Zeto Point Case Study

The swell window for my surf break, Zeto Point, was difficult to calculate since it is located in a bay. However, I was able to estimate the swell window from the mouth of the bay where swell would be able to enter. Zeto Point is located at latitude 51o54’16.58”N and longitude 176o33’28.39”W. Being located in a bay, there are several obstructions to wave energy, the coordinates tangent to the northern obstruction are latitude 52o04’37.96N and longitude 176o12’20.72”W, this point is located 32.068 km from the surf break with bearing 48.739o. The southern obstruction is located at latitude 51o52’08.68”N and longitude 176o21’44.53”W, this point is located 14.03 km from the surf break with breaking 106.328o. The northern bearing of 48.739o generates

They are the regions of high winds, located on the figure above by the colour orange. For my hypothetical storms I decided to keep it realistic for the time of year and consistent with the historical

The peak period from a wind speed of 7.5 m/s is calculated by multiplying the wind speed by 0.7500696 (7.5 x 0.7500696) which equals a peak period of 5.63 seconds. Wave group speed can be estimated by multiplying this value by 0.78 (5.63 x 0.78) which equals a wave group speed of 4.39 m/s. The time it takes for the swell to arrive to the surf break can be calculated by taking the distances between the surf break and the center of the storm and dividing it by wave group speed (144243m / 4.39m/s) which equals 328,529.25 seconds or 91.25 hours or 3.8 days. Significant wave height as the waves move away from the storm can be calculated by squaring the value of the wind speed and dividing it by the gravity constant then multiplying the products by 0.22 ([7.52 / 9.8] x 0.22) which equals 1.26 m or 4.13