Lower Red Basin Retention (LRBR) Study€¦ · 1.3. Otter Tail River below Orwell Dam near Fergus...

Lower Red Basin Retention (LRBR) Study Appendix B: Wahpeton Upstream Frequency Analysis & Balanced Hydrographs

January 2019

Prepared by:

U.S. Army Corps of Engineers St. Paul District 180 Fifth Street East, Suite 700 St. Paul, Minnesota 55101-1678

LRBR Study - Appendix B: Wahpeton Upstream Frequency Analysis & Balanced Hydrographs 1

Table of Contents

1. Locations of Interest at and above Wahpeton, North Dakota ............................................................. 5

1.1. Bois de Sioux River near White Rock, South Dakota (05050000) .................................................. 6

1.2. Bois de Sioux River near Doran, Minnesota (05051300) ............................................................... 7

1.3. Otter Tail River below Orwell Dam near Fergus Falls, Minnesota (05046000) .............................. 7

1.4. Red River of the North at Wahpeton, North Dakota (05051500), Downstream of Otter Tail River Diversion ......................................................................................................................... 7

2. Overall Methodology ............................................................................................................................ 8

3. Period of Record ................................................................................................................................... 8

4. Breakout Flows ..................................................................................................................................... 9

5. Projects Regulating Streamflow............................................................................................................ 9

5.1. Lake Traverse Flood Control Project .............................................................................................. 9

5.2. Orwell Reservoir ........................................................................................................................... 10

5.3. Reservoir Simulation .................................................................................................................... 10

6. Unregulated Streamflow Computation .............................................................................................. 10

6.1. Bois de Sioux River near White Rock, South Dakota .................................................................... 11

6.2. Bois de Sioux River near Doran, Minnesota ................................................................................. 11

6.3. Otter Tail River below Orwell Dam near Fergus Falls, Minnesota ............................................... 12

6.4. Red River of the North at Wahpeton, North Dakota (Downstream of Otter Tail River Diversion) ..................................................................................................................................... 12

7. Local Flow ........................................................................................................................................... 12

7.1. Record Extension – Bois de Sioux River near Doran, Minnesota ................................................. 13

8. Analytical Annual Instantaneous Flow-Frequency ............................................................................. 14

9. Unregulated Volume-Frequency Analysis .......................................................................................... 17

10. Synthetic Event Analysis ..................................................................................................................... 17

10.1. Unregulated Balanced Hydrographs ............................................................................................ 17

10.2. Unregulated Synthetic Input Hydrographs .................................................................................. 18

10.3. Synthetic Regulated, With Breakout Flow Hydrographs .............................................................. 21

11. Regulated Balanced Hydrograph Determination................................................................................ 22

11.1. Regulated Daily and Annual Peak Flows ...................................................................................... 22

11.1.1. Regulated Streamflow Record at Bois de Sioux River near White Rock, South Dakota ..... 22


11.1.2. Regulated Streamflow Record at Bois de Sioux River near Doran, Minnesota .................. 22

11.1.3. Regulated Streamflow Record at Otter Tail River below Orwell Dam near Fergus Falls, Minnesota ........................................................................................................................................... 22

11.1.4. Red River of the North at Wahpeton, North Dakota (Downstream of Otter Tail River Diversion) ............................................................................................................................................ 23

11.2. Regulated Flow-Frequency Analysis ............................................................................................. 23

11.3. Regulated Balanced Hydrographs ................................................................................................ 23

12. Results ................................................................................................................................................. 24

12.1. Unregulated Condition ................................................................................................................. 24

12.2. Regulated Condition ..................................................................................................................... 26

12.3. Balanced Hydrographs ................................................................................................................. 33

13. References .......................................................................................................................................... 38


Figures

Figure 1. USGS Stream Gage Locations at and above Wahpeton, North Dakota ................................ 6 Figure 2. Relationship to Convert Annual Mean Daily Peak Flow to Annual Instantaneous Peak Flow

– Bois de Sioux River near White Rock, South Dakota ........................................................ 15 Figure 3. Relationship to Convert Annual Mean Daily Peak Flow to Annual Instantaneous Peak Flow

– Bois de Sioux River near Doran, Minnesota ..................................................................... 15 Figure 4. Relationship to Convert Annual Mean Daily Peak Flow to Annual Instantaneous Peak Flow

– Otter Tail River below Orwell Dam near Fergus Falls, Minnesota.................................... 16 Figure 5. Example Smoothed, Balanced Hydrograph – Unregulated Flows ....................................... 18 Figure 6. Example of Manual Adjustments to Lake Traverse Inflow Hydrograph .............................. 20 Figure 7. Regulated Flow-Frequency Curve – Bois de Sioux River near White Rock, South Dakota .. 29 Figure 8. Regulated Flow-Frequency Curve – Bois de Sioux River near Doran, Minnesota ............... 30 Figure 9. Regulated Flow-Frequency Curve – Otter Tail River below Orwell Dam near Fergus Falls,

Minnesota ............................................................................................................................ 31 Figure 10. Regulated, with Breakout Flow-Frequency Curve – Red River of the North at Wahpeton,

North Dakota (downstream of Otter Tail River Diversion) .................................................. 32 Figure 11. Smoothed, Balanced Hydrographs for the Regulated Condition – Bois de Sioux River near

White Rock, South Dakota ................................................................................................... 33 Figure 12. Smoothed, Balanced Hydrographs for the Regulated Condition – Bois de Sioux River near

Doran, Minnesota ................................................................................................................ 34 Figure 13. Smoothed, Balanced Hydrographs for the Regulated Condition – Otter Tail River below

Orwell Dam near Fergus Falls, Minnesota ........................................................................... 35 Figure 14. Smoothed, Balanced Hydrographs for the Regulated, With Breakout Flow Condition – Red

River of the North at Wahpeton, North Dakota (downstream of Otter Tail River Diversion) ............................................................................................................................................. 36

Figure 15. Timing of Balanced versus Synthetic Hydrographs for Regulated 0.2-Percent Event at Doran ................................................................................................................................... 37


Tables

Table 1. Available USGS Streamflow Data .......................................................................................... 5 Table 2. Adopted Breakout Flow Relationship for Bois de Sioux River to Wild Rice River (Source:

Reference 8) .......................................................................................................................... 9 Table 3. Unregulated, No Breakout Flow Synthetic Hydrograph Inflow Multipliers ........................ 21 Table 4. Unregulated Annual Peak Discharge Frequency – Bois de Sioux River near White Rock,

South Dakota ....................................................................................................................... 24 Table 5. Unregulated Annual Peak Discharge Frequency – Bois de Sioux River near Doran,

Minnesota ............................................................................................................................ 25 Table 6. Unregulated Annual Peak Discharge Frequency – Otter Tail River below Orwell Dam near

Fergus Falls, Minnesota ....................................................................................................... 25 Table 7. Unregulated Annual Peak Discharge Frequency – Red River of the North at Wahpeton,

North Dakota (Reference 8) ................................................................................................ 26 Table 8. Regulated Synthetic Event Peak Flow at and upstream of Wahpeton, North Dakota ........ 26 Table 9. Regulated, With Breakout Flow Annual Instantaneous Frequency Curves at and upstream

of Wahpeton, North Dakota ................................................................................................ 27

Appendices

Appendix B1 - Nonstationarity Detection and Hydrologic Sensitivity Analysis of Unregulated Flows Upstream of Wahpeton, North Dakota

Appendix B2 - Reservoir System Simulation (HEC ResSim) Model Modifications for Extreme Event Modeling at Lake Traverse Project and Orwell Reservoir

Appendix B3 - Unregulated, No Breakout Condition Flow Frequency Curves at and Upstream of Wahpeton, North Dakota

Appendix B4 - Regulated, With Breakout Condition Flow Frequency Curves at and Upstream of Wahpeton, North Dakota


1. Locations of Interest at and above Wahpeton, North Dakota Balanced hydrographs were developed at three locations upstream of Wahpeton, North Dakota, and at a fourth location downstream of the Otter Tail River Diversion channel at Wahpeton, North Dakota/ Breckenridge, Minnesota:

1. Bois de Sioux River near White Rock, South Dakota;

2. Bois de Sioux River near Doran, Minnesota;

3. Otter Tail River below Orwell Dam near Fergus Falls, Minnesota; and

4. Red River of the North at Wahpeton, North Dakota (downstream of Otter Tail River Diversion).

The locations of the gages used to develop the balanced hydrographs are summarized in Table 1 and shown in Figure 1.

Table 1. Available USGS Streamflow Data

USGS Station Number Station Name

Period of Record

Drainage Area

(sq. miles) USGS Remarks 05050000 BOIS DE SIOUX RIVER NEAR

WHITE ROCK, SD OCT 1941 – Present

1,160 Flow regulated and sometimes impacted by backwater from Rabbit River.

05051300 BOIS DE SIOUX RIVER NEAR DORAN, MN

OCT 1989 – Present

1,880 Flow regulated.

05046000 OTTER TAIL RIVER BL ORWELL D NR FERGUS FALLS, MN

OCT 1930 – Present

1,7301 Flow regulated since 1953.

05051500 RED RIVER OF THE NORTH AT WAHPETON, ND

MAY – OCT 1942; MAR 1943 – Present

3,8802 Flow regulated. Flows partially diverted since 2005.

1 Drainage area is updated from the USGS-reported value of 1,740 square miles (Reference 5). 2 USGS-published drainage area of 4,010 square miles found to be in error (Reference 8).


Figure 1. USGS Stream Gage Locations at and above Wahpeton, North Dakota

1.1. Bois de Sioux River near White Rock, South Dakota (05050000) The USGS continuous streamflow gage 05050000 is located on the Bois de Sioux River 300 feet downstream from White Rock Dam and four miles south of White Rock, South Dakota. Flow is regulated by the Lake Traverse-Boise de Sioux Flood Control and Water Conservation project (Lake Traverse Project) and is impacted, at times, by backwater from the Rabbit River. The gage has been recording streamflow data since water year 1942, when the Lake Traverse Project began operating for flood control. The total drainage area regulated by the Lake Traverse Project is 1,160 square miles. The maximum instantaneous peak discharge recorded at the gage was 8,750 cfs on April 20, 1997, with the highest instantaneous peak stage of 16.90 feet recorded on the same day.


1.2. Bois de Sioux River near Doran, Minnesota (05051300) The USGS continuous streamflow gage 05051300 is located on the Bois de Sioux River 10 feet downstream from the County Highway 6 Bridge, three miles downstream from Rabbit River, and 4.3 miles southwest of Doran, Minnesota. The gage is located upstream of where flow breaks out from the Bois de Sioux River to the Upstream Wahpeton Breakout Reach and upstream of County Ditch 55, which experiences a reversal of flow during breakout events. Some of the breakout flow leaves the Bois de Sioux River watershed to enter the Wild Rice River by crossing Highway 127. The total drainage area at the gage is 1,880 square miles, which includes 720 square miles of incremental drainage between White Rock Dam and Doran, Minnesota.

Flow is regulated by the Lake Traverse Project. The gage has been recording streamflow data since water year 1990. The maximum instantaneous peak discharge recorded at the gage was 12,300 cfs on April 16, 1997, with the highest instantaneous peak stage of 24.42 feet recorded on the same day.

1.3. Otter Tail River below Orwell Dam near Fergus Falls, Minnesota (05046000) The USGS continuous streamflow gage 05046000 is located on the Otter Tail River 0.7 miles downstream from Orwell Dam on County Highway 15, 6.1 miles downstream from Dayton Hollow Dam, 8 miles southwest of Fergus Falls, and 11.1 miles downstream from Pelican River. Flow is regulated by Orwell Reservoir since March 1953, and by power plants upstream. Prior to October 1952, streamflow was published as "Otter Tail River below Pelican River, near Fergus Falls,” when the streamflow gage was located 6.1 stream miles upstream of its current location.

The gage has been recording streamflow data since water year 1931. The total drainage area above Orwell Dam is 1,730 square miles. The maximum instantaneous peak discharge recorded at the gage was 2,380 cfs on June 20, 2014, with the highest instantaneous peak stage of 5.70 feet recorded on the same day.

1.4. Red River of the North at Wahpeton, North Dakota (05051500), Downstream of Otter Tail River Diversion

The USGS continuous streamflow gage 05051500 is located on the Red River of the North at river mile 548.6 and 800 feet downstream from the confluence of the Bois de Sioux and Otter Tail Rivers. Flow at Wahpeton is historically impacted by flow leaving, or breaking out from, the Bois de Sioux River to the Wild Rice River upstream of Wahpeton during large flooding events. Additionally, flows are regulated by the Lake Traverse Project and Orwell Reservoir and are impacted since 2005 by the Otter Tail River Diversion, which partially diverts Otter Tail River flows around Breckenridge, Minnesota. The diverted flows are measured at streamflow station Otter Tail River Diversion at Breckenridge, MN (USGS station 05046475). The location of interest is on the Red River of the North downstream of where the Otter Tail River Diversion re-enters the Red River of the North. Therefore, daily discharge values used for the current analysis are combined flows from the Red River and from station 05046475.

As part of an analysis performed for Hickson, North Dakota, a regulated flow-frequency curve at Wahpeton, North Dakota, was developed (Reference 8). However, balanced hydrographs at Wahpeton


were not prepared at the time. The flow records developed for the Wahpeton location during the 2015 analysis are used herein to generate balanced hydrographs. Because improvements have been made to the HEC-ResSim models of the Lake Traverse Project and Orwell Reservoir since that analysis; synthetic regulated, with breakout flow hydrographs were (re)generated as part of the current study.

2. Overall Methodology A multi-step process is required to develop the regulated, with breakout flows balanced hydrographs at the locations of interest at and upstream of Wahpeton, North Dakota. The flows along the Bois de Sioux River and the Otter Tail River are regulated by the Lake Traverse Project and Orwell Reservoir, respectively. In turn the flows on the Red River of the North at Wahpeton, North Dakota, are regulated by both flood control projects. In addition to being regulated by upstream reservoirs, the flows at Wahpeton are impacted by breakout flow from the Bois de Sioux River to the Wild Rice River and by partial diversion of flows from the Otter Tail River to a location downstream of the Cities of Wahpeton, North Dakota, and Breckenridge, Minnesota, via a diversion channel.

Due to the effects of regulation at all four locations and the additional impact at Wahpeton of the breakout flows, graphical techniques must be applied to develop annual instantaneous peak flow-frequency curves and volume frequency curves at these sites. A combination of historic records and synthetic events are used to define the graphically-determined curves. Using these curves and an historic event as a pattern hydrograph, the regulated, with breakout flows balanced hydrographs are determined.

The primary steps required during the analysis are as follows:

(1) determine unregulated synthetic event flows,

(2) determine regulated, with breakout synthetic event flows,

(3) develop graphical flow-frequency curves, and

(4) prepare regulated, with breakout flows balanced hydrographs.

3. Period of Record The period of record used for analysis at the Bois de Sioux River near White Rock, South Dakota the Bois de Sioux River near Doran, Minnesota; and the Red River of the North at Wahpeton, North Dakota is 1942-2009. This is the same period of record used for the Red River of the North mainstem sites and was selected to be consistent with the Halstad Upstream Retention study as summarized in the main report. The period of record adopted at tributary sites throughout the Red River Basin varies depending on data availability. For tributary analysis data collected through water year 2016 was considered for incorporation into analysis. The period of record used for analysis at the Otter Tail River below Orwell Dam near Fergus Falls, Minnesota, is 1931-2016.

Nonstationarity detection and hydrologic sensitivity analysis were performed in order to identify any concerns regarding the period of record selected for the Bois de Sioux River and to ascertain whether


the full gaged record could be used at the Otter Tail River location. Details of the nonstationarity detection and sensitivity analyses are found at Appendix B1.

4. Breakout Flows Breakout flow from the Otter Tail River to the Red River of the North and from the Bois de Sioux River to the Wild Rice River have been previously modeled and documented (Reference 8). Three of the four locations of interest are not impacted by breakout flows. However, the Red River of the North at Wahpeton, North Dakota, is impacted by breakout flows. The analysis described herein adopts the breakout flow relationships used during the 2015 Hickson analysis and reproduced in Table 2 below:

Table 2. Adopted Breakout Flow Relationship for Bois de Sioux River to Wild Rice River (Source: Reference 8)

Bois de Sioux River to Wild Rice River Breakout Flow Relationship Flow at USGS Gage at Doran (cfs) Breakout Flow (cfs)

0 0 5,700 0 7,200 250 7,700 350 8,300 500 9,100 650

10,500 1250 13,400 2,900 16,500 4,700 19,800 6,700 23,000 8,700 27,000 11,200

5. Projects Regulating Streamflow

5.1. Lake Traverse Flood Control Project The Lake Traverse Flood Control Project is on the boundaries of Minnesota, North Dakota, and South Dakota. Lake Traverse forms the headwaters of the Bois de Sioux River. The Lake Traverse Project extends from the continental divide at Browns Valley, Minnesota, to a point along the Bois de Sioux River six miles south of Wahpeton, North Dakota/Breckenridge, Minnesota. The project became operational in 1942 and consists of the Browns Valley Dike, Reservation and White Rock Dams and associated reservoirs, and the Bois de Sioux River channel. The reservoir behind Reservation Dam is called Lake Traverse, and the reservoir behind White Rock Dam is called Mud Lake. The two reservoirs operate as a single pool with control at White Rock Dam once the elevation reaches approximately 976.8 feet (1912 MSL). The total capacity of the two reservoirs at the top of White Rock Dam (986.0


feet) is about 368,000 acre-feet (Reference 4). More information about the Lake Traverse Project is in Appendix B2.

5.2. Orwell Reservoir Orwell Dam is located in Minnesota on the Otter Tail River approximately six miles southwest of Fergus Falls, Minnesota. The project became operational in 1953. The total capacity of the Orwell Reservoir at the top of the surcharge pool (1073.0 feet 1912 MSL) is 17,750 acre-feet (Reference 6). More information about Orwell Reservoir is in Appendix B2.

5.3. Reservoir Simulation The Hydrologic Engineering Center’s Reservoir System Simulation (HEC-ResSim) model, version 3.1, (Reference 7) is used to determine both the unregulated and regulated synthetic event hydrographs. HEC-ResSim is used to model reservoir operations and can perform hydrologic routing, as well as simulate flow diversions, including breakout flows. The model is used during unregulated synthetic event development because it can quickly simulate flow routing for extended periods of record. Reservoir operating rules (water control operations) and the physical parameters of the Lake Traverse Project and Orwell Reservoir are defined so that the model can be used during regulated synthetic event development. The breakout flow relationships described in Section 4 Breakout Flows are prescribed in HEC-ResSim for use during the regulated analysis. The relationship between Otter Tail River flows and flows diverted to the Otter Tail River Diversion is also defined. The HEC-ResSim model developed and calibrated for use during the 2015 Hickson analysis (Reference 8) is adopted with reservoir system modifications for use in the current study. The modifications to the HEC-ResSim model are focused on extreme (high flow) events when the reservoirs are operating at or near maximum capacity or are overtopped. Details of the HEC-ResSim model and its modifications are contained at Appendix B2.

6. Unregulated Streamflow Computation Daily inflow (I) records to Mud Lake, Lake Traverse and Orwell Reservoir were calculated by reverse-routing observed, daily outflow data using Equation 1 within a Microsoft Excel spreadsheet. Daily outflow data (Q) consists of reservoir releases and evaporation losses. Daily evaporation losses are computed using the cumulative monthly evaporation data described in Appendix E of “The Use of Synthetic Floods for Defining the Regulated Flow-Frequency & Volume Duration Frequency Curves for the Red River at Hickson, North Dakota” (Reference 8), and elevation-area relationships for the reservoirs. Change in storage (Δ S) is computed using observed daily reservoir elevation data and elevation-storage relationships for the reservoirs.

Equation 1 𝑰𝑰𝑰𝑰𝑰𝑰𝒍𝒍𝒐𝒐𝒐𝒐 (𝑰𝑰)−𝑶𝑶𝑶𝑶𝑶𝑶𝑰𝑰𝒍𝒍𝒐𝒐𝒐𝒐 (𝑸𝑸) = 𝑪𝑪𝑪𝑪𝑪𝑪𝑰𝑰𝑪𝑪𝑪𝑪 𝒊𝒊𝑰𝑰 𝑺𝑺𝑶𝑶𝒐𝒐𝑺𝑺𝑪𝑪𝑪𝑪𝑪𝑪 (∆𝑺𝑺)

Observed daily reservoir elevation data are recorded by USACE St. Paul District Water Management (Reference 10). USGS streamflow records below Orwell and White Rock Dams represent reservoir outflows.


6.1. Bois de Sioux River near White Rock, South Dakota The Lake Traverse Project consists of Mud Lake and Lake Traverse, with Mud Lake being downstream of Lake Traverse with its outlet at White Rock Dam. Reservation Dam is located between Mud Lake and Lake Traverse and is the outlet for Lake Traverse. To determine the Lake Traverse unregulated inflow record, Equation 1 is first used to calculate the inflows to Mud Lake. Then those calculated inflows to Mud Lake are used as reservoir outflows from Lake Traverse.

The USGS observed streamflow at White Rock (station ID 05050000) was adopted as the outflow from Mud Lake. Reservoir water surface elevations have been recorded on a daily basis since the Lake Traverse Project became operational in 1942. Daily change in storage was determined from daily observed water surface elevations published by USACE St. Paul District Water Management (Reference 10) and Lake Traverse Project elevation-capacity curves (Reference 4). Missing data in the digital daily water surface elevation files were augmented with entries contained on hard copy log sheets for White Rock and Reservation Pools maintained in the USACE St. Paul District office.

To reduce effects of reservoir water surface oscillations resulting from wind seiche, HEC-DSSVue software was used to apply a center moving average smoothing function. Before using Equation 1 at Mud Lake and Lake Traverse, a center moving average of five was applied to the observed reservoir water surface elevations.

Mustinka River is a tributary to Lake Traverse. Daily streamflow is available at USGS gage 05049000, Mustinka River above Wheaton, Minnesota, for water years 1916-1924 and 1931-1958. Annual instantaneous peak streamflow is published for those same water years and for the period 1985-2016. The drainage area is 810 square miles. The Minnesota Department of Natural Resources established a continuous-record station downstream of this location in 2010.

The reverse-routed Lake Traverse inflows were adjusted based on Mustinka River gaged flow. Only those events when the annual peak flow at Mustinka River was greater than the calculated Lake Traverse inflow were adjusted: March 1946, July 1949, and April 1952. The adjusted, reverse-routed Lake Traverse daily inflow was adopted as the unregulated daily streamflow at Bois de Sioux River near White Rock, South Dakota.

6.2. Bois de Sioux River near Doran, Minnesota An unregulated flow record for Doran from 1942 to 2016 was developed using a multi-step process. First, the regulated daily flow record at Doran was back extended to 1942 using a flow duration curve algorithm using the long-term station at Wahpeton, North Dakota. Next, the local flow to Doran was determined by routing observed flows from USGS stream gage 05050000 near White Rock, South Dakota, to Doran using a calibrated HEC-ResSim model for the basin. The local flow was calculated as a holdout hydrograph, or the difference between the regulated daily flow record at Doran and the routed hydrograph at Doran. More details regarding the development of the local flow record at Doran are provided at Section 4.3.1 Record Extension – Bois de Sioux River near Doran, Minnesota.


Finally, the HEC- ResSim model was used to route the previously-determined unregulated flow for White Rock and combine that routed flow with the local flow at Doran. The results are adopted as the unregulated daily streamflow at Doran.

6.3. Otter Tail River below Orwell Dam near Fergus Falls, Minnesota An unregulated flow record from 1931 to 2016 was developed for analysis at Orwell. Gaged flows from 1931 to early 1953 were adopted because these represent unregulated flows before Orwell Dam was constructed and placed in service. Daily unregulated flows from late 1953 to 2016 were determined using reverse routing at Orwell Dam.

Reservoir water surface elevations have been recorded on a daily basis since Orwell Reservoir became operational in 1953. Daily change in storage was determined from daily observed water surface elevations published by USACE St. Paul District Water Management (Reference 10) and Lake Traverse Project elevation-capacity curves (Reference 6).

After using Equation 1 at Orwell Reservoir, a five-day center moving average function was applied to the calculated inflow record.

The combination of observed daily flow (1931-1953) and reverse-routed Orwell daily inflow (1953-2016) was adopted as the unregulated daily streamflow at Otter Tail River below Orwell Dam near Fergus Falls, Minnesota.

6.4. Red River of the North at Wahpeton, North Dakota (Downstream of Otter Tail River Diversion)

Unregulated flow records determined during the 2015 Hickson analysis (Reference 8) were adopted at Wahpeton, North Dakota.

7. Local Flow Daily local flow is not required for two locations upstream of Wahpeton, North Dakota. The gages below Orwell Dam on the Otter Tail River and below White Rock Dam on the Bois de Sioux River are sufficiently close to the dams that the local drainage area between the dam and the gage location is negligible. Therefore, the unregulated inflows to the reservoirs described in the previous section will be used to perform the unregulated flow analysis at the Otter Tail River below Orwell Dam and Bois de Sioux River near White Rock locations.

Incremental local drainage area at the Bois de Sioux River near Doran location of interest is 720 square miles, while the total incremental local drainage area at the Red River of the North at Wahpeton location is 270 square miles (Reference 8). Therefore, local streamflow data are required at both of these locations. The extension of streamflow records at Doran, Minnesota, are described below. A local flow analysis was performed as part of the 2015 Hickson hydrologic analysis at Wahpeton, North Dakota (Reference 8). The results of the 2015 analysis are used directly for the current analysis and are not re-evaluated herein.


7.1. Record Extension – Bois de Sioux River near Doran, Minnesota The period of record for analysis for locations on the Bois de Sioux River is 1942-2009. However, the daily streamflow record at Doran, Minnesota, only starts in water year 1990. To help define the local flow contribution, an approximation of the daily flow record at Doran, Minnesota is made between 1942 and 1989. The daily streamflow record at Doran, Minnesota is back extended using a flow duration curve algorithm using the long-term station at Wahpeton, North Dakota. This is the same technique used during the hydrologic analysis for Hickson, North Dakota (Reference 8). The only difference in the current analysis is that flow duration curves for each month of the year at the USGS gage at Wahpeton, North Dakota, are determined based on a longer available record (WY1990-WY2016).

Summary of Flow Duration Algorithm Record Extension Technique As described in the recent Hickson, North Dakota, hydrologic analysis (Reference 8), researchers D.A Hughes and V. Smakhtin (Reference 1) found that flow time series can be patched or extended using a spatial interpolation approach based on flow duration curves. This technique uses the 1-day flow duration curves for each month of the year and is based upon the assumption that flows occurring simultaneously at sites in reasonably close proximity to each other have similar flow duration percentages.

An estimate of the streamflow on any day at the short term gage site is made by identifying the percentage point position on the duration curve table of the streamflows on the same day at the long term station and reading off the flow value for the equivalent percentage point from the short term destination site’s duration curve.

Evaluation of Estimated Streamflow – Bois de Sioux River near Doran, Minnesota Between 1990 and the current year the Doran and Wahpeton gages are both recording daily flow measurements. The observed record at Doran is compared to the record at Doran estimated for the concurrent period using the flow duration curve algorithm. The Nash-Sutcliffe coefficient (N-S) was calculated to assess the predictive power of the flow duration curve algorithm for the top 10 streamflow events observed at Doran (1995, 1997, 2001, 2005, 2006, 2007, 2009, 2010, 2011 and 2013). The N-S coefficient can range from negative infinity to one. The closer the N-S efficiency coefficient is to 1, the better the match to modeled discharge data. An efficiency coefficient lower than zero indicates that using the average value associated with the observed data series would be a better predicator than the modeled data. The average N-S coefficient was found to be equivalent to 0.91 which is close to one (significantly higher than zero), indicating that the flow duration curve algorithm can be used to approximate the flow record at Doran, Minnesota.


Local Flow Estimate – Bois de Sioux River near Doran, Minnesota The local flow hydrograph at Doran, Minnesota, was determined by first routing flows observed at USGS gage 05050000 (White Rock Dam outflows) to Doran, Minnesota using the calibrated, hydrologic routing model (HEC-ResSim). The period of record (1942-2009) holdout hydrograph was computed using the combined observed/ approximated daily flow record at USGS gage 05051300 near Doran, Minnesota. The holdout hydrograph is defined as the difference hydrograph between the adopted Doran streamflow record and the routed outflow hydrograph from White Rock Dam. This holdout hydrograph is the local flow between White Rock Dam and Doran, Minnesota.

8. Analytical Annual Instantaneous Flow-Frequency Unregulated annual instantaneous peak flows are required for the analytical flow-frequency analysis. Unregulated annual maximum daily mean flows per water year are calculated within HEC-DSSVue. These are converted to annual instantaneous peak flows at each location of interest using a regression relationship.

Regression relationships are developed in Microsoft Excel using a linear trendline with intercept set to zero (0). Results are shown in Figure 2, Figure 3, and Figure 4. Only those years with annual instantaneous peak flows published by the USGS were used in the regression analysis. Also, for the Otter Tail River location, the regression excluded flows before 1953 when Orwell Dam went into operation. Because the unregulated flow-frequency results at Red River of the North at Wahpeton, North Dakota, are adopted from the 2015 Hickson analysis (Reference 8), the development of the associated annual instantaneous peak flows at that location are not repeated herein. The adopted unregulated annual instantaneous peak flows are tabulated in Appendix B3.


Figure 2. Relationship to Convert Annual Mean Daily Peak Flow to Annual Instantaneous Peak Flow – Bois de Sioux River near White Rock, South Dakota

Figure 3. Relationship to Convert Annual Mean Daily Peak Flow to Annual Instantaneous Peak Flow – Bois de Sioux River near Doran, Minnesota


Figure 4. Relationship to Convert Annual Mean Daily Peak Flow to Annual Instantaneous Peak Flow – Otter Tail River below Orwell Dam near Fergus Falls, Minnesota

Analytical flow-frequency curves were developed using the Hydrologic Engineering Center’s Statistical Software Package (HEC-SSP) and Bulletin 17B methods (References 9, 13). Consideration was given to using the draft Bulletin 17C methods (Reference 11) used at other tributary sites and downstream mainstem locations on the Red River. Recent synthetic event analysis carried out for the Bois de Sioux and Otter Tail Rivers and the Red River of the North at Hickson and Wahpeton (Reference 8) used Bulletin 17B methods. To be consistent with that recent analysis and because the four locations described herein are impacted by regulation and require graphical analysis, Bulletin 17B methods were adopted.

A comparison of flow-frequency curves developed using station skew and weighted skew shows the weighted skew generates slightly better results as compared to the plotted unregulated events at the upper end of the curve at the Bois de Sioux River and Otter Tail River locations. Appendix B3 contains details of the comparison of station skew and weighted skew and unregulated flow-frequency curves. Results are shown in Table 4 through Table 7 at Section 12.1 Unregulated Condition.

A regional skew coefficient of -0.509 with standard error 0.368 was used to weight the skew at Bois de Sioux River near White Rock, South Dakota, and near Doran, Minnesota. The regional skew values are taken from “Regional Regression Equations to Estimate Peak-Flow Frequency at Sites in North Dakota Using Data through 2009.” Hydrologic Zone A, identified in Figure 1 of the report, includes the Bois de Sioux River (Reference 14).

A regional generalized skew coefficient of -0.19 with mean standard error of 0.182 was used to weight the skew at Otter Tail River below Orwell Dam per “Generalized Skew Coefficients for Flood Frequency


Analysis in Minnesota” (Reference 2). Per email correspondence with USGS, Minnesota is updating regional skew for the State; however, the results were not available for use in the current study (Reference 12).

9. Unregulated Volume-Frequency Analysis Volume-frequency (flow-duration) analysis was carried out for the 1-, 3-, 7-, 15-, 30-, 60-, and 90-day volumes using the unregulated streamflow records determined at Bois de Sioux River near White Rock, Bois de Sioux River near Doran, and Otter Tail River below Orwell. An unregulated, no breakout flow volume-frequency analysis was previously conducted for Red River of the North at Wahpeton (Reference 8).

HEC-SSP was used to perform volume frequency analysis using an analytical Log Pearson Type III distribution in accordance with Bulletin 17B methods (Reference 13). To ensure the analytical frequency curves are consistent and do not cross one another for all durations the standard deviation and skew were adjusted per Engineer Manual 1110-2-1415 (Reference 3). The results of the volume frequency analysis, along with the adopted smoothed statistics, are shown in Appendix B3.

10. Synthetic Event Analysis

10.1. Unregulated Balanced Hydrographs A combination of HEC-SSP and Microsoft Excel is used to develop balanced hydrographs at each location of interest. The hydrograph volume and peak for the 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual chance exceedance unregulated flow events are defined using the results from the annual instantaneous flow-frequency analysis and volume frequency analysis described above. Balanced hydrographs are based on the 1-day (peak), 3-day, 7-day, 15-day, and 30-day volumes with the exception of the Otter Tail River below Orwell location which included the 60-day volume.

The shape of the hydrograph is determined using selected pattern events. Two pattern events were selected for synthetic hydrograph development at Bois de Sioux River near White Rock: the April 1969 event and the March-April 2006 event. A single pattern event was used for the synthetic hydrograph development at Bois de Sioux River near Doran: March-April 2006. Two pattern events were used at Otter Tail River below Orwell: May-June 1972 and June 1974. The 2015 Hickson analysis used two pattern events at Red River of the North at Wahpeton: March-April 2006 and March-April 2009 (Reference 8). These events were used to develop synthetic hydrographs for the 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual chance exceedance unregulated, no breakout flow events. Events that are unimodal and assumed to be representative of extreme event flow distributions were selected. The 2006 event was selected for analysis at Bois de Sioux River locations to be consistent with the pattern event used on the mainstem Red River of the North.

The rising and falling limbs of the balanced hydrographs are smoothed by redistributing the volume associated with several durations. During smoothing the volumes for each duration remain the same as


those determined during the volume frequency analysis. Figure 5 shows the initial and smoothed balanced hydrograph at Bois de Sioux River near White Rock for the 1-percent annual chance exceedance event.

Figure 5. Example Smoothed, Balanced Hydrograph – Unregulated Flows

10.2. Unregulated Synthetic Input Hydrographs At Bois de Sioux River near White Rock and Otter Tail River below Orwell the unregulated balanced hydrographs serve as the unregulated synthetic input hydrographs used to determine regulated synthetic event flows at these locations. At Bois de Sioux River near Doran and Red River of the North at Wahpeton the unregulated pattern inflow hydrographs and local flow hydrographs are multiplied and edited (if necessary) in order to match the flow volumes associated with the balanced hydrographs at these locations.

After developing balanced hydrographs based upon the results of the unregulated, no breakout flow analyses and the selected pattern events, HEC-ResSim is used to route and combine reservoir and local inflow hydrographs to Bois de Sioux River near Doran and Red River of the North at Wahpeton. The computed hydrograph at each location of interest is compared to the statistically-based balanced hydrograph at that location. HEC-ResSim allows the use of an Inflow Multiplier that can be applied to each inflow time series to increase or decrease entering flows. Manual adjustments are made to this


Inflow Multiplier, as well as to the shape of the reservoir inflow and local flow hydrographs, in an effort to match the balanced hydrograph volume and peak for the 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual chance exceedance unregulated, no breakout flow events.

Because the HEC-ResSim Inflow Multiplier option applies a uniform adjustment to all ordinates of the hydrographs, some additional manual adjustments are made to the reservoir inflow and local flow hydrographs. Figure 6 shows an example of how the inflow hydrograph to Lake Traverse was adjusted when developing the input hydrographs for Bois de Sioux near Doran.

A summary of this iterative process follows:

1. Apply HEC-ResSim inflow multiplier to reservoir inflow and local flow hydrographs. (Note that for the synthetic hydrograph development, HEC-ResSim is used solely for routing. There are no reservoir operations or breakout flows.)

2. Compare HEC-ResSim computed hydrograph at location of interest to the balanced hydrograph volume and peak.

3. Use HEC-DSSVue to manually adjust the shape of inflow hydrographs. Target peak flow within 0.1 percent of unregulated, no breakout annual instantaneous peak. Target volume within two (2) percent for the 3- and 7-day durations and within five (5) percent for the 15- and 30-day durations.

4. Increase or decrease Inflow Multiplier and rerun HEC-ResSim. Repeat steps 1 -4 until targets are met for each of 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual chance exceedance unregulated, no breakout flow events.


Figure 6. Example of Manual Adjustments to Lake Traverse Inflow Hydrograph

Once the targets are met using HEC-ResSim to route and combine the inflow hydrographs, the analysis is further refined using unsteady HEC-RAS. Backwater effects, natural storage, and a gentle channel slope make it difficult to capture the interaction between the Bois de Sioux River, Otter Tail River and Red River of the North accurately utilizing a hydrologic model. The unsteady HEC-RAS model described in the main body of the Lower Red Basin Retention Study report was adjusted to prevent breakout flows from the Bois de Sioux River during the unregulated, no breakout flow synthetic event analysis.

The HEC-RAS process is essentially the same as that outlined above for HEC-ResSim except that the targets described in step 3 are revised upward. Peak flow is targeted within one (1) percent of unregulated, no breakout annual instantaneous peak. Volume is targeted within five (5) percent for the 3- and 7-day durations and within 10 percent for the 15- and 30-day durations. The allowable margin of error is greater in HEC-RAS than in HEC-ResSim because unsteady-state HEC-RAS runtimes are significantly longer than HEC-ResSim runtimes.

The inflow multipliers resulting from the HEC-ResSim and HEC-RAS unregulated, no breakout flows synthetic hydrograph analyses are shown in Table 3.


Table 3. Unregulated, No Breakout Flow Synthetic Hydrograph Inflow Multipliers

Pattern Event

Percent Chance

Exceedance (%)

HEC-ResSim Inflow Multiplier HEC-RAS Inflow Multiplier3

Doran Wahpeton Doran

2006 0.2 2.52 2.79 3.21 0.5 2.29 2.45 2.69 1 1.97 1.98 2.28 2 1.68 1.622 1.95 4 1.44 1.288 1.44 10 1.03 0.88 1.05

2009 0.2

Only one pattern event used at Doran

1.87

Only one pattern event used at Doran

0.5 1.495 1 1.24 2 1.03 4 0.82 10 0.567

For the current analysis, HEC-RAS was used to refine the unregulated synthetic input hydrographs only at Bois de Sioux River near Doran. Because the 2015 Hickson analysis developed synthetic input hydrographs solely within HEC-ResSim for the 2-, 1-, 0.5-, and 0.2-percent annual chance exceedance unregulated, no breakout flow events (Reference 8); the 10- and 4-percent annual chance exceedance input hydrographs for Wahpeton were also determined using HEC-ResSim.

10.3. Synthetic Regulated, With Breakout Flow Hydrographs The HEC-ResSim model described in Appendix B2 is used to route the unregulated synthetic reservoir inflow hydrographs developed as described above through the reservoirs. (The inflow multipliers from Table 2 are applied prior to routing the unregulated synthetic hydrographs through HEC-ResSim.) This defines the regulated outflows from Orwell Dam and White Rock Dam for the 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual chance exceedance pattern events. In the case of Bois de Sioux River near Doran, these regulated reservoir outflow hydrographs are used as inflow hydrographs to the unsteady-HEC-RAS model, which routes and combines the regulated reservoir outflow hydrographs and synthetic local flow hydrographs to the locations of interest. The unsteady HEC-RAS model geometry that allows flows to breakout from both the Bois de Sioux and Otter Tail Rivers is used.

In the case of Red River of the North at Wahpeton, HEC-ResSim is used to route the regulated reservoir outflow hydrographs along the Otter Tail River and Bois de Sioux River, combining flows with local input hydrographs and allowing flow to breakout from both rivers, until reaching the Red River of the North.

3 The inflow multiplier determined with the HEC-RAS model is applied within HEC-ResSim in order to determine the regulated outflow hydrographs.


The synthetic peak flows for the regulated, with breakout condition at the locations of interest are listed in Table 8. These are used to anchor the upper end of the graphical frequency analysis.

11. Regulated Balanced Hydrograph Determination

11.1. Regulated Daily and Annual Peak Flows The historic flow record is used to aid in the definition of the graphical flow frequency curve for exceedance probabilities smaller in magnitude than approximately the 2-percent annual chance exceedance event. The period of record used for the hydrologic analysis is 1942-2009 for the Bois de Sioux River and Red River of the North locations, while the period of record is 1931-2016 for the Otter Tail River location as described at Section 3 Period of Record.

The historic annual instantaneous peak flows used for regulated flow-frequency analysis are tabulated in Appendix B4. For each location of interest the historic regulated flow record was determined as follows:

11.1.1. Regulated Streamflow Record at Bois de Sioux River near White Rock, South Dakota As described in Section 1.1, the published USGS streamflow record at gaging station 05050000 includes the current analysis period of record. Therefore, the published USGS streamflow record at this location is adopted for both regulated daily and annual peak flow.

11.1.2. Regulated Streamflow Record at Bois de Sioux River near Doran, Minnesota As described in Section 1.2, the published USGS streamflow record at gaging station 05051300 begins in water year 1990. To determine the regulated daily flow at Doran for the ungaged portion of the analysis period, HEC-ResSim was used to route published USGS streamflow from White Rock to Doran for the period 1942 to September 30, 1989. The combination of routed streamflow (1942-1989) and gaged flow (1990-2009) is adopted as the regulated daily flow at Doran. For the period 1942-1989, regulated annual maximum daily mean flows per water year are calculated within HEC-DSSVue. These are converted to annual instantaneous peak flows at Doran using the regression relationship shown in Figure 3. The combination of calculated annual instantaneous peak flow (1942-1989) and published USGS annual instantaneous peak flow (1990-2009) is adopted as the regulated annual instantaneous peak streamflow record at Doran.

11.1.3. Regulated Streamflow Record at Otter Tail River below Orwell Dam near Fergus Falls, Minnesota As described in Section 1.3, the published USGS streamflow record at gaging station 05046000 begins in water year 1930. To determine the regulated daily flow at Orwell for the period before Orwell Dam went into operation, HEC-ResSim was used to route the published USGS streamflow through Orwell Reservoir from 1930 to 1953. The combination of routed streamflow (1930-1953) and regulated gaged flow (1953-2016) is adopted as the regulated daily flow at Orwell. Note that Orwell Dam went into


operation during water year 1953 and regulated annual instantaneous peak flow was measured by the USGS gage that year. For the period 1930-1952, regulated annual maximum daily mean flows per water year are calculated within HEC-DSSVue. These are converted to annual instantaneous peak flows at Orwell using the regression relationship shown in Figure 4. The combination of calculated annual instantaneous peak flow (1930-1952) and published USGS annual instantaneous peak flow (1953-2016) is adopted as the regulated annual instantaneous peak streamflow record at Orwell.

11.1.4. Red River of the North at Wahpeton, North Dakota (Downstream of Otter Tail River Diversion) Regulated historic flow records determined during the 2015 Hickson analysis (Reference 8) were adopted at Wahpeton, North Dakota.

11.2. Regulated Flow-Frequency Analysis Due to the effects of regulation and flow breakouts (in the case of Red River of the North at Wahpeton), flow-frequency distributions cannot be fit using an analytical, Log Pearson Type III distribution. Instead graphical techniques are applied to develop annual instantaneous peak flow-frequency curves and volume frequency analysis at the four locations of interest at and upstream of Wahpeton, North Dakota. The synthetic events described in Section 10.3 are used to help define the upper portion of the flow-frequency curves.

The majority of the regulated flow-frequency analysis is carried out using Microsoft Excel spreadsheets and HEC-SSP. To develop the graphical annual instantaneous peak stream flow frequency curves, the historic annual instantaneous peak flows tabulated in Appendix B4 are plotted using Weibull plotting positions. The historic flows and synthetic event flows are plotted at their associated recurrence interval in Microsoft Excel and a graphical curve manually drawn through the plotted points. The resulting annual instantaneous peak flow-frequency curves are plotted in Figure 7 through Figure 10 in Section 12.2.

For the volume frequency analysis, HEC-SSP was used to extract volume-duration data from the regulated streamflow data for the period of record at each location. Additionally, Microsoft Excel was used to extract the average of the maximum three days, seven days, fifteen days, and thirty days of flow associated with the synthetic event hydrographs described in Section 10.3. These data and the historic volume-duration data are plotted for each duration in Microsoft Excel, and a graphical flow-frequency curve is manually drawn through the plotted points. For Orwell, an additional duration of sixty days was added to the volume-frequency analysis due to the duration of the historic hydrographs at that location. Results of the volume-duration analysis are tabulated and plotted in Appendix B4.

11.3. Regulated Balanced Hydrographs Balanced hydrograph volumes are based upon the volume duration frequency curves tabulated and displayed in Appendix B4. In order to be consistent with Red River of the North mainstem sites, the 2006 regulated flow hydrograph at each of Bois de Sioux near White Rock, Bois de Sioux River near


Doran, and the Red River of the North at Wahpeton is used as the pattern event for the current analysis. The 1974 regulated flow hydrograph at Otter Tail River below Orwell is used as the pattern event on the tributary. A Microsoft Excel spreadsheet is used to generate balanced hydrographs by applying multipliers to the pattern event in order to minimize the difference between balanced hydrograph volume and the volumes defined by the volume duration frequency analysis.

After allocating flow volumes in exact accordance with the volume frequency curves, the hydrograph limbs are smoothed by redistributing volume associated with several of the durations. Smoothed balanced hydrograph volumes are within 0.5 percent of the volumes initially specified by the volume frequency curves. The peak of each balanced hydrograph is defined by the regulated annual instantaneous peak flow frequency curve. The results of the balanced hydrograph analysis are displayed in Figure 11 through Figure 14.

12. Results

12.1. Unregulated Condition Peak flow frequencies associated with the unregulated, no breakout flow condition are shown in Table 4 through Table 7. The results for Red River of the North at Wahpeton, North Dakota, in Table 7 are taken from the 2015 Hickson analysis (Reference 8) and included herein for comparison purposes. Results of the volume flow-frequency analysis are displayed in Appendix B3.

Table 4. Unregulated Annual Peak Discharge Frequency – Bois de Sioux River near White Rock, South Dakota

Unregulated Annual Peak Discharge Frequency Analysis USGS Gage 05050000 Bois de Sioux River near White Rock, SD

Methodology: Bulletin 17B - Log Pearson Type III Annual Exceedance

Probability Annual Instantaneous 90% Confidence Limits (cfs)

Peak Flow (cfs) 5% 95% 0.2% 25,810 40,040 18,380 0.5% 20,190 30,190 14,760 1% 16,470 23,900 12,300 2% 13,160 18,510 10,060 4% 10,250 13,920 8,020 10% 6,940 8,970 5,610

Statistics Mean 3.367 Systematic Record 68 Years

Standard Deviation 0.372 Historic Period Adopted Skew -0.057 Years in Record 1942-2009


Table 5. Unregulated Annual Peak Discharge Frequency – Bois de Sioux River near Doran, Minnesota

Unregulated Annual Peak Discharge Frequency Analysis USGS Gage 050051300 Bois de Sioux River near Doran, MN



Peak Flow (cfs) 5% 95% 0.2% 27,260 41,970 19,480 0.5% 22,230 33,220 16,230 1% 18,680 27,230 13,880 2% 15,350 21,770 11,620 4% 12,240 16,850 9,470 10% 8,490 11,170 6,770



Table 6. Unregulated Annual Peak Discharge Frequency – Otter Tail River below Orwell Dam near Fergus Falls, Minnesota

Unregulated Annual Peak Discharge Frequency Analysis USGS Gage 05046000 Otter Tail River below Orwell near Fergus Falls, MN



Peak Flow (cfs) 5% 95% 0.2% 3,020 3,630 2,600 0.5% 2,690 3,190 2,350 1% 2,450 2,870 2,150 2% 2,200 2,550 1,960 4% 1,950 2,230 1,750 10% 1,620 1,810 1,480




Table 7. Unregulated Annual Peak Discharge Frequency – Red River of the North at Wahpeton, North Dakota (Reference 8)

Unregulated Annual Peak Discharge Frequency Analysis USGS Gage 050051500 Red River of the North at Wahpeton, ND



Peak Flow (cfs) 5% 95% 0.2% 29,730 42,960 22,330 0.5% 24,730 34,790 18,940 1% 21,170 29,120 16,480 2% 17,790 23,880 14,090 4% 14,590 19,070 11,770 10% 10,630 13,350 8,810



12.2. Regulated Condition A summary of annual instantaneous peak regulated synthetic events at locations of interest are shown in Table 8. The synthetic event magnitudes are used to augment the systematic flow record in order to aid in defining the upper end of the regulated flow-frequency curve. They do not define the magnitude of the 10-percent to 0.2-percent annual chance exceedance events, but help to inform the construction of the graphical flow-frequency curve. Generally, observed event magnitudes are given more weight than synthetic event magnitudes when determining the regulated flow-frequency curve. The adopted regulated, with breakout annual instantaneous flow frequency curves are shown in Table 9 and are displayed in Figure 7 through Figure 10. Results of the volume-frequency analysis are contained in Appendix B4.

Table 8. Regulated Synthetic Event Peak Flow at and upstream of Wahpeton, North Dakota

Synthetic Regulated Annual Instantaneous Peak Flow

Annual Exceedance Probability

Bois de Sioux River near White

Rock, SD

Bois de Sioux River near Doran, MN

Otter Tail River below Orwell

near Fergus Falls, MN

Red River of the North at Wahpeton, ND

(downstream of Otter Tail River Diversion)

Flow in cfs 0.2% 14,130 23,540 3,010 24,860 0.5% 8,280 14,420 2,680 21,810 1% 7,940 11,730 2,440 18,630 2% 7,650 10,030 2,190 16,070 4% 7,100 7,310 1,940 13,330 10% 1,100 5,260 1,530 9,460


Table 9. Regulated, With Breakout Flow Annual Instantaneous Frequency Curves at and upstream of Wahpeton, North Dakota

Annual Instantaneous Peak Flow-Frequency Curves for Regulated, With Breakout Condition


Bois de Sioux River near White

Rock, SD

Bois de Sioux River near Doran, MN

Otter Tail River below Orwell

near Fergus Falls, MN

Red River of the North at Wahpeton, ND

(downstream of Otter Tail River Diversion)

Flow in cfs 0.2% 14,200 22,900 3,010 25,100 0.5% 8,500 14,800 2,690 21,200 1% 8,300 12,300 2,440 17,900 2% 7,600 10,100 2,190 14,700 4% 3,950 8,000 2,000 11,800 10% 1,700 5,500 1,580 8,500

As can be seen in the graphical flow-frequency curve for White Rock (Figure 7), the synthetic event simulation indicates the Lake Traverse Project would be overtopped between the 0.5- and 0.2-percent annual chance exceedance events. The pool elevation at Mud Lake (White Rock Dam) has exceeded the flood control pool elevation of 981.0 feet (1912 MSL) only once since the construction of the project. On April 15, 1997, USACE St. Paul District Water Management recorded a pool elevation of 981.69 feet. The recorded pool elevation was 980.88 feet five days later when USGS gage 05050000 downstream of White Rock Dam recorded the annual instantaneous peak flow of 8,750 cfs. Historically, the three tainter gates at White Rock are open less than three feet each even when operations have transitioned to a single pool (Mud Lake and Lake Traverse controlled by White Rock Dam). During only four historic events has the total gate opening exceeded nine feet and recorded streamflow at White Rock neared or exceeded 4,000 cfs: 1969, 1997, 2001, and 2009. For all other events, operations at White Rock Dam have kept reservoir releases below 2,000 cfs. Only the synthetic event flows for the extreme events (2-, 1-, 0.5-, and 0.2-percent annual chance exceedance) are plotted on Figure 7 since the historical operation of the flood control project for more frequent events (10- and 4- percent) differs from simulated operations. The plotted historic events for these more frequent recurrence intervals were used to determine the graphical flow-frequency curve.

The graphical flow-frequency curve for Doran (Figure 8) is smoother through the 0.5-percent annual chance exceedance event than is the flow-frequency curve at White Rock. This is because the annual instantaneous peak streamflow at Doran is primarily comprised of runoff from the local drainage area between White Rock Dam and Doran. The drainage area above White Rock Dam is regulated and flows are held back while the local drainage area flows peak at Doran. During three of the four peak events at White Rock, the peak at Doran resulted from high local drainage area flows and preceded the peak at White Rock by at least four days. Because the 0.2-percent annual chance exceedance event is not fully regulated by the Lake Traverse Project, an increase in slope at the upper end of the flow-frequency curve is observed.


The graphical flow-frequency curve at Orwell (Figure 9) shows that Orwell Reservoir provides little or no flood control regulation above the 10-percent annual chance exceedance event. The reservoir is regularly filled to or above the flood control pool elevation of 1070.0 feet (1912 MSL) with 33 events out of 64 events reaching at least that elevation since Orwell Reservoir went into operation in 1953.

Figure 10 shows the graphical flow-frequency curve at Wahpeton downstream of the Otter Tail River Diversion developed for the current study. It is similar to that produced during the 2015 Hickson analysis with a slight reduction in the 0.2-percent annual chance exceedance flow from 25,500 cfs to 25,100 cfs here. The flows increase slightly for the 10- through 0.5-percent annual chance exceedance events shown in Table 8 as compared to those reported in Table 12 of the Hickson report (Reference 8). This is due to differences in the regulated, with breakout flows synthetic event results.


Figure 7. Regulated Flow-Frequency Curve – Bois de Sioux River near White Rock, South Dakota


Figure 8. Regulated Flow-Frequency Curve – Bois de Sioux River near Doran, Minnesota


Figure 9. Regulated Flow-Frequency Curve – Otter Tail River below Orwell Dam near Fergus Falls, Minnesota


Figure 10. Regulated, with Breakout Flow-Frequency Curve – Red River of the North at Wahpeton, North Dakota (downstream of Otter Tail River Diversion)


12.3. Balanced Hydrographs Balanced hydrographs for each of the 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual chance exceedance events for the regulated, with breakout flow condition are shown in Figure 11 through Figure 14.

Figure 11. Smoothed, Balanced Hydrographs for the Regulated Condition – Bois de Sioux River near White Rock, South Dakota


Figure 12. Smoothed, Balanced Hydrographs for the Regulated Condition – Bois de Sioux River near Doran, Minnesota


Figure 13. Smoothed, Balanced Hydrographs for the Regulated Condition – Otter Tail River below Orwell Dam near Fergus Falls, Minnesota


Figure 14. Smoothed, Balanced Hydrographs for the Regulated, With Breakout Flow Condition – Red River of the North at Wahpeton, North Dakota (downstream of Otter Tail River Diversion)

A potential limitation of using the 2006 event as the pattern event on the Bois de Sioux River is that this particular event was successfully regulated by the Lake Traverse Project. Peak flow at White Rock Dam occurred after the peak flow at Doran had already passed. The USGS gage at White Rock recorded an annual instantaneous peak streamflow of 1,460 cfs on April 12, 2006. At Doran the peak flow of 6,150 cfs was recorded ten days prior to that on April 2, 2006. As discussed above, the contribution of local drainage area runoff to peak flow is significant at Doran until the Lake Traverse Project no longer has capacity to regulate flow. Therefore, the timing of the peak flow at Doran would likely shift to a later day during the event if flows are initially contained by the Lake Traverse Project and then White Rock Dam is overtopped. This is seen when modeling a synthetic 0.2-percent annual chance exceedance event with HEC-ResSim and then routing the regulated flows to Doran using HEC-RAS. Figure 15 compares the timing of the 0.2-percent smoothed, balanced hydrograph patterned after the observed 2006 event to the modeled 0.2-percent synthetic event at Doran. Since an event exceeding the capacity of the Lake Traverse Project has not been observed, there is uncertainty in how the project would actually be operated during an extreme event. However, the synthetic simulation gives some idea of the timing of such an event.


Figure 15. Timing of Balanced versus Synthetic Hydrographs for Regulated 0.2-Percent Event at Doran


13. References 1. Hughes, D. A. and V. Smakhtin (1996). “Daily Flow Time Series Patching or Extension: A Spatial

Interpolation Approach Based on Flow Duration Curves.” Hydrological Sciences Journal 41, no. 6 (December): 851-871. Accessed August 3, 2017. http://dx.doi.org/10.1080/02626669609491555

2. Lorenz, D.L. (1997). “Generalized Skew Coefficients for Flood-Frequency Analysis in Minnesota.” U.S. Geological Survey Water Resources Investigation Report 97-4089. Mounds View, Minnesota.

3. U.S. Department of Defense, U.S. Army Corps of Engineers (1993). “Hydrologic Frequency Analysis: Engineer Manual 1110-2-1415.” Washington, D.C.

4. U.S. Department of Defense, U.S. Army Corps of Engineers (1994). “Water Control Manual: Lake Traverse Project. Lake Traverse Reservoir: Lake Traverse Reservoir and Mud Lake Reservoir, Including Reservation Dam and Mud Lake Dam; Bois de Sioux River, Red River of the North Basin; Minnesota, North Dakota and South Dakota.” St. Paul District, St. Paul, MN. Revised December.

5. U.S. Department of Defense, U.S. Army Corps of Engineers (2001a). “Red River of the North Hydrologic Modeling Study – Phase I.” St. Paul District, St. Paul, MN.

6. U.S. Department of Defense, U.S. Army Corps of Engineers (2001b). “Water Control Manual: Flood Control; Ottertail River, Minnesota. Orwell Reservoir: Ottertail River Flood Control Reservoir and Channel Improvement Project; Fergus Falls, Minnesota.” St. Paul District, St. Paul, MN. Revised August.

7. U.S. Department of Defense, U.S. Army Corps of Engineers (2013). Reservoir System Simulation (HEC-ResSim). Version 3.1 (May). Hydrologic Engineering Center: Davis, California.

8. U.S. Department of Defense, U.S. Army Corps of Engineers (2015). “The Use of Synthetic Floods for Defining the Regulated Flow-Frequency & Volume Duration Frequency Curves for the Red River at Hickson, North Dakota.” St. Paul District, St. Paul, MN.

9. U.S. Department of Defense, U.S. Army Corps of Engineers (2017a). Statistical Software Package (HEC-SSP). Version 2.1.1.137 (January). Hydrologic Engineering Center: Davis, California.

10. U.S. Department of Defense, U.S. Army Corps of Engineers (2017b.) Historical Data Download. USACE St. Paul District Water Management. Accessed July- August 2017. http://www.mvp-wc.usace.army.mil/

11. U.S. Department of the Interior, U.S. Geological Survey (2015). “Bulletin 17C Guidelines for Determining Flood Flow Frequency (Draft).” Advisory Committee on Water Information. Reston, VA.

12. U.S. Department of the Interior, U.S. Geological Survey. April 21, 2016. Email correspondence with A. Veilleux ([email protected])

13. Water Resources Council (1982). “Guidelines for Determining Flood Flow Frequency. Bulletin 17B.” Hydrology Committee, Washington, D.C.

14. Williams-Sether, Tara (2015). “Regional Regression Equations to Estimate Peak-Flow Frequency at Sites in North Dakota Using Data through 2009.” U.S. Geological Survey Scientific Investigations Report 2015–5096, 12 p., http://dx.doi.org/10.3133/sir20155096.

http://dx.doi.org/10.1080/02626669609491555

http://www.mvp-wc.usace.army.mil/

http://www.mvp-wc.usace.army.mil/

mailto:[email protected]

http://dx.doi.org/10.3133/sir20155096

Appendix B1 –

Nonstationarity Detection and Hydrologic Sensitivity Analysis of Unregulated Flows Upstream of Wahpeton, North Dakota

Appendix B1 - Nonstationarity Detection and Hydrologic Sensitivity Analysis of Unregulated Flows 1

Table of Contents

1. Overview .................................................................................................................................. 3

2. Bois de Sioux River near White Rock, South Dakota ............................................................... 3

2.1. Nonstationarity Detection................................................................................................ 3

2.1.1. Data Upload .............................................................................................................. 3

2.1.2. Nonstationarity Detector .......................................................................................... 3

2.1.3. Monotonic Trend Analysis ........................................................................................ 4

2.2. Hydrologic Sensitivity Analysis ......................................................................................... 7

2.3. Period of Record Recommendation ................................................................................. 8

3. Bois de Sioux River near Doran, Minnesota .......................................................................... 10

3.1. Nonstationarity Detection.............................................................................................. 10

3.1.1. Data Upload ............................................................................................................ 10

3.1.2. Nonstationarity Detector ........................................................................................ 10

3.1.3. Monotonic Trend Analysis ...................................................................................... 11

3.2. Hydrologic Sensitivity Analysis ....................................................................................... 15

3.3. Period of Record Recommendation ............................................................................... 16

4. Otter Tail River below Orwell Dam near Fergus Falls, Minnesota ........................................ 19

4.1. Nonstationarity Detection.............................................................................................. 19

4.1.1. Data Upload ............................................................................................................ 19

4.1.2. Nonstationarity Detector ........................................................................................ 19

4.1.3. Comparison to Regulated Flow Results .................................................................. 20

4.1.4. Monotonic Trend Analysis ...................................................................................... 22

4.2. Hydrologic Sensitivity Analysis ....................................................................................... 25

4.3. Period of Record Recommendation ............................................................................... 26

5. References ............................................................................................................................. 29


Figures

Figure 1. Results of Nonstationarity Detection Tool Using Unregulated Annual Instantaneous Peak Flows – Bois de Sioux River near White Rock, South Dakota ... 5

Figure 2. Monotonic Trend Analysis (1942-2009) – Bois de Sioux River near White Rock, South Dakota ............................................................................................................. 6

Figure 3. Monotonic Trend Analysis (1942-2016) – Bois de Sioux River near White Rock, South Dakota ............................................................................................................. 7

Figure 4. Sensitivity Analysis - Flow-Frequency Curves for Two Periods of Record: 1942-2009 and 1942-2016 - Bois de Sioux River near White Rock, South Dakota ..................... 9

Figure 5. Results of Nonstationarity Detection Tool Using Unregulated Annual Instantaneous Peak Flows – Bois de Sioux River near Doran, Minnesota .............. 12

Figure 6. Monotonic Trend Analysis (1942-2009) – Bois de Sioux River near Doran, Minnesota ............................................................................................................... 13



Figure 9. Sensitivity Analysis - Flow-Frequency Curves for Three Periods of Record: 1942-2009, 1942-2016, and 1993-2016 – Bois de Sioux River near Doran, Minnesota .. 17

Figure 10. Sensitivity Analysis Detail for Annual Exceedance Probabilities Less than 20 Percent - Bois de Sioux River near Doran, Minnesota ............................................ 18

Figure 11. Results of Nonstationarity Detection Tool Using Unregulated Annual Instantaneous Peak Flows – Otter Tail River below Orwell Dam near Fergus Falls, Minnesota ............................................................................................................... 21

Figure 12. Results of Nonstationarity Detection Tool Using Gaged Flows below Orwell Dam, Otter Tail River, Minnesota (Regulated Flows from 1953 to 2016) ........................ 22

Figure 13. Monotonic Trend Analysis for Homogenous Periods of Record: (a) 1931-1941, (b) 1942-1992, (c) 1993-2016 – Otter Tail River below Orwell Dam ............................ 23

Figure 14. Monotonic Trend Analysis (1931-2016) – Otter Tail River below Orwell Dam ...... 24 Figure 15. Monotonic Trend Analysis (1942-2016) – Otter Tail River below Orwell Dam ...... 25 Figure 16. Sensitivity Analysis - Flow-Frequency Curves for Three Periods of Record: 1931-

2016, 1942-2016, and 1993-2016 – Otter Tail River below Orwell Dam ................ 27 Figure 17. Sensitivity Analysis Detail for Annual Exceedance Probabilities Less than 20

Percent - Otter Tail River below Orwell Dam .......................................................... 28


1. Overview A Nonstationarity Detection Tool (References 2, 3) was used to identify nonstationarities in the unregulated annual instantaneous peak streamflows at the three locations of interest upstream of Wahpeton, North Dakota: (1) Bois de Sioux River near White Rock, South Dakota; (2) Bois de Sioux River near Doran, Minnesota; and (3) Otter Tail River below Orwell Dam near Fergus Falls, Minnesota. In addition, a hydrologic sensitivity analysis was performed on the same datasets. Nonstationarity detection and hydrologic sensitivity analysis were performed in order to identify any concerns regarding the period of record (1942-2009) selected for the Bois de Sioux River and to ascertain whether the full gaged record (1931-2016) could be used at the Otter Tail River location (Reference 4).

2. Bois de Sioux River near White Rock, South Dakota

2.1. Nonstationarity Detection The Nonstationarity Detection Tool at http://rsgis-rserver.crrel.usace.army.mil:3838/tst_app/ (Reference 3) was used to identify nonstationarities in the unregulated annual instantaneous peak streamflow record on the Bois de Sioux River near White Rock, South Dakota. US Geological Survey (USGS) stream gage 05050000 has been recording flows since 1942 at that location. The gaged period covers regulated flows on the Bois de Sioux River since the White Rock Dam (Lake Traverse Project) began operation in 1942.

2.1.1. Data Upload An unregulated flow record was developed using reverse routing through both White Rock and Reservation Dams. The annual peak daily mean flow was converted to annual instantaneous peak flows using the relationship between these at the gage. The full dataset (1942-2016) of unregulated annual instantaneous peak flows was uploaded to the Nonstationarity Detection Tool (Reference 3).

2.1.2. Nonstationarity Detector A “strong” nonstationarity is one for which there is a consensus among multiple nonstationarity detection methods, robustness in detection of changes in statistical properties, and relatively large change in the magnitude of a dataset’s statistical properties (Reference 1). No strong nonstationarities in the unregulated annual instantaneous peak streamflow record on the Bois de Sioux River near White Rock, South Dakota, are identified for the period 1942 to 2016.

http://rsgis-rserver.crrel.usace.army.mil:3838/tst_app/


Consensus. As shown in Figure 1, the statistically significant nonstationarity detected in the early 1990s has consensus between the Lombard Wilcoxon and the Mann-Whitney methods, both which detect a change in mean.

Robustness. Figure 1 shows that the nonstationarity detected in 1952 can be considered robust because statistical tests targeting both changes in the mean (Mann-Whitney) and overall distributional properties of the dataset (Cramer-von-Mises) are identifying statistically significant nonstationarities. As well, the smooth Lombard model identifies a long period that transects the 1950s portion of the record.

Magnitude. In the early 1990s the mean annual instantaneous peak flow approximately doubled from about 2,500 cfs to nearly 5,000 cfs. The variance and standard deviation also show large changes in the early 1990s and again near 2004.

Although the nonstationarity detected in the early 1990s demonstrates consensus and represents appreciable changes in the mean and variance/standard deviation, it cannot be considered strong because it does not demonstrate robustness. Similarly, consensus cannot be found for the nonstationarity detected in 1952, so it is reasonable to discount it.

2.1.3. Monotonic Trend Analysis Monotonic trend analysis was performed on unregulated flow for the following periods of record:

1942-2009 (period of record used for Red River of the North mainstem sites). The results (Figure 2) indicate that there is not a statistically significant trend for this portion of the record.

1942-2016 (full period of record). As shown in Figure 3, the Mann-Kendall Test detects a statistically significant, positive monotonic trend in the full period of record.


Figure 1. Results of Nonstationarity Detection Tool Using Unregulated Annual Instantaneous Peak Flows – Bois de Sioux River near White Rock, South Dakota


Figure 2. Monotonic Trend Analysis (1942-2009) – Bois de Sioux River near White Rock, South Dakota


Figure 3. Monotonic Trend Analysis (1942-2016) – Bois de Sioux River near White Rock, South Dakota

2.2. Hydrologic Sensitivity Analysis To test the sensitivity of the analytical flow-frequency curve to a truncated, unregulated flow dataset, the following periods of record were used:

1942-2009 (homogenous period of record with no statistically significant, monotonic trend) and

1942-2016 (full period of record).


Current Federal Emergency Management Agency (FEMA) guidelines require the application of an updated frequency curve for floodplain mapping when the existing curve fits outside a standard deviation, 68-percent confidence interval, of the new curve (Reference 5). To assess whether there is a significant change in the flow-frequency curve, the 68-percent confidence interval is plotted along with the computed analytical frequency curves in Figure 4.

Using the FEMA guidelines as a reference, the flow-frequency curve for the period 1942-2016 is not significantly different from the curve generated using 1942-2009 data. That is, the 1942-2009 curve falls within a standard deviation of the 1942-2016 curve. In other words, the results are not sensitive to this small difference in period of record.

2.3. Period of Record Recommendation The analytical flow-frequency curve determination and balanced hydrographs for the Bois de Sioux River near White Rock, South Dakota, will be based on the same period of record as used for the Red River of the North mainstem sites (1942-2009) for the following reasons: (1) no strong nonstationarities were detected in the unregulated flow dataset; (2) the period 1942 to 2009 shows no statistically significant, monotonic trend; (3) the frequency curve generated using 1942-2009 data is not significantly different from that generated from the full period of record; and (4) the Bois de Sioux River is considered an extension upstream of the Red River of the North and, thus, is considered part of its mainstem.


Figure 4. Sensitivity Analysis - Flow-Frequency Curves for Two Periods of Record: 1942-2009 and 1942-2016 - Bois de Sioux River near White Rock, South Dakota


3. Bois de Sioux River near Doran, Minnesota

3.1. Nonstationarity Detection The Nonstationarity Detection Tool at http://rsgis-rserver.crrel.usace.army.mil:3838/tst_app/ (Reference 3) was used to identify nonstationarities in the unregulated annual instantaneous peak streamflow record on the Bois de Sioux River near Doran, Minnesota. USGS stream gage 05051300 has been recording flows since 1989 at that location. The gaged period covers regulated flows on the Bois de Sioux River.

3.1.1. Data Upload An unregulated flow record for Doran from 1942 to 2016 was developed using a multi-step process. First, the regulated daily flow record at Doran was back extended to 1942 using a flow duration curve algorithm using the long-term station at Wahpeton, North Dakota. Next, the local flow to Doran was determined by routing observed flows from the USGS stream gage 05050000 near White Rock, South Dakota, to Doran using a calibrated HEC-ResSim model for the basin. The local flow was calculated as a holdout hydrograph, or the difference between the regulated daily flow record at Doran and the routed hydrograph at Doran. Finally, the HEC-ResSim model was used to route the previously-determined unregulated flow for White Rock Dam and combine that routed flow with the local flow at Doran. The results are the unregulated daily flow record at Doran. The annual peak daily mean flow was converted to annual instantaneous peak flows using the relationship between these at the gage. The full dataset (1942-2016) of unregulated annual instantaneous peak flows was uploaded to the Nonstationarity Detection Tool (Reference 3).

3.1.2. Nonstationarity Detector A strong nonstationarity in the unregulated annual instantaneous peak streamflow record on the Bois de Sioux River near Doran is identified in the early 1990s, as discussed below.

Consensus. As shown in Figure 5, the statistically significant nonstationarity detected in the early 1990s has consensus among the Lombard Wilcoxon, Pettitt, and Mann-Whitney methods, all of which detect a change in mean.

Robustness. Figure 5 shows that the nonstationarity detected in 1952 can be considered robust because statistical tests targeting both changes in the mean (Mann-Whitney) and overall



distributional properties of the dataset (Cramer-von-Mises) are identifying statistically significant nonstationarities. Similarly, the nonstationarity detected in the early 1990s can also be considered robust.

Magnitude. The nonstationarity detected in 1952 corresponds to a change of 1,700 cfs in the mean, 700 cfs in the standard deviation, and 3,200,000 cfs2 in the variance of the annual instantaneous peak streamflow. The nonstationarities detected in the 1990s correspond to a change of 3,200 cfs in the mean, 1,700 cfs in the standard deviation, and 11,800,000 cfs2 in the variance.

Because the nonstationarity detected in the early 1990s has consensus, can be considered robust, and demonstrates a relatively large change in statistical properties, it can be considered a strong, statistically significant nonstationarity.

3.1.3. Monotonic Trend Analysis Monotonic trend analysis was performed on unregulated flow for the following periods of record:

1942-2009 (period of record used for Red River of the North mainstem sites). The Mann-Kendall Test detects a statistically significant, positive monotonic trend in this portion of the record (Figure 6).

1942-2016 (full period of record). As expected, there is a statistically significant, positive monotonic trend detected in the full period of record as shown in Figure 7.

1993-2016 (statistically stationary period of record). There is no statistically significant monotonic trend for this period of record (Figure 8).


Figure 5. Results of Nonstationarity Detection Tool Using Unregulated Annual Instantaneous Peak Flows – Bois de Sioux River near Doran, Minnesota


Figure 6. Monotonic Trend Analysis (1942-2009) – Bois de Sioux River near Doran, Minnesota





3.2. Hydrologic Sensitivity Analysis To test the sensitivity of the analytical flow-frequency curve to the nonstationarities found in the unregulated dataset, the following periods of record were used:

1942-2009 (period of record used for Red River of the North mainstem sites);

1942-2016 (full period of record);

1993-2016 (homogenous period of record following detected nonstationarity).


Current Federal Emergency Management Agency (FEMA) guidelines require the application of an updated frequency curve for floodplain mapping when the existing curve fits outside a standard deviation, 68-percent confidence interval, of the new curve (Reference 5). To assess whether there is a significant change in the flow-frequency curve, the 68-percent confidence interval is plotted along with the computed analytical frequency curves in Figure 9. For purposes of the Red River Retention Study, the 10-year, 25-yr, 50-yr, 100-yr, 200-yr and 500-yr balanced hydrographs are required. Therefore, Figure 10 provides more detail in the upper portion of the curve to demonstrate results of the sensitivity analysis. It is only at this upper portion of the curve where the sensitivity analysis is applied.

Using the FEMA guidelines as a reference, the upper portion of the flow-frequency curve for the period 1942-2016 is not significantly different from the curve generated using 1942-2009 data (Figure 9 and Figure 10). That is, the 1942-2016 curve falls within a standard deviation of the 1942-2009 curve. As can be seen in the same figures, the curve generated using the statistically stationary (homogenous) period 1993-2016 is significantly different from the other frequency curves.

3.3. Period of Record Recommendation The dataset for the 1942-2009 period of record will be used for development of balanced hydrographs at the stream gage near Doran, Minnesota. This is because the frequency curve generated using 1942-2009 data is not significantly different from that generated from the full period of record and because the Bois de Sioux River is considered an extension upstream of the Red River of the North which uses the 1942-2009 period of record.

Future analysis should consider the use of the homogenous period of record from 1993 to 2016. This period of record follows the strong, statistically significant nonstationarity that was detected in the early 1990s and shows no statistically significant, monotonic trend.


Figure 9. Sensitivity Analysis - Flow-Frequency Curves for Three Periods of Record: 1942-2009, 1942-2016, and 1993-2016 – Bois de Sioux River near Doran, Minnesota


Figure 10. Sensitivity Analysis Detail for Annual Exceedance Probabilities Less than 20 Percent - Bois de Sioux River near Doran, Minnesota


4. Otter Tail River below Orwell Dam near Fergus Falls, Minnesota

4.1. Nonstationarity Detection The Nonstationarity Detection Tool at http://rsgis-rserver.crrel.usace.army.mil:3838/tst_app/ (Reference 3) was used to identify nonstationarities in the unregulated annual instantaneous peak streamflow record on the Otter Tail River below Orwell Dam near Fergus Falls, Minnesota. USGS stream gage 05046000 has been recording flows since 1931 at that location. The gaged period covers both unregulated (1931 to early 1953) and regulated flows on the Otter Tail River (early 1953 to present). Orwell Dam began operation in early 1953.

4.1.1. Data Upload An unregulated flow record from 1931 to 2016 was developed for analysis. Gaged annual instantaneous peak flows from 1931 to early 1953 were used directly because these represent unregulated flows before Orwell Dam was constructed and placed in service. Daily unregulated flows from late 1953 to 2016 were determined using reverse routing at Orwell Dam. The annual peak daily mean flow was converted to annual instantaneous peak flows using the relationship between these at the gage. The full dataset (1931-2016) of unregulated annual instantaneous peak flows was uploaded to the Nonstationarity Detection Tool (Reference 3).

4.1.2. Nonstationarity Detector Strong nonstationarities in the unregulated annual instantaneous peak streamflow record on the Otter Tail River below Orwell Dam are identified in the early 1940s and early 1990s, as discussed below.

Consensus. As shown in Figure 11, the statistically significant nonstationarity detected in 1941 has consensus between two methods that detect a change in distribution. For the statistically significant nonstationarity detected in the early 1990s, there is consensus between two methods that detect a change in distribution and among three methods that detect a change in mean.

Robustness. Figure 11 shows that nonstationarity identified near 1940 can be considered robust because statistical tests targeting both changes in the mean and overall distributional properties of the dataset are identifying statistically significant nonstationarities. For the same reason, the nonstationarity in the early 1990s can also be considered robust.



Magnitude. In the early 1940s the mean annual instantaneous peak flow nearly doubled from 530 cfs to 960 cfs. In the early 1990s the mean increased to 1300 cfs, representing nearly a 50 percent increase in mean annual instantaneous peak streamflow.

4.1.3. Comparison to Regulated Flow Results Figure 12 shows results from the Nonstationarity Detection Tool at http://corpsmapu.usace.army.mil/cm_apex/f?p=257:10:0::NO. This tool uses USGS gage data directly and does not adjust for regulation.

As with the unregulated flow record, the nonstationarity detection tool identifies two strong nonstationarities that are statistically significant (1941 and 1992).

What is interesting here is that the construction and operation of the Orwell Dam had no noticeable impact on the stationarity of the regulated flow record. Operation of Orwell Dam began in 1953, but there is no indication of nonstationarity at or near that time. Even when altering the tool’s sensitivity parameters to extreme values, the tool does not detect nonstationarity in 1953.

http://corpsmapu.usace.army.mil/cm_apex/f?p=257:10:0::NO


Figure 11. Results of Nonstationarity Detection Tool Using Unregulated Annual Instantaneous Peak Flows – Otter Tail River below Orwell Dam near Fergus Falls, Minnesota


Figure 12. Results of Nonstationarity Detection Tool Using Gaged Flows below Orwell Dam, Otter Tail River, Minnesota (Regulated Flows from 1953 to 2016)

4.1.4. Monotonic Trend Analysis Monotonic trend analysis was performed on the following statistically stationary (homogenous) periods of record based on the two nonstationarities identified. The analyses were performed on the unregulated flow record, and the results are shown in Figure 13.

1931-1941 – No statistically significant trend.




Figure 13. Monotonic Trend Analysis for Homogenous Periods of Record: (a) 1931-1941, (b) 1942-1992, (c) 1993-2016 – Otter Tail River below Orwell Dam

a. 1931-1941

b. 1942-1992

c. 1993-2016

Monotonic trend analysis was also performed on the following periods of record that are not statistically stationary.

1931-2016 (full period of record). As expected, there is a statistically significant, positive monotonic trend detected in the full period of record as shown in Figure 14.


1942-2016 (period of record following detected nonstationarity). As shown in Figure 15, there is a statistically significant, positive monotonic trend detected in this portion of the record.

Figure 14. Monotonic Trend Analysis (1931-2016) – Otter Tail River below Orwell Dam


Figure 15. Monotonic Trend Analysis (1942-2016) – Otter Tail River below Orwell Dam

4.2. Hydrologic Sensitivity Analysis To test the sensitivity of the analytical flow-frequency curve to the nonstationarities found in the unregulated dataset, the following periods of record were used:

1931-2016 (full period of record);

1942-2016 (record following detected nonstationarity);

1993-2016 (homogenous period of record following detected nonstationarity).


Current Federal Emergency Management Agency (FEMA) guidelines require the application of an updated frequency curve for floodplain mapping when the existing curve fits outside a standard deviation, 68-percent confidence interval, of the new curve (Reference 5). To assess whether there is a significant change in the flow-frequency curve, the 68-percent confidence interval is plotted along with the computed analytical frequency curves in Figure 16. For purposes of the Red River Retention Study, the 10-year, 25-yr, 50-yr, 100-yr, 200-yr and 500-yr balanced hydrographs are required. Therefore, Figure 17 provides more detail in the upper portion of the curve to demonstrate results of the sensitivity analysis. It is only at this upper portion of the curve where the sensitivity analysis is applied.

Using the FEMA guidelines as a reference, the upper portion of the flow-frequency curve for the period 1942-2016 is not significantly different from the curve generated using 1931-2016 data (Figure 17). That is, the 1931-2016 curve falls within a standard deviation of the 1942-2016 curve. From Figure 17 the curve generated using the statistically stationary (homogenous) period 1993-2016 is significantly different from the full period of record curve.

4.3. Period of Record Recommendation The dataset for the 1931-2016 period of record will be used for development of balanced hydrographs at the stream gage below Orwell Dam. This will use as much of the available record as possible, which is consistent with the methodology being applied at other tributary locations.

Future analysis should consider the use of the homogenous period of record from 1993 to 2016. This period of record follows the strong, statistically significant nonstationarity that was detected in the early 1990s and shows no statistically significant, monotonic trend.


Figure 16. Sensitivity Analysis - Flow-Frequency Curves for Three Periods of Record: 1931-2016, 1942-2016, and 1993-2016 – Otter Tail River below Orwell Dam


Figure 17. Sensitivity Analysis Detail for Annual Exceedance Probabilities Less than 20 Percent - Otter Tail River below Orwell Dam


5. References 1. Friedman, D., J. Schechter, B. Baker, C. Mueller, G. Villarini, and K.D. White (2016). “US

Army Corps of Engineers Nonstationarity Detection Tool User Guide,” US Army Corps of Engineers, Washington, DC.

2. U.S. Department of Defense, US Army Corps of Engineers Nonstationarity Detection Tool. Released March 2016. Accessed August 1, 2017. http://corpsmapu.usace.army.mil/cm_apex/f?p=257:2:0::NO

3. U.S. Department of Defense, US Army Corps of Engineers Nonstationarity Detection Tool Time-Series Toolbox (beta). Accessed August 1 – 8, 2017. http://rsgis-rserver.crrel.usace.army.mil:3838/tst_app/

4. U.S. Department of Defense, US Army Corps of Engineers (2017). “Guidance for Detection of Nonstationarities in Annual Maximum Discharges,” Technical Letter No. 1100-2-3.

5. U.S. Department of Homeland Security, Federal Emergency Management Agency (FEMA) (2009). “Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix C: Guidance for Riverine Flooding Analyses and Mapping.”

http://corpsmapu.usace.army.mil/cm_apex/f?p=257:2:0::NO



Appendix B2 –

Reservoir System Simulation (HEC ResSim) Model Modifications for Extreme Event Modeling at Lake Traverse Project and Orwell Reservoir

Appendix B2 - HEC ResSim Modifications for Extreme Event Modeling 1

Table of Contents

1. Summary of HEC-ResSim Modifications .................................................................................. 3

2. Physical Description of Reservoir Projects .............................................................................. 4

2.1. Lake Traverse Project ....................................................................................................... 4

2.1.1. Reservation Dam ....................................................................................................... 5

2.1.2. White Rock Dam ....................................................................................................... 6

2.2. Orwell Reservoir ............................................................................................................... 6

3. HEC-ResSim Model .................................................................................................................. 8

3.1. Overview .......................................................................................................................... 8

3.2. HEC-ResSim Adopted Modifications .............................................................................. 10

3.2.1. Extend Lake Traverse Project Reservoir Elevation-Storage Capacity Curves ......... 10

3.2.2. Revise Reservation Dam Release Capacity Curve ................................................... 11

3.2.3. Extend White Rock Dam Release Capacity Curve ................................................... 13

3.2.4. Lake Traverse Project Additional Operations Zones ............................................... 15

3.2.5. Remove Downstream Control from Orwell Reservoir ............................................ 15

4. Impact of Reservoir Model Revisions on Results ..................... Error! Bookmark not defined.

5. References ............................................................................................................................. 16


Figures

Figure 1. Aerial View of the Lake Traverse Project .................................................................. 5 Figure 2. Aerial View of Orwell Reservoir ................................................................................ 7 Figure 3. Tainter Gate at Orwell Dam ...................................................................................... 8 Figure 4. HEC-ResSim Network ................................................................................................ 9 Figure 5. Extrapolated Lake Traverse Project Elevation-Capacity Curves.............................. 11 Figure 6. Reservation Dam Outlet Capacity Curve ................................................................. 13 Figure 7. White Rock Dam Outflow Curve – Gates Wide Open (Source: Reference 4) ......... 14


1. Summary of HEC-ResSim Modifications A model was developed using the Hydrologic Engineering Center’s Reservoir System Simulation (HEC-ResSim) software, version 3.1 (Reference 6), to support The Use of Synthetic Floods for Defining the Regulated Flow-Frequency & Volume Duration Frequency Curves for the Red River at Hickson, North Dakota (Reference 7). That HEC-ResSim model was modified and adopted for use in the Red River of the North Retention Feasibility Study to determine balanced hydrographs at four locations affected by regulation: (1) Bois de Sioux River near White Rock, South Dakota; (2) Bois de Sioux River near Doran, Minnesota; (3) Otter Tail River below Orwell Dam near Fergus Falls, Minnesota; and (4) Red River of the North at Wahpeton, North Dakota (below Otter Tail River Diversion).

The following reservoir systems modifications were made to the HEC-ResSim model and are described in more detail in Section 3.2 HEC-ResSim Adopted Modifications:

1. Extended Lake Traverse Project reservoirs elevation-storage capacity curves to 990 feet. These were first extended to 986 feet, top of White Rock Dam, based on the Lake Traverse Project Water Control Manual (Reference 3) and then linearly extrapolated to 990 feet. The extrapolation to 990 feet was performed in case of dam overtopping. Per email and telephonic communication with the Hydrologic Engineering Center (HEC), HEC-ResSim does not automatically perform the extrapolation (Reference 8).

2. Revised discharge capacity rating curve for Reservation Dam outlet. a. Corrected gate flow calculations above 979 feet to increase consistently with

head. b. Extended discharge capacity rating curve to 990 feet to match the extended

reservoir elevation-capacity curves. The extended capacity curve includes Reservation Dam overtopping (flow over top of Highway 117).

c. Set the length of top of dam to zero (0) to avoid double-counting flow releases from Reservation above 983 feet (top of dam).

3. Revised discharge capacity rating curve for White Rock Dam outlet. a. The outlet capacity curve of the tainter gates was first extrapolated to 986.0 feet

(top of dam) based on a gates-wide-open elevation-outflow curve developed for a 1999 Lake Traverse Dam Safety Study.

b. The total discharge capacity rating curve was then extended to 990 feet to match the extended reservoir elevation-capacity curves. The extended capacity curve includes White Rock Dam overtopping (flow over top of County Road 10).

c. Set length of top of dam to zero (0) to avoid double-counting flow releases from White Rock above 986 feet (top of dam).


4. Added two operational zones to Lake Traverse Project reservoirs: Top of Dam (986 feet) and Overtopped (990 feet). Both include a new rule that sets all gates wide open. This results in outflows from White Rock at the maximum physical capacity of the gates plus flow over County Road 10 when the dam is overtopped.

5. Removed Wahpeton control from Orwell Reservoir. Because a downstream control function is required in HEC-ResSim, the function was revised such that the outflow was not limited by stage at Wahpeton. This modification was confirmed with St. Paul Water Management personnel.

2. Physical Description of Reservoir Projects

2.1. Lake Traverse Project The Lake Traverse Flood Control Project is on the boundaries of Minnesota, North Dakota, and South Dakota. Lake Traverse forms the headwaters of the Bois de Sioux River. The Lake Traverse Project extends from the continental divide at Browns Valley, Minnesota, to a point along the Bois de Sioux River six miles south of Wahpeton, North Dakota/ Breckenridge, Minnesota. The project became operational in 1942 and consists of the Browns Valley Dike, Reservation and White Rock Dams and associated reservoirs, and the Bois de Sioux River channel. The reservoir behind Reservation Dam is called Lake Traverse, and the reservoir behind White Rock Dam is called Mud Lake. The two reservoirs operate as a single pool with control at White Rock Dam once the elevation reaches approximately 976.8 feet (1912 MSL). The total capacity of the two reservoirs at the top of White Rock Dam (986.0 feet) is about 368,000 acre-feet (Reference 3).

The top of the flood control pool is 981.0 feet, and maximum flowage easement is at 983.0 feet (Reference 3). Figure 1 shows an aerial view of the project.


Figure 1. Aerial View of the Lake Traverse Project

2.1.1. Reservation Dam Reservation Dam is topped by Minnesota Highway 117. The dam/highway embankment is rolled-earth fill with a blacktopped highway surface and riprapped embankment sides. The highway crosses the South Dakota/ Minnesota State boundary. According to the 1994 Water Control Manual (WCM) for the project (Reference 3), the embankment on the Minnesota side is


about 9,100 feet long with a top elevation of 981.0 feet (+/- 0.5 foot) to provide additional spillway capacity during floods when the reservoir elevation exceeds approximately 980.5 feet. The embankment on the South Dakota side is about 1,100 feet long with a top elevation of approximately 983.0 feet. In 2001 the Minnesota Highway 117 top of roadway was surveyed from Reservation Dam’s right abutment eastward approximately 8,100 feet.

The Reservation Dam outlet structure consisted of 17 stop log sections (bays) across the top of the spillway until 2001, when the stop logs were replaced by Obermeyer bladder gates. The first record of Obermeyer bladder gates is March 2001 in the Lake Traverse Project log sheets. The outlet capacity curve is calculated using a Microsoft Excel spreadsheet populated with a weir flow formula obtained from the Obermeyer Corporation.

2.1.2. White Rock Dam White Rock Dam is topped by County Road 10. The dam/highway embankment is rolled-earth fill with a blacktopped highway surface. The upstream embankment slope is entirely riprapped, while only the base of the downstream embankment slope is riprapped. The highway crosses the South Dakota/Minnesota State boundary. The embankment is 14,400 feet long with a top elevation of 986.0 feet (Reference 3).

The White Rock Dam outlet structure is a reinforced concrete section topped with a bridge deck. The structure contains three reversed Tainter gates, each 13 feet wide by 16 feet high. In the closed position, the top of the gates is at elevation 981.0 feet or 9 feet above the normal conservation pool elevation of 972 feet. An elevation-discharge rating curve for the White Rock Dam outlet structure is provided in the project’s water control manual. As described in Section 3.2.3, the curve is linearly extrapolated to 986 feet (top of dam) for the current study based on a gates-wide-open elevation-outflow curve developed for a 1999 Lake Traverse Dam Safety Study (Reference 4).

2.2. Orwell Reservoir Orwell Dam on the Otter Tail River near Fergus Falls, Minnesota, was constructed in 1953. The conservation pool was set in 1986 at 1064 feet. The Otter Tail River capacity below the dam during normal (non-flood) conditions is 1,200 cfs. The top of the flood control pool is constrained by Dayton Hollow power dam, which is upstream of Orwell Reservoir. In order to not interfere with the tailwater rating curve at Dayton Hollow, the top of the flood control pool is set to 1070 feet. The top of surcharge pool is 1073 feet which coincides with the guide contour line (flood easement) for the reservoir. Orwell is a relatively small reservoir that provides just under 18,000 acre-feet of storage at the top of the surcharge pool (Reference 5).


Figure 2 shows an aerial image of Orwell Reservoir.

Figure 2. Aerial View of Orwell Reservoir

The Orwell Dam outlet structure (Figure 3) consists of a single Tainter gate that is 33 feet wide by 27.5 feet high with a radius of 30 feet. The gate seat is located on the ogee spillway just downstream of the spillway crest at elevation 1043.5 feet. The top of gate elevation is 1071.5 feet in the closed position.


Figure 3. Tainter Gate at Orwell Dam

3. HEC-ResSim Model

3.1. Overview A model was developed using the Hydrologic Engineering Center’s Reservoir System Simulation (HEC-ResSim) software to support The Use of Synthetic Floods for Defining the Regulated Flow-Frequency & Volume Duration Frequency Curves for the Red River at Hickson, North Dakota (Reference 7).

Figure 4 shows the HEC-ResSim network developed for the 2015 Hickson analysis. The locations of interest for this study are included in the existing HEC-ResSim model as junctions: White Rock Outflow, Orwell Release, Doran, and UpEnloe2. UpEnloe2 represents the combined flow from the Red River of the North at Wahpeton and the Otter Tail River Diversion. The flow at that junction is adopted to represent the Red River of the North at Wahpeton (downstream of Otter Tail River Diversion).

The performance of the existing HEC-ResSim model was compared to records of observed reservoir pool elevations and dam releases. Finding the simulation of historic data generally acceptable, the model was modified for extreme (high flow) events and adopted for use in the current study.


Figure 4. HEC-ResSim Network


3.2. HEC-ResSim Adopted Modifications The HEC-ResSim model modifications consist only of edits to the Lake Traverse Project and Orwell Reservoir physical properties and operations. No modifications are made to other components of the model. That is, breakout flow relationships and other flow diversions and routing parameters are adopted as defined during the 2015 Hickson analysis (Reference 7).

3.2.1. Extend Lake Traverse Project Reservoir Elevation-Storage Capacity Curves In order to simulate events that might fill or overtop the Lake Traverse Project reservoirs (Mud Lake and Lake Traverse), the elevation-capacity curves must be defined for an elevation higher than the top of dam. Per email and telephonic communication with HEC, HEC-ResSim does not automatically extrapolate elevation-capacity curves (Reference 8). White Rock Dam is at 986.0 feet, so an elevation of 990 feet was selected as the maximum elevation for the capacity curve. Capacity curves to approximately 985 feet (1912 MSL) are included as Plate 2-11 of the project WCM (Reference 3). These are linearly extrapolated as shown in Figure 5. Elevation-capacity curves to 990 feet replace those in the 2015 Hickson analysis HEC-ResSim model, which had been defined up to elevation 984 feet.


Figure 5. Extrapolated Lake Traverse Project Elevation-Capacity Curves

3.2.2. Revise Reservation Dam Release Capacity Curve The elevation-discharge (outlet release capacity) curve for the Obermeyer bladder gates at Reservation Dam is calculated using a Microsoft Excel spreadsheet populated with a weir flow formula obtained from the Obermeyer Corporation.

As shown in Figure 6, the outlet capacity curve used for the 2015 Hickson analysis does not increase consistently with head between elevations 979 and 980 feet (1912 MSL). This is due to how discharge coefficients are referenced by Microsoft Excel’s lookup function. To improve the outlet capacity curve, additional detail from Hydraulic Design Chart III-4 was added to the spreadsheet lookup table of submerged crest coefficients (Reference 1).

The outlet release capacity curve was extended to elevation 990 feet (1912 MSL) to match the extended reservation elevation-storage capacity curve. The curve used for the 2015 Hickson analysis extended to 983 feet (top of Reservation Dam) in order to account for roadway


overtopping that had been observed during the 2001 flood event. At that elevation most of the flow is due to roadway overtopping. Using a Microsoft Excel spreadsheet, the Federal Highway Administration’s broad-crested weir equation is used to calculate flow over the top of roadway. The gate flow is combined with the roadway overtopping flow to obtain a composite elevation-discharge curve for Reservation Dam.

Highway 117, which runs along the top of Reservation Dam, was surveyed after the 2001 flood event. The survey spanned a distance of 8,100 feet from the right abutment eastward along Highway 117 top of road. Overtopping of the roadway begins at approximately elevation 980.7 feet (1912 MSL). In order to extend the outlet release capacity curve to elevation 990 feet, additional top of road data was extracted from LiDAR flown in 2008-2009.

The length of Reservation top of dam is set to zero (0) to avoid double-counting flow releases from Reservation above 983 feet (top of dam). According to email correspondence with HEC, HEC-ResSim calculates uncontrolled releases from a dam based on the length of that dam specified within the model (Reference 8). If the pool elevation reaches top of dam, uncontrolled releases are automatically calculated unless the dam length is set to zero. Because dam overtopping is specified per the roadway overtopping calculations noted above, it is important to zero out any automated HEC-ResSim dam overtopping calculations so that flows over the dam are not counted twice.


Figure 6. Reservation Dam Outlet Capacity Curve

3.2.3. Extend White Rock Dam Release Capacity Curve The elevation-discharge (outlet release capacity) curve for the Tainter gates at White Rock Dam ended at 984 feet (1912 MSL) in the HEC-ResSim model developed for the 2015 Hickson analysis. To ensure the model can simulate extremely large events (up to the 0.2-percent annual chance exceedance event), the outlet release capacity is extended to elevation 990 feet to match the extended reservation elevation-storage capacity curve.

The elevation-discharge rating curve to elevation 981 feet is specified for the White Rock Dam in the Lake Traverse Project water control manual (Reference 3). The outlet release capacity curve of the Tainter gates was first extrapolated to 986 feet (top of dam) based on a gates-wide-open elevation-outflow curve developed for a 1999 Lake Traverse Dam Safety Study. A graph developed based on that study is shown as Figure 7.


Figure 7. White Rock Dam Outflow Curve – Gates Wide Open (Source: Reference 4)


An uncontrolled elevation-outflow curve is added to the White Rock Dam physical description within HEC-ResSim to represent flow over County Road 10 once the dam is overtopped. The uncontrolled elevation-outlfow curve is defined from elevation 986 feet (top of dam) to elevation 990 feet (1912 MSL) to match the extended reservation elevation-storage capacity curve. Using a Microsoft Excel spreadsheet, the Federal Highway Administration’s broad-crested weir equation is used to calculate flow over the top of roadway. Top of road data was extracted from LiDAR flown in 2008-2009 for County Road 10, which runs along the top of White Rock Dam. The Tainter gate flow is combined with the roadway overtopping flow within HEC-ResSim to describe a composite release capacity curve.

The length of White Rock top of dam is set to zero (0) to avoid double-counting flow releases from White Rock above 986 feet (top of dam). According to email correspondence with HEC, HEC-ResSim calculates uncontrolled releases from a dam based on the length of that dam specified within the model (Reference 8). If the pool elevation reaches top of dam, uncontrolled releases are automatically calculated unless the dam length is set to zero. Because dam overtopping is specified per the roadway overtopping calculations noted above, it is important to zero out any automated HEC-ResSim dam overtopping calculations so that flows over the dam are not counted twice.

3.2.4. Lake Traverse Project Additional Operations Zones Two operational zones are added to the Lake Traverse Project reservoirs for extreme event modeling: Top of Dam (986 feet) and Overtopped (990 feet). According to the Water Control Manual (Reference 3), gates are to be raised clear of the water surface when the water level in Lake Traverse/ Mud Lake reaches the top of flood control pool (981 feet). The maximum design pool elevation is 982 feet. Gate operations during an extreme event are not detailed in the Emergency Plan for the project (Reference 2). For purposes of modeling extreme events, it is assumed the gates would remain fully open. Both additional operation zones include a new rule that sets all gates wide open once the top of dam is reached. This results in outflows from White Rock at the maximum physical capacity of the gates plus flow over County Road 10 when the dam is overtopped.

3.2.5. Remove Downstream Control from Orwell Reservoir Because a downstream control function is required in HEC-ResSim, the function was revised such that the outflow was not limited by stage at Wahpeton. This modification was confirmed with St. Paul Water Management personnel.


4. References 1. U.S. Department of Defense, U.S. Army Corps of Engineers (1977). Hydraulic Design

Criteria. Waterways Experiment Station: Vicksburg, MS. Accessed August 25, 2017. http://www.dtic.mil/get-tr-doc/pdf?AD=ADA092237

2. U.S. Department of Defense, U.S. Army Corps of Engineers (1989). Dam Safety Program, Lake Traverse Project, White Rock Dam and Lake Traverse: Emergency Plan. St. Paul District, St. Paul, MN. October.

3. U.S. Department of Defense, U.S. Army Corps of Engineers (1994). “Water Control Manual: Lake Traverse Project. Lake Traverse Reservoir: Lake Traverse Reservoir and Mud Lake Reservoir, Including Reservation Dam and Mud Lake Dam; Bois de Sioux River, Red River of the North Basin; Minnesota, North Dakota and South Dakota.” St. Paul District, St. Paul, MN. Revised December.

4. U.S. Department of Defense, U.S. Army Corps of Engineers (1999). White Rock Dam Elevation-Outflow Curve – Gates Wide Open from Lake Traverse Rope Study. St. Paul District Water Management Section Chief internal notes attached to 1994 Lake Traverse Project Water Control Manual.

5. U.S. Department of Defense, U.S. Army Corps of Engineers (2001). “Water Control Manual: Flood Control; Ottertail River, Minnesota. Orwell Reservoir: Ottertail River Flood Control Reservoir and Channel Improvement Project; Fergus Falls, Minnesota.” St. Paul District, St. Paul, MN. Revised August.

6. U.S. Department of Defense, U.S. Army Corps of Engineers (2013). Hydrologic Engineering Center Reservoir System Simulation (HEC-ResSim) software version 3.1. Davis, CA. May.

7. U.S. Department of Defense, U.S. Army Corps of Engineers (2015). “The Use of Synthetic Floods for Defining the Regulated Flow-Frequency & Volume Duration Frequency Curves for the Red River at Hickson, North Dakota.” St. Paul District, St. Paul, MN. January.

8. U.S. Department of Defense, U.S. Army Corps of Engineers (2017). Email correspondence with J. Klipsch ([email protected]). September 6, 2017.

http://www.dtic.mil/get-tr-doc/pdf?AD=ADA092237

mailto:[email protected]

Appendix B3 –

Unregulated, No Breakout Condition Flow Frequency Curves at and Upstream of Wahpeton, North Dakota

Appendix B3 - Unregulated, No Breakout Condition Flow Frequency Curves at and Upstream of Wahpeton 1

Tables

Table 1. Unregulated Annual Instantaneous Peak Streamflow – Bois de Sioux River near White Rock, South Dakota ........................................................................................ 2

Table 2. Unregulated Annual Instantaneous Peak Streamflow – Bois de Sioux River near Doran, Minnesota ...................................................................................................... 3

Table 3. Unregulated Annual Instantaneous Peak Streamflow – Otter Tail River below Orwell Dam near Fergus Falls, Minnesota ................................................................ 4

Table 4. Unregulated Annual Instantaneous Peak Streamflow – Red River of the North at Wahpeton, North Dakota (USACE 2015) ................................................................... 6

Table 5. Unregulated Annual Peak Discharge Frequency – Bois de Sioux River near White Rock, South Dakota ................................................................................................. 10

Table 6. Unregulated Annual Peak Discharge Frequency – Bois de Sioux River near Doran, Minnesota ............................................................................................................... 10

Table 7. Unregulated Annual Peak Discharge Frequency – Otter Tail River below Orwell Dam near Fergus Falls, Minnesota .......................................................................... 11

Table 8. Unregulated Annual Peak Discharge Frequency – Red River of the North at Wahpeton, North Dakota, Downstream of Otter Tail River Diversion (USACE 2015) ................................................................................................................................. 11

Figures

Figure 1. Unregulated Flow-Frequency Curve – Bois de Sioux River near White Rock, South Dakota ....................................................................................................................... 7

Figure 2. Unregulated Flow-Frequency Curve – Bois de Sioux River near Doran, Minnesota 8 Figure 3. Unregulated Flow-Frequency Curve - Otter Tail River below Orwell Dam near

Fergus Falls, Minnesota ............................................................................................. 9 Figure 4. Unregulated Analytical Volume-Frequency Analysis – Bois de Sioux River near

White Rock, South Dakota ...................................................................................... 12 Figure 5. Unregulated Analytical Volume-Frequency Analysis – Bois de Sioux River near

Doran, Minnesota .................................................................................................... 13 Figure 6. Unregulated Analytical Volume-Frequency Analysis – Otter Tail River below Orwell

Dam near Fergus Falls, Minnesota .......................................................................... 14 Figure 7. Unregulated, No Breakout Analytical Volume-Frequency Analysis – Red River of

the North at Wahpeton, North Dakota, Downstream of Otter Tail River Diversion (Source: USACE 2015) .............................................................................................. 15


Table 1. Unregulated Annual Instantaneous Peak Streamflow – Bois de Sioux River near White Rock, South Dakota

Date

Unregulated Annual Instantaneous Peak

Streamflow (cfs) Date


Streamflow (cfs) 15 May 42 2,106 25 Mar 76 1,126 03 Apr 43 4,895 13 Mar 77 662 05 Jun 44 2,665 31 Mar 78 7,537

18 Mar 45 1,470 14 Apr 79 4,349 21 Mar 46 3,512 01 Apr 80 554 12 Apr 47 3,414 30 Apr 81 1,659 30 Mar 48 3,127 17 Apr 82 2,718

12 Jul 49 2,750 09 Mar 83 667 10 May 50 2,164 30 Mar 84 3,988 08 Apr 51 3,891 21 Mar 85 2,478 10 Apr 52 9,211 31 Mar 86 5,796 19 Mar 53 1,288 05 Nov 86 733 05 Jun 54 1,511 13 May 88 441 18 Apr 55 1,841 01 Apr 89 5,906 02 Apr 56 911 04 Apr 90 534 22 Apr 57 1,879 03 Jul 91 2,364 07 Apr 58 1,072 18 Jun 92 764 29 Jun 59 1,171 09 Jul 93 5,424

29 Mar 60 1,989 23 Mar 94 6,453 16 May 61 783 29 Mar 95 5,515 24 May 62 4,211 18 May 96 3,167 11 Jun 63 3,252 06 Apr 97 14,550 11 Apr 64 1,113 10 May 98 1,094 03 Jun 65 4,819 06 Jun 99 1,918

15 Mar 66 5,186 11 Mar 00 1,003 28 Mar 67 1,835 12 Apr 01 12,785 06 Apr 68 764 21 Jul 02 816 11 Apr 69 11,529 27 Jun 03 5,037 14 Apr 70 1,274 25 Sep 04 1,630 17 Mar 71 3,174 07 Jun 05 4,044 19 Mar 72 2,690 01 Apr 06 6,866 26 May 73 818 03 Apr 07 4,632 20 May 74 717 13 Jun 08 4,245

02 Jul 75 1,866 25 Mar 09 7,989


Table 2. Unregulated Annual Instantaneous Peak Streamflow – Bois de Sioux River near Doran, Minnesota

Date




Streamflow (cfs) 07 Jun 42 3,061 26 Mar 76 1,890 06 Apr 43 6,279 16 Mar 77 508 06 Jun 44 4,047 05 Apr 78 7,008

18 Mar 45 3,333 19 Apr 79 7,776 25 Mar 46 3,092 01 Apr 80 2,046 13 Apr 47 4,877 03 May 81 1,073 07 Apr 48 3,368 02 Apr 82 2,602 11 Jul 49 2,033 12 Mar 83 673

10 May 50 3,895 28 Mar 84 4,297 07 Apr 51 5,994 19 Mar 85 2,943 15 Apr 52 9,147 30 Mar 86 5,717 25 Jun 53 1,910 26 Mar 87 1,156 08 Jun 54 1,321 27 Mar 88 465 21 Apr 55 978 05 Apr 89 9,554 14 Apr 56 1,166 16 Mar 90 354 23 Apr 57 2,112 03 Jul 91 3,972 10 Apr 58 689 19 Jun 92 844 02 Jul 59 1,071 02 Apr 93 5,625

31 Mar 60 2,141 01 Apr 94 6,537 19 May 61 617 18 Mar 95 6,789 25 May 62 5,656 11 Apr 96 4,300 11 Jun 63 2,799 15 Apr 97 17,105 17 Apr 64 1,216 28 Jun 98 2,923 11 Apr 65 5,701 07 Jun 99 3,286 18 Mar 66 5,244 09 Mar 00 973 30 Mar 67 2,327 15 Apr 01 14,194 28 Apr 68 518 12 Jul 02 2,125 16 Apr 69 11,624 30 Jun 03 3,390 09 Apr 70 760 25 Sep 04 3,017 20 Mar 71 2,126 15 Jun 05 6,771 20 Mar 72 3,538 05 Apr 06 8,521 16 Mar 73 1,068 05 Jun 07 6,105 23 May 74 641 14 Jun 08 2,480

04 Jul 75 3,460 27 Mar 09 11,499


Table 3. Unregulated Annual Instantaneous Peak Streamflow – Otter Tail River below Orwell Dam near Fergus Falls, Minnesota

Date




Streamflow (cfs) 18 May 31 686 03 Jun 74 1,378 14 Jun 32 551 21 Jun 75 1,240 18 Jun 33 577 27 Mar 76 618

29 May 34 448 09 Mar 77 229 26 Jun 35 472 30 Mar 78 992 14 Apr 36 468 31 May 79 1,079 30 Jul 37 518 06 Apr 80 912

16 Jun 38 544 01 Aug 81 405 30 Nov 38 603 01 Apr 82 917 02 Sep 40 600 01 Sep 83 499 02 Jul 41 611 09 Jun 84 1,052

06 Jun 42 747 28 Jun 85 1,333 02 Apr 43 1,150 25 May 86 1,589 04 Jun 44 1,200 07 Nov 86 843

14 Nov 44 1,120 23 May 88 456 19 Jul 46 777 04 Apr 89 962

10 Jun 47 1,370 18 Jun 90 603 18 May 48 900 02 Jul 91 856

08 Jul 49 564 23 Apr 92 503 23 May 50 1,100 27 Jul 93 1,242 05 Apr 51 1,160 02 Oct 93 1,057 10 Apr 52 1,040 14 May 95 1,029 17 Jun 53 1,710 18 May 96 1,377 08 Jun 54 1,079 06 Apr 97 1,931 05 Jul 55 682 19 Jul 98 1,357

30 May 56 1,025 06 Jun 99 1,486 24 Jun 57 751 21 Apr 00 929 05 Oct 57 489 14 Jun 01 1,699 06 Jun 59 604 12 Jul 02 1,079

21 May 60 836 29 Jun 03 913 01 Jun 61 495 01 Jun 04 843 18 Jun 62 1,250 14 Jun 05 1,352 12 Jun 63 875 25 May 06 1,699

14 May 64 865 03 Jun 07 1,836 08 Jun 65 1,494 14 Jun 08 1,277


Date




Streamflow (cfs) 17 May 66 1,414 01 May 09 1,987 16 Jun 67 1,172 15 Sep 10 1,718

15 May 68 698 29 Oct 10 2,041 10 Apr 69 1,574 06 May 12 1,090

31 May 70 864 23 Jun 13 1,660 09 Apr 71 641 23 Jun 14 2,135

29 May 72 1,457 09 Jun 15 1,443 15 Mar 73 598 12 Aug 16 991


Table 4. Unregulated Annual Instantaneous Peak Streamflow – Red River of the North at Wahpeton, North Dakota (Source: USACE 2015)

Date




Streamflow (cfs) 07 Jun 42 4,293 26 Mar 76 3,151 07 Apr 43 7,653 16 Mar 77 676 06 Jun 44 5,542 31 Mar 78 9,221

18 Mar 45 4,697 14 Apr 79 9,437 22 Mar 46 4,214 01 Apr 80 3,639 13 Apr 47 6,358 03 May 81 1,279 07 Apr 48 4,164 02 Apr 82 4,140 10 Jul 49 3,051 13 Mar 83 1,184

10 May 50 5,342 28 Mar 84 6,335 07 Apr 51 7,304 02 Jun 85 4,631 16 Apr 52 10,039 30 Mar 86 8,690 22 Jun 53 3,452 26 Mar 87 2,029 09 Jun 54 2,760 27 Mar 88 1,014 03 Apr 55 1,828 05 Apr 89 11,924 14 Apr 56 2,132 18 Mar 90 1,028 22 Apr 57 3,098 04 Jul 91 3,699 09 Apr 58 1,265 08 Mar 92 2,144 01 Jul 59 1,838 01 Apr 93 7,284

07 Apr 60 3,088 27 Mar 94 7,387 19 May 61 1,075 17 Mar 95 7,996 25 May 62 7,991 19 May 96 5,976 11 Jun 63 4,733 15 Apr 97 19,470 17 Apr 64 2,039 29 Jun 98 4,688 11 Apr 65 7,841 07 Jun 99 4,908 18 Mar 66 7,533 10 Mar 00 2,271 30 Mar 67 3,439 17 Apr 01 13,537 27 Apr 68 1,032 12 Jul 02 3,849 16 Apr 69 12,590 27 Jun 03 4,601 09 Apr 70 1,860 25 Sep 04 3,544 21 Mar 71 2,635 15 Jun 05 8,926 20 Mar 72 5,628 01 Apr 06 11,967 16 Mar 73 1,698 04 Jun 07 10,637 23 May 74 1,655 08 Jun 08 3,710

04 Jul 75 4,783 24 Mar 09 17,548


Figure 1. Unregulated Flow-Frequency Curve – Bois de Sioux River near White Rock, South Dakota


Figure 2. Unregulated Flow-Frequency Curve – Bois de Sioux River near Doran, Minnesota


Figure 3. Unregulated Flow-Frequency Curve - Otter Tail River below Orwell Dam near Fergus Falls, Minnesota


Table 5. Unregulated Annual Peak Discharge Frequency – Bois de Sioux River near White Rock, South Dakota

Unregulated Annual Peak Discharge Frequency Analysis USGS Gage 05050000 Bois de Sioux River near White Rock, SD

Methodology: Bulletin 17B - Log Pearson Type III Exceedance

Probability (%) Annual Instantaneous 90% Confidence Limits (cfs)

Peak Flow (cfs) 5% 95% 0.20% 25,810 40,040 18,380 0.50% 20,190 30,190 14,760

1% 16,470 23,900 12,300 2% 13,160 18,510 10,060 4% 10,250 13,920 8,020 10% 6,940 8,970 5,610



Table 6. Unregulated Annual Peak Discharge Frequency – Bois de Sioux River near Doran, Minnesota

Unregulated Annual Peak Discharge Frequency Analysis USGS Gage 050051300 Bois de Sioux River near Doran, MN



Peak Flow (cfs) 5% 95% 0.20% 27,260 41,970 19,480 0.50% 22,230 33,220 16,230

1% 18,680 27,230 13,880 2% 15,350 21,770 11,620 4% 12,240 16,850 9,470 10% 8,490 11,170 6,770




Table 7. Unregulated Annual Peak Discharge Frequency – Otter Tail River below Orwell Dam near Fergus Falls, Minnesota

Unregulated Annual Peak Discharge Frequency Analysis USGS Gage 05046000 Otter Tail River below Orwell near Fergus Falls, MN



Peak Flow (cfs) 5% 95% 0.20% 3,020 3,630 2,600 0.50% 2,690 3,190 2,350

1% 2,450 2,870 2,150 2% 2,200 2,550 1,960 4% 1,950 2,230 1,750 10% 1,620 1,810 1,480



Table 8. Unregulated Annual Peak Discharge Frequency – Red River of the North at Wahpeton, North Dakota, Downstream of Otter Tail River Diversion (USACE 2015)

Unregulated Annual Peak Discharge Frequency Analysis USGS Gage 050051500 Red River of the North at Wahpeton, ND



Peak Flow (cfs) 5% 95% 0.20% 29,730 42,960 22,330 0.50% 24,730 34,790 18,940

1% 21,170 29,120 16,480 2% 17,790 23,880 14,090 4% 14,590 19,070 11,770 10% 10,630 13,350 8,810




Figure 4. Unregulated Analytical Volume-Frequency Analysis – Bois de Sioux River near White Rock, South Dakota


Figure 5. Unregulated Analytical Volume-Frequency Analysis – Bois de Sioux River near Doran, Minnesota


Figure 6. Unregulated Analytical Volume-Frequency Analysis – Otter Tail River below Orwell Dam near Fergus Falls, Minnesota


Figure 7. Unregulated, No Breakout Analytical Volume-Frequency Analysis – Red River of the North at Wahpeton, North Dakota, Downstream of Otter Tail River Diversion (Source: USACE 2015)


Reference:

U.S. Army Corps of Engineers. 2015. The Use of Synthetic Floods for Defining the Regulated Flow-Frequency & Volume Duration Frequency Curves for the Red River at Hickson, North Dakota. St. Paul District, St. Paul, MN. January.

Appendix B4 –

Regulated, With Breakout Condition Flow Frequency Curves at and Upstream of Wahpeton, North Dakota

Appendix B4 – Regulated, With Breakout Condition Flow Frequency Curves at and Upstream of Wahpeton 1

Tables

Table 1. Regulated Annual Instantaneous Peak Streamflow – Bois de Sioux River near White Rock, South Dakota ........................................................................................ 2

Table 2. Regulated Annual Instantaneous Peak Streamflow – Bois de Sioux River near Doran, Minnesota ...................................................................................................... 3

Table 3. Regulated Annual Instantaneous Peak Streamflow – Otter Tail River below Orwell Dam near Fergus Falls, Minnesota ............................................................................ 4

Table 4. Regulated Annual Instantaneous Peak Streamflow – Red River of the North at Wahpeton, North Dakota (Source: USACE 2015) ...................................................... 6

Table 5. Regulated Volume Frequency Curves – Bois de Sioux River near White Rock, South Dakota ....................................................................................................................... 7

Table 6. Regulated Volume Frequency Curves – Bois de Sioux River near Doran, Minnesota ................................................................................................................................... 7

Table 7. Regulated Volume Frequency Curves – Otter Tail River below Orwell Dam near Fergus Falls, Minnesota ............................................................................................. 8

Table 8. Regulated, With Breakout Flow Volume Frequency Curves – Red River of the North at Wahpeton, North Dakota (downstream of Otter Tail River Diversion ................. 8

Figures

Figure 1. Regulated Graphical Volume-Frequency Analysis – Bois de Sioux River near White Rock, South Dakota ................................................................................................... 9

Figure 2. Regulated Graphical Volume-Frequency Analysis – Bois de Sioux River near Doran, Minnesota ............................................................................................................... 10

Figure 3. Regulated Graphical Volume-Frequency Analysis – Otter Tail River below Orwell Dam near Fergus Falls, Minnesota .......................................................................... 11

Figure 4. Regulated, With Breakout Flow Graphical Volume-Frequency Analysis – Red River of the North at Wahpeton, North Dakota, Downstream of Otter Tail River Diversion (Observed Events Source: USACE 2015) ................................................. 12


Table 1. Regulated Annual Instantaneous Peak Streamflow – Bois de Sioux River near White Rock, South Dakota

Date

Regulated Annual Instantaneous Peak



Streamflow (cfs) 11 Jul 42 845 21 Mar 76 522

24 May 43 1,120 13 Mar 77 27 23 Jun 44 1,080 19 Apr 78 929 04 Apr 45 900 04 May 79 1,030 08 Apr 46 850 04 Jun 80 169

01 May 47 975 19 Jul 81 27 27 Apr 48 1,020 16 Apr 82 414 14 Jul 49 210 29 Nov 82 150 08 Jul 50 1,060 14 Apr 84 978

16 May 51 959 31 Mar 85 860 03 Jun 52 1,410 07 May 86 1,820

27 May 53 187 09 Oct 86 530 17 Sep 54 124 12 Apr 88 180 11 Jul 55 152 14 Apr 89 693

08 Aug 56 303 13 Mar 90 89 22 Jun 57 610 07 Jul 91 685 16 Apr 58 418 01 Aug 92 139 05 Jul 59 43 04 Aug 93 1,300

11 Jun 60 131 08 Apr 94 1,550 14 Sep 61 125 05 Apr 95 1,690 06 Aug 62 1,620 18 May 96 1,230 18 Jun 63 945 20 Apr 97 8,750 22 Apr 64 209 08 Mar 98 1,070 09 Jun 65 1,320 11 Jun 99 737 29 Apr 66 921 03 Mar 00 593 17 Apr 67 530 13 Apr 01 4,020 23 Apr 68 58 18 Jul 02 566 20 Apr 69 3,770 04 Jul 03 792 14 Oct 69 102 28 Sep 04 648 26 Jun 71 188 30 Jun 05 1,660 10 Apr 72 776 12 Apr 06 1,460 27 Mar 73 381 06 May 07 1,510 01 May 74 54 16 Jun 08 1,010

16 Jul 75 552 01 Apr 09 3,850


Table 2. Regulated Annual Instantaneous Peak Streamflow – Bois de Sioux River near Doran, Minnesota

Date




Streamflow (cfs) 07 Jun 42 1,626 26 Mar 76 1,321 05 Apr 43 3,356 25 Jun 77 10 06 Jun 44 2,458 01 Apr 78 3,982

18 Mar 45 2,198 14 Apr 79 5,196 22 Mar 46 1,610 01 Apr 80 1,681 12 Apr 47 2,908 02 Aug 81 7 07 Apr 48 1,181 01 Apr 82 1,736 10 Jul 49 1,124 13 Mar 83 324

02 Apr 50 2,518 28 Mar 84 2,814 07 Apr 51 4,357 01 Jun 85 1,743 12 Apr 52 5,267 11 May 86 3,911 22 Jun 53 1,512 26 Mar 87 878 09 Jun 54 590 27 Mar 88 302 02 Apr 55 214 05 Apr 89 6,152 14 Apr 56 961 16 Mar 90 96 22 Apr 57 1,221 02 Jul 91 2,980 16 Apr 58 134 18 Jun 92 436

27 May 59 175 01 Apr 93 3,660 07 Apr 60 1,181 01 Apr 94 3,100 09 Jun 61 13 16 Mar 95 4,290 11 Jun 62 3,747 19 May 96 3,640 11 Jun 63 1,799 16 Apr 97 12,300 17 Apr 64 622 28 Jun 98 2,580 11 Apr 65 3,930 07 Jun 99 2,580 18 Mar 66 2,831 09 Mar 00 1,340 15 Jun 67 1,167 15 Apr 01 8,860

18 May 68 49 12 Jul 02 1,720 10 Apr 69 6,642 26 Jun 03 2,740 09 Apr 70 495 24 Sep 04 2,450 18 Mar 71 319 09 Jun 05 4,380 19 Mar 72 1,835 02 Apr 06 6,150 16 Mar 73 590 04 Jun 07 4,500 15 Mar 74 388 07 Jun 08 2,140

03 Jul 75 2,376 26 Mar 09 8,340


Table 3. Regulated Annual Instantaneous Peak Streamflow – Otter Tail River below Orwell Dam near Fergus Falls, Minnesota

Date




Streamflow (cfs) 04 Oct 30 598 03 Jun 74 1,310 11 Apr 32 246 21 Jun 75 1,090 09 Jun 33 263 29 Mar 76 663 04 Apr 34 152 19 Sep 77 300 27 Jun 35 305 09 Apr 78 1,040 16 Apr 36 205 17 Apr 79 1,110 02 Jun 37 432 09 Apr 80 903 02 Jun 38 445 04 Aug 81 267

31 Mar 39 494 29 May 82 849 22 May 40 517 20 Jul 83 524 03 Apr 41 404 15 Jun 84 808 07 Jun 42 665 27 Jun 85 1,270 01 Apr 43 1,088 27 May 86 1,600 06 Jun 44 941 30 Jun 87 1,050

18 Mar 45 850 25 Mar 88 408 21 Jul 46 766 10 Apr 89 1,180

12 Jun 47 1,186 14 Jun 90 650 11 May 48 752 01 Jul 91 1,050 07 Apr 49 478 25 Jul 92 589

31 May 50 1,063 24 Jul 93 1,290 07 Apr 51 978 06 May 94 1,280 12 Apr 52 1,010 20 Mar 95 1,250 17 Jun 53 1,710 25 May 96 1,260 20 Jun 54 1,210 22 May 97 1,500 06 Aug 55 730 02 Jul 98 1,270 29 May 56 1,080 07 Jun 99 1,310 23 May 57 794 01 Jun 00 1,000 04 Mar 58 534 29 May 01 2,040 08 Jun 59 612 12 Jul 02 1,080

26 May 60 810 30 Jun 03 968 23 May 61 664 31 May 04 924 26 Jun 62 1,260 20 Jun 05 1,220 17 Jun 63 745 25 May 06 1,450

11 May 64 861 03 Jun 07 2,000 14 Jun 65 1,330 17 Jun 08 1,190


Date




Streamflow (cfs) 01 Jun 66 1,490 23 Apr 09 2,020

18 May 67 1,130 15 Sep 10 1,790 14 May 68 714 02 May 11 2,010 31 May 69 1,260 25 Jun 12 1,080 22 Jun 70 935 23 Jun 13 1,690 09 Apr 71 755 20 Jun 14 2,380 03 Jun 72 1,360 12 Jun 15 1,460

15 Mar 73 714 28 Apr 16 1,020


Table 4. Regulated Annual Instantaneous Peak Streamflow – Red River of the North at Wahpeton, North Dakota (Source: USACE 2015)

Date




Streamflow (cfs) 07 Jun 42 3,340 26 Mar 76 2,700 02 Apr 43 4,852 25 Jun 77 526 06 Jun 44 4,216 31 Mar 78 6,250

17 Mar 45 3,801 14 Apr 79 7,050 22 Mar 46 3,119 01 Apr 80 3,100 12 Apr 47 4,156 02 Aug 81 512 06 Apr 48 2,280 01 Apr 82 3,120 10 Jul 49 2,307 13 Mar 83 880

02 Apr 50 4,106 28 Mar 84 4,710 07 Apr 51 5,437 01 Jun 85 3,690 12 Apr 52 6,621 30 Mar 86 6,140 21 Jun 53 3,150 01 Oct 86 1,770 09 Jun 54 1,860 27 Mar 88 911 02 Apr 55 1,150 05 Apr 89 8,370 14 Apr 56 1,980 18 Mar 90 900 22 Apr 57 2,290 03 Jul 91 2,980 15 Apr 58 866 08 Mar 92 2,000

27 May 59 1,050 31 Mar 93 6,080 07 Apr 60 2,370 23 Mar 94 5,000 08 Jun 61 548 17 Mar 95 6,370 11 Jun 62 5,650 19 May 96 5,400 11 Jun 63 3,830 15 Apr 97 12,800

06 May 64 1,700 29 Jun 98 4,250 11 Apr 65 5,690 07 Jun 99 4,220 18 Mar 66 4,760 09 Mar 00 2,630 15 Jun 67 2,500 09 Apr 01 9,340

18 May 68 708 12 Jul 02 3,350 10 Apr 69 9,200 26 Jun 03 3,800 08 Apr 70 1,450 25 Sep 04 3,160 18 Mar 71 927 15 Jun 05 6,260 19 Mar 72 3,380 01 Apr 06 10,480 15 Mar 73 1,220 03 Jun 07 10,210 24 May 74 1,250 08 Jun 08 3,350

03 Jul 75 3,850 24 Mar 09 15,700


Table 5. Regulated Volume Frequency Curves – Bois de Sioux River near White Rock, South Dakota

Volume Frequency Curves for Regulated Flow Condition at Bois de Sioux River near White Rock, SD


Annual Instantaneous Peak

Flow-Frequency Curve

Maximum 3-Day

Average

Maximum 7-Day

Average

Maximum 15-Day Average


Flow in cfs 0.20% 14,200 13,700 12,200 10,300 8,400 0.50% 8,500 8,300 8,200 8,050 6,000

1% 8,300 7,900 7,800 7,300 4,650 2% 7,600 7,500 7,300 4,900 3,400 4% 3,950 3,700 3,600 3,100 2,500

10% 1,700 1,450 1,375 1,300 1,250

Table 6. Regulated Volume Frequency Curves – Bois de Sioux River near Doran, Minnesota

Volume Frequency Curves for Regulated Flow Condition at Bois de Sioux River near Doran, MN




Maximum 3-Day

Average

Maximum 7-Day

Average



Flow in cfs 0.20% 22,900 22,000 21,500 19,000 14,700 0.50% 14,800 14,400 14,000 13,600 10,900

1% 12,300 11,700 11,000 10,500 8,500 2% 10,100 9,800 9,000 7,800 6,200 4% 8,000 7,500 6,700 5,500 4,500

10% 5,500 5,200 4,600 3,400 2,450


Table 7. Regulated Volume Frequency Curves – Otter Tail River below Orwell Dam near Fergus Falls, Minnesota

Volume Frequency Curves for Regulated Flow Condition at Otter Tail River below Orwell Dam near Fergus Falls, MN


Annual Instantaneous

Peak Flow-Frequency

Curve

Maximum 3-Day

Average

Maximum 7-Day

Average


Maximum 30-Day

Average

Maximum 60-Day

Average Flow in cfs

0.20% 3,010 3,010 2,850 2,550 2,230 1,940 0.50% 2,690 2,690 2,550 2,375 2,140 1,890

1% 2,440 2,400 2,300 2,200 2,050 1,840 2% 2,190 2,150 2,050 1,975 1,925 1,775 4% 2,000 1,900 1,800 1,725 1,675 1,550

10% 1,580 1,550 1,525 1,500 1,425 1,350

Table 8. Regulated, With Breakout Flow Volume Frequency Curves – Red River of the North at Wahpeton, North Dakota (downstream of Otter Tail River Diversion

Volume Frequency Curves for Regulated Flow Condition at Bois de Sioux River near Doran, MN




Maximum 3-Day

Average

Maximum 7-Day

Average



Flow in cfs 0.20% 25,100 23,500 20,800 18,000 14,900 0.50% 21,200 20,200 18,000 15,200 12,300

1% 17,900 17,000 15,100 12,800 10,300 2% 14,700 13,800 12,200 10,400 8,500 4% 11,800 10,800 9,500 8,000 6,400

10% 8,500 8,100 7,000 5,200 4,000


Figure 1. Regulated Graphical Volume-Frequency Analysis – Bois de Sioux River near White Rock, South Dakota


Figure 2. Regulated Graphical Volume-Frequency Analysis – Bois de Sioux River near Doran, Minnesota


Figure 3. Regulated Graphical Volume-Frequency Analysis – Otter Tail River below Orwell Dam near Fergus Falls, Minnesota


Figure 4. Regulated, With Breakout Flow Graphical Volume-Frequency Analysis – Red River of the North at Wahpeton, North Dakota, Downstream of Otter Tail River Diversion (Observed Events Source: USACE 2015)


Reference:

U.S. Army Corps of Engineers. 2015. The Use of Synthetic Floods for Defining the Regulated Flow-Frequency & Volume Duration Frequency Curves for the Red River at Hickson, North Dakota. St. Paul District, St. Paul, MN. January.

Date post:	20-Sep-2020
Category:	Documents
Upload:	others
View:	4 times
Download:	0 times

Lower Red Basin Retention (LRBR) Study€¦ · 1.3. Otter Tail River below Orwell Dam near Fergus...

Documents