There are client side validations and server side validations. The Spry validations are the client side validations and the WA_Validation show if is for the server side validations. You can decide whether you want them both or not based on what you want for your site. You can turn off one or both by going to the Edit Design interface and choosing validations from the drop down menu. There will be a section labeled Type and you can select which ones you want applied.