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<br />~~~~~~~~~~~~A-~~~~.~~~~~"f~'
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<br />120
<br />
<br />CALlFORNU, FISH .~ND GAME
<br />
<br />tieadgate Rock Dam to Parker Dam (15 miles)
<br />
<br />Thi!l dam (1941) was constructed by the United States ~ndian ~en-ice and
<br />supplies irrigation water to the Colorado River Indian Reservation. W1th an ulti.
<br />mate diversion capacity of 2,100 c.f,s" only 200 to 300 c.f,s, are expected to bi used
<br />for several years. Tbe dam is merely a series of radial ~ates ~nd onl~ enough. of tbese
<br />are lowered to bring water into the canal. Only at low, flows 1S the ~lver backed up to
<br />any extent and even then no lake is formed. The dam has but httle effect on tbe
<br />fishery except in its creation of some favorabl,e Sl)ots to fish, ,
<br />From here to Parker Dam the stream 1S rather constncted but has a few allu.
<br />vial flats, The clear water is an astonishing sight to those wbo have known only the
<br />muddy Colorado.
<br />
<br />Parker Dam to Topock (Lake Havasu and Monav. Canyon) (42lni1e.sl
<br />
<br />This dam raises the water level j2 feet to form Lake Havasu. Discharge here
<br />is through spillway gates of the Stoney type, &Orne of which are always open, anu
<br />from a powerhouse. .
<br />Built bv the (jnited States Reclamation Service in 1938 W1th funds from .tbe
<br />Metropolitan 'Water District of Southern California, it ,is o~rated by. the Federal Gov.
<br />ernment at the District's expense. Its primary functlOn 1S to pronde water for tbe
<br />District's Colorado River Aqueduct. Other functions are reregulatio~ of tbe flow
<br />from Boulder flood control (of the Williams River) and the generation ?f power,
<br />The beadworks for the aqueduct (Intake Pumping Plant) is abo,ut two mile~ a\).)\,e
<br />the dam. From here water is carried through a series of pump-hfts, reservOl:-s.. ann
<br />conduits acros.., the deserts and mountains to supply Los Angeles and other cIties of
<br />southern California. '
<br />One tributary of intermittent flow, the Williams River, enters from the Arizona
<br />side just above the dam. Like the Gila it usually has no effect upon the Colorado, but
<br />flash floods of great intensity occasionally occur.
<br />
<br />FIG, 52,
<br />
<br />Headgate Rock Diversion Dam, upstream ,:Iew. photograph thruugh
<br />courtesy of U. S, Indian Service.
<br />
<br />
<br />T HE FISHERY OF THE LOWER COLORADO RIVER
<br />
<br />, ,vasu is a long and narrow reservoir but has an irregularshor1!line with malii
<br />.d coves. Due to the current peI'1iisting throughout ia course it is better termed
<br />he.ri"er lake than a lake in the sense,nf lAIkeM~d,__ HQwever, its expansions -- __._.._.::I__::~::"'::
<br />, swells out into old "alleys give it large, quiet water areas. ' Therelativec---
<br />!l of its fluvial and lacustrine characteristics await further stud:v,
<br />J full capacity (elevation 450.54 feet) it bas an area of 25,000 RereJi! and
<br />l1i,OOO acrc-ffoet of water.Witbthe spillwaygateselosed,the depth of the lake
<br />is 75 feet; 25 feet with the gates open. ' ., '''''' '
<br />
<br />'53, Upstream view of Parker Darn. Foundation for
<br />power house on left. Photograph by D. A. Clanton, Ja.n.
<br />25, 1939.
<br />
<br />:refficient pumping into the Col<,rado River Aqueduct the water surface should
<br />.,' ed between 440,54 and 450,54 feet. Therefore, under a contract between
<br />]ijlOlitan Water District nnd the United States, the Federal Government pos-
<br />ly the limited right to regulate the top 10 feet of storage except with the per-
<br />'9f the District or in case of an emergency. While even this limited fluctuation
<br />,;'l:armful to fish at times, it can in no way be compared to the excessive f1uctua-
<br />"d in so many western reservoirs,4 However, for various reasons the elevation
<br />.ie)Iavnsu has dropped below 440,54 feet several times since 1938, the lowest
<br />,D:bcing 412,09 feet ('n June 2;:), 1942, ~ot until October 11. 1942 did it again
<br />.54 feet and it has been above that stage since. In 1M3 the regulation of
<br />ter surface "as Yery favorable for fish, The resen-oir rose from 441 feet in
<br />:muary to 4;:;0 fHt by the first of April. It maintained a level between 450
<br />',.feet for over four monlhs and then gradually descended to an elevation of 44,'5
<br />.end of December. A favorable regulation is 0.11:'0 expected in 1944 with the
<br />Jf:Vel being raised by easy sta~es to 449 by May 1st and possibly to elevation 450
<br />__ eand July, Following July it will probably be lowered at about the same
<br />,",hi 1943. Tile continuance of such regulation should ensure successful repro-
<br />;~bass and sunfishes in this res~rvoir. insofar as it is governed by changes in
<br />
<br />eh'of the immediate shoreline and bottom is composed of small rubble, gravel,
<br />-,-There are patches of cattails, and a relatively narrow fringe of tamarillk
<br />. " ,1'00 grows in some places just at the highwater line. Otherwise, the
<br />g land vegetation is scanty and typical of the desert. Near the old river
<br />, ere still persist the submerged trees which once bordered it. Drowned trees
<br />b8i1re also found in the shallow waters of some coves. Naja, was the only
<br />~ plant seen in 1942 and is said to be increasing rapidly.
<br />ve the dam the lake is typically from one-half to a mile in width until it
<br />e, oldChemehue~'i Valley 20 miles upstream, Here is its greatest expansion
<br />miles; and here, at Needles Bont Landing, is the largest "resort" area
<br />
<br />example, Lake Mead has a. ... postulated annual water level ftuctua-
<br />,feet. - - ... according to Moffett (1943), The new Millerton Lake on the
<br />U1n River in California is expected to have an annual tluctuatlon of over
<br />'en in the most favorable years.
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