Figure 1. Location Plan

SWELL PROPAGATION AND NEARSHORE WAVE CLIMATE

Table 1. Historical Wave Measurements Conducted in Chile

7_Scott_Resio_Pantoja
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2

incident wave climate shows considerable

variability, with the following principal

considerations:

Brazil

Peru

Seas generated by the local wind

OCEAN O

PA C IF IC O

Bolivia

conditions, which vary along the

Aric a

Iquique

length of the country.

Paraguay

Antofag asta#

Swells generated in the southern

mid-latitudes by the passage of

Caldera

Isla de Pascua

Coq uim bo #

cyclonic systems. These swells,

Valparaiso #

Uruguay

in combination with the locally

Argentina

Constituc in#

generated seas, are an important

Concepc in #

consideration in establishing the

Golfo Coronados#

design conditions for coastal

structures.

OCEAN O

A TL A N TIC O

Swells generated in the northern

mid-latitudes, which propagate

Punta Arenas

some 15,000 km to impact the

Chilean coastline.

Figure 1. Location Plan

As will be shown in this paper, the long period wave energy in Chile, particularly in the northern part of the country,

is a seasonal interplay between the swells propagating from the northern and southern hemispheres.

Many of the existing ports in Chile are located in north-facing bays and are well protected from the southern seas

and swells, but can be highly exposed to northern swells. Figure 2 shows one typical example, at the Port of

Mejillones in Bahia de Mejillones, which is located at approximately 24 S. The importance of northern swells may

be seen in a short duration of wave records made in 10 m depth within the bay, as illustrated in Figure 3. This site

is almost completely sheltered from southern to western wave conditions, and the northern swells can be readily

isolated. The wave record shows the distinctive "sawtooth" pattern of swell generated by distant storm events.

Plotting the time series as a function of frequency and calculating the slope of the wave period progression, permits

an estimate of the time and distance to the generating storm to be developed. In this case, the storms were estimated

to be located in the order of 12,000 km to 15,000 km from the site.

1.6

1.4

1.2

0.8

0.6

0.4

0.2

12/15/1998

12/22/1998

12/29/1998

1/5/1999

1/12/1999

1/19/1999

1/26/1999

Figure 2. Mejillones Bay