USCID fifth international conference

Presented at the fifth international conference on irrigation and drainage, Irrigation and drainage for food, energy and the environment on November 3-6, 2009 in Salt Lake City, Utah.Includes bibliographical references.The Logan and the Blacksmith Fork irrigation systems in the Cache Valley, Utah, convey water distribution through earthen canals. Previous researchers and local water masters reported the existence of seepage problems in these canals, but there is very little knowledge of the amount of seepage, and of the spatial locations and temporal variation of these losses. The present study provides a better understanding of the seepage behavior within and between these canals throughout the irrigation area, as these canals pass through a varying landscape, including agricultural fields, steep slopes, marshes, and residential areas. Measurements of the canal seepage were performed from June to October, 2008. The inflow-outflow method was used to measure steady-state seepage loss rates in selected canal reaches, using an acoustic flow meter. As a result, seepage gaining streams, losing streams, and gaining-losing streams were identified. Spatial and temporal variation of the seepage was observed. In this regard, spatial variation was observed along the canals whereby a descending trend of the mean seepage loss was found in the downstream direction. Spatial variation was also found between canals because the reaches on canals located in the eastern part of Logan City presented higher seepage losses than those of the canal reaches in the western part of the city. Moreover, temporal variations were identified in that a monthly comparison of seepage losses within reaches indicated higher seepage losses in late July and August. Additionally, comments about the performance of the acoustic flow meter are presented in this paper