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<br />cross slopes and there is no safety problem., This would indicate
<br />that lining of these sections would not be needed for safety reasons.
<br />
<br />Another consideration to be used.to determine the need for
<br />extensive lining is the seepage losses from the canal. The water
<br />supply section of the annual project crop reports for the project
<br />showsan average seepage loss of about 4.2%. To verify this low
<br />reported loss the Bureau with cooperation of the Fire Mountain Canal
<br />Company made inflow outflow measurements on October 4 and 5, 1971.
<br />Measurements were made each of the two days and average seepage loss
<br />. measured was slightly less than 4%. The loss under actual operating
<br />conditions could be greater than that measured, probably about 5%.
<br />
<br />: .
<br />
<br />When the canal is at full capacity of 160 c.f.s., it would lose
<br />.8 c,f.s. or .27 c.f.s. per mile. This would be .22 cubic feet per
<br />square foot of wetted area per day. To justify lining, a loss of
<br />.50 or above is needed. As localized seeps develop and are located,
<br />the short sections of canal involved can be lined as part of the
<br />continuing maintenance program of the canal company.
<br />
<br />"
<br />
<br />As agreed at our meeting with the District and Company.Directors
<br />.onthe 25th of June 1971, Bureau personnel made a detailed inspection
<br />of the Fire Mountain Canal. This inspection was initiated on Septem- .
<br />ber 21, 1971, and completed October 22, 1971. On September 21 and 23,
<br />the canal was carrying about 165 c.fos. at its head and about 100 c.f.s
<br />at the Leroux Creek crossing and on October 21 and 22 water was out.
<br />
<br />j .
<br />
<br />Two days were spent inspecting the canal .whi1e it was full of
<br />water and 2 days were spent on the canal with. water out. To assist
<br />with details of the inspection, the station to station acount,
<br />included as appendix material to the District Report of May 28, 1971,
<br />was used along with aerial photographs with scale ofl inch. equals
<br />1000 feet to locate problem areas along the canal. Tracings of the
<br />canal location were made from eight aerial pictures and the conditions
<br />of the canal have been noted on the tracings. Copies of the tracings
<br />reduced to a scale of about 1 inch equals 2,000 feet are in this re-
<br />port on pages. 2'5 to .30. Typical canal sections were photographed
<br />on October 4 a~ while water was in the canal and on October 21 and
<br />22 when water was out. Prints of some of these pictures are included
<br />in this report, on pages /3 ,to: 2? .
<br />
<br />Picture No. P551-427-146, taken at approximately station 24+00,
<br />shows a section of the canal in which the District proposes concrete
<br />lining. The picture shows the canal section to be wel1al'mored .with
<br />rock and in relative excellent condition. This section will provide
<br />water delivery service with only minor maintenance. This section
<br />may have some seepage loss but this is rioprob1em because the seepage
<br />water returns to the river immediately so that it is available for
<br />diversion from .the river to meet senior downstream water rights.
<br />During the future.years, minor amounts of coarse gravel protection
<br />Will. be needed on the bank on the outside of curves in this section
<br />of the canal.
<br />
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