FLOOD04145

• County: Adams
• Community: Thornton, Adams County
• Basin: South Platte
• Title: Major Drainageway Planning
• Date: 10/1/1980
• Prepared For: Thornton, Adams County
• Prepared By: UDFCD
• Contract/PO #: &&
• Floodplain - Doc Type: Floodplain Report/Masterplan

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TABLE IV-2

ALTERNATIVE INVESTKlATED - PHASE "AfT
DIRECT FLOW AREA 0054

Reach Location Alternative Examined Frequency
1 Confluence with South a. Existing condition
Platte River to Riverdale b. Grass-iined channel 2 & 100-Year
Road
c. Land acquisition 2, 10 & 100-Year
2 Riverdale Road to Holly a. Existing condition
Street b. Underground conduit 2 & 100-Year
c. G rass-iined channel 2,50 & 100-Year
d. Concrete-lined 2 & 100-Year
e. Selected structural improvements 2,10 & 100-Year
f. Selected structural improvements 10 & 100-Year
g. Land acquisition 100-Year
h. Non-structural 100-Year
3 Holly Street to East 112th a. Existing condition
Avenue b. Grass-iined channel & selected 10-Year
structural improvements
c. Concrete-lined channel & 10 & 100-Year
selected structural improvements
d. Underground conduit 100-Year
e. Detention facilities 100-Year

East 112th Avenue to
Upstream Study Limits

4

a. Existing condition
b. Selected structural improvements
c. Selected structural improvements

10,50 & 100-Year
10-Year

d. Grass-lined channel
e. Land acquisition

2,10 & 100-Year
10 & 100-Year

f. Grass-lined channel & selected
structural improvements
g. Detention facilities

10 & 100-Year

N-4

Remarks

Floodplain zoning and regulation without modifications to existing channel.
Construct continuous grass-lined channel and improve irrigation ditch
crossing at Lower Clear Creek Canal.
Acquire all land area within reach subject to flooding.

Floodplain zoning and regulation without modifications to existing channel.
Construct continuous underground culvert for entire reach.
Construct continuous grass-iined channel for entire reach and improve
culvert at Riverdale Road.
Construct continuous concrete-iined channel for entire reach and improve
culvert at Riverdale Road.
Improve cul vert at Riverdale Road
Provide collector ditch along Riverdale Road and culvert beneath 112th
Avenue and Holly Street for Middle and Northern Branches.
Acquire flood prone property and relocate residents.
Flood proof residence by constructing earthen levee around the structure.

Floodplain zoning and regulation without modifications to existing channel.
Construct grass-lined channel from 112th Avenue to Upper Pond and improve
culverts and spillway of Upper and Lower Ponds, relocate Colo. Ag. Canal to
east of Holly St.
Construct concrete-lined channel from 112th Avenue to Upper Pond and
improve culverts and spillway of Upper and Lower Ponds, relocate Colo.
Ag. Canal to east of Holly St.
Continue culvert from 112th Ave. to Upper Pond.
Continue culvert from 112th Ave. to Upper Pond. Enlarge Upper Pond to
16 A.F. and Lower Pond to 12 A.F. either separately or simultaneously
in conjunction with 22 A.F. Pond above East 112th Ave.

Floodplain zoning and regulation without modifications to existing channel.
Enlarge underground conduit and inlet at East 112th Way cul-de-sac.
Regrade East 112th Place from East 112th Way to Cherry Drive to divert
flows away from cul-de-sac.
Construct grass-iined channel from Cherry Drive to East 112th Ave.
Acquire flood prone property and relocate residents in vicinity of E. 112th
Way cul-de-sac.
Combine alternatives (b) and (d) above, continuous channel improvements
from East 112th Way cul-de-sac to East 112th Ave.
Enlarge East 112th Avenue Pond to 18, 22 or 27 A.F.