Highland Park Dam Mitigation Project Appendix C - Partners for ...

Figure 3 100-year Flood Event Comparison
100 year - Calibrated v. Existing v. Original Output
Recreated Existing Original Thalweg
Elevation, ft
620
610
600
590
580
570
560
550
0.00 1.00 2.00 3.00 4.00 5.00
River Miles from Maumee
Existing Conditions Low Flow Analysis
JFNew staff observed in November 2007 low flow conditions. Their observations included an edge-ofwater
elevation measurement of 574.44 ft at the dam, cross-section 3. Based on this elevation, the
theoretical flow rate over the existing dam would be approximately 22 cfs assuming a spillway
coefficient, C, of 3.33, a weir length, b, of 59 feet, and an average water depth, H, of 0.23 feet (Q =
CbH (3/2) ).
The flow rate in the model was adjusted to match the observed elevation measurement. The
corresponding model flow rate was determined to be 30 cfs. In addition to adjusting the flow rate, the
HEC-2 model was truncated to just the portion through Highland Park. This was done due to a
downstream control in the original model which controls the flow so that the water level is approximately
10 feet higher than observed levels.
Table 2 shows the results of simulating 30 cfs through the model as compared to the observed water
surface elevations at a perceived low flow. The greatest difference between the observed and modeled
data is 0.12 feet. Figure 4 shows this comparison graphically.
SECTIO
N NO.
Table 2 Comparison of WSE at 30 cfs to Observed Data
CROSS-
MODEL
SECTION RIVER WSE OBSERVED DIFFERENCE
(Nov. 2007) MILES (30 cfs) WSE
(M-0)
24.318 18 4.03 571.76 571.76 0
24.327 17 4.09 571.78 571.77 0.01
24.336 16 4.11 571.78 571.76 0.02
24.345 15 4.14 571.8 571.84 -0.04
24.354 14 4.18 571.81 571.81 0
24.363 13 4.21 571.81 571.81 0
7