Red River of the North Basin-Wide Modeling Approach
Hydrologic Modeling – HEC-HMS Model Development
Various Tributaries below the Red River of the North at Halstad, MN
100% Submittal Park River, ND
Versions:
Date
15 December 2014
Description
Initial submittal
Incorporation of submittal comments
Final submittal
Firm Name: U.S. Army Corps of Engineers, Saint Paul District
A. SUBMITTAL OVERVIEW:
The 100% deliverable is an application of the calibrated model to several precipitation
scenarios. The scenarios of interest are:
 10-Day 25-Year scenario from NOAA TP-49 (“S10D025Y_P”)
 10-Day 50-Year scenario from NOAA TP-49 (“S10D050Y_P”)
 10-Day 100-Year scenario from NOAA TP-49 (“S10D100Y_P”)
 10-Day 100-Year effective precipitation scenario derived from NRCS TR-60
runoff (“S10D100Y_R”)
 24-Hour 2-Year scenario from NOAA TP-40 (“S24H002Y_P”)
 24-Hour 5-Year scenario from NOAA TP-40 (“S24H005Y_P”)
 24-Hour 10-Year scenario from NOAA TP-40 (“S24H010Y_P”)
 24-Hour 25-Year scenario from NOAA TP-40 (“S24H025Y_P”)
 24-Hour 50-Year scenario from NOAA TP-40 (“S24H050Y_P”)
 24-Hour 100-Year scenario from NOAA TP-40 (“S24H100Y_P”)
B. SYNTHETIC HMS MODEL EVENTS:
Once the calibration process was completed, a series of synthetic storm
scenarios were simulated. Precipitation amounts for these scenarios were based
on information provided in Technical Paper No. 40 - Rainfall Frequency Atlas of
the Eastern United States for Duration from 30 minutes to 24 hours and Return
Periods from 1 to 100 years (TP40) and Technical Paper No. 49 - Rainfall
Frequency Atlas of the United States. The durations and return periods
simulated are listed below.
 2yr, 5yr, 10yr, 25yr, 50yr, and 100yr – 24hr Rainfall
 25yr, 50yr, and 100yr – 10day Rainfall
100% Submittal – Park River, ND Tributary
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During these simulations the loss rate parameters (CN and Ia) were reset to the
initial values determined based on the soil and landuse type. The other
calibrated unit hydrograph parameters (i.e. R, Tc, …) were adjusted to match the
median calibrated parameters from calibration events. These simulations were
completed using the following rainfall distribution patterns.
 24-hr events - SCS Type II Distribution
 10-day events– Figure 6-4 from Mn Hydrology Guide (Principal Spillway
Hydrograph).
In addition, a synthetic 100yr-10day runoff scenario was developed in an attempt
to simulate conditions similar to those that occur during a spring flood event. To
accomplish this, the following Phase 1 methodology approach was utilized.
1. The approximate composite 24hr CN for the area above Halstad was
determined (using the contributing areas only).
2. A rainfall/precipitation depth grid was developed by determining the
rainfall/precipitation depth required to obtain the resultant runoff depth
shown in TR60 for each cell within the study area based on the calculated
composite 24hr CN for the area above Halstad.
3. HEC-HMS simulation was then completed utilizing this rainfall/
precipitation depth grid, the 24-hr CN values, and the 10-day precipitation
pattern shown in Figure 6-4 from Mn Hydrology Guide (Principal Spillway
Hydrograph).
Note that no depth-area reduction factor was applied on the synthetic events.
Instead, each simulation is listed as a scenario and not a specific frequency
based event. Updated Discharge-Frequency data was obtained from Barr
Engineering for use in selecting the Annual Exceedance Probability at each gage
location. Table B.1 provides the Flow Frequency Analysis for reporting stream
gage along with the synthetic model results.
100% Submittal – Park River, ND Tributary
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Table B1. Synthetic Model Run
Discharge-Frequency Data - Based on Gage Data
Percent Chance
Exceedance
0.2
0.5
1.0
Return Period
500
200
100
Discharge (cfs)
18,850
15,633
13,194
10,782
2.0
50
7,700
5.0
20
5,507
10.0
10
3,499
20.0
5
1,259
50.0
2
364
80.0
1.25
174
90.0
1.11
90
95.0
1.05
23
99.0
1.01
Source: Barr Engineering. Grafton, North Dakota Hydrology Update Discharge
Flow-Frequency Curves. Prepared for City of Grafton, ND. October 17, 2014.
100% Submittal – Park River, ND Tributary
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Scenario No.
S24H002Y_P
S24H005Y_P
S24H010Y_P
S24H025Y_P
S24H050Y_P
S24H100Y_P
24-hr Rainfall Scenarios
Annual Exceedance
Probability Based on
Peak Discharge
Discharge Frequency
[cfs]
Curve
2,000
3,900
5,800
8,400
10,600
12,900
35%
18%
10%
4.5%
2.3%
1.25%
Return Period Based on
Discharge Frequency
Curve
3 yr
6 yr
10 yr
22 yr
44 yr
80 yr
10-day Rainfall Scenarios
Scenario No.
S10D025Y_P
S10D050Y_P
S10D100Y_P
Peak Discharge
[cfs]
Annual Exceedance
Probability Based on
Discharge Frequency
Curve
7,000
9,300
11,800
6.8%
3.3%
1.5%
15 yr
30 yr
67 yr
10-day Runoff Scenario
Scenario No.
S10D100Y_R
Peak Discharge
[cfs]
Annual Exceedance
Probability Based on
Discharge Frequency
Curve
16,800
0.39%
100% Submittal – Park River, ND Tributary
4
256 yr