Thesis - Open Access
Master of Science (MS)
In recent years, drainage has been recognized as essential to the development of a large-scale irrigation project. South Dakota is now planning for the irrigation of approximately one-half million acres of land through the proposed Oahe Irrigation Unit located in the northeastern part of the state. There are two main bodies of land in the Oahe Unit – the Lake Plain area which is the postglacial “Lake Dakota” and the larger portion of the project, and the Missouri Slope Area which is part of the Great Plains province lying east of the Missouri River. A large percentage of this project’s total developmental cost will be for tile drainage. The principal function of tile drainage is to control water table levels. The Bureau of Reclamation in the 1965 Oahe Unit Report (21) recommends that tile drains be placed from 6 to 12 feet in depth with spacings from 400 to 900 feet in the Lake Plain Area to control water table levels. These tile drains will range from 4 to 6 inches in diameter. The soil textures prevailing at the 6 to 12 feet depth in the Lake Plain Area are silt loam, silty clay loam, sandy loam and silt. Silt is the most predominate base material for the tile drains. To ensure a longer life for the tile-drainage system, it is often necessary to place a more permeable backfill material than the base material around the tile drain. This material, placed on either the top, bottom or sides of the drain, singularly or in combination, is called an envelope. The three-fold purpose of an envelope is a follows: 1. To exclude fine soil particles from moving into the drain and resulting in clogging. 2. To increase the effective drain diameter by providing a highly permeable zone around the drain. 3. To serve as a stabilizing foundation for the drain.
Library of Congress Subject Headings
South Dakota State University
Bucks, Dale A., "A Gravel Envelope for a Tile Drain in a Coarse Silt Base Material" (1968). Electronic Theses and Dissertations. 3421.