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View Full Version : Irriac, before and after the inundations used to lift the siege



Caenwyr
11-27-2012, 11:03 AM
This is a very early version, but I thought I'd already share it with you guys, so you could show me the right direction. The city this is about is called Irriac, and can be found on the western shores of this map (http://www.cartographersguild.com/regional-world-mapping/21036-map-twin-kingdoms-aran-ilan-2.html) (a few dozens of miles north of Fyrnan). It lies in an area that generally lies lower than high tide, and is only protected from the sea by a series of dykes. When threatened by a siege, the inhabitants of Irriac can open the locks on the outer ditch during high tide in order to inundate the surroundings. The city itself as well as the island on the sea side have been built on higher ground, and will not be flooded.

What I'm trying to create is a map that shows the city under normal conditions, and another after the inundations.

Here is my first go. What do you think of it?


50259 50260

Rhotherian
11-27-2012, 12:37 PM
Interesting concept. I'd like to see the city itself and also the dykes in future versions. :) What confuses me on the map a bit is the moat in that the dykes (or rather, what I assume to be the dykes) are open in both images. Or is the first image at low tide? If that's so, perhaps you should make three maps: the city and surroundings at low tide, the city and surroundings at high tide with the dykes closed and the city and surroundings at high tide with the dykes open.

Triplicate
11-28-2012, 08:40 PM
Or is the water level in the first image below sea level?
I guess that would make sense. The moat in the first image is (maybe) at the same level as the sea at low tide, but remains at that level all the time unless the dikes are opened...
Wait a minute, where are the dikes? Are they even on the map? I first assumed the black lines around the city were walls, with the dots being towers.

Caenwyr
11-29-2012, 03:57 AM
The black lines and dots represent walls indeed. Dykes are show as yellower/lighter colorations since they are higher than the surrounding land. You don't only see them at the coast, but also in the East and South, where they're crested with roads.

Basically there's a double moat, and the water level in both is close to the low tide level. The dyke between the two moats is high enough to keep the water out at high tide, but the outer dyke of the outer moat is structurally too low. If you open the outer locks (or lock, one would be enough) the surrounding land gets flooded when the tide comes rushing in. Opening the inner locks would have just minor effects, since the city is built on higher ground than high tide. The inner moat is there mainly as another defensive structure.

However, I'm thinking of changing that. Imagine a city that can be flooded entirely when the walls are breached. It would mean a massive obstruction for the enemy's march to the otherwise now poorly defended castle. People wouldn't have to suffer too much, the whole idea of inundation is to have a layer of water of a mere foot deep: too deep for an attacking army to advance rapidly on foot, too shallow for boats. None of the inhabitants should drown, and chances are their belongings would suffer less than when the enemy was actually able to sack the city. What do you think?

amberroberts09
11-29-2012, 04:43 AM
I don't know but it don't seem perfect to me!!!

Caenwyr
11-29-2012, 05:19 AM
I don't know but it don't seem perfect to me!!!
If you were the lord of this city, and you had the choice between certain death for yourself and the sack of your city on the one hand, and giving your people wet feet on the other (in the process defending not only yourself but also them from the enemy), what would you do? If you're unsure as to the meaning of the word "sack", make sure to look up the atrocities that happened during the Sack of Rome (http://en.wikipedia.org/wiki/Sack_of_Rome_(1527)) in 1527. I don't know about you, but If I could prevent that from happening to my people, I'd gladly be prepared to make them suffer a bit from the defense I'm offering them. Anything is better than being sacked.

Don't forget, this is just an "if all else fails" measure. As long as the walls stand, the city wouldn't need to be inundated at all.

On a different note: I just realized that everything having to do with water in the defense of this city would depend on the control they have over the locks. Controlling just one of the two pairs would suffice, but you'd need to defend them strongly. Way stronger, perhaps, than I did in the initial drawing. I wonder if it wouldn't be better to drop one of the two lock pairs, and move the castle right over the other one. On the other hand, that would mean a better defense for the city itself, but a more urgent reason for the enemy to immediately storm the castle instead of the city. Let me know what you think.

Hmph, medieval city defenses. Not so easy as I first thought.

atpollard
11-29-2012, 10:38 AM
Castles and cities are built for different reasons and with different priorities.

Stone walls require strong foundations and the strategic ‘high ground’ is paramount for defense of a castle.
So the castle will occupy the military strongest defensive point, displacing whatever it needs to.

The city serves an economic purpose with ‘defense’ as only one of several important factors that need to be balanced. Resources need to flow to shops/factories. Finished Goods need to flow to other markets.

The ability to flood the streets and countryside seems like an interesting strategic advantage for the defenders who can optimize their militia and tactics to maximize that advantage … soldiers trained to fight from flat-bottom punts, buildings with second floor living quarters that can serve as sniper posts.

As a side note: with 1 foot of water, dirt streets may turn to mud and make travel difficult, but paved streets will render a foot of water little more than a minor nuisance … waist to chest deep water would be more effective at forcing the invaders into boats (creating small, vulnerable clumps of men subject to hit and run ambushes). Perhaps deep roads and shallow alleys, forcing the invader to choose between advancing through narrow spaces (which favor the defenders) or splitting the force into small boat-sized units (easily ambushed by crossbow snipers).

It is an unusual defense, but not unimaginable.

PS. A surprise attack by an army large enough to storm a castle seems unlikely. You should have plenty of time to flood the city before an enemy can take control of the locks ... and it only takes one small breech in the dike.

vither999
11-29-2012, 11:22 AM
On a different note: I just realized that everything having to do with water in the defense of this city would depend on the control they have over the locks. Controlling just one of the two pairs would suffice, but you'd need to defend them strongly. Way stronger, perhaps, than I did in the initial drawing. I wonder if it wouldn't be better to drop one of the two lock pairs, and move the castle right over the other one. On the other hand, that would mean a better defense for the city itself, but a more urgent reason for the enemy to immediately storm the castle instead of the city. Let me know what you think.

Yeah. Looking at it tactically, that'd be the first place to get hit. As atpollard mentioned, it's very unlikely the city could be "surprised" by a large army, and so if a big enough army to pose an actual threat came near they'd probably inundate to be on the safe side. But if that army had some kind of guerilla combat troops, they could head out way in front, take out the locks, and thus prevent inundation: or worse, undo inundation by opening the gates at low tide.

Another (cheaper) tactic to having more fortifications around the locks might be just to have more of them: taking two before word gets out that an attack is going down seems fairly reasonable, but taking ten? Not quite as likely...

[EDIT] Spelling.

Lyandra
12-02-2012, 05:43 PM
A very interesting and unusual project... I really like it. I cannot wait to see the finished product! ^^

anstett
12-14-2012, 05:14 PM
Interesting concept for a defense.

Quirky that the advertisement showing for me is a Water Damage Repair company :)

I agree that there needs to be multiple ways of flooding or it will not work. A commando raid of adventurers captures the one or two breach points spoils it. The other problem is water flows down so the sea will have to be up above the level of the city ground floor for this to work. Very hard to regulate how much how fast that water pours in .

If there is a reasonable way of emptying the water back out this works as a defensive scheme very well and not just a last desperate drown then all before they get killed sort of thing.

BOB

Larb
12-14-2012, 09:29 PM
Actually that was my thought. Flooding the whole area makes for a great defensive measure but how long would it take to reverse it after military action is over? Is it even possible? Would a permanent moat not serve the same purpose? Even if the area was flooded, couldn't the enemy just go for the same "starve you out" tactics anyway?

The whole defensive measure seems more like a one-time trap for a powerful invader. I can only see it working once, used to destroy (at least partially) an attacking force.

The map itself is quite fine! Nice clear and vibrant colours. Although the grid approach to the building placement I am not a fan of, it does illustrate the built up areas so does serve that purpose!