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Any way to tell if some remote lots I have ever floods? It's 3 hours away and i've been there a few times and even after rains seems not, but I'd like to be sure. would driving some white wood stakes in a bunch of places and coming back in a few months show a water mark?

Anything distinctive in the grass or soil indicate flooding?

Do any of these images indicate rain run off flooding? Right now being winter in Central Florida and everything looks dry and brown like this.

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UPDATE 4/20/2020: Something like this?

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    Have you looked at a USGS flood map for the area? – George Anderson Apr 20 at 0:51
  • yes. FEMA maps are saying these lots lots are in some very small patches of Flood Zones though they are not near any bodies of waters. there is only a dried out pond that is 200 feet away that according to Google Earth elevations is about 4 feet lower than my lots. I do have a neighbor that is maybe 2 feet higher than me. The soil is very sandy and porous. I would need to pay for an elevation survey to challenge the FEMA maps. Also because of the classification the county wan't an environmental study report to confirm they are not in a wetland or have protected species. – Hell.Bent Apr 20 at 11:10
  • Also want to point out I have no development within a mile of me. streets are not paved and no storm drains. I got the lots bundled into a deal with another lot that has no issues. I was aware of the Fema map but after standing on the lots and checking Google elevations I was convinced the Fema maps can't be right. Also their is always land fill and reshaping with ditches. Because the lots were basically free, i'm not looking to invest too much in surveys or reports until it makes sense. – Hell.Bent Apr 20 at 11:22
  • A study of google earth elevations shows major irregularities with what FEMA thinks is a low lying area flood area in here. For example most of my lot is at 115-116' above sea level and I have neighbors right next to me at 112' above sea level that Fema is saying is not in the flood zone. The center of the dried out pond 200' feet away is at 108' above sea level . I dont know how much i can trust Google Earth elevations though. I stood there and don't see a wet land or flood zone. – Hell.Bent Apr 20 at 12:03
  • Wait -- you bought a bunch of land with intent to build but didn't get flood history or any sort of permitting done first? Why? – Carl Witthoft Apr 20 at 19:23
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You could make indicators, e.g. stakes with a water-soluble dye (food coloring? water-color marker?) at various levels, covered by a plastic tube, and with a cone over the top, leaving some air-space between cone and tube. Direct rain should not be able to hit the stake, but standing water would rise in the tube, blurring the dye marks.

These indicators would be very inexpensive and easy to make, so set out a fair number in different locations.

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    ...but test them. There is also "water-finding paste" intended for showing water in fuel tanks, but it might be affected by humidity / dew inside the tube. – Ecnerwal Apr 20 at 1:56
  • Thanks. gonna do some testing. Down here it rains sideways some times – Hell.Bent Apr 20 at 11:47
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You really can't test based on one season or one year, that's why there are flood maps. The house I grew up in flooded once in 20 years. The first year of ownership it didn't flood, it flooded 15 years later.

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    Great point - monitoring for 1 year might confirm a positive, but it can't confirm a negative. If the property only floods during a 10-year storm, you'd only find that out after monitoring the property for, on average, 10 years. You can't say the lot never floods, but you can say it does/doesn't flood under whatever conditions you tested. – Nuclear Wang Apr 20 at 14:52
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The fourth picture looks like the initial growth after a flood event. Not certain. Check the species (on the gardening SE), if it is a swamp/wetland plant then it may be growing to indicate the edge of the standing water (plants start growing in the shallow water). The line of young trees may approximately follow the contour line. Look at known flood sites to see the same pattern.

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Ecological and geological tests.

The fourth picture looks like the initial growth after a flood event. Not certain. Check the species (on the gardening SE), if it is a swamp/wetland plant then it may be growing to indicate the edge of the standing water (plants start growing in the shallow water). The line of young trees may approximately follow the contour line. Look at known flood sites to see the same pattern.

Also, if flooding with still water there may be a very thin layer of silt that would not occur otherwise, difficult to check years later.

Possibly, a surface soil scraping left in a covered bowl of shallow water will hatch the invertebrates (mosquitoes etc) - then check if they are water species.

Lastly, investigate the topology around the site (up and down hill) looking for the temporary streambeds where runoff flows. These are easier to identify even a year or two after flooding.

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