Hydrosystems Engineering (EACEE 3250 / 4250)
Spring 2025
Homework #5 (Due Friday, May 9th, 11:59 pm)
Homework Guidelines:
Your solutions to homework assignments will be submitted and graded through Gradescope (see the Gradescope tab on your Courseworks dashboard).
You will have two options for submitting your work in Gradescope, either: 1) upload individual scanned images of your handwritten pages (e.g., using your phone), one or more per question; or 2) upload a single PDF that you create which contains the whole submission (e.g., merge files on your computer or phone with a software of your choice). Please use the naming convention Lastname_HWxx.pdf when submitting your homework assignment. You may choose to type up your calculations, in which case show all your steps and highlight your solution. Note: During the upload, Gradescope will ask you to mark which page/s each problem is on (see example here). It is important that you follow that step for grading purposes.
It is acceptable to discuss problems with your colleagues, and questions are encouraged during office hours, but all work must be done independently. Make sure to clearly show all work on each problem and that your solutions are presented in an orderly fashion. It is your responsibility to make your solutions easy to grade.
Topics/Chapters covered:
• Chapter 10: Runoff and streamflow
• Chapter 11: Watershed Modeling
Problem #1 (50 pts)
Runoff
After many years of flooding the local Museum of Science, the town planners of Lion Town have decided it’s time to construct a unit hydrograph that represents the rate of discharge at the Museum of Science per 1cm of runoff generated over the Lion Town River Basin. The data below shows the flow at the Museum of Science generated by runoff produced by the Lion Town River Basin (A = 50 km2) for a storm last year.
|
Time (hr)
|
Flow (m3/s)
|
|
0
|
14.16
|
|
6
|
33.98
|
|
12
|
63.71
|
|
18
|
82.68
|
|
24
|
75.61
|
|
30
|
58.55
|
|
36
|
40.49
|
|
42
|
31.15
|
|
48
|
25.77
|
|
54
|
22.09
|
|
60
|
19.26
|
|
66
|
16.99
|
|
72
|
15.29
|
|
78
|
14.44
|
|
84
|
14.16
|
a) Plot the hydrograph of the storm above.
Please use a scientific plotting software of your choice such as MATLAB, Python, Excel, etc. and show your work as needed.
b) Calculate the total volume of overland runoff produced by the storm above by assuming a baseflow of 14.16 m3/s.
c) Over the area of the basin, what is the average depth of runoff for this storm?
d) Construct and plot a Unit Hydrograph (hydrograph corresponding to unit depth of runoff over area of basin) for the Lion Town River Basin.
Assuming an instantaneous pulse of rainfall falling at 6AM on both Saturday and Sunday:
e) Plot the hydrograph for Saturday’s storm which produces 10.9 cm of runoff.
f) Plot the hydrograph for Sunday’s storm which produces 12.44 cm of runoff.
g) Plot the total hydrograph.
Problem #2 (10 pts)
Open channel/streamflow
Estimate the steady-state uniform flow in a prismatic rectangular channel with a width of 5 m, a water depth of 2 m, a bed slope of 0.001 and a Manning roughness coefficient of 0.03.
Problem #3 (40 pts)
Watershed Modeling
Access the free, web-based platform Model My Watershed, as reviewed in class (the week of 4/28): https://modelmywatershed.org/.
Go through the app workflow covered live in class. Further instructions can be supplied, upon request.
• Choose a location of interest to you. It can be in the greater NYC area, your hometown, or anywhere covered by the software. Note that for rural watershed-scale areas, turn on HUC-12 Watershed boundaries using "Select by Boundaries". For smaller urban areas, use "Draw Area" to define your area of interest.
• Go through the Analyze Tab, learning about the data in your selected area.
• Go to the Model Tab and select the Watershed Multi-year (annual) Model. Using your watershed model, add New Scenarios (+) and apply various Conservation Practices to these scenarios. Explore how basin runoff and other variables change as a result. Use the simulations to test your understanding and/or hypotheses about hydrologic response to static basin characteristics.
Create at least 3 engineered scenarios, capture/append the scenarios report from the “Compare” button (top left), and give a brief explanation comparing and contrasting these the influence of changing static parameters (on runoff and streamflow in particular).