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12 Special Series: What the Heck Should Be in My Spec? Part 1: Earthwork Considerations A thorough set of technical specifications for any dam construction project helps ensure the owner and regulator that the desired product is attained, provides the contractor with a clear understanding of requirements for bidding, and helps reduce risks for construction claims. There are many considerations for technical specifications that are unique for dam construction projects. In this special series we will present some of the key topics that are distinctive and important for dam specifications through a series of 3 articles: 1. Earthwork Considerations 2. Dewatering and Diversion – Writing “team effort” specifications. 3. The Devil is in the Details – specification tips to make your construction project move ahead smoothly Purpose of Technical Specifications Technical specifications, along with the design drawings, are the guiding documents which enable the project to be constructed according to the intent of the design engineer. They provide a roadmap of sorts for the appropriate procedures and processes to be used to achieve the desired end result. Technical specifications, when properly tailored specifically to the project for which they were written, will provide an enveloping description of how the works shown on the construction drawings are to be assembled and any special considerations and conditions which are not readily shown on the drawings. The technical specifications serve the purpose of explaining the drawings, and ensure that a detailed set of instructions are documented for the purpose of implementing dam construction projects in accordance with the current state of practice for civil engineering work involving dams. It is oftentimes true that both design engineers and contractors will devote the vast majority of their attention to the development and understanding of the detailed construction drawings for a project, while the technical specifications are seemingly relegated to a lesser position of importance. However, construction contracts are almost invariably written stating that, in the event of inconsistency or disagreement between the drawings and specifications, the written specifications take precedence over the drawings. For this reason alone, it is imperative that the technical specifications be written specifically and accurately for the project at hand, and be unambiguous in their content and meaning. The use of broadly-based, standard earthwork specifications which may be based on other forms of heavy civil construction, such as highways or support of structures, may result in rejection by the regulatory agency having jurisdiction, conflicts during construction, or worse yet, a constructed project which utilizes inappropriate construction techniques and methodologies rather than the original intentions of the designer. This first article of the series will focus on specifications requirements common for earth materials in dam construction. Filter Placement Filters and drains are placed in embankment dams to provide for the safe transmission of seepage water through the dam and out the downstream side. As such, they are placed on the downstream side of the impervious portion of the dam, which is constructed of fine grained soils and is referred to as the core. Filters are used to protect the core from movement of soil particles due to seepage forces, while providing some measure of drainage ability. Drains are designed for the removal of water, so must be relatively free- flowing and designed to prevent the migration of granular filter particles into the drain. Design and construction considerations of filters were discussed in Issue 1, Volume 1 of this Technical Note publication (March 2013). Four primary items are generally specified in contract documents that relate to construction of filter and drainage zones: