The University of British Columbia
Department of Civil Engineering
CIVL 417 – Coastal Engineering
ASSIGNMENT 5:
LONG WAVES AND WATER LEVELS
Due: 11 pm, November 6, 2023
Please submit your response by the above deadline via the appropriate link on Canvas.
Upload
a single pdf file (copying an EXCEL spreadsheet if you wish) with the file name "Student#-
Assignment#." (e.g. 12345678-5).
_____________________________________________________________________________
1.
Using the relevant tide tables, tabulate the local times and elevations of the high and low tide
levels (above Chart Datum) for May 20 – 23, 2023 at Gibsons, BC.
Plot the surface elevation vs.
time, in May 21 hours.
Estimate the maximum rate of change of surface elevation for May 21.
Based on continuity considerations (i.e., by equating the increase or decrease in volume in the
marina per unit time to the volume flow rate into or out of the marina), develop an equation for
the current speed U at the marina entrance in terms of the marina surface area S, the entrance
width w, the entrance depth d and the rate of change of tide level in the marina.
If the marina
covers an area of 84,000 m
2
, the seabed elevation at the entrance is 4.0 m below Chart Datum,
and the width of the entrance is 40 m, estimate the maximum tide-induced current at the entrance
that day.
Note: you may download the 2023 tables for Gibsons (Volume 5) from:
https://charts.gc.ca/publications/tables-eng.html
2.
The seabed profile approaching a site corresponds to deep water offshore, with a shelf that is 15
m deep 2 km from the shore and has a uniform slope to zero depth at the shoreline, see the
figure.
Estimate the wind setup at the shore for a design wind of 100 kph that blows directly
onshore.
Assume that the effective drag coefficient
k
= 3.3 × 10
-6
and that there is no setup
associated with winds blowing beyond the shelf.
417 students
.
Use the simplified formula with
a uniform depth assumed to be d/4.
540 students
.
Use a numerical approach based on the
equation for
D
S in terms of
D
x, in which the shelf is discretized into 20 segments as indicated in
the figure (S1, S2, … denote the segments, and P1, P2, … denote the segment end-points). See
the “hints” document for additional information.
Note: the relevant equation for
D
S/d' on page
7-18 of the text and page 7-9 of the notes has a typo: gd' should be gd'
2
.
3.
A residential development is intended along the shoreline near Powell River, with a design life
extending to the year 2080.
For this location, what is the RSLR value for 2080 relative to 2023
as needed for
FCL calculations?
For this location, the 200-year combined tide + storm surge
elevation is 2.95 m GD (using CGVD2013), the 200-year storm surge itself is 1.00 m, and the
200-year wave runup (2%) is 1.44 m.
What are the FCL values (relative to GD) based on the
Combined and Probabilistic Methods?
Note: you may access HHWLT and relevant RSLR data
(use "AR6" and RCP of 8.5) from the site:
https://gisp.dfo-mpo.gc.ca/portal/apps/experiencebuilder/experience/?id=760c4e0033ef4023ba395127a406d3a7&locale=en
