Application number: WPCC501 (Abstraction)
Licence number: WA/060/0001/003
NRW Area: South West
Date of Application: 02/08/2013
Applicant details: Hydro Electric Development Ltd, Wellington House, 273 – 275 High Street, London Colney, Hertfordshire, AL2 1HA.
Summary of the proposal:
The applicant has applied to install and operate a new hydropower scheme on the Afon Tywi approximately 1.5 kilometres (km) downstream of Llyn Brianne Reservoir at Rhandirmwyn, Llandovery. The proposed scheme consists of a new intake structure (the impoundment licence required for the intake structure will be applied for at a later date and therefore the intake structure has not been considered in the determination of this abstraction licence application), a gravity feed pipe, a power house (not considered for the abstraction licence, but required as part of the scheme to operate), tailrace and outfall structure. The applicant has proposed to abstract all flow above a Q85 residual flow (780 litres per second (l/s)) all year and additional elevated residual flows at specified periods throughout the year up to a maximum rate of 4,200 l/s (Qmean).
All abstracted water will be returned to the Afon Tywi at National Grid Reference (NGR) SN 77530 45920, approximately 2.8 kilometres downstream of the abstraction point.
Source of Supply:
Inland water (river) known as the Afon Tywi at Rhandirmwyn, Llandovery, Carmarthenshire.
Point of abstraction and quantities:
Point of abstraction – National Grid Reference SN 78560 47560
Quantities – 362,880 cubic metres per day
132,451,200 cubic metres per year
At a rate of 4,200 litres per second
Means of abstraction:
Intake works and a gravity feed pipe of an internal diameter not exceeding 2,200 millimetres controlled by an automated control system.
Purpose of abstraction:
A pre-application enquiry was submitted in May 2011, proposing a hydro power scheme at National Grid Reference SN 78575 47566 on the Afon Tywi. The pre-application was assessed by NRW’s predecessor the Environment Agency Wales. A pre-application response letter was sent on 28 July 2011 advising that in principle we had no objections to the proposal and we were willing to consider a formal application. The letter advised that the abstraction regime would have to prevent impacts on migratory salmonids.
A formal application was received on 5 July 2013. However it was initially considered invalid because rights of access information had not been included and reports requested at pre-application stage had not been submitted. The application was accepted as valid on 2 August 2013, once a draft lease agreement (to support the applicants right to access) and additional reports had been received.
Justification of quantities:
The maximum instantaneous rate applied for, 4,200 l/s, is consistent with the applicant’s Qmean estimate and is therefore in accordance with the Environment Agency’s Hydropower Good Practice Guidelines (GPG, Published August 2009, and relevant guidance during the determination of this application) which recommends that maximum abstraction should not exceed Qmean. The Q85 residual flow proposed, 780 l/s, is in accordance with the residual flow agreed at the pre-application stage. The NRW agrees with the applicant’s flow estimates.
The proposed annual quantity is equivalent to 365 times the maximum daily quantity; this is more than the 220 days maximum recommended by the GPG. However, this has been deemed acceptable by the NRW as the residual flows are considered sufficient to ensure the ecology within the depleted reach is protected.
The net head for this scheme has been determined by the applicant as 47.5 metres. The applicant has based the electrical output on a maximum flow rate of 4,200 l/s, and states that the scheme will have a maximum output of 1,800 kilowatts (kW). The following equation gives an estimate of the power (P) that can be generated (in kilowatts) based on the abstraction rate (Q), acceleration due to gravity (g) and head difference:
P = Q x g x h
Q = 4.2 cubic metres per second
g = 9.81 metres per second squared
h = 47.5 metres
P = 4.2 x 9.81 x 47.5 = 1,957 kW
System efficiency is the product of the individual efficiencies of the scheme, and for this proposal based on the power output calculation above, the design system efficiency has been calculated as 92 per cent (1,800/1,957 * 100) which is very good. The applicant has advised the average power output will be 856 kW and efficiency is 85% which is also good.
The NRW considers the quantities of water applied for as fully justified and reasonable.
The Catchment Abstraction Management Strategy (CAMS) resources assessment status for this area is ‘Water Available’. This proposal has been subjected to the Water Abstraction Licensing Ecological Scoring (WALES) methodology and Habitats Regulations to establish the permitted abstraction/residual flow regime. A bespoke abstraction regime is required following the outcomes of the Habitats Regulations assessments.
Impact assessment of proposal:
Abstraction regime: There are no concerns regarding the impact on flows as a result of proposed abstraction as the Afon Tywi at this point is already heavily regulated by the compensation releases made by DCWW from Llyn Brianne Reservoir. The abstraction/residual flow regime determined during the pre-application enquiry would be licensed as applied for within the abstraction licence. Low flows will be protected by the residual flow of 780 l/s. This is equal to the existing minimum compensation flow set by the NRW for Llyn Brianne Reservoir and is estimated to be between the Q90 and Q85 naturalised flow for the site (ie without the reservoir). The residual flow of 780 l/s will be required all year. The Licence Holder would be allowed to abstract all water above the residual flow of 780 l/s, subject to additional residual flows at specific times to protect fish migration, up to the maximum instantaneous abstraction rate of 4,200 l/s. The permitted abstraction/residual flow regime will be secured by an automated control system.
Carmarthenshire Council were consulted on 3 September 2013 and replied on 2 October 2013 with no concerns. The consultation was undertaken as part of the Habitats Regulations assessment to inform the in-combination part of the assessment.
No protected rights or lawful users have been identified as being at risk of derogation as a result of this proposal.
An Appendix 11 assessment was completed for the Afon Tywi Special Area of Conservation (SAC), Elenydd-Mallaen Special Protection Area (SPA) and the Cwm Doethie - Mynydd Mallaen SAC. The assessment concluded that there would be no significant effect on the Elenydd-Mallaen SPA but, as a result of consultation with the Designated Conservation Officer, it was not possible to conclude that the proposal was not likely to have a significant effect upon Afon Tywi SAC and Cwm Doethie Mynydd Mallaen SAC. An Appropriate Assessment (Appendix 12 assessment) has therefore been completed by Natural Resources Wales as the relevant competent authority.
The Appropriate Assessment considers the impact of changed water chemistry on the anadromous fish (Allis shad, River Lamprey, Sea lamprey, Twaite shad) feature of the Afon Tywi SAC specifically looking at the effects from suppression of water temperatures on Shad.
The Appropriate Assessment also considers the impact of a change in surface flooding on the Dry Woodlands and scrub (Old oak woods with llex and Blechnum in the British Isles) features of the Cwm Doethie – Mynydd Mallaen SAC, specifically looking at the effects from reduction in mist zones on riparian bryophytes.
The Appropriate Assessment considers the above in line with the relevant conservation objectives and information/monitoring work provided by the applicant and concludes that there will be no adverse effect on the integrity of the Afon Tywi SAC and Cwm Doethie – Mynydd Mallaen SAC, alone or in combination with other plans or projects, as a result of the proposed abstraction.
An Appendix 4 assessment was completed for the Cwm Doethie – Mynydd Mallaen Site of Special Scientific Interest (SSSI) and sent to the Designated Conservation Officer for consultation. The assessment was updated following a change to the licence conditions, the amended assessment was signed off on 16/04/2015.
No adverse effects upon the social and economic well-being of local communities in the rural area are perceived as a result of this proposal.
The scheme may encourage others to produce electricity in this way.
Biodiversity and sustainable development:
No licence will be issued as a result of this application. However, there were no concerns regarding impacts on Biodiversity and sustainable development.
Conclusion and recommendation:
NRW has chosen to refuse the application because the applicant has not submitted evidence to show that the necessary rights of access have been granted; this is a legal requirement under section 35 Water Resources Act 1991. Without this evidence, NRW are unable to issue an abstraction licence.