<br />.Water in the Balance.
<br />
<br />Colorado's Typical Wet and Dry Seasons by Basin
<br />
<br />II is common and necessary practice in watershed management to combine data from an entire basin including both
<br />high and low elevations. II is important to recognize, however, that the seawnality of precipitation may vary greatly
<br />within each basin, and that precipitation at different times of year across the basin may not be well correlated.
<br />
<br />For many water management and planning applicalions, Colorado is divided into seven walerdivisions (see figure).
<br />Each of these basins originate in high mountain environments and descend through mountain valleys and eventually
<br />drop to mUl;h lower elevations. Thus. we can roughly divide each basin into an upper and lower basin based on
<br />approximate elevation and mountain proximity. The table below is not definitive. but is meant to give a general picture
<br />aflhetypical wct and dry periods experienced across Colorado. W t D'" V
<br />Water Di~'ision I a a H'/SlOn
<br />South Platte. Upper; Wet Dec.-Apr.. Drv June and again in CoIorndo. Upper: Wet late Nov.-Apr., Dry Jun-mid-Jul.
<br />Aug.-Oct. - Colora~o. Lo"er: On a.verage. there is nocle~wetordry
<br />South PI. It I - . . "'-. N -F b '" < A -J 1 season In the lower portion of the Colorado RIver baSin,
<br />, a e.L.U"er.V1Y av. e., we pro u. . ' .
<br />Water Di\'ision II Water Dn'l$lOn VI
<br />Arkansas. Upper: Wet Dec.-Mar., Jul.-Aug., Dry (al the Yampa-White, Up~r: Wet lale~ov.-M~y, ~ ~id-Jun.-
<br />highest mountains) May-Jun. Scpo (NOTE: The high mountains OflhlS ba~1n Include
<br />Arkam;a.... Lower: Dry Nov.-Feb.. Wel !\1ay-Aug. some of the wel~est areas of.the state, receiving an average
<br />mUer Di\'ision III of more than 50 m/yrofpreclpltatlon.)
<br />RioGrnnde. Upper; Wet O\."C.-~lar. and mid-Jul.-early Yampa-While.lo"er; Similar to the lowerponion of the
<br />Oct.. Dry May-mid-July. Colorado River Basin. with no clear seasons, and less
<br />R. G d' -, - Dry Nov.A W' <nu'd.J 1_"'- likelihood of receiving rain from the summer monsoon.
<br />10 rnn e. L.U"er. . pr., e u ,'>I;p.
<br />(NOTE: The San Luis Valley. which includes Great Sand \VOla Division VII
<br />Dunes National Monument, receives the least precipita- San Juan, Upper: Wel ~.-:vIar. ~d late Jul-early-OcL,
<br />tion in the state, wilh an annual average of less than eight Dry May-early Jul. and mld~Oct-mld-Nov. (NOTE: lbe .
<br />inches of precipitation.) high moun tams of thiS ha.<;m are also among the wettest In
<br />Water Dil'ision 1\' Ihe Slale, recei\'ing more than 50 inlyr a\'erage annual
<br />Gunniwn. Upper: Wel mid-Nov.-Mar., Dry mid-May-mid- precipItation.)
<br />J San Juan. Lo"'er. Wel Dec.-Mar. and lale Jul-early-Oct..
<br />"U,
<br />Gunnlo.on. Lower: No significant wet sea.\on. Dry laic Dry May-early J~1. and mid-Oct-mid-Nov, (NOTE: similar
<br />May-Jun, slightly wet mid-Jul-Aug to the upper basLn. but less wet m the wet seasons.)
<br />
<br /> SubbasLn ,,, F,b Mar A , ..ta )" )" A, S, 0" NOli Do<
<br /> Up. S Plalle ~~_...~.....-....~......_....-.-_..
<br /> ---
<br /> Lo_ S Plalle - -
<br /> -- -
<br /> Up, Arkan5u ~ - ~
<br /> -- -
<br /> 1.0. Arkllns.1s ~-~-~--""'!"-~
<br />I Up, Rio Gr. ~
<br /> - -- - --- -
<br /> 1.0. RIO Gr. Kf-....~
<br /> ,
<br />,
<br /> Up. Gunnison ~ c::=o I I ..-.......---:.
<br /> ,
<br /> Lo. Gunnison I I J I
<br /> ~
<br /> Up. Colorado -- - --- I """"""'"
<br /> Lo, Colorado I I
<br /> ~oelur"'elo'dr~ .elloDl
<br /> Up, Vamp' ~"''''-~'='''~~---j'- ....1 ~_.....,
<br /> Lo, YJmpa I I I I :'<odul "'elordr~ .ellon.
<br /> Up, S" Juan ~ ~ S ~:.-=.~
<br /> Lo, S" JUJn L h.:t...__~_"'..."...~ ~
<br /> ~ "'--_.t-
<br /> , ~ ' , , , , , , , ,
<br /> Legend: Wet ~_-....-- Dry , , I
<br />
<br />10
<br />
|