FLOOD02643

• County: Denver
• Community: Northeastern Colorado
• Stream Name: South Platte and Tributaries
• Basin: South Platte
• Title: Post Flood Report South Platte Floods of May-June 1973
• Date: 7/1/1974
• Prepared For: State of Colorado
• Prepared By: US Army Corps of Engineers
• Floodplain - Doc Type: Flood Documentation Report

V II . FLOOD DAMAGE

27. SCOPE: OF FLOODING

a. In the South Platte River basin, flooding extended
from Littleton, Colorado north and eastward to the Colorado-
Nebraska 'border, a distance of about 317 river miles. The
main stem of the South Platte River went out of its banks from
Douglas County, located direct~ south, or upstream, of the
Denver metropolitan area, and crested in Denver proper during
the late evening of 6 May and the ear~ morning of 7 May. Many
tributary streams of the South Platte River contributed to the
flood. Left-bank tributaries originating in the higher eleva-
tions along the Front Range of the Rockies were fed lJy snowmelt
and by rainfall runoff as they moved toward the heart of Denver.
Bear Creek, Clear Creek, and their tributaries affected flood
stages in Metropolitan Denver; farther north, other left-bank
tributaries, such as St. Vrain Creek and the Big Thompson and
Cache :La Poudre Rivera, contributed to floodflows along the
downstream reaches of the South Platte River.

b. Although information is not available on tributary
inflow downstream frOIlJ. the Cache la Poudre River, the rainfall
pattern shown on plate 3 of this report indicates that right-bank
tributaries, such as I3oxelder, Kiowa, Bij ou, and Beaver Creeks,
probably contributed to the flood runoff as a result of the
7 May rainfall. The South Platte River crested at Denver about
1 a.m. on 7 May; gaging stations all along the river, from
Littleton to the Colorado-Nebraska State line, registered
significant increases in streamflow.

c. Flooding along the South Platte River wi thin Metropolitan
Denver "'l.S severe in several locations. The Centennial Race track
at Littleton and the Corps of Engineers' Chatfield Dam southwest
of Denver received flood and erosion damage. Other areas affected
in Denver were the Westwood section, in the vicinity of the rail
yards, and in the communities of Commerce City, Henderson, and
Brighton. Downstream from Denver, flooding "'l.S general throu€,llout
the South Platte River basin. On 8 May, the gages at Kersey and
at Weldona, Colorado registered record peak discharges at 4 a.m.
and at 10: 30 p.m., respectively. The flood crest on the South
Platte River reached the gaginp, station at North Platte, Nebraska
at 3:30 a.m. on 13 May.

d. Flooding in the Denver metropolitan area was augmented
by urban runoff and by the lack of adequate drainage facilities.

48