Redwall

[Icefire]

I always thought it was for drainage purposes... like, when it rains a lot, the ditch is probably filled with water.

That could be true, but then why wouldn't the ditch be all the way up and down the path instead of just by redwall?
Maybe (and this is a long shot) but in The Long Patrol , it said that after Kotir was destroyed, most of the area where Redwall was was a swamp. Maybe parts of the castle fell and made a big hole in the ground that later hardened and the ditch. Again, probably not true BUT a possibility.

I guess I just assumed it was connected with the destruction of Kotir...I never really thought about it before.

[Lutra]

Never thought anything about the ditch until it was brought up.  My first thought was Kotir...maybe something caved in, or something of that sort, and voila, there's a ditch.  There's no explicit mention to my knowledge if Redwall is directly over Kotir or were their portions of the former that sank into the earth in time or crumbled away.  Interesting conversation piece here.

[Captain Tammo]

I just realized, it could be connected to Kotir's destruction because the ditch goes way past the abbey in both directions

[Lutra]

^ About all that's been brought up is the pond and that having been Gloomer's home.  If that was once inside Kotir's walls, and its now inside Redwall's then they could be the same size, but you would think of settling ground, especially if Redwall is built over the foundations of Kotir.

[Captain Tammo]

It said in the long patrol that Kotir was literally buried naturally and redwall went over it. Then they discovered a spring in the middle of the abbey grounds and it became the pond. I think that was glommer's pond because it had to be a spring under Kotir. I doubt the guards would bring all that water down to the tunnels beneath Kotir just because.

[Lutra]

Alright, I pulled out Mossflower, read it through, and based on the book, Kotir crumbled within the natural lake formed when it was flooded.  If this is what became the abbey pond, then Kotir's ruins are in the depths of the pond and probably along the grounds.  It seems less likely the foundations are the cause of the ditch.

[Lily]

I just assumed the ditch was always there as a natural formation. It's mentioned before the abbey was built and seems to continue for a long way down the path.

[Nightfire]

I wonder about the sparrows. They don't come in any other books after Mattimeo. Did the sparras leave? Did they die out?

The Dibbuns are very naughty. Don't go to the ditch!

Remember? Their Queen and most of the others died, so I think they must have died out or something.

No they didn't! In the epilogue of Mattimeo, it clearly states that the Sparra are flourishing and maintaining contact with the Redwallers. They renamed the roof spaces "Warbeak's Loft" in honor of their fallen queen, but they did not die out. I highly recommend you re-read the epilogue of Mattimeo.

[Taggerung_of_Redwall]

It didn't draw any attention to technical details regarding their fate, it only stated they were floruishing.

[Nightfire]

I think that the ditch was caused when one of the tunnels use to flood Kotir caved in. It seem very likely.

[Taggerung_of_Redwall]

I think that the ditch was caused when one of the tunnels use to flood Kotir caved in. It seem very likely.

The tunnels were in a different area than the ditch, and the ditch was already there.
There was a big deal over Martin, Gonff and Dinny's three vermin pursuers getting over it.

[Nightfire]

It could have been a stream or creek that dried up.

[Log-a-Log]

Yeah, I think it might be a runoff from the river that eroded the ditch, then eventually dried up

[Nightfire]

Yes. There is a 99.99% chance that the ditch is a dried up stream.

[Taggerung_of_Redwall]

There's no such thing as percentage in this kind of thing, that's just fanon.
Afterall, there is no explanation, and there won't be.