There are several possible methods available for extreme flood estimation applicable for UK dams and reservoirs. New models continue to be released to calculate both rainfall and runoff. This paper gives a short summary of the methods that are currently recommended for use in reservoir flood studies, and the methods that have been recommended in the past. This is intended to help inform reservoir owners, panel engineers and hydrologists of current best practice and the extent of changes in methodology since historical flood studies were undertaken. A simplified approach for sensitivity testing of multiple methods is proposed.
{"title":"An updated reference table for extreme flood hydrology methods at UK dams","authors":"Robert Fraser","doi":"10.1680/jdare.2024.13","DOIUrl":"https://doi.org/10.1680/jdare.2024.13","url":null,"abstract":"There are several possible methods available for extreme flood estimation applicable for UK dams and reservoirs. New models continue to be released to calculate both rainfall and runoff. This paper gives a short summary of the methods that are currently recommended for use in reservoir flood studies, and the methods that have been recommended in the past. This is intended to help inform reservoir owners, panel engineers and hydrologists of current best practice and the extent of changes in methodology since historical flood studies were undertaken. A simplified approach for sensitivity testing of multiple methods is proposed.","PeriodicalId":505716,"journal":{"name":"Dams and Reservoirs","volume":"12 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141920871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
When Wales' largest natural lake, Llyn Tegid, required significant reservoir safety works, the execution of sympathetic yet well-engineering solutions ensured that the scheme could stand the test of time and achieve multiple benefits for future generations. Placing sustainability at its heart, the scheme, delivered in Spring 2023, totalling £7 million, has involved strengthening works to 3 km of embankments to protect the popular tourist town of Bala from extreme weather. Boosting the wellbeing of residents and visitors within the picturesque Snowdonia landscape, works on the high-risk reservoir did not come without unique challenges. From designing for overflowing events and significant mature tree removal, to protecting internationally important habitats and working within the live reservoir basin, to name just a few. The scheme's success has been a testament to building the right team, implementing the right contractual and management controls, and establishing the right culture for compliant and high-quality solutions. Opportunities for carbon reduction and maximising value for money have been taken alongside new works to facilitate possible future expansion of Bala Lake Railway. Involving the community at every stage of this award-winning scheme, the delivery of benefits has been many, and the experiences are ones to live on for all.
当威尔士最大的天然湖泊 Llyn Tegid 需要进行重大的水库安全工程时，我们采用了富有同情心但又精心设计的解决方案，确保该计划能够经受住时间的考验，并为子孙后代带来多重益处。该计划以可持续发展为核心，于 2023 年春季交付，总投资达 700 万英镑，包括加固 3 公里长的堤坝，以保护著名旅游城市巴拉免受极端天气的影响。为了提高居民和游客在风景如画的斯诺多尼亚地区的生活质量，该高风险水库的工程面临着许多独特的挑战。从设计溢流事件和大量移除成龄树，到保护具有国际重要性的栖息地和在活水库盆地内施工等等，不一而足。该计划的成功证明了建立了正确的团队、实施了正确的合同和管理控制，以及建立了正确的文化，从而提供了合规和高质量的解决方案。在开展新工程的同时，还抓住了减少碳排放和实现资金效益最大化的机会，为巴拉湖铁路未来可能的扩建提供了便利。在这一屡获殊荣的项目中，社区参与了项目的每一个阶段，从而获得了诸多益处，这些经验也将为所有人所铭记。
{"title":"The delivery of multiple benefits on the Llyn Tegid reservoir safety improvements project","authors":"Andrew Basford","doi":"10.1680/jdare.2024.12","DOIUrl":"https://doi.org/10.1680/jdare.2024.12","url":null,"abstract":"When Wales' largest natural lake, Llyn Tegid, required significant reservoir safety works, the execution of sympathetic yet well-engineering solutions ensured that the scheme could stand the test of time and achieve multiple benefits for future generations. Placing sustainability at its heart, the scheme, delivered in Spring 2023, totalling £7 million, has involved strengthening works to 3 km of embankments to protect the popular tourist town of Bala from extreme weather. Boosting the wellbeing of residents and visitors within the picturesque Snowdonia landscape, works on the high-risk reservoir did not come without unique challenges. From designing for overflowing events and significant mature tree removal, to protecting internationally important habitats and working within the live reservoir basin, to name just a few. The scheme's success has been a testament to building the right team, implementing the right contractual and management controls, and establishing the right culture for compliant and high-quality solutions. Opportunities for carbon reduction and maximising value for money have been taken alongside new works to facilitate possible future expansion of Bala Lake Railway. Involving the community at every stage of this award-winning scheme, the delivery of benefits has been many, and the experiences are ones to live on for all.","PeriodicalId":505716,"journal":{"name":"Dams and Reservoirs","volume":"107 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141665911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A new over-the-dam spillway and 3m dam raising was selected as the preferred option for resolving matters in the interest of safety for an existing dam in Zambia. The cost of supplying concrete at the dam site has the greatest effect on overall project capital costs, and thus optimising the size of the concrete spillway is critical. Both ogee and labyrinth weir designs were developed for a hydraulic head of 5m in the safety check flood. The ogee shape design was developed to achieve high efficiency and required a weir width of 81m. For labyrinth weirs, a limiting factor to the allowable head is the ratio between the water head and weir height above its foundation apron. Using published state-of-the-art research, sixty labyrinth weir configurations were tested, with varying angles, leg lengths, and number of cycles. The optimal of these configurations was chosen as the one with the minimum overall spillway width and volume of concrete. This labyrinth configuration provided a spillway width of 64.45m, and a 22% potential reduction in concrete volume compared to the ogee. The labyrinth design was taken forward for CFD modelling to prove the concept and for further development into a detailed design.
{"title":"Efficiency of labyrinth vs ogee spillways at high hydraulic heads - case study in Zambia","authors":"Veronika Martin","doi":"10.1680/jdare.2024.8","DOIUrl":"https://doi.org/10.1680/jdare.2024.8","url":null,"abstract":"A new over-the-dam spillway and 3m dam raising was selected as the preferred option for resolving matters in the interest of safety for an existing dam in Zambia. The cost of supplying concrete at the dam site has the greatest effect on overall project capital costs, and thus optimising the size of the concrete spillway is critical. Both ogee and labyrinth weir designs were developed for a hydraulic head of 5m in the safety check flood. The ogee shape design was developed to achieve high efficiency and required a weir width of 81m. For labyrinth weirs, a limiting factor to the allowable head is the ratio between the water head and weir height above its foundation apron. Using published state-of-the-art research, sixty labyrinth weir configurations were tested, with varying angles, leg lengths, and number of cycles. The optimal of these configurations was chosen as the one with the minimum overall spillway width and volume of concrete. This labyrinth configuration provided a spillway width of 64.45m, and a 22% potential reduction in concrete volume compared to the ogee. The labyrinth design was taken forward for CFD modelling to prove the concept and for further development into a detailed design.","PeriodicalId":505716,"journal":{"name":"Dams and Reservoirs","volume":" 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141129671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dam T was constructed around 1880 as a water supply to Greater Manchester and is a Category A impounding reservoir, comprising an earth embankment with a central puddle clay core and storage capacity of approximately 934,000m3. It is one of the earliest dams constructed by Bateman and lies in a cascade of three reservoirs. As part of United Utilities (UU) Portfolio Risk Assessment (PRA) an Internal Erosion Toolbox, flood and slope stability studies were undertaken. These identified that the reservoir's primary failure mechanism was internal erosion through the embankment and presented an unacceptable risk. In order to confirm the conclusions and target a potential solution a Willowstick survey was undertaken which identified two potential seepage flow paths, one flowing into the existing outlet conduit upstream of the core and the other suggesting a compromised central core. This paper summarises the grouting works undertaken to target and remediate the potential core defect in a constrained and environmentally sensitive site. It highlights the benefits of collaborative working, supported by specialist contractors, the Qualified Civil Engineer (QCE) and catchment teams, the use of innovative techniques and lessons learnt from previous projects as well as the challenges presented by the proximity of the public and nesting birds. A total of 322,980 litres of grout was carefully injected into the Tube-a-Manchette (TAM) installations with the works completed in June 2023, two months ahead of programme and significantly below predicted costs, enabling the local walking routes to be reopened prior to the school holidays.
{"title":"A Moorland dam - remedial grouting works","authors":"Tom Rigby","doi":"10.1680/jdare.24.00011","DOIUrl":"https://doi.org/10.1680/jdare.24.00011","url":null,"abstract":"Dam T was constructed around 1880 as a water supply to Greater Manchester and is a Category A impounding reservoir, comprising an earth embankment with a central puddle clay core and storage capacity of approximately 934,000m3. It is one of the earliest dams constructed by Bateman and lies in a cascade of three reservoirs. As part of United Utilities (UU) Portfolio Risk Assessment (PRA) an Internal Erosion Toolbox, flood and slope stability studies were undertaken. These identified that the reservoir's primary failure mechanism was internal erosion through the embankment and presented an unacceptable risk. In order to confirm the conclusions and target a potential solution a Willowstick survey was undertaken which identified two potential seepage flow paths, one flowing into the existing outlet conduit upstream of the core and the other suggesting a compromised central core. This paper summarises the grouting works undertaken to target and remediate the potential core defect in a constrained and environmentally sensitive site. It highlights the benefits of collaborative working, supported by specialist contractors, the Qualified Civil Engineer (QCE) and catchment teams, the use of innovative techniques and lessons learnt from previous projects as well as the challenges presented by the proximity of the public and nesting birds. A total of 322,980 litres of grout was carefully injected into the Tube-a-Manchette (TAM) installations with the works completed in June 2023, two months ahead of programme and significantly below predicted costs, enabling the local walking routes to be reopened prior to the school holidays.","PeriodicalId":505716,"journal":{"name":"Dams and Reservoirs","volume":"135 24","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140668631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This briefing note summarises the current progress of ICOLD Technical Committee C – Hydraulics for Dams, which provides guidance on new developments in hydraulics for dams, including new types of spillways and energy dissipators. The note includes references to completed technical bulletins about to be published and details of one currently being drafted.
本简报概述了 ICOLD 技术委员会 C - 大坝水力学目前的进展情况，该委员会为大坝水力学的新发展提供指导，包括新型溢洪道和消能装置。说明中提到了即将出版的已完成技术公报和正在起草的技术公报的详细信息。
{"title":"ICOLD 2023, Gothenburg Sweden – Update on Technical Committee C","authors":"Viktor Pavlov, Paul Dickens","doi":"10.1680/jdare.23.00300","DOIUrl":"https://doi.org/10.1680/jdare.23.00300","url":null,"abstract":"This briefing note summarises the current progress of ICOLD Technical Committee C – Hydraulics for Dams, which provides guidance on new developments in hydraulics for dams, including new types of spillways and energy dissipators. The note includes references to completed technical bulletins about to be published and details of one currently being drafted.","PeriodicalId":505716,"journal":{"name":"Dams and Reservoirs","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139341223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This briefing note summarises the presentations given at Technical Workshop 4 held at the ICOLD 2023 conference. The workshop was titled ‘Operational Safety of Dams and Reservoirs’ and identified the need for systems thinking and systems engineering approaches in the management and analysis of the operational safety of dams and reservoirs.
{"title":"ICOLD 2023, Gothenburg Sweden – Report on Workshop 4","authors":"Alice Davis","doi":"10.1680/jdare.23.00301","DOIUrl":"https://doi.org/10.1680/jdare.23.00301","url":null,"abstract":"This briefing note summarises the presentations given at Technical Workshop 4 held at the ICOLD 2023 conference. The workshop was titled ‘Operational Safety of Dams and Reservoirs’ and identified the need for systems thinking and systems engineering approaches in the management and analysis of the operational safety of dams and reservoirs.","PeriodicalId":505716,"journal":{"name":"Dams and Reservoirs","volume":"72 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139341022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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