led ▁to ▁the ▁Colorado ▁River ▁Valley ▁with ▁about ▁ 8 0 0 ▁people , ▁almost ▁a ▁fifth ▁of ▁the ▁entire ▁Moh ave ▁Nation . ▁General ▁James ▁Henry ▁Car leton ▁thought ▁a ▁res ervation ▁was ▁unnecessary , ▁and ▁engineer ▁H erman ▁Ehren berg ▁disag re ed ▁with ▁Post on ' s ▁proposed ▁location ▁on ▁the ▁basis ▁that ▁the ▁soil ▁was ▁too ▁al kal ine ▁for ▁far ming , ▁the ▁need ▁for ▁ir rig ation ▁too ▁great , ▁and ▁the ▁task ▁of ▁raising ▁the ▁river ▁too ▁ins ur mount able . ▁Non eth eless , ▁on ▁March ▁ 3 , ▁ 1 8 6 5 , ▁ ▁Congress ▁established ▁the ▁Colorado ▁River ▁Indian ▁Res ervation ▁at ▁Post on ' s ▁proposed ▁location . ▁Ehren berg ' s ▁concerns ▁proved ▁valid , ▁and ▁neither ▁Post on ▁nor ▁any ▁subsequent ▁US ▁authority ▁was ▁willing ▁to ▁dedic ate ▁the ▁considerable ▁resources ▁required ▁to ▁make ▁the ▁location ▁suitable ▁for ▁far ming . ▁The ▁res ervation ▁was ▁established ▁without ▁a ▁treat y ▁having ▁been ▁established ▁between ▁the ▁Moh ave ▁and ▁the ▁US ▁government . ▁▁ ▁The ▁boundaries ▁were ▁expanded ▁and ▁clar ified ▁by ▁executive ▁orders ▁issued ▁by ▁ ▁President ▁Grant ▁in ▁ 1 8 7 3 , ▁ 1 8 7 4 ▁and ▁ 1 8 6 7 . ▁ ▁Most ▁of ▁the ▁Moh ave ▁refused ▁to ▁leave ▁their ▁ancest ral ▁hom el ands ▁for ▁the ▁res ervation , ▁but ▁I rat aba ' s ▁conv iction ▁that ▁the ▁res ervation ▁was ▁their ▁best ▁option ▁marked ▁the ▁beginning ▁of ▁a