|
<br />:-::-:.
<br />
<br />00296J
<br />
<br />~'~.>;':.~.
<br />>:?':.."
<br />
<br />.-....,_..
<br />
<br />'..'
<br />:. ....
<br />
<br />1ft;}
<br />
<br />;~i/Ii1;
<br />.'~::~:::'~
<br />
<br />',...; .'
<br />
<br />Lake Granby and Willow Creek Reservoirs
<br />
<br />;. ,':'
<br />
<br />.-
<br />
<br />Lake Granby contained 499,000 acre-feet of water at the beginning of Water Year
<br />1971 which was nearly 130,000 acre-feet above the 10~year average. Storage in
<br />Willow Creek Reservoir was nearly normal, 9,500 acre-feet. Precipitation above
<br />Lake Granby was normal or better until early June and generally much below nor-
<br />mal thereafter until September when it was nearly normal.
<br />
<br />':..' '.
<br />
<br />~ .'~. .~.
<br />":;.::.
<br />....':..
<br />
<br />.-.......
<br />
<br />The snowpack above Lake Granby and Willow Creek reservoirs was about 12;; and
<br />115 percent of average, respectively, on Aprill. In view of the overall water
<br />supply. and utilization prospects on the Colorado- Big Thompson project, it was
<br />wisely decided to forego pumping of water from Willow Creek .Reservoir.. Con-
<br />trolled releases were made from Willow Creek Reservoir throughout the runoff
<br />season and there was no pumping to Lake Granby until August and September.
<br />
<br />~:;.'?::
<br />
<br />;>:;:l::'~
<br />
<br />;"
<br />" ,'.:'
<br />i"
<br />
<br />" ....
<br />
<br />~~fs~~
<br />
<br />Inflow to Lake Granby was normal or better throughout the year except during May
<br />and early June. Controlled release of anticipated surplus water was made from
<br />Lake Granby starting in May. Transfer of water to fill eastern slope storage and
<br />controlled release to the river lowered Lake Granby to a seasonal minimum con-
<br />tent of 423,000 acre-feet early inMay. With good snowmelt runoff, the reservoir
<br />filled to capacity early in July and remained virtually full throughout the month.
<br />Sustained high inflow of about 3,000 c. f. s. occurred for 10 clays late inJune with
<br />peak inflow of 3, 250 c. f. s.' on June 25. A total of 50,000 acre-feet of water in
<br />excess of project needs was released to the river at Lake Granby during the May-
<br />July period. Snowmelt runoff into Lake Granby amounted to 238,000 acre-feet
<br />which was 125 percent of average.
<br />
<br />t\fi:~?:
<br />::}~{.::
<br />~r:~~;:;~~t
<br />?:~~:;}\; ,
<br />(~r:MJ
<br />~~f};~~1;
<br />....,.1
<br />~~~
<br />\~h~~
<br />."':.....:...
<br />':"-'.,'.'
<br />':'.':~:'-~'-$::
<br />:.;....:: .~.::..:
<br />
<br />
<br />II
<br />
<br />
<br />~.:.. :.:. . .~.
<br />;<<7..':.
<br />:.-(.><~.
<br />:'.-.;.;....:
<br />
<br />With a near perfect water supply forecast, much of the above normal runoff was
<br />stored with controlled release to the river limited to 1,500 c. f. s. for a few days.
<br />This rate of release allowed about 3 inches of freeboard on the Colorado River
<br />at Hot Sulphur Springs' sewage treatment plant. Additional flow would have caused
<br />serious damage. This fortunate degree of regulation was achieved through excel-
<br />lent forecasts, early season preparatory releases, and District assistance in
<br />delivery of non-charge water to project users. Non-charge water is defined to
<br />be that water needed and usable by the crops which is declared to be available
<br />early in the season of good water supply years but which is not charged to the
<br />allotment previously declared. Total delivery in 1971 was only a 70 percent allot-
<br />ment or 0.7 of an acre-foot per share instead of the entitled 1. 0 acre-foot.
<br />
<br />.. '.
<br />;::;:..c';
<br />
<br />,.....
<br />
<br />Total water year inflow to Lake Granby amounted to 282,000 acre-feet which was
<br />121 percent of average. Carryover storage in Lake Granby at the end of the year
<br />was 518,000 acre-feet, the maximum of record.
<br />
<br />..........
<br />
<br />,.:;....-....
<br />
<br />'..
<br />rc:)
<br />
<br />
<br />12
<br />
<br />:. ~~...:'"I". ..:.....:. "': -~;';, ;.~-,:..:< ;' ~:. ;. .... ;:'-"~},::~./'. _ ._ '.". '. .. ..:) ... ~~ ,.~: ..~ ~:.': ~:."...-' ~~. ,.~ ')j' /; ~'.~.:....; '~:,.;^ ': .:'~ ,,<~~,..<.,.,>,~~.:,~'.- ';/-:~. :~.,..,.,..~:,..::...::....:.,..:'.:.::.'.....~....':~.':~ ;y.:.:~.:.., ,.
<br />','~;>:~;:::~ ;,"c':':;';:' "::';'~:<:'::,:;Sl~::;;'~~"~':{.;i::(;~:~::c~,":'i"~'~',,,?~i;i;:,;:;,~~::; i:~::::;:;::;;':'::";';. .. . ... . ..... '.. .: " '.: .."" .,...
<br />
<br />,_.,.0"
<br />
<br />'~-'.'~."<; ~
<br />
|