代写EESB04 "PRINCIPLES OF HYDROLOGY" Assignment #2: Areal Estimation of Rainfall代做留学生Matlab编程

EESB04

"PRINCIPLES OF HYDROLOGY"

Assignment #2: Areal Estimation of Rainfall (43 marks total)

The objectives of the assignment are to:

1.  Learn and apply methods for scaling point measurements of precipitation to entire watersheds.

2.  Understand why estimates may differ between these methods.

3.  Improve your interpolation and mapping skills.

4.  Continue to hone your inferential skills by associating patterns with probable processes.

Instructions:

You will find attached a map showing the boundaries of a fictitious watershed and the locations of 21 rain gages. You will be required to use this map and values to estimate “average” precipitation by three different methods.  The numbers on the  map are the gage catches (amount of precipitation) for a particular storm in mm. Each square on the map is equal to one hectare (10,000 m2) in area. You may wish to review your text, your class notes, lecture videos and the help provided to you by your TA during tutorial.

Assignment format: Submit your assignment via Quercus as a pdf document using 12-point font. Follow the submission upload instructions on Quercus under “Assignment #2” . Where an answer requires a table, simply make a table in the   appropriate part of this assignment. Organize your assignment according to the order of the questions below. For the maps, I suggest you print the maps at the end of this assignment and work on your answers using pen and pencil. Then, you may take photos of your completed maps and paste the photo into the appropriate section of your answers. Part marks may be given, so it is important to lay out calculated answers (or an example if there are multiple of the same calculation) in a way that shows your work, where this is applicable. Remember – the use of proper significant figures in your answers ALWAYS applies.

Areal Estimation of Rainfall

1.       What is the total area of the watershed? No example calculation required (1 mark)

2.       Compute the average rainfall falling within the watershed using the arithmetic average approach.  Be sure to write out your calculation to show your work (3 marks).

3.        Draw “eyeball” isohyets on the attached watershed map (end of

assignment) at a contour interval of 20 mm, and on the 20’s (e.g., 20, 40, 60, 80, etc as necessary) (8 marks).

4.        Using the eyeball isohyetal method, fill in the following table and estimate the average rainfall across the watershed (6 marks).

i	pi- (mm)	pi+ (mm)	i (mm)	Fraction of Area, ai/A	(ai/A) · i (mm)
1	0	20
2
3
4
5
6
7
			Total:

5.        Draw  Thiessen  polygons  on  the  attached  watershed   map  –   end  of

assignment; same map for this and Q3 (8 marks). …continued next page …

6.        Estimate the area of your polygons (5 marks).   Use the Thiessen polygon method to fill in the fill in the following table (4 marks).  What is the total “average” precipitation in the watershed? (1 mark)

g	pg (mm)	Fraction of Area, ag/A	(ag/A)
			(mm)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
		Total:

7.       Write a short paragraph (<1/2 page) comparing the results of the three

methods, patterns you observe, and discussing which method seems most appropriate for this situation.  Given the isohyetal pattern, do you think this is frontal, convectional, or orographic lifting and why (7 marks)?