FLOOD10070

• County: Larimer
• Community: Fort Collins
• Basin: South Platte
• Title: Master Drainage Plan Update Colorado State University
• Date: 1/1/1998
• Prepared For: Fort Collins
• Prepared By: Ayres Associates
• Floodplain - Doc Type: Floodplain Report/Masterplan

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The results of the simulated canal overtopping were then input into the revised campus
model. The model for the CSU campus was then run. Table 2 summarizes the results of
the simulation for the event and compares these results to the measured high-water line
data.

Table 2. Results of the Simulation of the July 28-29, 1997 Storm.
SWMM Water Differ,
HWM Model Location Surface Simulation From
Element Elevation Actual
#15&16 14 College Gym 4986.6 4986.2 -0.4
#17-20 15 Heating Plant and Oval 4993.0 4993.3 0.3
#21-2 224 Engineering Parking Lot 4993.4 4993,9 0.5
#22 53 Lagoon NW of Student Center 5004.7 5004.8 0.1
#26 53 Eddy Building Door 5004.9 5004,8 -0.1
53 Library Generator 5005.0 5004.8 -0.2
#31 259 Athletic Fields - Football Practice 5024.6 5024.1 -0,5

As can be seen from Table 2 the results from the simulation of the 1997 event generally
match the high-water levels measured in the field. The elevation of the student center
lagoon ponding area was within less than 0.1 ft. The engineering parking lot was within 0.5
ft. This was probably due to the estimated rating information that was used for this area,
while the oval area was within 0.3 ft. The oval area ponding was over-estimated by the
model and the College Street gym area was under-estimated by about 0.4 ft. This was
probably due to the estimate of the extended rating curve in the oval area. Generally the
results match the storm event well enough to be able to evaluate the performance of the
proposed system improvements.

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Ayres Associates