fO (1A - s j 0 [ £ MANAGING WATER RESOURCES IN WELSH REGION

National Rivers Authority E n v i r o n m e n t A g e n c y

NATIONAL LIBRARY & INFORMATION SERVICE

AN G LIA N REGION

Kingfisher House, Goldhay Way, Orton Goldhay, Peterborough PE2 5ZR

Thanks to the National Museum o f Wales for the illustration on

page 1 of the Caergwrle bowl. ENVIRONMENT AGENCY WEQ2952K AKPI. iiig iiiiiiu 089562 Wafer is vital to life.

Making the best use o f this essential resource is one o f the prime statutory responsibilities of the National Rivers Authority (NRA). It includes conserving water and balancing the competing needs of abstractors and o f the water environment. This complex role is accomplished through:

• Continuously measuring • Predicting future water rainfall, evaporation, river demands o f all kinds. flows, and groundwater levels. • Planning environmentally • Analysing these data to sustainable works to augment establish the availability and water resources to reflect reliability o f water resources. changing demands.

• Controlling abstractions from rivers and groundwater.

A line drawing o f the Caergurle bowl, a votive model boat made o f slate and decorated with gold inlay, fonnd in Caergwrle, Clwyd. (9th-8th Centuries B.C.) The Welsh Region Severn catchment. It also includes

The NRA has eight Regions, covering those parts o f the Dec and Wye

England and Wales. Welsh Region is the catchments which lie in England. The fourth largest covering an area of landscape is very diverse, ranging

21,262 square km. It com prises the from the distinctive mountainous w h o le o f W ales apart from that part o f areas o f North Wales to the low-lying mid Wales which falls into the Upper coastal areas o f the Gwent levels.

PRINCIPAL WATER RESOURCES OF THE WELSH REGION

Key

General direction —* of transfen

• River abstraction

▲ Reservoirs

Welsh Political lloundary

NRA Welsh Region Boundary

Area Boundary

Main Rivers

• Principal Towns

r LLYSVFRAN, I*— HAVFRFOteWf . L. CANASTON

□ Water Resources of the Welsh Region with 845 mm per year in the rest o f Rainfall and Rivers England and Wales. Distribution

Rainfall is the sole source of fresh ranges from less than 700 mm in the water. Welsh Region has more o f it Welsh Borders to over 4,000 mm in than any other NRA Region: over 1310 Snowdonia. mm per year on average, compared Over the Region about 45% of the

AVERAGE ANNUAL RAINFALL (1941-70)

□ STQo

rainfall evaporates o r is used by in permeable rocks known as aquifers. plants. The 730 mm per year which The main aquifers comprise the remains is called the “effective" Carboniferous Limestone, the Permo rainfall. Some of this quickly finds its Triassic Sandstone and the Old Red way to the river systems and the sea, Sandstone. Supplies from valley while the remainder is delayed by gravels are also o f local significance. infiltrating into soils and rocks, or by Drought being stored in lakes and reservoirs. Droughts are natural phenomena This may then be released slowly to caused by long periods o f low rainfall. maintain river flow s during dry During such periods the effective periods, or used to satisfy demands by rainfall in a year may be reduced by industry, agriculture and the public. half. The proper management of water

Groundwater resources requires assessment o f the

Groundwater is found throughout the available resource during droughts.

Region and is important where sufficient quantities of water are held River flows are maintained by the

□ Although Wales has plentiful water Water Qudty resources, they are heavily utilised by The Welsh Region has very good man. The quantity licensed for quality water in its rivers and lakes. abstraction is more than half the However, in some upland areas the average effective rainfall. In drought effects o f acidification are o f years abstraction quantities appear to concern, and in the larger river exceed the water available. However, valleys intensive agricultural nearly all the water used within the practices can affect both surface and

Region is returned to the rivers after groundwater. Across the Region use. This water maintains flow’ and mining and other industries have left keeps the aquatic environment in a contaminated land, and current healthy state. The NRA also sets industrial activity and waste disposal conditions on licences to reduce the pose a pollution risk. The Region’s impact o f abstractions during periods rivers and streams provide w'ater for when water resources are limited. the dilution o f effluent.

The main needs for water are as Conservation follow s Many wildlife and landscape features which contribute to the natural Fisheries beauty o f W'ales have developed in The fisheries resource o f the Region is response to the climate and high extensive, diverse and valuable. Fish rainfall of the Region. They rely on rely upon an adequate supply of water the continued availability o f water, throughout their life cycle. O f particular often of high quality and in large importance is the effect o f water flow quantities. The rivers Wye, Usk, Dee, on the migrations of salmon and sea Tywi and Teifi harbour species such trout. Generally, increases in river flow, as otter, dipper, goosander, salmon, known as spates, stimulate these sea trout and shad; the fast flowing movements and are important in mountain streams in North and West enabling adult fish to negotiate Wales support fragile plant obstructions. communities dependent on a moist uncontrolled abstractions can create

environment; the extensive areas of problems, particularly when the

blanket and lowland bog throughout rivers used to feed canals are

the Region are home to unique plant themselves suffering from low flows.

communities. Water Abstractions

Recreation Water is abstracted from the

The Region’s landscape provides the Region’s surface and groundwaters

venue for the local population and for a variety of uses. Currently there

tourists to enjoy a wide variety o f are about 4,100 licences in force,

recreational pursuits. Th e river W ye which authorise the abstraction of

offers an unrivalled length of river some 24,368 Megalitres per day (Ml/

for canoe touring, with a trip d). There are also very many small

through countryside of outstanding unlicensed abstractions which,

scenic beauty. Other rivers offer although important, are not

white water and slalom canoeing, significant users o f water. The

and on the Tryweryn these uses are Region’s abstractions are covered

enhanced through releases of water under the following categories:

from Llyn Celyn reservoir. In Hydro Electric Power: About three-

addition to the extensive uses of quarters o f all the water licensed in

rivers, lakes and reservoirs for the Region is used at 41 sites to

angling, they are a popular choice for generate electricity'. No water is lost-

bankside walks and picnics. in this process, but the large changes Gnds in river (low can have a major impact

The canals o f the Region provide on the aquatic environment and

important waterways for pleasure other users of the watercourse.

boating and other waterside Three of the largest schemes

reacreational use. They are operated recirculate the water used for power by British Waterways and private generation and so limit the companies. However, the rights to downstream impact. take water to feed the canals predate Agriculture: The major agricultural the w ater resources legislation and abstractive uses are for spray so remain unregulated. These irrigation and fish farming.

□ Spray irrigation often occurs o f the Region's licensed total. Actual

when flows in rivers and streams abstraction is well below the licensed

are at their lowest and the quantities available.

potential impact at its greatest. Public Water Supply: Water Nearly all water is used by plants Companies are licensed to abstract or evaporated away. around 3,100 Ml/d of water to supply

Fish farms account for 80% of the domestic households, commercial

Region's agricultural water use. buildings and industry. Some 1,100

However, nearly all water Ml/d is licensed for export from the

abstracted is returned after use. Region. Typically about 70% of

The Region’s rivers are not ideal public water supply abstraction is

for this use due to the low summer returned to rivers via the sewerage

flows. system. However, in Welsh Region

Industry: Direct abstraction for only about 30% is returned. This is industrial use ranges from the low due to the large volumes exported water loss mineral washing, through from the Region, and the high to high water loss evaporative cooling. percentage of effluent discharged

Industrial use accounts for around 5% directly into the sea.

LICENSED QUANTITY IN WELSH REGION

SI and Mw7« PWS 12.1* o lh ir Agrfc SI and tfnc 2 n

M ro fW 737%

GROUNOWATfE: 325 Ml/d SURFACI WATIfc 2404J NU/il

H Upland Wales has deep valley least 364 Ml/d is maintained over locations for containment of water, Chester W eir in all but the most coupled with high rainfall. As a result testing o f droughts. This safeguards many Welsh river flows are the passage o f migratory fish, and augmented by water released from limits the ingress o f saline water over reservoirs: a process known as river the weir. A further 1028 Megalitres regulation. (M l) o f storage is held to:

The NRA has made statutory • mitigate the effects of pollution, agreements with the reservoir • enable canoe events on the Afon owners, Dwr Cymru, to operate the Tryweryn on a number o f days, reservoirs for the benefit of abstractors and the rivers. • provide fishery freshets to

Agreements are now in operation on safeguard the grilse and spawning six rivers in Welsh Region:- runs.

Dee Bala Lake and Llyn Celyn are also used for short term retention of flood The natural flows of the River Dee, water until it can be safely released. during dry summer weather, would be insufficient to sustain any Tywi significant abstractions. By taking The construction o f Llyn Brianne dam w ater into storage in Bala Lake, and in 1972 provided an impoundment of in the reservoirs o f Llyn Brenig and 61.000 Ml o f water with which to Llyn Celyn at times of high river flow, regulate the River Tywi. Releases of water may be released to supplement reservoir water into the River Tywi low natural flows when they occur. In primarily support licensed 1994, the Dee scheme allowed the abstractions by Dwr Cymru near authorised abstraction o f almost 830 Llandeilo and Carmarthen. However, Ml/d by fou r w ater com panies and a further 15 Ml/d is available for British Waterways. allocation to other potential

In addition, a residual flow of at abstractors. Additionally, up to 9092 Ml of water can provide fishery freshet releases.

Wye

The Elan Valley

Reservoirs were originally constructed by

Birmingham

Corporation to impound 99,106 Ml The Elan Valley reservoirs o f water from the provide water to the Midlands Rivers Elan and Claerwen for direct and South Wales supply of water to Birmingham.

Subsequent changes in operation of Alwen aqueduct. The river the scheme have enabled additional augmentation releases are required releases to be made from the to support D\ v t Cymru’s abstractions reservoirs to supplement low flows in o f up to 13 6 Ml/d at Llannerch. A the Lower Wye. Consequently, further 1 Ml/d is available for additional abstractions are now allocation to other potential possible at Lydbrook and Monmouth abstractors. There are no specific totalling 181 Ml/d. Additionally, up to environmental releases of water.

1818 Ml o f water is available to However, releases from the artesian provide fishery freshet releases. augmentation boreholes between early May and autumn frequently CKvyd exceed downstream abstraction

The Clwyd differs from the other requirements, thereby conferring schemes in that much o f the water additional benefits to the river used to regulate river flow is taken environment. from up to seven boreholes in the

Triassic Sandstone aquifer o f the Vale AiedondDwyfor of Clwyd. In addition, up to 6.8 Ml/d Smaller scale agreements are in force of water can be discharged from the on the Aled and Dwyfor systems. □ FUTURE WATER USE

In March 1994 the NRA published sources or be deferred by

“Water, Nature’s Precious Resource”. improvements in demand and

This milestone report (available resource management. In some rural through HMSO at £22.50) sets out a areas and in the Dee catchment, water resources strategy for England supplies are insufficient to meet and Wales for the next 30 years. A future demands. These projected Welsh Regional strategy, due for shortfalls could be met through publication in the autumn of 1995 will modest schemes such as new build upon this foundation. groundwater abstractions, or through

In preparing this strategy the works to increase the capacity o f Welsh Region of the NRA has existing reservoirs. published a consultation document This consultation document is the

“Water for Welsh Region” which is first stage in the preparation of an designed to invite comment on the environmentally sustainable water management of water resources. This resource strategy for the Welsh report considers the likely change in Region. This strategy will build upon demand up to the year 2021. Over this the detailed resource assessment and 30-year p eriod grow th in water use is planning work already carried out and anticipated. scheduled for the coming months. The

T h ere is the potential for a com m ents received on this threefold increase in hydroelectric consultation document will aid the power generation demand and development of the strategy. d ou b lin g o f spray irrigation in the

Region by 2021. In practice, these Copies o f the consultation demands are likely to be constrained document are available from: by resource availability. Water Resources Section Demand for public wrater supply National Rivers Authority could increase above current levels by Welsh Region as much as 26% o ver the planning Rivers House, St. Meltons period. Much o f this could be met by CARDIFF CF3 OLT enhancement of existing licensed

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