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1 <br /> ' was found to spill to the north along the right bank at three points. These three spill <br /> points included a right bank spill discharging towards Manhattan Circle between Cross <br /> Section 140 and 150 and a right bank spill discharging at the RTD Park-N-Ride facility <br /> just downstream of Cross Section 130 and the main spill location at Cross Section 90 at <br /> ' Apache Road. The delineation and flow spills for this condition are depicted on Figure <br /> 6. <br /> 1 � <br /> The right bank spill discharging toward Manhattan Circle was calculated using the split <br /> ' flow option in HEC-2. The discharge from the RTD Park-N-Ride facility was calculated <br /> only for the opening located on the east side of the facility. The discharge through the <br /> opening was calculated using normal depth calculations. <br /> ' The split flow analysis in the main channel model at U.S. 36 for Condition 2, 100-Year <br /> ' FEMA Certified Flood Protection Levee, indicates approximately 2,620 cfs of the 100- <br /> year flood discharge of 6,160 cfs in South Boulder Creek leaves the main channel and <br /> ' flows to the west along U.S. 36. The spill discharge of 2,620 cfs is approximately 1,000 <br /> cfs greater than the spill discharge of 1,660 cfs reported in the regulatory (G&O) model <br /> at this point. The remaining 3,540 cfs flows to the north within the main channel and <br /> through the U.S. Highway 36 bridge structure to the north. Of the 2,620 cfs 100-year <br /> spill discharge, 2,020 cfs of this flow enters the U.S. 36 Overflow area and flows along <br /> the highway embankment in a westerly direction, while 600 cfs enters the U.S. 36 South <br /> ' Overflow. <br /> ' The 2,020 cfs discharging along the U.S. 36 Overflow flows westwardly along the east- <br /> bound lanes until it overtops the median upstream of Cross Section 140. The water <br /> ' surface elevations equalize between the east and west bound lanes at this point. The <br /> HEC-2 analysis indicates that the spill towards Manhattan Circle is about 195 cfs. The <br /> ' right bank spill at the RTD Park-N-Ride structure is estimated to be 400 cfs and spills <br /> toward South Boulder Road. The remaining 1,425 cfs rejoins the 600 cfs flowing along <br /> ' the U.S. 36 South Overflow route downstream of the Park-N-Ride. A total of 2,025 cfs <br /> leaves U.S. 36 at Cross Section 90, discharging towards Apache Road. <br /> -18- <br /> 1 <br />