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<br />MARCH 1981
<br />The d"~' WRl
<br />water JstnuutJOn system of the Pro"eel c . .
<br />ranging in capacity from 13 000 acre ft ~to 1530nOOOslsts Oftbfree major reservoirs
<br />188 600 000, " - ,acre. t (16 000 000 '
<br />, , m), In addItion Over 80 mil 12 ' , m to
<br />and inverted siphons provjd~ delivery es (, 8 km) _ of open canal, tunnels,
<br />cfs (0,2 m'ls to 42,0 m'/s)_ capacllles rangmg from 8 cfs to 1,500
<br />
<br />The demand curve for domestic water from h
<br />different shape in 1977 and 1979 d t e system takes on quite a
<br />, as compare to 1957 both' , ,
<br />(FIg, 8). A peak monthly demand for m "I ',m tlUle and quantIty
<br />10,000 acre-ft (12300 000 m3) ( wu,clpa -domestIc water service of over
<br />a minim " 110 mgd) IS not now uncommon In addifo
<br />um monthly demand of nearly I 000 aCre ft (I 200 ' ,In,
<br />is now being met from the system through'out the - t ' ,000 m ) (II mgd)
<br />W'thin h wa er year,
<br />1 t e system as now constructed is the ability to provide domestic raw
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<br />Commi!JSl1lJ1;Iws
<br />
<br />Year
<br />
<br />FIG. 7.-Colorado River Flows at 00t8ero. Colorado
<br />
<br />water service to Some 37 cities towns and a1 .
<br />facilities either by direct delivery' or b ' h mr domestic water treatment
<br />S' 1957 yexc ange through other systems
<br />it, :C~:ding ;w~~;~~e:::Si:::: t~Ot~: ~~tIwater delivery facilities added to
<br />to provide improved water delivery se . t et works of one of the reservoirs
<br />of tbe.se facility additions are in the r;;,:, :;0.::21 domestic entities. Most
<br />condUIt taps to the reservoir outlet d canal turnouts or closed
<br />. an power penstock works M t .
<br />Improvements were constructed to provide yea _ d . ~s project
<br />customer, as opposed to the 0 e r roun water service to the
<br />irrigation deliveries durino th p n canal and turnout system associated with
<br />. .-C e summer months only.
<br />Canal system mamtenance in the form flinin
<br />flume protection, and joint sealing we~e fo g replacem~n.t,. dragline cleaning,
<br />r years achVltIes that could be
<br />
<br />WR 1 WATER SUPPLIES 9,
<br />
<br />accomplished between late October and early May when the system was down
<br />The change in demand curve, as reviewed earlier, has in some years forced
<br />these activities into a much smaller time frame for completion, and to SQme
<br />degree has been responsible for an increase in District operations and maintenance
<br />staffing in recent years.
<br />Canal system water quality, in terms of chemicals used to control algae within
<br />the system. is now becoming a concern of some domestic water users taking
<br />delivery of their raw water supplies below the points of treatment. Since the
<br />late 1950s, the District has controlled algae by injecting copper sulfate inr0
<br />the canal systems. In recent years, most domestic water users on the system
<br />have requested that their delivery facilities be shut down when this maintenance
<br />procedure is being performed. Since the use of copper sulfate for algae control
<br />is a weekly occurrence between late May and early September, it has resulted
<br />in additional operations time required on the part of the operator in conjunction
<br />with the requested interruption of service.
<br />Some canal automation facilities have been added in recent years which provide
<br />
<br />TABLE 1.-Annual Cost Comparison, Windy Gap Project Versus CaT Project Water
<br />
<br />Project item
<br />{ll
<br />
<br />Windy Gap Project
<br />debt retirement and fixed costs
<br />CBT facilities char8e
<br />operations and maintenance
<br />power charges
<br />CaT Project
<br />53,000 X 0_07
<br />annual assessment
<br />
<br />T atal cost per
<br />acre-foot,
<br />in dollars
<br />(2)
<br />141
<br />
<br />Item cost per
<br />acre. foot.
<br />in dollars
<br />(3)
<br />
<br />80
<br />13
<br />6
<br />42
<br />
<br />217
<br />
<br />210
<br />7
<br />
<br />savings in operations man.hours and to some degree offset additional operator
<br />time now incurred in these added activities. Furthermore, many of the new
<br />domestic systems are metered and require only weekly or monthly inspection
<br />by the operator.
<br />The use of soil sterilants and herbicides along the canal system right~of.way
<br />(for the control of broadleaf weeds), and access road growth over the years.
<br />have also changed to some degree because of their threat to an ever increasing
<br />potable water supply and adjacent land development, The labeling and restricted
<br />use o( certain sterilants and herbicides as a result of the Federal Pesticide
<br />Act have forced the District and other water supply entities to utilize products
<br />that are either more expensive or less effective, or both, to control weeds
<br />within the canal right-of-way system,
<br />One of the greatest impacts on the system attributable to urbanization is
<br />that of urban development adjacent to the canal system itself, In the past decade,
<br />numerous subdivisions have been developed along canal rights.of-way, requiring
<br />major changes in right-of-way fencing requirements and policies, new public
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