| Abstract/Description or Keywords |
Project background and objectives: In the Cariboo region, agricultural dams play a significant role in retaining water for agriculture during the production season. With the effects of climate change on hydrology and temperatures, ensuring sustainable water supply for agriculture will become increasingly critical in the future. However, in recent years challenges have emerged related to maintaining accessible, reliable water sources and meeting dam safety requirements under the B.C. Dam Safety Regulation. The underlying goal of this project is to help to ensure the availability of sustainable and adequate water supply for future agricultural production in the Cariboo region. In the interests of supporting this goal, the project objectives are to: 1) Improve the knowledge of the existing agricultural dams, with regards to their status, condition and associated issues; 2) Identify potential cost and risk-__sharing models for inspections, upgrades, and maintenance of agricultural dams; 3) Outline collaboration and partnership opportunities to address the requirements for dam safety and sustainable agricultural water supply; and 4) Identify, describe, and document the co-__benefits associated with maintaining and enhancing agricultural dams. While the issues with agricultural dams and their safety are pressing, it was not the purpose of this report to provide direction or to be definitive in terms of the issues, options and next steps. The report is intended to support a constructive dialogue amongst dam owners, relevant agencies and potential partners about how best to address the issues and challenges related to agricultural dams. It is hoped that the report will support the necessary near-__term actions, starting with a workshop to bring together Cariboo dam owners, related agencies and partners on November 25, 2015. Project scope: The scope of work for this project included an inventory of agricultural dams within the region and consultation with local stakeholders (i.e. local producers, provincial government agencies, and Ducks Unlimited Canada) to assess the magnitude and nature of issues and challenges. Also included is an analysis of how climate change will impact agricultural dams and a summary of the various costs associated with the regulatory requirements for dam owners. In addition, potential solutions for the identified challenges are explored, along with options for sharing risks and costs associated with agricultural dams. The project scope did not include detailed assessment or inspection of individual agricultural dams. Project scope also didn’t involve evaluation of the physical infrastructure or technical issues with individual dams. Therefore, the study does not provide solutions that are specific to individual dam owners and instead focuses on shared issues and concerns. The scope did not include evaluation of the provincial B.C. Dam Safety Regulation or the B.C. Dam Safety Program. Climate change & agricultural dams: Some of the anticipated impacts of climate change to the Cariboo region’s agricultural dams are summarized below. More details may be found in the full report. _ Higher temperatures and longer dry periods during summer are likely to decrease water supply and increase the need for water storage and yield capacity of agricultural dams. _ Higher temperatures and less frequent precipitation are anticipated to increase the risk of wildfire events. Wildfires can have long-__term impacts on soil, vegetation and runoff hydrology in watersheds and fire-__fighting could compete for water supplies. _ The timing and volume of peak runoff flows may have negative impacts on agricultural water storage, as the early season flows may not coincide with the growing season. _ Earlier and greater freshet flow is expected to result in increased flooding, erosion, debris supply, and channel changes. _ Greater freshet flows could lead to increased flow requirements for spillway capacity and dike crest elevation. _ increased variability and changes in timing of streamflow may make operation of dams more difficult. This is most likely to occur where dam operation is integrating multiple objectives such as flood control, habitat (water fowl, fish, amphibians), recreation, irrigation and/or livestock water. Requirements of dam ownership in .C.: The full report includes a high level summary of dam safety regulations in B.C. including the definition of a dam, the requirements of a Dam Safety Management System and the frequency of associated activities. A series of tables outline the range of potential costs associated with the following aspects of dam ownership: • Cost estimates for the operation and maintenance typical earthfill dams with different consequence ratings • Costs of additional studies and investigations potentially required during detailed Dam Safety Review for High and Very High consequence classified dams • Costs for upgrades based on generic deficiencies potentially identified through a DSR, dam audit, or routine surveillance and maintenance. Inventory Summary: The inventory includes 403 dams. Of these, the majority, or 60%, have a low consequence classification. Another 20% have a significant classification, and 8% have high classification, while two dams (.5%) have a very high classification. The remainder are either undetermined (6%) – indicating that it’s likely that the dam does not meet the definition covered of a dam under the current regulation – or unknown (5%), meaning that consequence information is not available. Priority issues & potential solutions Agricultural dams in the Cariboo region are diverse with respect to location, age, condition, consequence classification and available water yield. Although each dam is unique, through the inventory, consultation and background research, a series of common issues emerged; primarily pertaining to meeting the requirements of the B.C. Dam Safety Program or to water yield. The priority issues and potential solutions have been divided into the following four categories: 1) Dam Safety Management System, 2) Dam Operation, Maintenance & Surveillance, 3) Dam Safety Reviews; and 4) Water storage. The tables that follow summarize the more detailed descriptions of priority issues and solutions provided in the full report. |
