FLOOD05761

• Designation Number: 211
• County: Larimer
• Community: Fort Collins
• Stream Name: West Vine Drainage Basin
• Basin: South Platte
• Title: Major Drainageway Planning - West Vine Drainage Basin
• Date: 12/1/1980
• Designation Date: 3/1/1983
• Floodplain - Doc Type: Floodplain Report/Masterplan

direction to the intersection of the colorado and Southern
Railroad and Shield~ Street. From this location, the storm
runoff diverges in various directions and eventually drains
to the Cache La Poudre River which is a9proximately 1700 ft.
north of the intersection of the C. & S. ?,R. <Ind Shields StrN't.

with discharge from the exiRting emen",ncy spillway. t,ssumptions
used when analyzing the hydrology of the lake arc detailed in
Section IV,D., page 16,

11,8, Man~~de Features

The Colorado and Southern Railro,'ld ernk",nkrnent just west o.f
ShieldS Street credteS the northeasterly boundary of the drainage
basin, The embankl'lent at this location is a~proximately 6 to
10 ft. high. An existing 48 inch reinfolCced concrete culvert
located approximately 300 ft. west of Shields carries storm
runoff to the north side of the embankment,

Four major irrigation ditchcs traverse the West Vine Drainage
Basin, These are, in order of location from the westerly end
of the basin, the Pleasant Valley and Lake Canal, the New
Mercer Canal, the Larimer County No. 2 Canal, and the Arthur
Ditch. At the current level of development, it is evident that
the ditches intercept a significant portion of the minor storm
runoff, However, as the drainage basin continues to develop,
and the drainage basins between the West Vine Basin and the
Cache .La poudre River continue to develop, the existing irrigil-
tion ditches will not be able to carry a significant 9ortion of
the storm runoff, especially during the irrigation season, In
addition, to the south of the ~cst Vine Drainage Basin, the
drainage basin between ~ulberry Street and Spring Creek, the
Spring creek Drainagu 8asin, the Foothills Drainage Basin, the
McClcllands Drainilgc iLlSir., and thc Milil Creek Or<'lin,1gc B<lsi~
are all currently contributing various amounts of runoff to one
or more of the ditches and mayor rroy not do so in the future,
Until this situation is studied in detail, it is rcco~nded that
runoff throughout the !>'est Vine Drainage Basin be kept out of
the ditches.

Five detention or retention areas along the west edges of
Overland Trail and Taft Hill Road have been created by the con-
struction of the road embankments, At the current level of
development, the areas along Overland Trail do not create flOOding
hazards and actually function to attenuate peak rates of runoff.
Ho.....evcr, the LlreaG .'llong TLlft Hill R::><.ld, ;J.lthough they do aid in
attenuating peak rates of runoff downstream of Taft Bill, do
pose a flooding threat to several residences located adjacent to
the west side of the street. Several other natural depressions
or retention areas exist througho'ut the drainage b;J.sin.

College La~e is located in Sections 8 and 17 in the westerly
portion of the basin as shown on Figure 1. The lake is utilized
to store and regulate water for irrigation and research purposes
at Colorado State university~l) The ca~acity of the lake is
1000 to 1100 acr.... feet and it has 1m approxi.mate surface aTea of
70 acres when full to the existinq emergency spillway crest.
Approximately 415 acres drain into col1e':l'~ Lake and d'Jring a
major storm the lake would function as a detention facility

II.C. State of Development

Approximately 50 percent of the drainage basin east of Overland
Trail is fully developed in tcr:r:s of impervious area. "'his
development mainly consists of relatively high density (4 to 6
units per acre) multi-fLlmily and single family residential develop-
ment and agricultural ground, As mentioned previously, the
area west ot Overland Trait within the drainage basin is primdrily
owned by C.S.D_ and is less tha~ 10 percent developed in terms
of impervious areas.

-7-

+