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I I I I I I I I I I I I I I I I I I I B. and is in a natural state. The 100-year flow in this reach is contained in the channel. After this study had been started and mapping completed, development began east of Clarkson Street (extended). Flooding in this new develop- ment should be minimal, as the preliminary plans for it indicate that the channel will remain as open space. From County Line Road to the headwaters, Lee Gulch is well defined and in a natural state. The culvert at County Line Road is inadequate to pass even the minor storms and the road will be flooded with a depth of 1.4 feet for the 100- year event. LITTLE CREEK The 100-year flood plain limits and the 100-year and 10-year water surface profiles for Little Creek are shown on the attached Flood Hazard Area Delineation Maps, Sheets 13 through 21. The 100-year water surface elevation, discharge, and floodway for each cross-section are tabulated on Table II.B. From the South Platte River to Bemis Street the channel is not defined and has been heavily developed. The flow path follows Low Street through downtown Littleton. Flooding in this area is extensive with depths in Low Street ranging from 2 to 4 feet and velocities of up to 11 F.P.S. Numerous business and industrial Luildings are subject to inundation by the 100-year flood. This flood will cross the north boundary of Little Creek along Alamo Street and at the intersection of Bowles Avenue and Santa Fe Drive. Some flow leaves Little Creek Basin to the south at the railroad tracks and along Church Street west of Santa Fe Drive. From Bemis Street to Caley Street the channel passes through Sterne Park and is contained in the median of Sterne Parkway. Sterne parkway will be inundated by the 100-year flood with a potential flow depth of up to 3 fep.t. Vp.locities in the channel can be expected to be as great as 11 F.P.S. Street crossings will be overtopped with flow depths varying from 2.7 to 4.1 feet. There are 33 residential structures within the flood plain. From Caley Street to Elati Street the channel is defined but unimproved. Flooding is generally confined to the channel but backwater from street crossings will inundate the streets and residences. Flow depths of 2.7 feet at Caley Street and 2.3 feet at Gallup and peakview may be expected from the 100-year flood. There are 26 residential structures within the flood plain. After the mapping was flown, con- struction of a small subdivision west of Gallup,began. It appears that this supdivision will be in the flood plain. From Elati Street to Broadway, which is the Littleton-Arapa- hoe County border, the channel is again constructed in the median of Sterne Parkway until Apache Street, where it crosses Little's Creek Park. Street crossings are inadequ- ate and overtopping will occur during the 100~year flood.' Flow depths and velocities similar to the reach from Lake Street to Caley Street may be expected. Little's Creek Park is subject to inundation by the 100-year storm. The potential flooding at Apache Street is increased because . water along Little's Creek Park is not properly directed into ,the channel along Sterne,Parkway. From Broadway to the Highline Canal the thalweg of the chan- nel has been incorporated into a park-open space area for an apartment-townhouse complex. ,This complex is susceptible to flooding caused by spillage from the Highline Canal and back- water from the culvert crossing Broadway. Broadway may be overtopped by minor storms, with a flow depth of 2.1 feet over the street during the 100-year flood. From the Highline Canal to East Dry Creek Road, the historic channel of Little Creek has been replaced with a storm drain which discharges directly into the Highline Canal. Nineteen residential structures lie within the 100-year flood plain along this reach, with the majority of them along S. Pennsyl- vania Street immediately upstream of the canal. These -6-