Show LOSS OF CANAL WATER too steep grades are sometimes responsible for leaks when ditches are built through gravelly soils seepage losses are naturally heavy unless measures are taken to prevent there Is not an irrigating canal in this country from which there Is not more or less loss 0 water in transit these losses are generally spoken 0 as caused by seepage and evaporation however it has been demonstrated that the evaporation losses as compared to those caused by seepage are so light that they may be disregarded the loss by seepage unusually occurs from the character 0 the soil through which the canals run says the denver field and farm when this Is a finely divided sandy loam such as occurs in many places the losses from this cause are generally light but when the canals are built through soils which are very gravelly or perhaps nearly pure gravel the seepage losses are naturally lly very heavy unless astren bous measures are adopted to prevent them in other places much water is lost along parts of the canals where abo excavation has been through seamy basaltic rock or decomposed sandstone too steep grades sometimes are responsible or much seepage this condition la found on some ol 01 the smaller early ditches built through gravelly soil we have heard it argued that when the water Is to be conducted through gravel or a porous forma tion it should go fast but in canals built on this theory the velocities ara bubli as to prevent silting of the chan nels and thus actually promote seepage in the construction of canals many fills are made across short gul lies or depressions where to follow the contour of the land would lecessi ate wide detours and frequently the upper banks are either omitted or destroyed which allows the water to spread out over the land above the canal and form lakes in cases where the fills are of considerable sid erable height quite large areas of land are sometimes flooded and below such lakes are invariably found heavy seepage losses large enough often to run in small streams away from the canal to prevent these losses the upper banks of the canals have been built up so as to prevent the forma tion of the lakes on the canals where the difficulty la due to gravelly boll it has been the practice to some extent to excavate a toot or so below grade and then fill in with clay or fine material so as to form a puddle the clay Is camped tamped in the bottom and then the bottom and sides are plastered several inches thick with a mortar formed of the clay in plastic state this Is then covered with a layer of gravel to prevent washing the results of this work are quite satisfactory but it Is difficult to find suitable clay tor the purpose and cement has to be used which Is more ex pensive but considerably more durable some measurements have been made on our canals to learn the extent of seepage but on the smaller ditches it Is almost impossible to get any reliable results on account of the numer ous diversions which there is no satisfactory is means of measuring and if these are shut off along a stretch two or three miles long the extra water hlll cause such a rise in the canal be low as to be dangerous the loss oft en amounts to fifty per cent and this Is more than any business can stand |