Mississippi Valley Association, Mississippi River Basin1945-03-01unknownhttp://rightsstatements.org/vocab/NKC/1.0/enghttp://congressarchives.org/record/CAC_CC_053_4_0000_1_90CHydrologic Map: This map illustrates comprehensive plans for soil conservation, irrigation, flood control, navigation, and related purposes, serving as the third in a series of three maps. Dimensions: 90C (based on ID reference).