For the Iowans about to get douched down again:
Flood Preparation 101:
Water's getting pretty high in Central Iowa right now hmm? Yea well it aint done raining yet kids - Sailorville Lake is less than 2ft below the '93 levels and if it spills it has no place to go but down town Des Moines...
Things To Do Around The Home:
Firstly, evaluate the layout of your home and property. The cardinal rule of hydrology is that water will always attempt to find and fill the lowest point toward the center of the earth's gravity and will proceed to fill up and out from that point. If your home is built on a hill - great, you're ten steps ahead. However, the majority of homes in cities are directly in the flood line - why? Because almost all cities are built in valleys, because that's where the initial settlers found water.
So - where will the water come from? Two major places, it will swell up and out of waterways such as creeks, rivers and canals - and it will back up through plumbing, both city plumbing such as storm drains, and eventually internal plumbing such as your toilet.
You want to move your most treasured posessions upstairs in short order and make copies of all your important paperwork which you will then seal in ziplock bags. If you have a water/fire proof document safe - extra credit for you - if you have a water/fire proof gun safe, reorganize and put your shit in there. Since we're on the subject, a quick note about ammunition - modern ammunition is SPLASH and DUNK proof. It is not designed to be immersed in water for long periods - move it.
Nextly: locate your breaker box and figure out which fuse is connected to each and every room in your home. If flood waters enter your home, you need to turn off the power in every flood area where hot wires exist - if you're unsure just turn off all of your power. Better to go a few days on field rations and flashlights than get electrocuted or cause a fire.
Things To Be Aware Of If A Flood Happens:
You have three major enemies in a home flooding scenario, we will discuss each of them in order of priority.
The first, and most ironic, is drinking water. Seems pretty ridiculous to be worried about finding a drink when your home and street are filled with a couple feet of water right? Wrong. Under no circumstances whatsoever should you be drinking flood water - why? Flood water, although generally starting out pretty clean as either river or rain water, swiftly mixes with all kinds of nastiness from sewer water to chemicals and becomes extremely dangerous to drink. Your first defense against this is to ensure you have a decent supply of fresh drinking water on hand - you can get 4x1 gallon cases of spring water at Walmart for just over two bucks. Generally, unless overly active, you require 1/2oz. of water per pound bodyweight per day to remain sufficiently hydrated - so plan ahead. Once this supply has been depleted, fear not, you're not yet fucked. A Britta type counter top water filter (with spare filters) (kitchenware at Walmart) coupled with emergency water purification tablets (camping aisle) will make a very, very good attempt at removing a lot of the nastier shit from water - boiling it will do even more - a combination of these three techniques will make most ordinary residential flood water acceptable in emergencies.
Secondly, waterborne infection. A minor nick or scrape which would ordinarily cause you next to no problems can become a serious issue if it's immersed in dirty water. Remember, this water is mixed with chemicals, bacteria, sewage - it's not fucking clean - at all. Your first defense is to attempt to keep the wound out of the water - but this isn't always practical. Ensure you have a good quality, well stocked first aid and trauma kit around the home - when dressing the wound you will need to waterproof it - this is as simple in an emergency situation as liberally coating it with Vaseline and dressing it tightly. Finally, regularly clean, dry/breathe and redress the wound using a strong antibacterial ointment.
Finally, hypothermia. It's very easy to become hypothermic in a situation where you have a lot of cold water and not much to do. Everyone in the household should keep an eye on everyone else for symptoms - it can be a killer as sure a a bullet if left unchecked. I may post an entirely separate post just about this subject at some point because it's important information.
After The Flood:
As the water subsides you will find yourself having to assess and deal with the water damage. First thing's first - EVACUATE WATER SLOWLY - especially from basements. Pumping water out too fast can lead to structural problems in your home. When pumping, be sure that the water is being pumped/dumped to an area which is not going to cause further flooding for you or your neighbors. Once water is all gone, being to dry the effected areas immediately in a safe manner - open your windows and doors and use large box fans to circulate and direct air.
If your flooding was serious enough, you should have your wiring inspected for corrosion and potential fire hazards. You will also want to completely flush your plumbing system to ensure it is entirely free of dangerous flood water.
Products:
Normally I don't do plus, but I will give links to two items - one of which is potentially invaluable for all of you, the other only one or two of you might be interested in.
The first: Self inflating 1-33lb sand bags, water activated, $60.00 / case of 10.
http://www.cheaperthandirt.com/TRW147-969-544.html
The second: Mossberg 500 Cruiser 12ga Pump, sealed in watertight, floating tube with survival kit (you can use the tube to also keep your documents) $310.99
http://www.impactguns.com/store/015813513401.html
Two options for my next knowledge dump, comment with your preference:
1) Basic water traversal, currents, eddies, flows and navigation.
2) Hypothermia in detail, prevention, symptoms, treatment.