Impact of Reservoirs in the UK on the Surrounding Community - Dissertation Example

Literature Review Impact of Reservoirs in the UK on the Surrounding Community In order to better appreciate the literature relating to the impact of reservoirs in the UK on the surrounding community; it is important to gain a proper understanding of reservoirs and their function in the society. This will allow for a better grasp of the issues relating to their impact on communities in which they are built and to which they supply water for drinking and household activities. Definition Reservoirs are man-made bodies of open water serving as public water supply sources, as winter storage for crop irrigation or as flood storage facilities in association with river corridors (FWR 2011). FWR (2011) describes two types of reservoirs – upland reservoirs and lowland reservoirs. Upland reservoirs are built across river valleys and so they are described as upland reservoirs. Reservoirs such as those to which water is pumped from a nearby river source rather than filling naturally as with impounding reservoirs are known as lowland reservoirs (FWR 2011). Development of reservoirs in the UK According to FWR (2011.) much of the water supply infrastructure in the UK was developed at the end of the 19th century when impounding reservoirs were constructed in upland locations in order to provide water supply to conurbans which were often many miles away. Reservoirs were often located in areas where the catchment encountered little or no disturbance and so the quality of water supplied was in most cases fully acceptable without any need for either filtration or disinfection. However, as the standards relating to public hygiene evolved, many of these supplies were improved with the provision of chlorination systems. The regulation in relation to water quality ensures that all supplies are now provided with full treatment, including coagulation and filtration. FWR (2011) points out that in England and Wales two-thirds of drinking water comes from surface water, including reservoirs, lakes and rivers, and the rest from ground waters. There are also areas that receive water from mixed sources. Water is treated and tested along the way to ensure the highest quality. As it is with lakes reservoirs support rich and diverse flora and fauna and some rely on these habitats for their entire lifecycle. The classification is based on their nutrient status. Eutrophic standing waters are usually highly productive as they consist of lot plant nutrients. Legislation relating to Dam Safety Reservoir safety is critical to the British Dam Society which they indicate as the driving force behind many of the meetings, events and research work that they undertake (British Dam Society 2011). The Reservoir Act 1975 provides the legal framework to ensure the safety of dams with capacity of 25,000 cubic metres of water above natural ground level. Safety legislation in the UK was first introduced in 1930 after several reservoir disasters which resulted in loss of life. This was later superseded by the Reservoir Act 1975 (Environment Agency 2011). The Act indicates that reservoir owners have ultimate responsibility for the safety of reservoirs. They are also required to appoint a Panel Engineer – a specialist civil engineer who has qualifications and experience in reservoir safety to continuously supervise reservoirs and carry out periodic inspections. Supervision and inspection will be provided by qualified persons performing in the capacity of supervising and inspecting engineers respectively. Those reservoirs that are below the 25,000 cubic metres capacity are managed by the Health and Safety Executive and the Local Authorities under the Health and safety at Work, etc Act 1974 and the Building Act 1984 respectively. The Flood and Management Bill was given Royal Assent in April 2010, thus making it possible to bring aging reservoir safety legislation up to date by providing clarity on roles and responsibilities of those persons who manage flood and coastal risks in England and Wales (Environment Agency 2011). Reservoir construction and Management According to Wildi (2010) at the end of the 20th century approximately 45,000 large dams with a total reservoir surface of about 500,000km2 have been exploited in the world, mainly for irrigation, hydroelectricity and as drinking water reservoirs. Reservoirs provide a major contribution to the economic development of industrial as well as of developing and rural countries, and are often considered as sustainable, for example, sustainable hydropower or green hydropower (Wildi 2010; Truffer et al 2003; Bratrich et al 2004). There are a number of potential impacts and hazards which have been linked to the exploitation of dams and reservoirs (Findlay 1994; Wildi 2010). They include: The impact on inhabitants The impact on the flow of water The impact on landscape and visual effects The impact on the hydrological system and river dynamics; Impact on physico-chemical cycles; Impact on soil, surface and groundwater quality including environmental toxicity; Impact on ecosystems; Archaeological impact; and End-of life planning. Impact on inhabitants The building of dams can have positive as well as negative impacts on inhabitants of an area. In addition to relocation for many it provides a constant flow of water to carry out daily household functions in a hygienic manner. In order to build the first reservoir in Wales – Lake Vyrnwy Liverpool the reservoir owner had to purchase about ten farms and the village of Llanwddyn. It seemed as if no formal consultation was carried out among the villagers. This can be devastating for individuals whose livelihood depends on farming. A farm is not built overnight and so relocation can have economic as well as social impact on families who have to readjust to a new way of life. In the case of Carsington in Derbyshire (Crowe et al 2002) there were widespread concerns before its construction. General areas of concern included the existence of alternative water supplies, landscape intrusion, loss of high quality farmlands, impact on wildlife and archaeology, and other impacts on the life of the village. However, after the opening of Carsington reservoir the people’s perceptions are very different as the need for water supplies is critical. Impact on the flow of water Objections were raised in relation to the reservoir at Lake Vyrnwy Liverpool. This was in relation to the anticipated reduction in the flow of water that would result and the impact of the construction of the aqueduct. Businesses which utilised water from this source to carry on their business operations would be at a disadvantage. However, the benefits to communities of a regular supply of water cannot be outweighed by this effect. Impact on landscapes and visual effects Findlay (1994) has provided a list of the environmental areas which are most likely to be affected by the construction of a reservoir and provide details on some of the associated problems and solutions. In terms of landscape and visual effects Findlay (1994) indicates that these problems which are related to soil erosion are usually addressed with embankment type dams. Surplus or otherwise unsuitable materials that exist as overburden can be used in a cost effective manner to shape the embankment or the site generally. In the case of the Carsington Dam in Derbyshire, the failure of the original structure made a significant amount of disturbed fill available. This was suitable for landscaping and so it was incorporated in the embankment in order to make produce gently sloping and curved. This blended with the surrounding typography and therefore helped to reduce the overall impact of the dam on the landscape. Other problems mentioned by Findlay (1994) relates to archaeology, fisheries and fish migration, downstream water quality, resettlement of inhabitants, construction activity effects, tourism/recreation and its effects on locals. Impact on the hydrological system and river dynamics In relation to the impact of dams and reservoirs on hydrological and river dynamics Wildi (2010) points out that river diversion may occur both upstream and downstream as major changes in the river system occur. When it occurs upstream this is likely to be in conjunction with bringing water into the reservoir in order to increase its capacity. This may result in the partial dehydration of landscapes and it may also have an impact on surface and groundwater levels. The general rule is that groundwater levels decrease in areas with diverted rivers and increase in areas which are close to and downstream of reservoirs. Rivers are usually diverted downstream for hydroelectric purposes as well as for navigation or irrigation. This measure provides elevation and therefore pressure to the system in order to make the venture successful. Cause (2001 qtd in Wildi 2010) indicates that in accordance with the mode of management, although irrigation may have some important benefits in relation to improving agricultural production it may also have negative effects such as the salinisation of the soil. However, Wildi (2010) indicates that in the event of reservoir contamination, either chemical or microbiological, impacts on human health may be expected. The downstream effects of flushing a reservoir include inundation, massive sediment transport and damage to the ecological communities. Wildi (2010) also points out that reservoir sedimentation may also lead to an increase in the erosive capacity of the river. River banks may also be affected (Palmieri et al 2001; Wildi 2010). The riverbed along with any constructions including things like the basement of bridges may also be affected (Wildi 2010). Impact on physico-chemical cycles Physico-chemical cycles refers to sediment cycles; nutrients, contaminants and major element cycles; and carbon and oxygen cycles. In relation to sediment cycles a fundamental process of a reservoir is to trap solid matter which can have a number of environmental implications (Wildi 2010, p. 190). The efficiency levels of reservoirs in trapping sediment has been reported to lie somewhere between 70 and 90 per cent of the volume of sediments that have been delivered from watersheds (Sundborg 1992; and Toniolo and Schultz 2005 qtd in Wildi 2010). This has led to an approximate 30 to 40 per cent of suspended matter which is transported by river networks throughout the world that have not being able to access sea coasts, oceans and major lakes but is being retained in reservoirs which are man made as long as their infrastructure is intact (Vorosmarty et al 1997 qtd in Wildi 2010). Approximately 46 per cent of the water in the 108 most important rivers of the world flows into a reservoir before it gets to lakes and the sea (WCD 2000). Some of the somewhat obvious environmental implications alluded to by Wildi (2010) and other researchers include: changes in the delta and coastlines sediment budgets. Malini and Roa (2004, qtd in Wildi 2010) indicate that there is a reduction in the level of sediment input by river deltas on oceans and lakes. Additionally, some of these deltas have passed from progression of coastlines to regression. Wildi (2010) indicates that the limited levels of sedimentation on the delta plain no longer compensate tectonic subsidence and eustatic rises in the sea level. Then transgresses on the delta and so increases the effects of current sea level rise due to global warming. Furthermore, the ability of the reservoirs to trap suspended matter depends on a number of factors and its trapping efficiency decreases with continuous sedimentation. WCD (2000) indicates that capacity of reservoirs to trap suspended mater is reduced by an average of 1 per cent per year. In relation to nutrients (including organic matter, carbon, phosphorous), contaminants (including metals and organic substances) and major element (including silica, sulphur and iron) cycles a number of environmental hazards can result. Wildi et al (2004) indicates that sediment erosion, organisms and infiltration may lead to the remobilisation of contaminants from sediments and lead to their return to the tropic chain. Jaccard (2008, qtd in Wildi 2010) indicates that reduction in primary production in offshore areas resulting from the reduction of nutrient inputs to the coastal areas of oceans and seas my have a negative effect on the balance of marine carbon and therefore impact climate change. In terms of carbon and oxygen cycles Wildi (2010, p. 191) indicates that the depletion of oxygen may result in deoxygenated or the possibility of anoxic conditions in deep water and in the sediments. Impact on soil, surface, groundwater quality and environmental toxicity Cause (2001, qtd in Wildi 2010) indicates that salinisation may occur during irrigation. This can be attributed to the maintenance of a high ground water level especially when evaporation and evapo-transpiration are strong. The contamination of soil in areas that are prone to flooding by sediments from reservoirs may also be expected. Justrich et al (2006, qtd in Wildi 2010) links this to the accumulation of contaminants in reservoirs. Various reservoir processes such as authigenous production, sedimentation and degradation, evaporation, and nitrogen, iron, manganese, and sulphur and silica cycles may influence the quality of water. There are various ways in which contamination can take place. However, Pote et al (2008) indicates that the major impact on the quality of the water results from biological processes such as the contamination caused by the release of water from wastewater treatment plants. Pote (2009) indicates that sedimentation may also contribute to the persistence of contaminants in the water. Wildi (2010) points out that the turbidity of water may be increased by a high concentration of plantation. Additionally there may be the risk of malaria due to the proliferation of mosquitoes, rats and other such nuisances. AGS (2009, qtd in Wildi 2010, p. 192) points out that there may be a reduction in the quality of ground and drinking water as a result of the depletion of dissolved oxygen due to increased levels of filtration. This can lead to an increase in the levels of ammonium and the remobilisation of iron and other substances including contaminants. Pardos (1996, qtd in Wildi 2010) indicates that sediment contamination by micro-pollutants as well as anoxic conditions with high levels of sulphur can lead to an increase in the levels of environmental toxicity. Justrich et al (2006, qtd in Wildi 2010) also supports this point. Impact on ecosystems Wildi (2010, p. 192) indicates that some of the ecological consequences of damming include the loss of forests and the habitats of wildlife, the ‘loss of species populations and the degradation of upstream catchment areas due to inundation, loss of aquatic biodiversity, including upstream and downstream fisheries, and loss of the services of downstream floodplains, wetlands, and riverine, estuarine and adjacent marine ecosystems.’ Wildi (2010) also points out that reservoirs can have a cumulative impact on the quality of water, the composition of species and natural flooding, habitat loss where several dams are situated on the same river. This may also result from changes in the supply of sediments, flow conditions and a reduction in nutrients delivered in the water. In the case of Carsington Crowe et al (2002) points out that the impact on wildlife and biodiversity is difficult to assess. However, the value of the site for wildfowl and water birds in particular are clear. Through ongoing management the area is managed on an ongoing basis in relation to selected wildlife habitats and in particular woodland and grassland management. Crowe et al (2002) also point out that their were positive social and economic impacts as individuals and businesses point to increased trade as well as the enhanced amenity value that the site provides. Archaeological impact In the case of Carsington Crowe et al (2002) points out that the loss of Archaeological interest when the Henmore Valley was flooded was of major concern. End of life planning Quinn (1999, qtd in Wildi 2010) indicates that the average life span of dams is 50 years. As they age their structure begins to deteriorate and so they may no longer serve their originally intended purpose. The cost of rehabilitating them is excessive even before considering the cost of maintaining them in the future and the liability insurance cost if it is left in place. Although Quinn (1999, qtd in Wildi 2010) makes specific reference to the United States the situation in the UK would be similar. Some of the key problems that are associated with dam removal include: the elimination and disposal of sediments; the management of sediments; the re-vegetation and rehabilitation of the river system; the management of new ground and drinking water. The management of this situation has major implications for the environment as it is usually a very costly operation that has a major environmental impact. Measures to improve sustainability Sedimentation is a major issue in relation to the operations of reservoirs. Palmieri et al (2001) lists a number of sediment management measures. They include: Carrying out various measures to reduce sediment yield in the catchment area. They include soil conservation measures, measures aimed at the prevention of landslides and accelerated levels of erosion, as well as reforestation. They also propose setting up dams for debris to intercept sediments with coarse grains coming from streams located in mountainous areas. The channelling of sediments through off-stream reservoirs, setting up structures that will exclude sediments from passing through them, and using other methods such as sluicing. Sediment flushing Removal of sediments via dredging or hydraulic removal. However, Palmieri et al (2001) also emphasized that the result of these reservoir management methods are specific to a particular site and so standardisation is therefore not possible. According to Findlay (1994), the UK is blessed with a legacy of water supply schemes that are based on dam and reservoirs that suffer a minimum of environmental problems that were initially caused by the suitability of conditions in the country and latter as a result of public consultations that were carefully carried out. Findlay (1994) also points out that engineers shaped their structures aesthetically and produced water based ecosystems that enhanced the environment and increased the quality of life well beyond the immediate need for water. Reference Abandonedcommunities.co.uk. (n.d.). Abandoned Communities … Reservoirs of Wales. [Online] Available at: http://www.abandonedcommunities.co.uk/page32.html [Accessed 15th December 2011] Bratrich, C., Truffer, B., Jorde, L., Markard, J., Meir, W., Peter, A., Schneider, M. and Wehrli, B. (2004). Green Hydropower: a New Assessment Procedure for River Management. River Research and Applications. 20, p. 865-882 British Dam Society. (2011). Reservoir Safety. [Online] Available at: http://ww.britishdams.org/reservoir_safety/default.htm. [Accessed 15th December 2011] Crowe, L, Rotherham, I.D., Doncaster, S. and Egan, D. (2002).Carsington Water Derbyshire: An Assessment of its Social, Economic and Environmental Impacts – Final Report. Centre for Environmental Conservation and Outdoor Leisure, School of Sport and Leisure Management, Sheffield Hallam University. Environment Agency (2011). Reservoirs Act 1975. [Online] Available at http://www.environment-agency.gov.uk/business/sectors/64246.aspx [Accessed 15th December 2011] Findlay, J. W. (1994). Reservoir development in semi-arid countries – a human ecology perspective, in Reservoir safety and the environment. British Dam Society. London: Thomas Telford FWR. (2011). Lakes and Reservoirs. [Online] Available at: http://www.euwfd.com/html/lakes_and_reservoirs.html. [Accessed 15th December 2011] Londonprepared.gov.uk (2010). London Strategic Flood Framework. [Online] Available at: http;//www.londonprepared.gov.uk/downloads/London-strategic-flood%20-framework-Jan-10v1.pdf. [Accessed 15th December 2011] Palmieri, A., Shah, F. and Dinar, A. (2001). Economics of Reservoir Sedimentation and Sustainable Management of Dams. Journal of Environmental Management. 61, p. 149-163 Pote, J., Goldscheider, N., Haller, L., Zopfi, J., Khajehnouri, F., and Wildi, W. (2008). Origin and Spatial-temporal distribution of faecal bacteria in a Bay of Lake Geneva, Switzerland. al of Environmental Monitoring and Association. 154, p. 337-348 Pote, J., Haller, L., Kottelat, R., Sastre, V., Arpagaus, P., and Wildi, W. (2009). Persistence and growth of faecal culturable bacterial indicators in water column and sediments of Vidy Bay, Lake Geneva, Switzerland. Journal of Environmental Sciences. 21, p. 62-69 Truffer, B., Bratrich, C., Markard, Peter, J.A., Wuest, A. and Wehrli, B. (2003) Greenpower: The Contribution of Aquatic Science Research to the Promotion of Sustainable Electricity. Aquatic Sciences: 65(2), p. 99-110 World Commission on Dams (WCD). (2000). Dams and Development: A Framework for decision-making. [Online] Available at: http://.www.internationalrivers.org/en/way-forward/world-commission-dams. [Accessed 15th December 2011] Wildi, W,. Dominik, J., Loizeau, J.L., Thomas, R.L., Favarger, P.Y., Haller, L., Perroud, A. and Peytremann, C. (2004). River, Reservoir and Lake Sediment Contamination by Heavy Metals Downstream from Urban Areas of Switzerland. Lakes and Reservoirs: Research Management. 9(1), p. 75-87. Wildi, W. (2010). Environmental hazards of dams and reservoirs, in NEAR Curriculum in Natural Environmental science, 2010, Terre et Environment. 88, p. 187-197 Read More