reservoir system; i.e. headpond, tailpond, shafts and tunnels remains constant. This constant




volume of water is simply moved between the upper and lower reservoirs during the

generating/pumping cycle.

1.3.6 The Development is essentially a pure pumped storage system. Figure 1 below shows the inputs

and outputs to the closed reservoir system.

Figure 1: Glyn Rhonwy Pumped Storage Scheme – input / output schematic

1.3.7 Overall water management within the reservoirs, including draw-down, release and abstraction of

excess water is summarised in Table 5 below and is shown on the Water Management Schematics

in Appendix A.

1.4 DISCHARGE LOCATIONS

1.4.1 When it is necessary to release water from the system, the primary mechanism to discharge water

will be from Q6 to Llyn Padarn. Water in Q1 can be released to the Nant y Betws, although this is not

done in the normal operation of the scheme. Release of excess water from Q1 would be to Llyn

Padarn via the penstock and Q6. Discharge locations, for both the reservoir spillway and the relief

valve outlets, are shown in Table 2 below:

Table 2 – Glyn Rhonwy Pumped Storage Scheme, discharge locations

Reservoir Discharge Location Waterbody / Watercourse Discharge Location Grid Ref

Q1 Headpond Nant y Betws SH 55110 59660

Q6 Tailpond Llyn Padarn SH 57290 61190

1.4.2 These locations are indicated as “outlet to Nant y Betws” (Q1) and “ intake/outlet” (Q6) on DrawingSHT-10-ZN00-G-001 in Appendix A.

House




1.5 ABSTRACTION LOCATION

1.5.1 If it is necessary to abstract water to top up the closed reservoir system; water would be abstracted

from Llyn Padarn to the Tailpond (Q6). The abstraction location is the same as for the discharge

outlet to Llyn Padarn:

Table 3 – Glyn Rhonwy Pumped Storage Scheme, abstraction location

Reservoir Discharge Location Waterbody / Watercourse Discharge Location Grid Ref

Q6 Tailpond Llyn Padarn SH 57290 61190




2.1 EXCESS WATER MANAGEMENT

2.1.1 The hierarchy and logic diagram for operational discharges contained within Appendix A.

2.1.2 Positive “+” excess water is expected if over time rainfall exceeds evaporation and

infiltration/seepage from the reservoirs. During normal operation “+ Excess Water” is to be

released to Llyn Padarn from the tailpond Q6.

2.1.3 Negative “-” excess water may occur if over time losses from the system (evaporation,

infiltration/seepage) exceed the incoming rainfall falling on the surface of the reservoirs. In this

circumstance, the Development will require abstraction of water from Llyn Padarn to top up to

the required volume.

2.2 RELEASE OF + EXCESS WATER

2.2.1 The surface area of the reservoirs are approximately 54,000 m2 and 34,000 m2 for Q1 and Q6

respectively. Average annual rainfall is around 1850 mm, average annual evaporation is

expected to be around 450 mm. Ignoring other losses there may be up to 123,000 m3 of net

volume increase from rainfall. It is intended to release this volume from Q6 to Llyn Padarn; this

will be done on an irregular basis (rainfall dependant) and at a rate not exceeding the draw-

down capacity of the Q6 reservoir (see Section 2.4 below).

2.2.2 The maximum allowable rate of water release is to be addressed together with the discharge

consent and any other conditions to be agreed with NRW. These conditions will be

incorporated into the final “Excess Water Management Strategy” for as required by

Requirement 20 of the DCO.

Table 4 – Reservoirs data

Reservoir: Headpond Reservoir (Q1) Tailpond Reservoir (Q6)

Surface Area 54,000 m3 34,000 m3

Top Water Level (TWL)[level of reservoir spillway]

393.0 mAOD 154.5 mAOD

Maximum OperationalWater Level (Max OWL)

392.0 mAOD 154.0 mAOD

Minimum Operational WaterLevel (Min OWL)

340.0 mAOD 90.0 mAOD

2 EXCESS WATER MANAGEMENT




2.2.3 Under normal operation the water level in Q1 will not exceed the Maximum Operational Water

Level (Max OWL) of 392.0 mAOD, 1.0 m below the Top Water Level (TWL) of 393.0 m AOD,

and the Max OWL of 154 mAOD in Q6, 0.5 m below the Q6 TWL of 154.5 m AOD. Top Water

Level is the level of the reservoir spillway above which water will spill out of the reservoir.

2.2.4 Under normal operation of the scheme all release of excess water will be from Q6 to Llyn

Padarn under controlled circumstances; there is no anticipated need to allow the reservoirs to

spill or to release water to the Nant y Betws.

2.2.5 Excess water from direct rainfall on both Q1 and Q6 will be managed within the freeboard of

the reservoirs, the available capacity between Max OWL and TWL, and then released from the

system via Q6 to Llyn Padarn.

2.2.6 With positive excess water within the system, transfer of water from Q1 to Q6 will cause the

level in the tailpond (Q6) to rise above the Max OWL. Positive excess water is to be released

from Q6 to Llyn Padarn to maintain the optimum volume within the system.

2.2.7 For a release of “+ excess water” to take place:

· System Volume > Optimum (e.g. Max OWL in Q1 & Min OWL in Q6)

· AND Llyn Padarn level < a level specified by Natural Resources Wales

2.2.8 In the event of an extreme rainfall event, the available storage between Max OWL and the

reservoir spillway allows + excess water to be held safely within the system, and subsequently

released days after the event. Depending on the position in the generation cycle, the system

will have varying capacity to accept incoming water without spill. In the worst case position (Q6

at Max OWL) the system has capacity to accommodate 0.5 m depth of rainfall without spill.

2.3 ABSTRACTION FOR - EXCESS WATER

2.3.1 All water within the Development, with the exception of the contribution of direct rainfall, will

have been abstracted from Llyn Padarn to Q6. Top up abstraction in the event of negative

excess water is also from Llyn Padarn as circumstances require.

2.3.2 For an abstraction of top up “- excess water” to take place:

· System Volume < Optimum

· AND Llyn Padarn level > a level specified by Natural Resources Wales

2.4 RESERVOIR SAFETY FEATURES AND INCIDENTAL RELEASE OF WATER

Relief Valve at Q1

2.4.1 The Development includes a relief valve from Q1 to Nant y Betws; this is a reservoir safety

feature and is not for use in regulating excess water. The Q1 relief valve provides a secondary

method for the reservoir water level to be lowered, if required; the primary means is by transfer

of water to Q6 via the penstock.




2.4.2 The relief valve (a reservoir safety feature) is to allow, in the event of an emergency, the

reservoir to be drawn down to 50% of the volume impounded by the dam within 7 days. This

equates to a flow of approximately 0.60 m3/s.

2.4.3 For a release of water to the Nant y Betws to take place, the following conditions are required:

· When the there is a need to lower the water level behind the dam,

· AND water cannot, for whatever reason, be drawn down through the penstock to Q6.

2.4.4 These conditions determine when water (not “excess water”) would be released from Q1 to the

environment.

2.4.5 For maintenance; to ensure the valve is operational as part of the dam safety regime, it will be

necessary from time to time to briefly operate the valve. The volume and rate of water released

in this circumstance is considered negligible in regard to the management of excess water and

is ignored in this strategy.

Q1 Spillway

2.4.6 There is the possibility of discharge to the Nant y Betws watercourse from the Q1 dam spillway

(also known as the overflow). The spillway is an essential reservoir safety feature, the operation

of which is likely to be extremely rare.

2.4.7 For a release of excess water via the spillway to the Nant y Betws to take place, the following

conditions are required:

· Prolonged period of the system being out-of-operation; i.e. the reservoir remaining full for

a significant period of time.

· AND a build up of excess water (likely several months required) eventually causing the

level in Q1 to increase above the spillway level.

2.4.8 The reservoir has more than sufficient capacity to accommodate the direct rainfall from the

Probable Maximum Precipitation (extreme rainfall event for reservoir safety design) above the

Maximum OWL without spilling.

Relief Valve at Q6

2.4.9 The Development includes a relief valve from Q6 to Llyn Padarn; this is a reservoir safety

feature and also the means by which excess water is released from the system.

2.4.10 The relief valve arrangement of the Q6 reservoir is expected to have a minimum draw-down

capacity of 0.3 m3/s (draw-down of 50% of the volume impounded by the dam within 7 days). It

is considered that the design draw-down rate for Q6 could be increased to in the region of

between 0.6 – 1.0 m3/s with negligible increase in flood risk within the downstream catchment

as a result of the released flow.




2.4.11 Release of excess water is as described in the preceding section. For the release of water to

take place, over and above the normal release of excess water, the following conditions are

required:

· When there is a need to lower the water level behind the dam,

· AND water cannot, for whatever reason, be transferred by pumping to Q1.

2.4.12 These conditions determine when water (not “excess water”) would be released, e.g. for dam

safety purposes, from Q6 to the environment.

2.4.13 For maintenance; to ensure the valve is operational as part of the dam safety regime, it will be

necessary from time to time to briefly operate the valve. The volume and rate of water released

in this circumstance is considered negligible in regard to the management of excess water and

is ignored in this strategy.

Q6 Spillway

2.4.14 There is the possibility of discharge to Llyn Padarn from the Q6 dam spillway (also known as

the overflow). The spillway is an essential reservoir safety feature, the operation of which is

likely to be extremely rare.

2.4.15 For a release of excess water via the spillway to Llyn Padarn to take place, the following

conditions are required:

· Prolonged period of the system being out-of-operation; i.e. the reservoir remaining full for

a significant period of time.

· AND a build up of excess water (likely several months required) eventually causing the

level in Q6 to increase above the spillway level.

2.4.16 The reservoir has more than sufficient capacity to accommodate the direct rainfall from the

Probable Maximum Precipitation (extreme rainfall event for reservoir safety design) above the

Maximum Operational Water Level without spilling.

2.5 ENVIRONMENTAL MANAGEMENT SYSTEMS

2.5.1 The type of environmental management system (EMS) that will be implemented is to be

determined at a later date by the scheme operator.

2.5.2 Chapter 4 Project Description in the Environmental Statement states that an Environmental

Management System (EMS) will be in place for the operational hydro-scheme. Snowdonia

Pumped Hydro do commit to having an environmental policy and management system in place,

but this is subject to confirmation at a later date as to which specific EMS the scheme will

implement.

2.5.3 It is envisaged that the electricity generation company operating the developed scheme will

establish an appropriate system.




Table 5 – Glyn Rhonwy Pumped Storage Scheme, water management & operation

Reservoir Operation Management and Release of Water

Q1 Headpond

NormalOperation

Inflow from Direct Rainfall.

All direct rainfallaccommodated within the1.0m between Max OWL andTWL.

Water transferred from Q1 to Q6 andreturned by pumping to Max OWL. i.e.excess water remains within Q6.

Drawdown ConditionWater transferred to Q6.

i.e. no release of water to the environment.

UnusualCircumstance

Prolonged inflow over timefrom Direct Rainfall, with notransfer of water to Q6.

i.e. WL allowed to build up toTWL.

Direct Rainfall may discharge to Nant yBetws via overflow if Q1 exceeds TWL.

Drawdown Condition, withoutmeans to transfer water fromQ1 to Q6.

Water discharged from Q1 to Nant y Betws;water released via Relief Valve at anappropriate rate (in consideration of floodrisk downstream) until WL below the damlevel.

Q6 Tailpond

NormalOperation

Direct Rainfall and excesswater from Q1.

All direct rainfall istemporarily accommodatedwithin the 1.0m between MaxOWL and TWL.

Excess water released to Llyn Padarn.

Drawdown Condition

Water transferred to Q1, and/or waterreleased to Llyn Padarn.

Preference would be to transfer water to Q1for future use rather than release to LlynPadarn.

UnusualCircumstance

Prolonged inflow over timefrom Direct Rainfall, with notransfer of water to Q1.

i.e. WL allowed to build up toTWL.

Direct Rainfall may discharge to Llyn Padarnif Q6 exceeds TWL.

Drawdown Condition, withoutmeans to transfer water fromQ1 to Q6.

Water discharged from Q6 to Llyn Padarn viaRelief Valve at an appropriate rate (inconsideration of flood risk downstream) untilWL below the dam level.




Drawing 4.1 of the ES – Development Overview

Drawing 2.05 of the DCO –Scheme Layout Plan

Drawing SHT-10-ZN00-G-0001 – Scheme Schematic Diagram

Water Management Schematic, 1 of 5 – Water Management at Glyn Rhonwy

Water Management Schematic, 2 of 5 – Release of +Excess Water

Water Management Schematic, 3 of 5 – Abstraction of -Excess Water

Water Management Schematic, 4 of 5 – Spill of +Excess Water

Water Management Schematic, 5 of 5 – Reservoir Draw-down

Appendix A:Drawings & Figures

_̂_̂

_̂

_̂

_̂_̂

_̂

_̂

_̂_̂

_̂Q8

Q7Q6

Q5

Q4

Q3

Q2

Q1

Q3a

© Crown copyright, All rights reserved. 2012 Licence number 0100031673

This document has been prepared by AECOM for the sole use of our Client (the "Client") and in accordance with generally accepted consultancy principles, the budget for fees and terms of reference agreed between AECOM and the Client.

Verified:Date:

Checked:Approved:Scale at A3:

Drawing Number:

Any information provided by third parties and referred to herein has not been checked or verified by AECOM, unless otherwise expressly stated in the document. No third party may rely upon this document without the prior and express written agreement of AECOM.

Ü

0 500 Metres

Drawn:

A3

LCSC

LCCA

OCTOBER 2015GR_151001_4.1_v8

KEY:Order Limits

_̂ Quarry Location_̂ Proposed Pumping Station_̂ Alternative Pumping Station

Spillway InfrastructurePenstockTemporary Tunnel and Access ShaftTailraceTemporary Construction CompoundDam FootprintReservoir EdgeExcess Slate MoundQ1 Permanent Public Car ParkQ1 Temporary Public Car ParkPower HousePower House Compound

1:10,000Title:

Project:Client: GLYN RHONWY PUMPED STORAGE DEVELOPMENT CONSENT ORDER

FIGURE 4.1 - DEVELOPMENT OVERVIEW1 Callaghan SquareCardiffCF10 5BT

T +44 (0)29 2067 4600F +44 (0)29 2067 4699

www.aecom.com

Issues

Stones

Drain

1

8

Stepping

'Rallt Goch

Drain

Path

(um

)

FB

Issues

FB

Ty Newydd

Silos

Ty-newydd

Pond

Groeslon

T

ra

c

k

Tan-hafotty

Spring

Padarn

Pen-gilfach

127.7m

132.7m

Glyn Peris

128.9m

Cottage

Lodge

Glyn

Glyn Peris

Water

122.4m

130.1m

D

r

a

in

Sinks

C

l

i

f

f

MS

P

a

t

h

(

u

m

)

W

e

l

l

Tan-y-ffynnon

Issues

Hafod Wen

Well

Gwel Llyn

(Hotel)

Issues

Tip

LB

Tip

Lay-b

y

Pond

Pond

T

r

a

c

k

FB

Mast

L

a

y

-

b

y

Tip

(disused)

Pond

Sheepfold

I

n

c

l

i

n

e

(

d

i

s

u

s

e

d

)

T

r

a

c

k

FB

Barrack-mawr

P

a

t

h

(

u

m

)

Issues

(

d

i

s

u

s

e

d

)

Issues

Sheepfolds

(disused)

(d

is

u

s

e

d

)

Tip

P

a

t

h

(

u

m

)

T

r

a

c

k

In

c

lin

e

F

W

(d

is

u

s

e

d

)

In

c

lin

e

Llys Ellen

Clegyr

I

n

c

l

i

n

e

Pen-y-bwlch

Pond

Issues

Issues

Sinks

Foot Bridge

C

S

P

a

th

(

u

m

)

Issues

(disused)

P

a

t

h

(

u

m

)

P

a

t

h

(

u

m

)

Pond

Water

Slate Quarry

U

n

d

E

D

B

d

y

E

D

B

d

y

F

W

U

n

d

Tra

ck

D

is

m

a

n

tle

d

T

r

a

m

w

a

y

(disused)

Slate Quarries

Cook and Ddôl

D

i

s

m

a

n

t

l

e

d

T

r

a

m

w

a

y

D

i

s

m

a

n

t

l

e

d

T

r

a

m

w

a

y

T

u

n

n

e

l

(

d

is

)

Workings (dis)

Chwarel Cefn-dû

(disused)

Cefn Du

(dis)

P

a

th

Trial Level

Quarry

F

W

E

D

B

d

y

E

D

B

d

y

(dis)

Tips

441m

ED Bdy

P

a

t

h

P

a

t

h

(

u

m

)

Stone

Und

El P

Trial

Tip

Level

(dis)

El P

Bwlch-y-groes

(Quarry disused)

Chwarel

El P

(dis)

Level

Bwlch-y-groes

El Ps

El P

El P

El P

(disused)

(dis)

Trial Level

Pond

Quarry

Tip

El P

El P

El P

El P

El P

El P

El P

(dis)

Nant y

Betw

s

Trial Levels

Tip

Tip

P

a

t

h

(disused)

P

a

t

h

Pond

(dis)

Tip

El P

El P

Trial

Level

El P

U

n

d

Bryn-mawr

Quarry

(dis)

E

T

L

T

r

a

m

w

a

y

D

ism

antle

d

Donen Lâs

Sarn

C

S

E

D

B

dy

Sinks

C

W

Issues

P

a

t

h

(

u

m

)

Pond

T

r

a

c

k

Bryn Clyd

Issues

D

r

a

in

Pen-draw

Pond

Issues

Gallt-y-celyn

Issues

T

r

a

c

k

Pond

Pond

CG

(Disused Quarry)

Path

Chwarel Fawr

(disused)

Sheepfold

Sheepfold

Tips

E

T

L

El Ps

El Ps

D

rain

D

r

a

i

n

N

a

n

t

y

B

e

t

w

s

Drain

Pond

Pond

El Ps

Donen Lâs

Pen-y-ffrîdd

Issues

Sheepfold

Hafotty

Path

(um

)

Issues

(disused)

Cliff

Capel Clegyr

Sheepfold

Pond

P

a

t

h

(

u

m

)

Sinks

Issues

Issues

Quarry

Inclin

e (dis

used)

Sinks

(disused)

In

c

lin

e

(disused)

(

d

is

u

s

e

d

)

Chwarel Cae'r-meinciau

P

a

t

h

(

u

m

)

Issues

Issues

Sheepfold

Quarry

T

r

a

c

k

(disused)

Path (um)

(disused)

Quarry

Quarry

(disused)

Cae'r-ty

Reservoir

P

o

n

d

Tip

(disused)

Incline (

dis

used)

Cae'r-meinciau

Issues

P

a

th

(u

m

)

Pond

Issues

Ffridd-glyn Slate

Quarry

Issues

A

f

o

n

G

ly

n

(disused)

D

r

a

i

n

Heap (dis)

Pond

Heap (dis)

D

i

s

m

a

n

t

l

e

d

T

r

a

m

w

a

y

D

i

s

m

a

n

t

l

e

d

T

r

a

m

w

a

y

Glyn-rhonwy Slate Quarry

(disused)

T

r

a

c

k

Workings (dis)

T

r

a

c

k

Heap (dis)

Heap (dis)

P

a

th

(

u

m

)

Ford

Ty-dû

Plas Garnedd

Bronallt

Spring

D

r

a

i

n

C

a

r

l

i

n

i

g

K

M

P

Bryn

1

2

0

1

Ty-newydd

P

a

t

h

(

u

m

)

S

T

R

Y

D

I

A

N

C

I

2

Car Park

(

C

o

m

m

u

n

i

t

y

W

o

r

k

s

h

o

p

s

)

104.7m

1

G

w

a

i

t

h

d

a

i

C

y

m

u

n

e

d

o

l

7

(disused)

2

Sheepfold

4

D

r

a

in

TCP

Henryd

E

l

A

f

o

n

G

i

y

n

Glyn

1

9

FB

S

u

b

S

t

a

Cave

Path (um)

Ynys-wen

Coed Mawr

Rhonwy

9

Llwyn Dyrus

1

2

3

5

1

(Fron Deg Terrace)

3

1

2

9

7

G

L

Y

N

R

H

O

N

W

Y

2

2

1

9

2

3

Gw

ynant

9

Hyfryd

1

52

C

a

m

b

r

ia

n

Spring

1

0

8

Bod W

enallt

Y

S

T

A

D

1

Path

(um

)

3

C

ra

ig

w

e

l

Issues

D

D

I

W

Y

D

I

A

N

N

O

L

El

1

1

D

r

a

i

n

1

4

3

0

GVC

2

2

Rhes Fron Deg

Pond

2

5

T

a

n

k

1

5

S

T

R

Y

D

W

A

R

D

E

N

/

W

A

R

D

E

N

S

T

R

E

E

T

Sub Sta

2

0

1

0

R

h

e

s

1

Llainwen Isaf

LB

Fron Oleu

Llainw

en

Quarry

5

Derw

yn D

eg

Rhes

Wells

Rhes Olra/Olgra Terrace

Sheepfold

2

U

c

h

a

f

Llyn

Ponds

4

49

9

1

7

3

9

Eilian

Y

G

L

Y

N

Ael-y-Glyn

(

P

a

t

h

a

n

d

C

y

c

l

e

P

a

t

h

)

105.1m

7

1

Well

P

a

t

h

(

u

m

)

F

F

O

R

D

D

T

Y

D

U

/T

Y

D

U

R

O

A

D

1

6

5

Tan Dinas

Hafan

P

a

th

(u

m

)

P

a

t

h

(

u

m

)

Frondeg

Uchaf

Coed Doctor

Glan Llyn

Issues

(disused)

F

F

O

R

D

D

C

L

E

G

IR

Gallt-y-glyn

L

o

n

L

a

s

P

e

r

i

s

T

r

a

c

k

Works

Sluice

P

a

t

h

(

u

m

)

CG

Ford

Quarries

Shelter

Ford

Ystabl-gôch

Lake)

Tomos / Lewis

Ty'n-y-mynydd

(disused)

Chwarel Bwlch-y-groes

Path (um

)

Tips

(disused)

Bryn Mawr

D

r

a

in

Sheepfold

Dinas

E

T

L

D

is

m

a

n

tle

d

T

r

a

m

w

a

y

(

L

l

a

n

b

e

r

i

s

L

a

k

e

R

a

i

l

w

a

y

)

Llyn Padarn

Boundary Slate Quarry

(disused)

Sinks

P

a

t

h

(

u

m

)

E

D

B

d

y

C

L

a

k

e

T

r

a

c

k

Slate Quarry

A

4

0

8

6

Y Glyn

Path (um

)

Glyn-rhonwy

Cei Llydan

S

M

(

P

a

t

h

&

C

y

c

l

e

T

r

a

c

k

)

Factory

L

o

n

L

a

s

P

e

r

i

s

PC

A

4

0

8

6

Glyn Padarn

L

o

n

L

a

s

P

e

r

i

s

Fn

Boat House

FB

(disused)

(

P

a

t

h

&

C

y

c

l

e

T

r

a

c

k

)

P

a

t

h

(

u

m

)

C

a

r

P

a

r

k

INTAKE/OUTLET

TEMPORARY

TUNNEL

ACCESS

SHAFT

POWER

HOUSE

COMPOUND

PUMPING STATION LOCATION

SPILLWAY

INFRASTRUCTURE

PENSTOCK

INLET/OUTLET

SHAFT

RISING

MAIN

INLET

COMBINED OVERFLOW/

SCOUR/RISING MAIN TOWER

TEMPORARY

ACCESS

TUNNEL

RETAINING

WALL

NEW

SPOIL

MOUND

HEAD POND

TAIL POND

DAM

DAM

SPILLWAY INFRASTRUCTURE

TO NANT Y BETWS

COMBINED RELIEF

VALVE/ OVERFLOW

TOWER

HEAD POND

NEW

SPOIL

MOUND

1 Callaghan Square

Cardiff

CF105BT

T +44 (0)29 2067 4600

F +44 (0)29 2067 4699

www.aecom.com

Drawn:

Verified:

Date:

Drawing Number:

Checked:

Approved:

Scale at A1:

Project:Client:

This document has been prepared by AECOM for the sole use of our Client (the "Client") and in accordance with generally accepted consultancy principles, the budget for fees and terms of reference agreed between AECOM and the Client. Any information provided by third parties and referred to herein has not been checked or verified by AECOM, unless otherwise expressly stated in the document. No third party may rely upon this document without the prior and express written agreement of AECOM.

A1

GLYN RHONWY PUMPED STORAGE DEVELOPMENT CONSENT ORDER

2.05 Indicative Layout Plan

2.05

JJA AH

CA CA

07.08.15 1:5000

Ordnance Survey © Crown Copyright, All rights reserved. 2015 Licence number 0100031673.

ORDER LIMITS

EXTENTS OF EARTHWORKS

MAX. OPERATIONAL WATER LEVEL

EXTENTS OF RE-PROFILING

PERMANENT DIVERSION

NEW DAM OPERATIONAL ACCESS

TRACK

PERMANENT REPLACEMENT PUBLIC

CARPARK

1. ALL DIMENSIONS IN METERS UNLESS

OTHERWISE NOTED. DO NOT SCALE.

2. ALL LEVELS IN METRES AND REDUCED TO

ORDNANCE DATUM UNLESS OTHERWISE

NOTED.

LEGEND

NOTES

0 125 250

1:5000

m

MAX OWL 392 mAOD

Q1

HEADPOND

RESERVOIR

RELIEF

OUTLET

OVERFLOW

SPILLWAY

STILLING BASIN

TURBINE/PUMP

LLYN PADARN

PUMP

OVERFLOW

SPILLWAY

OUTFALL WITH

COARSE SCREEN

ABSTRACTION

INTAKE WITH

FINE SCREEN.

FLOW

MONITORING

WATER LEVEL

MONITORING

NANT Y BETWS

FLOW MONITORING:

1. ABSTRACTION FLOW AT PUMP

STATION.

WATER LEVEL MONITORING:

1. HEADWATER RESERVOIR LEVEL.

2. TAILWATER RESERVOIR LEVEL.

3. STILLING BASIN ON HEADWATER

RESERVOIR OUTLET.

4. DOWNSTREAM WATER LEVEL IN

NANT Y BETWS.

5. LLYN PADARN (PUMPING STATION).

OUTFALL

TO NANT Y

BETWS

PUMPED ABSTRACTION

FOR INITIAL FILLING AND

LATER TOP UP.

MIN OWL 340 mAOD

TWL 393 mAOD

MIN OWL 90.0 mAOD

TWL 154.5 mAOD

DAM

MAIN INLET

VALE

PENSTOCK

NORMALLY OPEN FOR

RELIEF, WILL BE

CLOSED FOR

ABSTRACTION

PUMPING

NORMALLY CLOSED

VALVE, WILL BE OPEN

FOR ABSTRACTION

PUMPING

Q6

TAILPOND

RESERVOIR

RELIEF

OUTLET

MAX OWL 154.0 mAOD

DAM

RELIEF VALVE

RELIEF

VALVE

TWL TOP WATER LEVEL

OWL OPERATING WATER LEVEL

I/R DATE DESCRIPTION

ISSUE/REVISION

A 17.02.15 DRAFT ISSUE

B 06.07.15 ISSUED FOR REVIEW

1 10.07.15 FINAL ISSUE

Filenam

e: F

:\P

RO

JE

CT

S\E

NE

RG

Y - G

LY

N R

HO

NW

Y E

NG

IN

EE

RIN

G\03 E

XE

CU

TIO

N\04-C

AD

\20-S

HE

ET

S\60332577-S

HT

-10-Z

N00-Z

-0001.D

WG

PROJECT

GLYN RHONWY PSH

PROJECT NUMBER

60332577

SHEET TITLE

GLYN RHONWY

SCHEME SCHEMATIC DIAGRAM

SHEET NUMBER

60332577-SHT-10-ZN00-Z-0001

CONSULTANT

AECOM

1 Tanfield

Edinburgh, EH3 5DA

+44 (0) 131 301 8600 tel 8699 fax

www.AECOM.com

LEGEND

NOTES

1. DRAWING IS A SCHEMATIC: THIS IS NOT

INDICATIVE OF SIZE OR SCALE, AND DOES

NOT INCLUDE DETAIL.

Snowdonia Pumped Hydroc/o Quarry Battery Company

CB1 Business Centre, 20 Station Road

Cambridge, CB1 2JD

+44 (0) 1223 65 3026 tel.

www.snowdoniapumpedhydro.com

I/R DRAWN BY CHECKED

APPROVED FOR ISSUE

APPROVED

A LGB WHR JIG

CLIENT

Water Management at Glyn Rhonwy: Scheme Schematic

Water Management Schematic - Page 1 of 5

Rainfall

Q1Headpond

PowerHouse

Infiltration / Seepage

Evaporation

Rainfall

Infiltration / Seepage

Evaporation

Max OWL

Min OWL

Q6Tailpond Llyn Padarn

Release of+ Excess Water

Initial Fill &Top-up ( - Excess

Water)

If over time Rainfall > Losses (evaporation / infiltration):“Positive Excess Water” is to be released to the Llyn Padarn

If over time Rainfall < Losses (evaporation / infiltration):“Negative Excess Water” will require the closed scheme to betoped-up

Q1 HEADPOND

Q6 TAILPONDLLYN PADARN

Excess Water: Release of +Excess Water

Rainfall > LossesExcess Water released to Llyn Padarn

Excess water within systemmanaged within freeboard ofreservoir; i.e. without spill.Excess water is later released toLlyn Padarn via the relief valve.


Q1 HEADPOND


Water Shortage: Abstraction of –Excess Water

Rainfall < LossesTop-up abstraction from Llyn Padarn

Lack of waterwithin system

Top-upabstraction


Q1 HEADPOND


Spill of +Excess Water

Rainfall > Losses =Build-up of + “Excess Water”

Excess waterwithin system

Only after a prolonged period of no operational activity would thebuild-up of excess water reach the spill.

Each reservoir would eventually spill only incoming rainfall


Reservoir Draw-down

Q1 HEADPOND


Use of Penstockunavailable

Note:Only water impounded by damreleased under draw-down


Under Normal Circumstances:• Drawdown of Q1 is by transfer of water from Q1 to Q6• Drawdown of Q6 is by transfer of water from Q6 to Q1

Only Under Abnormal Circumstances; would drawdownof Q1 or Q6 required release of water from the system.

glyn rhonwy pumped storage development consent order · glyn rhonwy pumped storage development...

Documents