FLOOD10328

• County: Boulder
• Community: Lyons
• Stream Name: North Saint Vrain and Saint Vrain Creeks
• Title: Floodplain Information Report, North Saint Vrain Creek, Saint Vrain Creek, Floodplain Update, Town of Lyons, Boulder County, Colorado
• Date: 6/1/1998
• Prepared For: Lyons
• Prepared By: BRW, Inc
• Floodplain - Doc Type: Floodplain Report/Masterplan

I

I

Floodplain Information Report
K:\35600\004\FLOODPLAIN INFORMATION REPORT.doc

16

June

1998

Floodplain Information Report
K:\35600\004\FLOODPLAIN INFORMATION REPORT.doc

17

June

998

I

During the flood tons of silt, sand and rocks were carried down both the North and South St. Vrains as well as poles,
lumber and trees.

East of Longmont, the bridge on the County Line at the Old Dixon Mill was washed out.

The Crane Hollow bridge west of Hygiene was strongly supported by piling, but trees and other debris drove against
.he piling until it finally gave way and another bridge was gone.

I

I

I

L.T. Burgess, chief hydrographer from the state enginee~s office, and J.E. Whitter, division engineer for the Platte
area, took slope measurements and found that at the peak of the flood the depth was 8.07 feet compared with a
normal of 3.26. At 2:14 a.m. Sunday and for two hours the St. Vrain was measured at 8,900 second feet. Today it
measured 595 second feet average. The average for Sunday was 2,000 second feet. The river rose to 8,900
second feet in 30 minutes. The highest ever registered previously was 9,600 second feet, Commissioner Maier said.
The date of this record rise was not available.

One of the abutments of
fell in.

what is known as the Neighbors bridge was washed out and

The south approach to the bridge on the Hoover

the south portion of this bridge

Road went out Sunday morning and widened during the day.

I

Roaring out of darkness split by almost continuous lightning and thunder, thousands of tons of water swept down the
North and South St. Vrain canons early Sunday morning causing the flood which also took three homes away,
damaged roads, flooded a half dozen houses in Lyons, wrecked bridges and inundated farm lands

An approach to the bridge on South Sunset was washed out, closing the road.

The "Old Iron Bridge,. east of Lyons and just below the Longmont filtration plant at
to flood water. This bridge had withstood many floods over the years, but always
when it gave way in the middle.

the Ruski place finally succumbed
remained firm until Sunday morning

I

I

Longmont Times - Call
Monday June 23, 1941

51.

Vrain Floods

A total of almost three inches of rain fell here during the storm, according to records at the experimental station of the
sugar company. During the high point Saturday night, the St Vrain was flowing some 6,700 second feet of water,
Commissioner Carl Maier reported. Flood stage is from 2,000 to 2,500 feet when the river starts leaving its banks. In
summer flash floods, previously, as high as 10,000 second feet had been measured.

Water also flooded over Highway 87
several stores and filling stations

I

I

St. Vrain Creek east of Lyons,

I

I

I

I

I

1941

(Longmont-Denver road) just

No. 30, the southbound C. & S. was several hours late Sunday and arrived here at 8 a.m., ... It was held until 1
while a stretch of track near the Golden West mill, which had been undermined by the water was re-inforced.
carloads of limestone were dumped along the track where the water was waist-deep.

south of

the First Avenue

tracks, inundating

p.m.
Two

As a result of weekend heavy rain in this district and in the mountains, the St. Vrain went on
Saturday night the local chapter of the American Red Cross removed several families from
town near the Western Solvents Plant when water surrounded them

rising slowly. At 11 p.m.
their homes southwest of

A spring flood, which cause the St. Brain River to burst
delayed trains, inundated highways, field sand houses
children, struck here with force late Saturday night and early Sunday.
Monday afternoon.

ts banks, made all
and necessitated

bridges between here and Lyons useless,
I the evacuation of 35 men women and
The river had reached flood stage again

ALL BRIDGES BETWEEN LONG MONT AND LYONS MADE IMPASSABLE BY WEEK-END FLOODS - HOMES,
HIGHWAYS AND FIELDS INUNDATED - RIVER CLIMBS TO 6,700 SECOND FEET - WATER LINE DAMAGED
AND TRAINS DELAYED.

35 Rescued As 51.

Excerpts from the Longmont Times-Call
Monday, June 6,1949

Vrain Goes Rampage Here

I

I

I

1941

North St. Vrain & St.
Floodplain Update

FLOOD

Vrain Creeks

Town of Lyons

1949 FLOOD

North St. Vrain & St.
Floodplain Update

V rain Creeks

Town of Lyons