While determining the spell itself would be fine, it doesn't determine the level, so it's only slightly useful. We know the spell isn't nice to us, just get rid of it!
At 10th, I get my Prof bonus on dispels, yes, which is nice. There's still that random factor if the spell is higher than the dispel cast level. Just means a better chance to dispel higher level spells. We could still waste 3rd level castings trying to remove spells if the rolls go low.
Dungeon Master, can we get a bit more info on this cursed net that appears to be thwarting our advance? Does it look like there may be some underwater manuever we could attempt to swim around it or is it sort of blanketing us completely such that the only way through it is to cut it? Is there a way to try and figure out the trap here (I.e. What's it look like this thing does if we touch it?) Happy to make a suitable roll to figure any of this out.
I would make you roll to figure it out, but I'd judge the DC low enough that I'm sure someone will make it. So let's save some time.
The net appears to be woven tension wires, intended to dislodge a large rock embedded in the roof. The rock falling through the water would not be a significant threat, suggesting that there's something else involved.
Some of the smaller party members might be able to slip through if they are careful. But Poljen, Velon and Morgaine aren't even close to being able to make it.
A larger hole could be made, or the net severed entirely, but doing it without triggering the trap would take a sleight of hand check.
As one potential alternative, could a rogue do it with Thieves' Tools, as if it were a normal trap? Regardless, while any attempts to either clear the net or pass through/by the net are being made, everyone else should hug the walls. There may be more to the rock, but I guarantee that the water won't slow it enough to prevent it from doing some amount of damage.