What are my options for getting rid of water?

[Tagard]

I made a trench leading from a river to a mote i dug out around my base. After finishing i spotted some iron under the water trench between the river and my mote. I filled in the trench with dirt completely hoping it would delete the water minecraft style, allowing me to get at that sweet sweet iron. BTW i tried just mining the iron under the water but it didnt seem possible.

Once the trench was filled in with dirt i started clearing the dirt out again only to find the water has not left, it is acting as though the dirt blocks i placed were made of water, and breaking them releases the water again.

Has anyone figured out a way to clear out water?
Should i be using different blocks?
Would I need to dig out an underground tunnel and try to drain the water away?

Any help would be great!

[Tagard]

Thank you for the advice. I ended up digging under the water to get at the iron, it was a huge spot i have all im gonna need for this playthrough.