Ice Dagger. This is the better basic water arcana of the two. The Ice Dagger has a massive knockback, whereas Water Arc has lower knockback and only slightly higher damage.
Frost Feint/Wave Front. Both dash arcana are powerful, but for different purposes. Frost Feint is an offensive one that deals 25 points of damage, although it offers zero knockback. Wave Front is designed for defensive purposes, but it deals almost no damage.
Aqua Beam. Of all standard arcana, Aqua Beam has the lowest cooldown of only 1 second. It offers a decent damage of 10 and quite a large knockback of 20. This is overall the best standard water arcana you can get.
Glacial Cross. This is the most powerful signature arcana of all. Although it has a large cooldown of 7 seconds, it deals 50 damage and 70 knockback, which is huge.