FLOOD01211

• County: Pueblo
• Community: Pueblo
• Stream Name: Fountain Creek
• Title: Pueblo Flood Control Project
• Date: 1/1/1990
• Prepared For: Pueblo County
• Prepared By: US Army Corps of Engineers
• Floodplain - Doc Type: Project

proposed levee. Soils along the center line are generally loose to Dledium .
dense silty sands with some very loose layers. The sands are predominantly
fine near the surface with the grain sizes varying with depth. The remaining
borings in this area were taken in areas designated as areas of channel
excavation. The soils are generally poorly graded sands with a small IlDlount
of silt. On the west side of the creek, shale was encountered at depths of 8
to 18 feet below the natural ground and precluded advancement of the aug.!r.

4-06. The third area is bounded on the north by the AT&SF railroad bridge and
on the south by the confluence of the Arkansas River with Fountain Creek. Ten
of the borings are located in this area. Seven borings were located on a
terrace of the creek approximately 12 feet above the elevation of the l~iver.
These borings were located on the east side of Fountain Creek in the general
area of the proposed levee centerline. The materials encountered varied from
high plasticity clays to poorly graded sands. The predominantly silty and
clayey soils occurred near the surface, and the sandy soils were deeper in the
soil profile. The soils are medium dense and interbedded with occasional
loose layers. Moisture contents were low to high and increased with clepth.
Three of the borings are located near the confluence of Fountain Creek with
the Arkansas River. The soils are silty sands with variable amounts of silt.
Groundwater was encountered in the exploratory borings at depths generally
less than 10 feet except where the borings were located on higher terra.:es of
the creek.

4-07. Three additional borings were located in a proposed borrow area
approximately one mile east of the north end of the proposed project. The
area in the vicinity of the borings is currently being used as a quauy for
brick materials. The borings were advanced to a depth of 25 feet. Materials
in the borings included very clayey sand, sandy clay, sandy silt, silty sand,
and sand. The clays are medium to high plasticity, the silts were non-plastic
to low plasticity. The sands are poorly graded and predominantlj' fine
grained. The cohesive soils are stiff to very stiff and the sands var)' from
loose to dense with increas ing depth. Shale is exposed in the brick 'quarry
excavation and hard shale was encountered at a depth of 25 feet in one c,f the
borings. No groundwater was encountered in the borings.

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4-08. Slope Stability Analvses. Levees On the proposed project wi.ll be
constructed of locally available soil materials. Proposed side slopes for the
soil levees are 1 vertical on 3 horizontal for the streamside slopes and 1
vertical on 2.5 horizontal for the landside slopes with a l2-foot top 'width.
A section of soil cement, located On the east side of Fountain Creek fre.m Sta
29+60 to Sta 35+70 will be used as bank protection for in situ materials on an
excavated slope between the 4th Street and 8th Street bridge. A soil e:ement
levee section will also extend approximately 400 feet upstream of the 8th
Street bridge on the east side of the river and for 337 feet downstream ,of the
floodwall On the west side of the river. The soil cement levee will have a
10-foot top width with 1 vertical on 1.5 horizontal side s lopes on both the
riverside and landside. An inspection trench will be excavated for the soil
cement levee On the west side of the river. The soil cement bank
protection will be constructed with a minimum horizontal width of 10 feet,
have a slope of 1 vertical On 1.5 horizontal and will extend a minimum Eo feet
below the channel thalweg.

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