spell selection help. (eldritch theurge in a unique-ish situation)

[Blackheart,The]

Hello there peoples who are smarter than myself, i could use some advice.

you see, I've been in a long running game for a few years now, started as a level 2 human warlock, and now we're level 14 and our group owns a substantial amount of land, and we have a fort in need of magical protection, the issue being that, as a warlock11/hellfire warlock3, i am the closest thing our group has to a true magic user, and the other PCs refuse to lend me gold to pay for all the wands and scrolls we need.

so take that into consideration and then realize that I'm just a plain ol' 14th level warlock, so when in combat i hardly contribute anything anymore, this all combines into me not being very happy with the mechanics of this anymore (though i still love the character and story). My DM has noticed this and agreed to let me rebuild this character as warlock3/wizard3/eldritch theurge8 as part of an adventure, but with a few conditions, which i have gladly agreed to.

1. i am a focused specialist evoker (i choose to ban illusion, enchantment and necromancy for reasons)
2. i will not start with a spellbook, i will have to spend time making one after the change.
3. as such, i will only know as many spells as a wizard would from gaining class levels

with that in mind, i want to spend my starting spells known on utility things that will help the party, and things that will help a Fort stay safe in a nation that's been suffering through a magical drought

TD;DR

what do you think are the best utility spells for a character that has to protect both his friends, and his home?

[Fouredged Sword]

Well, first, a magic drought is solvable with a basic item. Craft a Decanter of Endless Water and install it in the fort. Then it's a matter of cannals and irrigation. 30gal every 6 seconds isn't something to be scoffed at. It will irrigate a small area of farmland.

Spells that are REALLY USEFUL for guarding a fort

6th level spells
Guards and Wards (http://www.d20srd.org/srd/spells/guardsAndWards.htm) - Great for slowing down an attack. It also grants you a backdoor into casting suggestion.
Planner Binding (http://www.d20srd.org/srd/spells/planarBinding.htm) - If you only get one spell, this is it. You can bind all kinds of nice elementals and outsiders who can do a ton of things to protect a fort. Look for things with cleric casting or useful SLA's.
Contingency (http://www.d20srd.org/srd/spells/contingency.htm) - You didn't ban evocation, so here you go, shinny reward for your efforts. Best defensive spell in the game.
Move Earth (http://www.d20srd.org/srd/spells/moveEarth.htm) - Dig in.

5th level spells
Fabricate (http://www.d20srd.org/srd/spells/fabricate.htm) - Because sometimes you want a mundane object, or lots of mundane objects.
Private Sanctum (http://www.d20srd.org/srd/spells/magesPrivateSanctum.htm)- Nobody can shoot your archers for 24 HOURS! See permenancy for even more fun.
Wall of Force (http://www.d20srd.org/srd/spells/wallOfForce.htm) - Short term stop anything. For a long solution, see permanency
Wall of Stone (http://www.d20srd.org/srd/spells/wallOfStone.htm) - Long term stop most things
Permanency (http://www.d20srd.org/srd/spells/permanency.htm) - Worth the cost for a lot of the area effects.
Mud to stone (http://www.d20srd.org/srd/spells/transmuteMudToRock.htm)- Cast Move Earth. Dig a 20ft deep foundation for your fort. Fill the bottom 10ft with mud, cast this a bunch. Fill the last 10ft with mud. Cast some more. Laugh as someone attempts to undermine a wall on a 20ft thick stone foundation.

4th level spells
Stone shape (http://www.d20srd.org/srd/spells/stoneShape.htm) - Wall of stone means you have as much stone as you want. Get creative, add fortifications to the tops of your walls. Add stone spikes all around your fort except for one main path. If you can't think of an awesome stone thing to add, you are not thinking enough.
Wall of Fire (http://www.d20srd.org/srd/spells/wallOfFire.htm) - You have permanency, this can be AWESOME
Fire Trap (http://www.d20srd.org/srd/spells/fireTrap.htm) - Funny funny funny, and permanent by default.

3rd level spells
Wind Wall (http://www.d20srd.org/srd/spells/windWall.htm) - Just say no to archers.
Arcane Sight (http://www.d20srd.org/srd/spells/arcaneSight.htm) - Permanency is worth it
Explosive Runes (http://www.d20srd.org/srd/spells/explosiveRunes.htm) - Better than Fire Trap, easier to set off by mistake.
Snake Sigil (http://www.d20srd.org/srd/spells/sepiaSnakeSigil.htm) - a nasty non-lethal hit. Expensive though.

2nd level spells
Alter Self (http://www.d20srd.org/srd/spells/alterSelf.htm) - Least Polymorph.
Continual Flame (http://www.d20srd.org/srd/spells/continualFlame.htm) - Not a bad light
See invisible (http://www.d20srd.org/srd/spells/seeInvisibility.htm) - You have permanency right?
Arcane Lock (http://www.d20srd.org/srd/spells/arcaneLock.htm) - keep people out of some rooms
Web (http://www.d20srd.org/srd/spells/web.htm) - Another good wall for permanency. Consider using it in submerged areas like a moat. People who fall into the moat are trapped by the web and drown. It can't be burned underwater.
Unseen Crafter - For all those tasks that just require a craft check and are too big for fabricate. Cast 5 or so of them and have them aid other for high skill checks. Back it up with a temp int boost if you have to, to get them up to a +5 mod to take 10 while aiding other.

1st level spells
Unseen Servant (http://www.d20srd.org/srd/spells/unseenServant.htm) - Can do a lot of drudge work

This is just of the top of my head. Hope this helps.

Ask your DM if you get the 2 spells per level for the PRC levels. IF you do, great, if not, you are going to have only a spattering of level 1 and 2 spells.

Prioritize Move earth, wall of stone, shape stone, and fabricate. With those you can slowly make a castle worth living in.