WSP07313

• File Number: 8220.114.J
• Description: Dolores Participating Project
• State: CO
• Basin: San Juan/Dolores
• Water Division: 7
• Date: 7/18/1975
• Author: Mack/Lawrence - CSU
• Title: Evaluation of Potential Irrigation on the Ute Mountain Ute Indian Reservation as Part of the Dolores Project
• Water Supply Pro - Doc Type: Report/Study

of seepage from the canal increases to replace tqis moisture.
7~ The amount of sediment contained in wat.er--the larger the quantity

I

and finer the grade of the sediment, the greater is the sealing

~

'.

of the soil pores and consequent loweri~g of the seepage rate.

'8. . The depth of water flow in the cana1--the greater the depth the
higher the seepage rate.

9. The ground water level in the locality relative to the canal--the

gound water level controls the hydraulic gradient through the soil
and the hydraulic gradient affects the rate of seepage loss,

10. Other factors--percentage of entrained air in the soil, capillary

tension in the soil, barometric pressure and the chemistry of the

soil and water are some of the other factors which affect the perm-

e~bility of soil and ther~fore the seepage los~es.

2.8.2 Estimation of Seepage Losses from Towaoc Canal

The Towaoc Canal is expected to be earth-lined. A survey of the soil

profile along the proposed canal has not yet been made. Thus, accurate logging

.of the characteristics of the soil and expected earth-lining material are not

available and accurate determination of seepage losses is not possible at the

,
present time. Estimation of Canal 0 & M is also not possible at this

,

time.

/

Estimation of the seepage will be made empirically using the Moritz
\
formula (USBR, 1967; Kraatz, 1971):

S . 0.2 C IQJV

. (2.6)

where S = seepage loss in cfs per mile length of canal,

,

Q . canal discharge in cfs,
V .' mean velocity of flow in canal infi/sec, and

C . average rate of water loss (seepage) through the wetted surface of
the canal in ft3/ft2/day.

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