How to Prepare For a Flood: Understanding Your Land’s Flooding History

It can be hard to piece together your land’s history of flooding, but with a little sleuthing, you may be able to determine whether your new land (or rented acres) have been underwater in recent years.

Your research may take you from the internet to your local records office, to the doors of neighbors and to the lab for soil analysis. And this last piece is important: Your soil’s health is a key datapoint in your farmland’s valuation.

Whether this is your first attempt to assess your soil’s health or you’re just looking for a refresher, here’s what you need to know about the relationship between your land and its history of flooding and current flood zones.

What is your flood zone? Sources for your land’s flood history

So, where exactly should you look to find out if your land has been flooded? There are a few key sources, and they aren’t all accessible online. If you’re a remote landowner, you may need to visit your land to dig up this dirt.

  • County records. Your county office will have your flood zone map on file. This is also where you’ll need to go to find out if the farm is in a flood plain and review historical flood maps for the farm.
  • Federal Emergency Management Agency (FEMA). You can do some research on the FEMA website. For insurance purposes and as a best practice, you should know your flood zone. This will tell you how likely it may be that your land will flood if nearby waters rise or in the event of heavy rainfall.
  • Ask another local farmer. Every farmer is an expert in their area. Other farmers will have a sense of how much water is on the farm on an average year and if it was impacted during any floods in recent memory. A lot of this knowledge is still held locally—all you have to do is ask.
  • Contact a local insurance agent. The USDA Farm Service Agency is probably not going to give you much information, but an insurance agent who knows the area may be able to provide some background.

If you’re a remote landowner, you’ll need to find a resource that can give you an idea of how often their farm has flooded. Even if it’s been 20 years since you’ve been back, check in with a local. Your soil’s health can’t be assessed from satellite pictures.

What’s so bad about flooded land?

At the risk of stating the obvious, flooded land can’t be planted until the waters have receded and any excess moisture dissipates. If your crops are already in the ground when your land floods, the immediately results will be likely be rotted roots, but the floodwater can also cause other long-term issues where your soil’s health is concerned:

Floodwaters bring silt. If your farmland is located along a river or a body of water, silt filtering on the bottom ground is typically not a good thing, especially if that silt is sandy.

Compression. Water is heavy. The weight of floodwater can also compact the soil, especially if there’s ponding on your land. If this happens on a no-till farm, this compression can have a very negative impact that can last a decade.

Crop residue. After a flood, if you’re downstream, you may be stuck with crop residue from neighbors’ farms if you’re on the bottom. If the floodwater doesn’t drain off, general ponding will sit on top of your soil and starve the microbes of oxygen. That’s where you’ll see a long die-off. After that, your soil may lack nutrition; building your soil back up again will take time and money.

Contamination. If there’s a dump site or a manufacturing plant close to the flow of water, you may find that your soil has been contaminated after a flood.

Quality control. Floods move soil around. In the best-case scenario, if you’ve got poor soil and your neighbor’s soil washes down, that’s good for you. It’s more likely that a flood could carry your nutrient-rich soil away from your farm, bringing in soil that’s been sprayed and treated by someone else who lives nearby. You may need to do a soil test to find out how your soil stacks up after a flooding event.

Soil health can be difficult to assess: a soil test kit from a home improvement store may be a fine start, but if your land undergoes a flooding event or if you’re seeing any issues with your crops, it’s a good idea to send a soil sample to a lab that can help you test your soil for nutrients (and contaminants).

Building healthy soil doesn’t happen in a day, and it’s important to make soil tests a part of your seasonal rental practice.

How to prepare for a flood if you’re in a flood zone

Your land may have flooded five years ago, and it may flood again next spring. There’s nothing you can do to stop the weather from happening, but being well-informed about your land’s flood history and your soil’s health will help you to be the best possible steward of your farmland.

Your best bet is to make sure you have a strong farmland rental agreement and a positive attitude. Next year will bring a new crop and new yield; there’s no reason not to be optimistic.

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