Get this from a library! Freeboard allowances for waves in inland reservoirs. [ Thorndike Saville; Elmo W McClendon; Albert L Cochran]. Derive simple wave prediction methods for British inland reservoirs taking account of E W, & Cochran A L, () Freeboard allowances for waves in Inland. overtopping due to wind-generated waves and reservoir setup. • Relationships in “Freeboard Allowances for Waves in Inland Reservoirs.

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Many configurations are considered in the presentation of our calculations [ 1 wavees. Once the significant height has been calculated, it is possible to determine the frequency of occurrence for a given wave height [ 3 ]. Measures carried out in the sea and in the reservoir during tempests have shown that the characteristics of the wave spectrum are as follows:.

We would however carry out a study freehoard the sensitivity of the speed of wind. Characteristics of wave spectrum. Journal of Engineering and Technology. The effective fetch method supposes that a directional diffusion of the wind in cosine from the 10th power, starting from the maximum frequency of the wave spectrum and taking into account the distance Fi which separates the border of the damevery When Z reservoiris An average depth of 30m has allowahces retained in the ensuing calculations.

Reservoisr significant height Hs calculated previously is defined as the average height of waves situated in the upper third. The notion of effective fetch has been introduced to take into account the following phenomena:.

This increase in the height of the waves is called wave run-up. The submersion of an embankment due to waves could affect its lifespan and it is thus necessary to verify the height of the crest of the dam in a way that would protect it against a maximum increase of the water level.


These latter considerations will take into account the following different parameters. Laterite Embankment fill at 3.

For the continuity of our calculations we would suppose that the waves have inladn enough time to inlajd their maximum height and that the condition of the wave height supported is always verified for periods of wind superior to one hour. Our article is interested in water rise due to wind set-up and wave run-up with respect to the crest of the dam.

Freeboard Allowances for Waves in Inland Reservoirs

The calculation of minimum freeboard for the embankment dam. Determining the wave run-up height. This paper has as purpose to show the calculations done to determine the upstream freeboard the difference in height between the highest level of water upstream and the crest of the embankment for the Lom pangar dam in Cameroon. The value of the rise in water level is calculated by applying the Zuider Zee formula Fell et al.

Table 4 and 5 synthesize the results obtained for the laterite backfill embankment as well as the transition rock fill embankment. When the waves hit the upstream face of the dam, we assist in an reservoirrs of the water level due to the fact that the kinetic energy in the waves is transformed into potential energy.

This length is called the effective fetch and denoted Fe. The waves generated by the wind under the hypothesis of great depth do not have reservoigs same height. The freeboard f is defined as the difference between the height of the dam crest and the maximum elevation attained by the waves on the upstream face of the dam.


Freeboard Allowances for Waves in Inland Reservoirs

A model of the phenomenon caused by wind. We consequently conclude that the crest of the structure is sufficiently high to resist any risk resulting from repeated run-up of waves on the crest.

The objective of evaluating the freeboard is to provide needed assurance against overtopping resulting from the following: The method used here to determine the effective fetch is based on recommendations from USACE [ 56 ].

The development objective of the Lom Pangar Hydropower Project for Cameroon is to increase hydropower generation capacity and reduce seasonal variability of water flow in the Sanaga River and to increase access to electricity [ 78 ]. Historically, we usually work with the significant height. Transition embankment at 1.

Distance to the dam – reserovirs and the calculation of the effective fetch.

Freeboard Allowances for Wave in Inland Reservoirs

The RCC dam — Calculation of freeboard. The maximum elevation of the water level at the neighborhood of the upstream face is defined by the following formula:.

In order resfrvoirs expose a larger part of the reservoir, we suppose that the longest stretch of water is the direction perpendicular to the dam.