WO2018063431A1

WO2018063431A1 - Wave generator with wave damping

Info

Publication number: WO2018063431A1
Application number: PCT/US2017/014065
Authority: WO
Inventors: Bruce Mcfarland
Original assignee: American Wave Machines, Inc.
Priority date: 2016-09-27
Filing date: 2017-01-19
Publication date: 2018-04-05
Also published as: US20180266129A9; US20180087284A1

Abstract

A wave-generating apparatus is disclosed. The apparatus includes a wave pool with a bottom, wherein the bottom is upwardly-inclined along a length of the wave pool and defines a deep edge and a beach edge. A wave generator is placed adjacent to the deep edge. An open wave-damping trough is placed adjacent to the beach edge and adapted to retain water. The apparatus is constructed such that when the wave generator is not actuated, the pool retains water defining a static water level and a portion of the beach edge is above the static water level. When the wave generator is actuated, it creates a wave that propagates across the wave pool from the deep edge to the beach edge, and the wave energy is dampened when the wave encounters the water retained in the trough.

Description

WAVE GENERATOR WITH WAVE DAMPING

1.0 TECHNICAL FIELD

[0001] The present invention relates generally to a wave-forming apparatus and is partially concerned with water rides of the type provided in water-based amusement parks, particularly a wave-forming apparatus and method for forming surfable waves, or a water toy.

2.0 RELATED APPLICATIONS

[0002] This application is related to U.S. Patent Application No. 14/808076, filed on July 24, 2015, titled "SEQUENCED CHAMBER WAVE GENERATOR CONTROLLER AND METHOD", the disclosure of which is herein incorporated by reference in its entirety. This application is also related to U.S. Patent Application No. 15/246233, filed on August 24, 2016, titled "WAVE GENERATING APPARATUS AND METHOD," the disclosure of which is also herein incorporated by reference in its entirety. This application is also related to U.S. Patent Application No. 15/277521, filed on September 27, 2016, titled "WAVE GENERATOR WITH WAVE DAMPING," the disclosure of which is also herein incorporated by reference in its entirety.

3.0 BACKGROUND

[0003] Wave generators are often used for recreational purposes. Wave generators create one or more waves in a pool or the like, and people typically either play in the waves or use the waves for aquatic sports such as board sports. Aquatic board sports, such as surfing and bodyboarding, require that the waves be rideable. Enthusiasts in these types of sports often use wave generators for competition, practice or entertainment.

[0004] Existing wave generators can use wave-generating chambers or submerged or partially- submerged moving objects to produce a wave that travels in a direction where the peak of the wave is substantially parallel to the chambers and to the beach as it travels from the chambers toward the beach. The wave is produced when the wave -chambers (either one chamber or multiple chambers) are all activated simultaneously, resulting in the water being pushed away from the wave-generating chambers and then traveling at an angle away from the chambers. Such a system is disclosed in U.S. Patent No. 9, 103,133 and patent application number 15/246233, filed on August 24, 2016; the contents of both are incorporated herein by reference.

[0005] To provide for a more authentic experience, sand may be placed on the beach edge of the wave pool - i.e., the edge that is opposite to the wave generators. When the wave breaks, however, the wave turbulence can cause the sand to dislodge and travel away from the intended beach edge. Not only does this affect the authenticity of the experience, the sand can also travel into the pumps and other mechanisms of the wave-generating apparatus, causing damage or premature failure.

[0006] Even without sand, unbroken waves and Whitewater that reach the shore elevation of a surf pool typically run up a slope and back into the pool. This creates unwanted backwash and reflections, resulting in a reduction of wave quality and the buildup of energy in the pool.

[0007] What is needed, therefore, is an apparatus that overcomes the shortcomings of the prior art, including minimizing backwash and the unwanted movement of sand.

4.0 SUMMARY

[0008] To address the shortcomings in the prior art and to improve artificial wave generation a wave-generating apparatus with a wave-damping trough is disclosed and claimed herein. The apparatus includes a wave pool with a bottom, wherein the bottom is upwardly-inclined along a length of the wave pool and defines a deep edge and a beach edge. A shore is adjacent to the beach edge. A wave generator is placed adjacent to the deep edge. An open wave damping trough is placed adjacent to shore and adapted to retain water. The apparatus is constructed such that when the wave generator is not actuated, the pool retains water defining a static water level and a portion of the beach edge is above the static water level. When the wave generator is actuated, it creates a wave that propagates across the wave pool from the deep edge to the beach edge, and the wave energy is dampened when the wave encounters the water retained in the trough. The trough water creates a hydraulic jump that abruptly changes the flowing water velocity, absorbing the wave propagation energy.

[0009] In one embodiment, the pool bottom may have different angles of inclination at different portions of the pool. The angle of inclination of the pool bottom may be steepest near the wave generator. Further, the wave generator may actually comprise a plurality of wave generators. The beach edge may be semi-circular.

[0010] The trough may also have a pump that creates a current in the trough, wherein the direction of the current may be substantially orthogonal to the direction of the wave propagation.

[0011] To optimize energy dissipation, the trough may have a width that is at least twice the maximum wave height, optimally four times the maximum wave height, and the shore may have a width that is similar to the trough width, optimally at least twice the trough width.

[0012] Additional aspects, alternatives and variations as would be apparent to persons of skill in the art are also disclosed herein and are specifically contemplated to be included as part of the invention. The invention is set forth only in the claims as allowed by the patent office in this or related applications, and the following summary descriptions of certain examples are not in any way to limit, define or otherwise establish the scope of legal protection.

5.0 BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The invention can be better understood with reference to the following figures. The components within the figures are not necessarily to scale, emphasis instead being placed on clearly illustrating example aspects of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views and/or embodiments. It will be understood that certain components and details may not appear in the figures to assist in more clearly describing the invention.

[0014] Fig. 1 is an isometric view of a wave-generating apparatus with a novel wave-damping trough.

[0015] Fig. 2 is a top view of the wave-generating apparatus with several cross- sections indicated.

[0016] Fig. 3A is the cross-sectional view along line A-A shown in Fig. 2.

[0017] Fig. 3B is an enlarged section of the wave generator found in Fig. 3A.

[0018] Fig. 3C is an enlarged section of the wave-damping trough and beach edge found in Fig. 3A.

[0019] Fig. 3D illustrates a mound elevator.

[0020] Fig. 4 is the cross-sectional view along line B-B shown in Fig. 2. [0021] Fig. 5 is the cross-sectional view along line C-C shown in Fig. 2.

[0022] Fig. 6A is a snapshot of a model illustrating the formations of a wave within the wave-generating apparatus, wherein the snapshot is a cross-sectional view that is orthogonal to the travel direction of the wave.

[0023] Fig. 6B is a snapshot of the model taken moments after the snapshot depicted in Fig. 6A, wherein the wave has begun to curl.

[0024] Fig. 6C is a snapshot of the model taken moments after the snapshot depicted in Fig. 6B, wherein the wave has broken and created turbulent white water.

[0025] Fig. 6D is a snapshot of the model taken moments after the snapshot depicted in Fig. 6C, wherein the white water is turbulently traveling towards the beach end of the wave generating apparatus.

[0026] Fig. 6E is a snapshot of the model taken moments after the snapshot depicted in Fig. 6D, wherein the white water is turbulently traveling towards the beach end of the wave generating apparatus.

[0027] Fig. 6F is a snapshot of the model taken moments after the snapshot depicted in Fig. 6E, wherein the white water is turbulently traveling towards the beach end of the wave-generating apparatus and is about to reach the wave-damping trough.

[0028] Fig. 6G is a snapshot of the model taken moments after the snapshot depicted in Fig. 6F, wherein the white water has reached and slammed into the water residing in the wave damping trough.

[0029] Fig. 6H is a snapshot of the model taken moments after the snapshot depicted in Fig. 6G, wherein the white water has mixed with the water in the wave damping trough and the mixture has been significantly dampened as the mixture continues its travel towards the beach end of the wave-generating apparatus.

[0030] Fig. 61 is a snapshot of the model taken moments after the snapshot depicted in Fig. 6H, wherein the white water has completely mixed with the water in the wave-damping trough and the mixture has been substantially completely dampened as the mixture reaches the edge of the beach end of the -generating apparatus.

[0031] Fig. 7A is a snapshot of the model after the wave-generating apparatus has created a wave and the wave has propagated across the wave pool forming Whitewater, wherein the snapshot is a cross-sectional view that is orthogonal to the travel direction of the wave. [0032] Fig. 7B is a snapshot of the model taken moments after the snapshot depicted in Fig. 7A, wherein the white water has reached and slammed into the water residing in the wave damping trough.

[0033] Fig. 7C is a snapshot of the model taken moments after the snapshot depicted in Fig. 7B, wherein the white water has mixed with the water in the wave damping trough and the mixture has been significantly dampened as the mixture continues its travel towards the beach end of the wave-generating apparatus.

[0034] Fig. 7D is a snapshot of the model taken moments after the snapshot depicted in Fig. 7C, wherein the mixture of Whitewater and the water in the wave damping trough have formed back wash and the backwash is propagating in a direction opposite to the original wave.

[0035] Fig. 7E is a snapshot of the model taken moments after the snapshot depicted in Fig. 7D, wherein the propagation of the backwash is significantly dampened by the wave damping trough.

[0036] Fig. 7F is a snapshot of the model taken moments after the snapshot depicted in Fig. 7E, wherein a relatively minor portion of the backwash has traveled outside of the wave dampening trough.

6.0 DETAILED DESCRIPTION

[0037] Reference is made herein to some specific examples of the present invention, including any best modes contemplated by the inventor for carrying out the invention. Examples of these specific embodiments are illustrated in the accompanying figures. While the invention is described in conjunction with these specific embodiments, it will be understood that it is not intended to limit the invention to the described or illustrated embodiments. To the contrary, it is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.

[0038] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. Particular example embodiments of the present invention may be implemented without some or all of these specific details. In other instances, process operations well known to persons of skill in the art have not been described in detail in order not to obscure unnecessarily the present invention. Various techniques and mechanisms of the present invention will sometimes be described in singular form for clarity. However, it should be noted that some embodiments include multiple iterations of a technique or multiple mechanisms unless noted otherwise. Similarly, various steps of the methods shown and described herein are not necessarily performed in the order indicated, or performed at all in certain embodiments. Accordingly, some implementations of the methods discussed herein may include more or fewer steps than those shown or described. Further, the techniques and mechanisms of the present invention will sometimes describe a connection, relationship or communication between two or more entities. It should be noted that a connection or relationship between entities does not necessarily mean a direct, unimpeded connection, as a variety of other entities or processes may reside or occur between any two entities. Consequently, an indicated connection does not necessarily mean a direct, unimpeded connection unless otherwise noted.

[0039] The following list of example features corresponds with FIGS. 1-61 and is provided for ease of reference, where like reference numerals designate corresponding features throughout the specification and figures:

[0040] 10- Wave-generating apparatus

[0041] 11- Apogee

[0042] 12- Perigee

[0043] 15- Wave pool

[0044] 16- Deep edge

[0045] 20- Wave generators

[0046] 25A- Shore

[0047] 25B Beach edge of pool

[0048] 26 Shore terminal edge

[0049] 27- Static water level

[0050] 28- Portion of shore above static water level

[0051] 29- Grade level

[0052] 30 Wave-damping trough

[0053] 31A- Mound

[0054] 31B- Mound maximum height point

[0055] 31C- Plane

[0056] 31D- Trough bottom

[0057] 31E Intersection point of trough bottom

[0058] 32- First portion of upwardly-inclined wave pool bottom [0059] 33- Second portion of upwardly-inclined wave pool bottom

[0060] 34- Width of wave damping trough

[0061] 35- Pump

[0062] 36A- Bladder

[0063] 36B- Piston/ram

[0064] 36C- Cam

[0065] 37- Flexible covering

[0066] 38- Variance in mound height

[0067] 40- Wave-generating chamber

[0068] 42- Throat

[0069] 45- Wave (Curling)

[0070] 50- Wave (Curling-breaking)

[0071] 55- Wave white water

[0072] 60- Wave white water first dampened by trough

[0073] 65- Wave white water dampened with more of the water in trough

[0074] 70- Wave white water dampened with all of the water in trough

[0075] 75 Wave white water

[0076] 80 Wave white water first dampened by trough

[0077] 85 Wave white water dampened with more of the water in trough

[0078] 90 Formation of backwash

[0079] 95 Propagation of backwash dampened by water in trough

[0080] 100 Minimal backwash propagating out of the trough

[0081] Figures 1-5 illustrate a wave-generating apparatus 10 with an oval pool 15 with an apogee of 750 feet (line 11) and a perigee of 245 feet (line 12). The wave pool 15 has a bottom (32, 33) with two portions: the first portion 32 has an angle of inclination relative to horizontal that is steeper than the angle of inclination of the second portion 33. The variance in steepness assists in creating the wave. The pool bottom may alternatively have a single angle of inclination or multiple angles of inclination.

[0082] The pool bottom (32, 33) defines a deep edge 16 and a beach edge 25B, and adjacent to the deep edge 16 are the wave generators 20. When the wave generator 20 is not actuated, the pool 15 retains water defining a static water level 27 and a portion of the shore edge 28 is above the static water level 27. In the embodiment illustrated in figures 1-5, the portion of the beach edge 28 is at grade level and is two feet above the static water level 27. [0083] Adjacent to the beach edge 25B is a shore 25 A which may have an upwardly-inclined bottom. An open wave-damping trough 30 is disposed adjacent to the shore 25A and retains water, and optionally the trough can drain water or have a water level that can be controlled. Fig. 3C illustrates an enlargement of the trough 30 and the shore 25A. Between the trough 30 and the pool bottom (32, 33) is a mound 31 A that has a maximum height point 3 IB. The trough 30 has a trough bottom 3 ID that begins at the maximum height point 3 IB and slopes down and up, forming a bowl in which water can be retained. Drawing a horizontal plane 31C intersecting this maximum point 3 IB defines one edge of the trough 30, while the other edge is defined by the point where the trough bottom 3 ID intersects the plane 31C (shown as point 3 IE). From point 3 IE to the point where the shore bottom is substantially horizontal defines the shore 25A and the shore terminal edge 26. In the embodiment illustrated in figures 1-5, the depth of the open wave-damping trough 30 is about one foot below the static water level 27, the width of the trough is about 25 feet (as shown by bracket 34), and the width of the shore 25A is approximately 50 feet. The trough 30 can be initially dry, then filled by the wave surge.

[0084] Shown in 3B is one of the wave generators, which includes a pump 35 and a wave-generative chamber 40, that pushes water through the throat 42, causing the water in the pool 15 that is adjacent to the wave generators to rise rapidly, forming a wave that propagates across the wave pool 15 towards the beach edge 25B. The actual operation of the wave generator illustrated in Fig. 3B is detailed in U.S. Patent No. 9,103,133 and patent application number 15/246233, filed on August 24, 2016, the contents of which are both incorporated herein by reference. When this wave encounters the wave-damping trough 30, the trough 30 provides inertial resistance to the incoming surge, thereby decreasing its momentum energy. The loss of wave surge energy minimizes the problems of backwash and reflections that result in reduction of wave quality and unwanted sand migration.

[0085] While figures 1-5 illustrate a chamber-base wave generator, other wave generators can use the damping trough disclosed herein. For example, one type of wave generator uses a sled submerged in an existing body of water such as a lake. The sled includes a scoop, and as the sled is moved towards the beach or shore of the lake, it creates a wave on the surface. The energy in that wave could case reflection, diminishing the quality of the waves, and undesirable sand migration.

[0086] As an additional feature, the water in the wave-damping trough may be static or can be pumped to create a current of water. The current may be, for example, substantially orthogonal to the direction of the wave propagation. Such a current opens the possibility of using the trough for other recreational activities such as stand up paddle boarding. Optionally, the trough can be separately drained or pumped away or back into the pool 15. Further, the level of water in the trough 30 can be controlled through pumping to further optimize its damping ability.

[0087] The trough 30 can also contain sand so as to act as a water filter. By pumping water from the wave pool into and then out of the trough 30, the sand bed can act as a particulate filter. This filtration function may be used whether or not the wave- generating apparatus is producing rideable waves. Additionally, the mound 31A may have a controllable height so as to let more water from the wave pool 15 into the trough 30. Controlling the mound 31 A height can find tune the damping ability of the trough 30, and can also be used to allow more effective filtration. For example, in the embodiments shown in figures 1-5, the mound maximum height point 3 IB is at the same height as the static water level 27, so in a placid wave pool 15 lowering the mound 31A would allow water from the wave pool 15 to freely flow into the trough 30. Therefore, the mound 31A could be set a height shown in Fig. 3C during wave generation, and when the apparatus is in non-wave generation mode the mound 31A could be lowered to allow water to freely flow into the trough 30 and be filtered therein. The adjustability of the mound 31 A may be on certain segments of the trough 30 or on the entire length of the trough 30.

[0088] Fig. 3D shows three different mound elevators: a bladder 36A, a piston or ram 36B and a cam 36C. Any of these mound elevators may be covered with a flexible covering 37, which may be _reinforced or unreinforced PVC typical of pond liners or other suitable materials.. This flexible covering 37 is the surface which may contact the user and would prevent the user from harm should the user come into contact with the mound elevator. In the case of the bladder 36A, the mound 31A is lowered by releasing fluid from the bladder 36A as shown on the right side of Fig. 3D. Arrow 38 shows the amount the mound 31A was lowered. Likewise, the piston/ram 36B is retracted and the mound 31 A lowers. And finally, the cam 36C is rotated which lowers the mound 31 A. It would be apparent that other mechanisms may be used.

[0089] Fig. 4 is the cross-sectional view along line B-B shown in Fig. 2. Fig. 5 is the cross-sectional view along line C-C shown in Fig. 2.

[0090] Figures 6A-6I are several snapshots of a model illustrating the formations of a wave within the wave-generating apparatus and the subsequent reduction in energy of the wave. This model is based on the embodiment illustrated in Figures 1-5. These snapshots are taken at a cross-section that is orthogonal to the travel direction of the wave. This is the same perspective as that of Fig. 3A discussed above.

[0091] Fig. 6A is the first snapshot showing the initial creation of the wave by the wave generator 20. Also show in in Fig. 6 A is the wave pool 15, the wave pool bottom (32, 33), the trough 30, the shore 25A and the beach edge 25B. For simplicity, these reference numerals are not repeated in figures 6B-6I. Fig. 6B is a snapshot taken moments after the snap-shot depicted in Fig. 6A, wherein the wave 45 has been created and has begun to curl. Moments later (shown in Fig. 6C), the wave has broken and created a wave that is curling and breaking 50.

[0092] Figs. 6D, 6E and 6F illustrate the resultant white water 55 that is approaching the wave-damping trough 30. At Fig. 6G, the white water has reach and slammed into the water residing in the wave-damping trough 30. Here, the wave surge from the white water has first begun to damp out as it mixes 60 with the water in the damping trough 30. In Fig. 6H, yet more of the white water surge has mixed with the water in the wave-damping trough 30 and the mixture 65 has been significantly dampened. Finally, Fig. 61 illustrates that the white water has completely mixed with the water in the wave-damping trough 30, and the mixture 70 has been substantially completely dampened as the mixture 70 reaches the shore and the beach edge and flows over the portion of the shore that is above the static water level 27.

[0093] Fig. 7A-C are several snapshots of a model illustrating the formations of a wave within the wave-generating apparatus and the subsequent reduction of backwash into the wave pool. Backwash from a previous wave can reduce the quality of subsequent waves. To avoid these negative effects, the current practice is to wait until the wave pool is placid (or close to it) before actuating the wave-generating apparatus to product another wave. This delay reduces the efficiency of the wave pool by limiting the number of rideable waves produced within a given time. Reducing or eliminating backwash allows the wave-generating apparatus to operate more efficiently, resulting in higher profitability for the operators of the apparatus. 7A is a first snapshot of the model after the wave- generating apparatus has created a wave and the wave has propagated across the wave pool forming Whitewater 75, wherein the snapshot is a cross-sectional view that is orthogonal to the travel direction of the wave. Also show in in Fig. 7A is the wave pool 15, the wave pool bottom (33), the trough 30, and the shore 25A. For simplicity, these reference numerals are not repeated in figures 7B-7F. Fig. 7B is a snapshot taken moments after the snap-shot depicted in Fig. 7A, wherein the white water 80 has reached and slammed into the water residing in the wave damping trough. Moments later (shown in Fig. 7C), the Whitewater has mixed with the water in the wave damping trough and the mixture 85 has been significantly dampened as the mixture continues its travel towards the beach end of the wave-generating apparatus.

[0094] Figs. 7D, 7E, and 7F illustrate the damping of the backwash formed. Fig. 7D is a snapshot of the model taken moments after the snapshot depicted in Fig. 7C, wherein the mixture 90 of Whitewater and the water in the wave damping trough have formed back wash and the backwash is propagating in a direction opposite to the original wave. Moments later (shown in Fig. 7E) the propagation of the backwash 95 is significantly dampened by the wave damping trough, such that at Fig. 7F a relatively minor portion of the backwash has traveled outside of the wave dampening trough.

[0095] The wave peak created by the model was approximately six feet above the static water level, and, for such a wave, the model show that more than 50% of the energy from the wave surge is dissipated across the trough 30. Reducing the wave trough width in half to 12 feet, or approximately twice the size of the maximum wave height, while maintaining a one-foot depth, resulted in 25% energy dissipation. Because the size of the apparatus can affect maintenance and constructions costs, it is important to size the beach edge appropriately to optimize expenses. It therefore appears that an optimal relationship is a wave trough that is approximately four times as wide as the produced wave height.

[0096] The modeling found that a trough width that is twice the width of the shore as measured at the shore terminal edge 26 is effective. To reduce the overall footprint of the apparatus, it was found that 50% of the energy can be dissipated if the width is only 50% larger than the trough width. If the energy maintained by the wave surge continues to propel water, a berm or upslope may be necessary on the outer edge of the apparatus to retain the water therein.

[0097] Although exemplary embodiments and applications of the invention have been described herein including as described above and shown in the included example Figures, there is no intention that the invention be limited to these exemplary embodiments and applications or to the manner in which the exemplary embodiments and applications operate or are described herein. Indeed, many variations and modifications to the exemplary embodiments are possible as would be apparent to a person of ordinary skill in the art. The invention may include any device, structure, method, or functionality, as long as the resulting device, system or method falls within the scope of one of the claims that are allowed by the patent office based on this or any related patent application.

Claims

1. A wave-generating apparatus, comprising:

a wave pool with a bottom, wherein the bottom is upwardly inclined along a length of the wave pool and defines a deep edge and a beach edge;

a shore adjacent to the beach edge;

a wave generator adjacent to the deep edge, wherein when the wave generator is not actuated, the pool retains water defining a static water level and a portion of the shore is above the static water level;

an open wave-damping trough adjacent to the shore and adapted to retain water; wherein when the wave generator is actuated it creates a wave that propagates across the wave pool from the deep edge to the beach edge, and wherein the wave energy is dampened when the wave encounters the water retained in the trough.

2. The apparatus of claim 1, wherein the wave pool comprises a shore terminal edge abutting the beach edge and the wave energy is dampened by greater than 50% when the wave has reached the shore terminal edge.

3. The apparatus of claim 1, wherein the bottom comprises two portions, the first portion having a first angle in inclination relative to horizontal and the second portion having a second angle relative to horizontal, wherein the first angle is greater than the second angle.

4. The apparatus of claim 3, wherein the first portion is closer to the wave generator than the second portion.

5. The apparatus of claim 1, wherein the wave generator is comprised of a plurality of wave generators.

6. The apparatus of claim 1, wherein the beach edge is semi-circular.

7. The apparatus of claim 1, wherein the wave has a peak height as measured from the static water level and the trough has a width parallel to the direction of the wave propagation, and the width is greater than twice the peak height.

8. The apparatus of claim 1, wherein the wave has a peak height as measured from the static water level and the trough has a width parallel to the direction of the wave propagation, and the width is greater than four times the peak height.

9. The apparatus of claim 1, wherein:

the wave-damping trough and the pool bottom are separated by a mound, the mound having a maximum height point and a plane parallel to horizontal and intersecting the maximum height point, wherein the trough has a trough bottom and trough width defined where the trough bottom intersects the plane;

wherein the shore has an upwardly-inclined shore bottom and a shore width defined on one edge where the shore bottom intersects the plane and on an opposite edge where the shore bottom is substantially horizontal; and wherein the shore width is at least 50% larger than the trough width.

10. The apparatus of claim 1, wherein:

wherein the shore has an upwardly-inclined shore bottom and a shore width defined on one edge where the shore bottom intersects the plane and on an opposite edge where the shore bottom is substantially horizontal; and wherein the shore width is at least twice the trough width.

11. The apparatus of claim 1, wherein the trough further comprises a pump that creates a current in a direction substantially orthogonal to the direction of the wave propagation.

12. The apparatus of claim 1, wherein the wave trough and the pool bottom are separated by a mound and the height of the mound is controlled by a mound elevator.

13. The apparatus of claim 12, wherein the trough comprises a sand filter and pump, wherein when the mound elevator is actuated it lowers the mound below the static water level, allowing the pump to pull water from the wave pool into the trough and through the sand filter.

14. The apparatus of claim 12, wherein the mound elevator is selected from a group consisting of: a ram, a piston, a cam or a bladder.

15. The apparatus of claim 1 wherein the trough comprises a sand filter and pump.