Seepage losses from irrigation canals in southern Alberta

摘要

Ponding tests were performed in 11 irrigatic districts in southern Alberta to determing seepage rates in soils of different textures. Seepage rates were determined for three soil textural groups: fine-, medium-, and coarse-textured soils. These seepage rates were used to calculate the seepage rate per segment of canal for use in the Irrigation District Model. The AGRASID database, the primary source of soils information, was used in conjunction with a GIS and the Irrigation District Model to estimatethe total volume of seepage within the irrigation districts. Results indicated that seepage volumes were significantly less than estimated earlier. Estimates made in 1991 indicated that about 15% of the proposed total licensed allocation was lost from irrigation district canals (seepage and evaporation), whereas the volume of water lost to seepage within the irrigation districts in 1999 was about 91 x 10~6 m~3 or 2.5% of the total licensed allocation proposed in the 1991 regulation. Canal rehabilitation has played a significant role in reducing seepage in conveyance works, making seepage losses a negligible factor in canal operations. Seepage losses will likely be reduced even further in the future as irrigation districts continue to modernize their conveyance systems.