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CE 421 Hydrology –Course Project – 2023 – CE Department, UND 1

Civil Engineering- CE 421 Hydrology – 2023 Fall Semester

Hydrology Course Project

Instructor: Dr. Howe Lim, Professor, Department of Civil Engineering, University of North Dakota

1. Flood Mitigation Dam Project There was a big flood event in Duluh, Minnesota in 2012 which caused substantial damage to

the city. The community living downstream of Miller Creek has proposed to build a concrete gravity dam at Longitude: 92 08.958 W and Latitude: 46 47.119 N for providing flood mitigation purposes. The exact location is shown in Figure 1, a zoomed-in map of the area map. The regional map is uploaded to the Blackboard site under Course Project called MN_Duluth_Heights_geopdf.pdf. It is a special pdf file with embedded digital geographic coordinate system.

Figure 1. Dam Location (at the tip of the triangle pointing at the stream, in the upstream direction)

Using the topographic information (contour lines) given on the map, you have the first task of delineating the entire outline of the Miller Creek Basin with the outlet location as defined by the dam location. The basin will need to be subdivided into a number of sub-basins.

There are several design specifications of the dam that must be determined by creating and running several hydrologic models in HEC-HMS. The idea is to see how the dam can perform under extreme hydrologic runoff at the site.

The crest of the dam governs how much storage can be provided by the water reservoir formed behind the dam. Three options for the crest height of the dam above the stream bed are proposed: Option A-100 ft, Option B- 90 ft, and Option C-80 ft. The contour lines of the topographic maps

CE 421 Hydrology –Course Project – 2023 – CE Department, UND 2

correspond to “above mean sea level”, a.m.s.l, according to the North American Vertical Datum of 1988 (or NAV88). Hence, you will need to report the crest of each dam option corresponding to a particular NAV88 value. For example, the elevation of the streambed near the dam site is estimated as 1200 ft. The contour interval for this map is 10 feet.

The dam will be made of concrete with an upstream face vertical and downstream face set as 1 in 4, a crest width of 25 ft, and a variable crest length (depending on the topography). Refer to a sketch of storage in a general dam reservoir in the Appendix.

A step spillway is proposed to be constructed to prevent overtopping of the dam under flooding conditions. The spillway crest is set at a certain height below the crest of the dam. A freeboard of 8 feet will be allowed.

A dry weather flow pipe passing through the dam (pipe-outlet) must be provided to allow downstream habitats to thrive and maintain sizeable storage during normal to low-flow conditions. The pipe outlet centerline may be set at 5 ft above the stream bed.

Being a project design engineer, you must select the best dam-crest option and size the spillway structure (optimum dimensions) which satisfies this demand: To provide flood regulating function for the downstream areas.

The pool level during flood flow must be set to allow safe storage while permitting 200-year recurrent flood flow to be discharged through the step spillway structure safely within a freeboard of 8 ft. The targeted minimum peak flood attenuation is aimed at 20%, i.e., the peak flood flow is reduced by 20% or more.

2. Methods

The methods expected to be used include hydrologic and hydraulic calculations, topographic interpretations, web-sourced data compilations, setting hydrologic parameters, and running a HEC- HMS model. You will apply what have learned on the go in the hydrology course for this project. Make sure you follow the class lecture materials closely and complete time-sensitive Project Checks for submissions. You are required to work ahead with the guidance of the Project Checks.

You would be required to prepare map-based data, unit hydrographs, a storage-elevation curve, a dam spillway rating curve, and other relevant functions.

You must prepare an HEC-HMS model for the current condition (pre-development) and for each of the three dam-crest options (post-development).

The model should output the hydrographs at the sinks (downstream of the dam) under pre- development and post-development scenarios. You should compute the peak flood attenuation factors and select the best dam crest option.

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3. Data

3.1 Sources

Use the topographic map given to obtain the physical characteristics of the site. You will need the hydrologic data or information to be obtained from various sources including those you have learned in this course, e.g. WebSoil Survey, NWS publications and web servers, USGS Surface-Water Data for the Nation, and NOAA-NCEI.

3.2 Specific Basin‐related Data‐ Pre‐model Tasks

The following data are known, and you may use them in creating a HEC-HMS Basin model for the area:

a. Delineate sub-basins to model the whole basin. The data for sub-area and channel length can be measured from the topographic map(s) provided. In practice, a general guidance on the size of the sub-basins: a sub-basin should not be too large (>20% of the total basin area) or too small (< 5% of the total basin area). However, for the sake of uniformity in answers, you are given the spatial coordinates of fixed streambed locations where the outlet of each sub-basin will be located. For example, the confluence of two streams. The list of coordinates is posted on the Course Project site.

b. Loss Method and Land Use: Use the Websoil Survey to determine the Curve Number for each sub-basin so that you can use SCS Curve Number Method for considering the Loss Method. You should sample a few AOI’s (areas of interest) in each sub-basin and weigh the predominant soil group with the area. For rural North Dakota and Minnesota, you may assume most areas are pervious with about 5% only being considered impervious (mainly related to roads). For the developed area, the impervious % would be higher. Make an estimation of the % of the area being impervious (road, highway, buildings, etc.) using Google Earth or Map -Satellite view.

c. Choice of Transform Method –we opt to use a user-specified unit hydrograph for each sub- area. A unit hydrograph can be developed for a distinct flood hydrograph observed at the gaging site which had a corresponding observed storm total.

First, develop a unit hydrograph from an observed storm hydrograph at a gaging station at Site X of Bears Creek, another basin near the project site, with a drainage area of 15 square miles (see Table 1). The basin has similar geomorphologic characteristics as the Miller Creek Basin. Second, create a unit hydrograph for each sub-basin in Miller Creek Basin by using the proportionalities of basin areas (assuming that the basins are of the same hydrologic characteristics).

Bears Creek Basin at Site X Miller Creek Basin at Dam Site

X

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The time of concentration tc for the Miller Creek Basin will need to be estimated so that corresponding storm durations that will produce the maximum runoff response can be specified. However, the methods for estimating tc are mostly empirical and simplistic. Since HEC-HMS can be used efficiently to simulate the runoff from different-duration storms, we will specify a few storm durations that are close to the estimated tc. This means different UH’s will need to be transformed from the observed UH at Site X using the Lagging or S-hydrograph methods.

d. Baseflow Method – Use a constant monthly of 1 cfs based on the study of the nearby basin at site X. Use the same estimate as in the unit hydrograph derivation (flow per area) and proportioned by the subbasin areas. For this project, you may assume the baseflow is the same for all the months.

e. A field trip was made to investigate the channel routing characteristics of the watershed is shown in Appendix B.

Table 1. Observed Precipitation and Runoff discharges at Site X of Bears Creek for a storm event *

Time (Day) Precipitation (in) Discharge in cfs. 1 1.00 2 1.00 3 1.5 ** 1.80 4 39.00 5 18.00 6 10.00 7 8.00 8 5.50 9 4.20 10 4.50 11 4.20 12 3.80 13 3.30 14 2.90 15 2.60 16 1.00

* Note on storm discharges: the runoff discharges 2 days before the arrival of the rainstorm are given.

**Notes on precipitation: The 12-hr rainstorm, which started at 12 noon on Day 3 and ended by the midnight of Day 3, was measured as 1.5 inches by a rain gauge found within the basin.

CE 421 Hydrology –Course Project – 2023 – CE Department, UND 5

3.3. Meteorological model

Compile design storm data using the data for the nearby city Duluth Airport Station. Use T=200-year design storms in your investigation. For the current condition (without any structure), consider three storm duration cases in model runs, and select the case that created the maximum peak discharge at the proposed dam site (you need to run the completed model to tell). You may then just use the selected design storm in all other design runs, i.e., post-development with three different dam-crest options.

3.4 Channel Routing Model

You will perform an analysis of the data collected during the investigative trip as shown in Appendix B and use the results to calibrate the channel routing parameters for the HEC-HMS model.

3.5. Reservoir and Outlet Structures

Appendix A shows a general sketch of a reservoir with various storage definitions. The reservoir size and volume can be estimated from the topographic map. Use the area measurement tools (e.g. TerraGo Toobar) at your disposal to produce a stage-storage function (approximated in a table of stage-volume) or stage-area function (approximated in a table of stage-area) and enter via the Paired Data Manager of the HEC-HMS (under Components).

Define the outlet structure using a stage-discharge function (approximated in a table of stage versus discharge). Hint: Specify step spillway equation to generate a table of stage-discharge by fixing the coefficient of discharge. State your assumptions.

More will be posted on the Blackboard on this topic.

4. Project Tasks There will be a series of “Project Checks” (up to 4 checks) which will be defined and to be posted on the Project Section on the Blackboard. The course master schedule shows the anticipated release of the checks and due dates. Submit your answers to the checks before the due dates. Project Checks Briefly, the Project Checks are described in Table 2. Project Checks 1 through 3 are to be submitted. Working/Task Plan You will need to list the project tasks and prepare your working timeline. To help you plan well, you should derive your own task list like the one shown in Table 3. The report should be progressively written as the project moves forward. Revise, if necessary, by getting feedback from the checks. Do not wait until the last minute to write or submit.

CE 421 Hydrology –Course Project – 2023 – CE Department, UND 6

Table 2. Project Checks to be submitted

Project Check No.

Contains

1. Delineations of basin and sub-basins, area measurements, channel junctions, and reaches measurements Derive Curve Numbers for each sub-basin Setup preliminary schematic of basin model in HEC-HMS

2. Meteorological Model (IDF Curve, Time of Travel – tc, Design Storm – making use of IDF curve and tc.) Reservoir Storage Function (reservoir elevation-area data)

3. Hydrologic Routing: Channel Routing (channel routing parameters) Meteorological Transform Method: derive a user-specified unit hydrograph

4. A. Running “Current Condition” Basin Model in HEC-HMS

B. Building Reservoir Model in HEC-HMS C. Spillway Setup and inputs to HEC-HMS D. Running Models for Basin with Dam Reservoirs in HEC-HMS

Table 3. A sample task list

Tasks Action by-date 1. Basin and sub-basin delineations 2. Channel measurements 3. Basin sub-division and setup basic basin in HEC-HMS 4. Reservoir storage curve preparation

Check 1 due

5. Storm selections 6. Unit hydrographs analysis Check 2 due 7. Basin sub-division and setup basic basin in HEC-HMS 8. Set channel and reservoir routing parameters Check 3 due 9. Set up reservoir /structures 10. Runs with and without dam options, comparisons of results Check 4 due

Table 4 illustrates various hydrologic conditions of the modeling exercises in fulfilling the minimum modeling requirements of this project. You certainly can work and show extra consideration when time permits.

CE 421 Hydrology –Course Project – 2023 – CE Department, UND 7

Table 4. Hydrologic conditions for the required models

Models Flow Conditions Storm durations 1 Current condition 200-year recurrent flow At least 3 storm durations 2 Dam crest option A 200-year recurrent flow Use selected duration in 1 3 Dam crest option B 200-year recurrent flow Use selected duration in 1 4 Dam crest option C 200-year recurrent flow Use selected duration in 1

5. Project Report

An individual project report is expected to be submitted by the due date, including all the relevant model results in properly numbered and labeled tables and figures. The final Report’s due date is fixed as stated in the course master schedule. This is a firm date (no room for an extension because we will be busy preparing for the end-of-year exams, grading, and other presentation activities).

It is recommended to compile all your results in a single professional report (in a Word file and print as a PDF file). All students will upload a single PDF file containing the report on the BlackBoard.

Discussions are encouraged among the students but make sure all the work items submitted are done by each individual student. Reports that show evidence of collusion or plagiarism may be considered scholastic dishonesty (see course syllabus on the process).

Contents and Style of report

The suggested order of items to be presented: a title page, a table of work distribution among team members (for grading), a table of content, an executive summary page (1 page by itself), a full project description (Introduction, Objectives, …., Conclusion). You may refer to the Project Grading Scheme for some ideas on section headings. A clear concluding section addressing the project objectives is expected. Full project descriptions would let a reader knows the method used, data compiled, analysis done, and discussions on the results. For a lengthy report, use appropriate headings for sections (numbered 1, 2, 3…) and sub-sections (1.1, 1.2,….).

A major screenshot of or actual plot of a runoff hydrograph, etc., is expected to be shown written after a description in the text. Do not place a major finding (plot or table of values) in an appendix. You may place other minor or repeated plot cases in an appendix. Your own tables and graphs (using Excel) are expected to be produced when comparing different model outputs. This obviously is an important finding. Paging and formatting are necessary to ensure that the document follows the style of a professional technical report. This project brief is an example of a well-formatted ‘report’.

Use ASCE’s Journal writing as a standard. Use numbered captions for all figures and tables, e.g.

Note: Do not copy the Project Checks exactly and paste them into your report. A report must describe the results found in Project Checks and other working materials in narrative order.

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Figure 6. Unit hydrograph

Table 10. Peak Discharges at Junction 5.

Place the caption for a table on top of the table but for a figure, place the caption below it (see the examples found in this project brief).

6. Grading Scheme

Refer to a grading scheme that will be posted on the Blackboard’s Course Project Section. It may help you in organizing the contents of your report.

CE 421 Hydrology –Course Project – 2023 – CE Department, UND 9

Appendix A

Figure 2. Storages in a typical dam reservoir

Spillway crest level

Pipe Outlet

Height of dam = 0

Dam Crest

Stream bed

CE 421 Hydrology –Course Project – 2023 – CE Department, UND 10

Appendix B Field Trip Report and Recommendations on Channel Routing

The project team had a meeting to decide the best option for estimating the channel routing parameters. Muskingum-Cunge Routing method was agreed to be used for channel routing. This method estimates the Muskingum’s K and x parameters using simple physical characteristics of the reaches. This method is practical since the physical characteristics of the reaches can be obtained by making an interpretation of the maps and using supplemental field survey information. A field trip report with recommendations for Miller Creek is summarized below.

A. Field Trip Report The project team has visited the site primarily to check out the Manning’s roughness parameters for the reaches found in the Miller Creek Basin. The descriptions of the main channel and floodplain areas are compiled in Table 5. (see Figure 6 on the Reach ID used). Table 5. Field Survey Summary: Channel Characteristics of Miller Creek

Reach ID

Reach Main Channels

Left and right floodplain

A Reaches found upstream of Swan Lake Road culvert

Natural, mountain stream, no vegetation in channel, bottom of gravel. Trapezoidal, bottom width about 10 ft

Trees, with heavy stand of timber, few down trees, little undergrowth, flood depth above branches

B Reaches downstream of Reach A but upstream of West Arrowhead Road culvert

Natural, irregular sections with deep pools and a slight meander, heavy brush on bank. Trapezoidal, bottom width of 15 ft

Brush, with scattered brush and heavy weeds

C Reaches found upstream of West Arrowhead Road culvert, on west branch of Miller Creek (parallel to US Highway 53)

Natural, regular sections with heavy brush on bank. Trapezoidal, bottom width of 15 ft

Brush, medium to dense brush in summer

D Reaches found downstream of West Arrowhead Road culvert but upstream of Anderson Road culvert

Natural, regular sections, straight, some light bush on banks. Trapezoidal, bottom width of 20 ft

Brush, scattered brush and heavy weeds

E Reaches found downstream of Anderson Road culvert

Natural, regular sections, straight, some light bush on banks. Trapezoidal, bottom width of 25 ft

Trees, heavy stand of timber, flood depth below branches

CE 421 Hydrology –Course Project – 2023 – CE Department, UND 11

Recommendations for the Modeler on Data Preparation for Muskingum-Cunge Routing Muskingum-Cunge Routing for channels is an option incorporated in HEC-HMS software. The descriptions can be found in the manuals of the software. The method requires some simplified cross- sectional data to be estimated from the topographic maps and the field trip. For example, Cross Section A as shown in Figure 3 can be estimated and modeled by: 1. measuring the distance between the contour intervals crossed by the transect B-B 2. incorporate the channel width obtained from the field survey (during low flow) 3. assume the channel marking on the map is the center-line of the channel (and the elevation of the

channel bed) 3. form an approximate cross section using 8 points (no more than 8) 4. create a cross section as a Paired Data (using Paired Data Manager) in HEC-HMS for each of the

channel reach you have modeled 5. enter routing specification for each of the reach and specify Muskingum-Cunge as the routing

method, and make linkage with the cross section (paired data)

Figure 3 Example of a Cross Section to be Plotted

Channel as seen from the map

Width, from field trip

From map’s contour lines on right bank

1400

1380 1370

1400

1360

1390

From map’s contour lines on left bank

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Example on Plotting Cross Section A with channel width 20 ft observed at lowflow condition

Table 6. Cross Section A: Station-Elevation Pairs and Sources of Data Point used Station (ft) Elevation (ft) Sources

1 0 1380 From map 2 72 1370 From map 3 211 1360 From map

4 213 1358 Station obtained by negative offset of half the channel width (survey info) from centerline (next point X); elevation taking from point X

X 223 1358 Channel’s centerline station (position) and elevation of bed are obtained from the map

5 233 1358 Station obtained by positive offset of half the channel width (survey info) from centerline (next point X); elevation taking from point X

6 237 1360 From map 7 265 1370 From map 8 293 1380 From map

Note: 1. Point X is not used further in HEC-HMS as shown in Figures 2 and 3 below. 2. The origin of the station is on the left bank looking in the downstream direction (USGS’s standard)

Figure 4. Plot of Cross Section A in HEC-HMS

Figure 5. Table of Cross Section A in HEC-HMS

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Figure 6. Field Trip Reach ID Used

CE 421 Hydrology –Project Check 4 Part A Solution Dr. Howe Lim UND Civil Engineering 1

2023 CE 421 Hydrology Course Project

Check 4 Part A

Due: 11/21/2023

A. Preparation for Current Condition Model

Item 1 for submission of Check 4:

The User Specified Unit Hydrograph you entered for the largest sub-basin in Miller Creek Basin. Show the

graphical plot and the table input value of the UH in HEC-HMS. State the storm duration of the UH.

CE 421 Hydrology –Project Check 4 Part A Solution Dr. Howe Lim UND Civil Engineering 2

6, 12 and 24-hr UH for the Largest Sub-basin in Miller Creek Basin

Subbasin-11 Subbasin-11 Subbasin-11

Area (sq mile) 2.038 Area (sq mile) 2.038 Area (sq mile) 2.038

Time 6-Hr UH Time 12-Hr UH Time 24-Hr UH

hr cfs hr cfs hr cfs

0 0.00 0 0.00 0 0.00

6 0.23 12 0.23 12 0.12

12 0.23 24 0.46 24 0.35

18 0.46 36 11.21 36 5.84

24 0.46 48 21.97 48 16.59

30 11.21 60 15.90 60 18.93

36 11.21 72 9.83 72 12.86

42 21.97 84 7.51 84 8.67

48 21.97 96 5.20 96 6.36

54 15.90 108 4.62 108 4.91

60 15.90 120 4.05 120 4.34

66 9.83 132 3.32 132 3.69

72 9.83 144 2.60 144 2.96

78 7.51 156 2.23 156 2.41

84 7.51 168 1.85 168 2.04

90 5.20 180 1.94 180 1.89

96 5.20 192 2.02 192 1.98

102 4.62 204 1.94 204 1.98

108 4.62 216 1.85 216 1.89

114 4.05 228 1.73 228 1.79

120 4.05 240 1.62 240 1.68

126 3.32 252 1.47 252 1.55

132 3.32 264 1.33 264 1.40

138 2.60 276 1.21 276 1.27

144 2.60 288 1.10 288 1.16

150 2.23 300 1.01 300 1.05

156 2.23 312 0.92 312 0.97

162 1.85 324 0.46 324 0.69

168 1.85 336 0.00 336 0.23

174 1.94 348 0.00

180 1.94 186 2.02 192 2.02 198 1.94 204 1.94 210 1.85

CE 421 Hydrology –Project Check 4 Part A Solution Dr. Howe Lim UND Civil Engineering 3

216 1.85 222 1.73 228 1.73 234 1.62 240 1.62 246 1.47 252 1.47 258 1.33 264 1.33 270 1.21 276 1.21 282 1.10 288 1.10 294 1.01 300 1.01 306 0.92 312 0.92 318 0.46 324 0.46 330 0.00

0.00

5.00

10.00

15.00

20.00

25.00

0 50 100 150 200 250 300 350 Time in hours

6-Hr UH For Subbasin 11 (largest, 2.038 sq.miles)

CE 421 Hydrology –Project Check 4 Part A Solution Dr. Howe Lim UND Civil Engineering 4

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

20.00

0 50 100 150 200 250 300 350 400Time in hours

24-Hr UH For Subbasin 11 (largest, 2.038 sq.miles)

0.00

5.00

10.00

15.00

20.00

25.00

0 50 100 150 200 250 300 350 400 Time in hours

12-Hr UH For Subbasin 11 (largest, 2.038 sq.miles)

CE 421 Hydrology –Project Check 4 Part A Solution Dr. Howe Lim UND Civil Engineering 5

cont.

cont.

Item 2 for submission of Check 4:

Show a table of Muskingum-Cunge parameters that you have entered in

your 1st Current Condition model. In your model, click on the menu

“Parameters”, “Routing” and “Muskingum-Cunge”. Use screen shot.

CE 421 Hydrology –Project Check 4 Part A Solution Dr. Howe Lim UND Civil Engineering 6

Three flood hydrographs are expected. Only one is shown as an example here for 6 hour storm simulated outflow at the outlet (junction 6 for this example): Ouflow

or using “Graph”

Item 3 for submission of Check 4:

Show the screenshot of the simulated flood hydrograph at the outlet of your three current condition models.

Tip: In model, click on “Results” under the explorer-type window as shown below, and select the junction that

associate with the basin outlet. Select Outflow and or Graph. Get a screen shot the hydrograph.