what is impact of blowing a bridge?

[rtropp]

I have searched through the manual and the forum but am still a bit confused about the benefit of blowing a bridge or road that crosses a river.
If I blow a bridge across water, can the enemy still cross it?
If they can cross it, what do you gain by blowing them?
I ask because it seems my friendly troops who were caught on the wrong side of the river were able to cross it back to safety seemingly without any problem when retreating.
I am just trying to evaluate if it pays to blow all the bridges to slow down the enemy advance into France while playing "Home before the leaves fall, 1914" in TOAW IV.

Thanks to all.

[btd64]

Blowing a bridge can have multiple implications. From slowing the flow of supply to slowing the advance of troops....GP

[larryfulkerson]

There are bridges over minor rivers that don't stop the flow of troops but I'm thinking that blowing
the bridge over a major river WOULD stop the flow of troops. Unless and until they repair the bridge
or bring in some ferry bridging engineers to ferry the troops across on pontoons. I like to drop the
Soviet bridges when I'm the Axis player to slow down the flow of reinforcements to the front lines.

[rtropp]

Thanks, that was very helpful. I have gone back and finally noticed some rivers being called "super rivers", some just "rivers" and other "canals". Now I know what to look for and will start to gauge their impacts on movement as well as supply.
Boy, this is fun.
Thanks

[Nicholas Bell]

Also note that if units have at least 10% ferry capability specific to the river type they are crossing, they will be able to cross without a bridge by expending additional movement points.