water waves ( script + ripple )
The purpose is to show a wave effect over water.
We gonna use sprites and scripts.
I suppose you know well how to create objects, thus I will not insist on.
⇒ animation with effet Ripple ⇐
⇒ animation without effet Ripple ⇐
Remark :
I have seen an existing example without any explanation.
Let's see another example based upon.
First, download background image. 
Creating Objects
1 - Set up Movie sizes 680x260 (nay background color).
Set Frame Rate equal to 25 (case Ripple effect)
and 70 (case without Ripple effect).
It 'll be reminded further.
2 - Insert background image eau.jpg
3 - Convert to sprite. Name : fond
4 - Now draw a rectangle (sizes of the scene). This 'll be 1st mask
5 - Now draw an ellipse : X = 0 , Y = 0 , W = 3 , H = 1. This 'll be a 2nd mask
6 - In Outline, select sprite named fond. Copy it using "CTRL C".
Then select Scene_1, paste using "CTRL V". Name it clone
7 - In Outline, select clone AND Shape2. Menu : Modify / Grouping / Group as Sprite
Name it onde
Shape2 'll be a mask for clone. onde 'll be the basic sprite, which alpha 'll change using a script.
8 - In Outline, select onde AND Shape1. Menu : Modify / Grouping / Group as Sprite
Name it conteneur
Shape1 is a mask for onde.
9 - Outline 'd look like
Scripts
In Outline, select conteneur. Enter the following script :
In Outline, select onde. Enter the following script :
Set frame rate to 70. Test with "CTRL T". This is a wave effect.
Using Ripple Effect from library
Set frame rate to 25.
In Timeline, select frame 1 to Shape1.
Click Add Effect / Looping continuously / Rippling water. Set data :
Test with "CTRL T". You get ripple water.
Try out another values. For instance :
Duration : 30. Amplitude : 10 Frequency : 2
Duration : 30. Amplitude : 15 Frequency : 3
You could adjust more accurately values after having toggled Author
Tips :
Change only a value at a time, then test.
Mainly, note the values on a sheet with your comments about the results.