| Construction
by November this year. After the diversion, the river will flow through the diversion system and re-join its natural course downstream of the main dam site. Construction work is currently progressing on 13
different sites at the project. The upstream starter (coffer) dam to facilitate river diversion under stage-1 has been completed, while work on the downstream starter (coffer) dam is going on and expected to be completed by November for stage-1 diversion. Diamer Basha Dam has a gross water storage capacity of 8.1 MAF to irrigate 1.23 million acres of additional land. Power generation capacity of the project stands at 4,500MW, with annual energy of 18 billion units green and clean hydel electricity. A sum of Rs.78.5 billion is being spent on resettlement of affectees and CBMs in health, education and infrastructure development. The dam has however not been without incident. On 7 April an incident at the site claimed the lives of three workers and injured others.
Dam raise Global infrastructure company Acciona recently
celebrated a significant milestone in the Carén reservoir expansion project in Chile. The completion of the dam’s construction, symbolized by its topping out, signifies a major achievement for the project. Awarded the contract for the expansion of the Carén
reservoir’s seventh stage by Codelco’s El Teniente Division in December 2021, Acciona continues to add to its extensive portfolio of projects with the national mining company. Currently engaged in underground works at the Chuquicamata mine and at Rajo Inca in the El Salvador Division, Acciona’s involvement in the Carén reservoir expansion further solidifies its presence in the region. Located in the municipality of Alhué, within the
Metropolitan Region of Chile, the Carén reservoir expansion project necessitates the execution of various civil works. The primary objective is to increase the reservoir’s earthen wall height by 62m, from 175 to 237m, while reinforcing it by 32m from elevation 128 to elevation 160. The construction process focused on moving earth with different grain sizes and plasticity, utilizing materials from both existing quarries within the project and external sources. Each material served a specific function, ranging from impermeable material to core fill and filter material, meticulously arranged vertically along the entire length of the dam. Spanning nearly 23,000 hectares, the Carén
reservoir is an integral part of Codelco’s El Teniente Division’s production system. Its expansion supports the division’s ongoing efforts to enhance the efficiency and capacity of its infrastructure, contributing to the sustainable growth of the mining operations. With the Carén reservoir expansion project nearing completion, Acciona looks forward to the positive impact it will have on the local community, the mining industry, and the region as a whole. Over in the US, the US Army Corps of Engineers Sacramento District is moving forward with the Folsom Dam Raise Project to help further reduce flood risk in the Greater Sacramento area. The overall project includes the following authorized components: a three-and- a-half foot raise of the Folsom Facility dikes, Mormon Island Auxiliary Dam (MIAD), Left Wing Dam (LWD), and Right Wing Dam (RWD), along with modifications to the
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main dam’s Tainter gates; construction of automated temperature control shutters at the main dam to benefit American River fisheries, and; habitat restoration at two sites along the lower American River - Bushy Lake Restoration Site and Woodlake Restoration Site. The overall project also included construction of the Folsom Dam Bridge, which was completed in 2009. In April this year, Folsom Dam Constructors (FDC), a joint venture between California Engineering Contractors, Inc. and Shimmick Construction Company, was awarded a $114.4 million construction contract by the US Army Corps of Engineers Sacramento District for the Folsom Dam Raise project. Under this contract, Folsom Dam Constructors will undertake the task of raising the main dam, as well as the left and right wing dams, by up to 3.5ft. Additionally, they will be responsible for modifying the eight spillway gates by adding top seals, reinforcing the gates, and raising the gate piers. These enhancements will significantly improve the control over water releases from the dam during large flood events and expand the temporary storage capacity of Folsom Lake. This increased capacity will help mitigate flooding in the greater Sacramento area, benefitting around 500,000 residents and safeguarding approximately $58 billion worth of assets downstream. Elvan Childs, the USACE project manager, expressed
his team’s dedication and excitement, acknowledging that there is still much work ahead. This contract award marks the culmination of several years of effort. The Folsom Dam Raise project builds upon the
progress made by the Joint Federal Project (JFP) initiated by the U.S. Army Corps of Engineers and the Bureau of Reclamation, which operates the Folsom Dam facility. The JFP’s primary objective was the construction of the Folsom Dam auxiliary spillway, which was completed in 2017. In 2020, the first phase of the project involved raising Dike 8, located on the southeastern side of Folsom Lake, by 3.5 feet. The subsequent stages of the project will include raising the remaining seven dikes and the Mormon Island Auxiliary Dam, as well as reconfiguring the Folsom Dam penstock gates by integrating modernized temperature control shutters. The anticipated completion date for the Folsom Dam Raise project is 2027.
References
1. 2023 World Hydropower Outlook
https://www.hydropower.org/ publications/%202023-world- hydropower-outlook
Below: Folsom dam aerial. Photo by Michael Nevins. The USACE is moving forward with a project to raise the main dam to help reduce flood risk
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