What to do about this cache in a floodplain?

[raubana]

https://www.geocaching.com/geocache/GCB3QKP

This is placed under a bridge with a river running underneath it. It is in a floodplain and my container is hollow, so it would float away for sure if the water level gets high enough. What should I do?

[Keystone]

For starters, maybe don't hide a cache under a State Highway Bridge?  Aside from the Geocaching Hiding Guidelines on Off-limits locations, you'll want to consider a container that would survive flooding.  Waterproof, and secured in place.

[+barefootjeff]

45 minutes ago, raubana said:

This is placed under a bridge with a river running underneath it. It is in a floodplain and my container is hollow, so it would float away for sure if the water level gets high enough. What should I do?

 

In 2016 I placed a cache in a cavity inside a rock retaining wall alongside a creek, about a metre and a half above the normal water level:

 

 

My original container, a regular-sized Sistema, disappeared after the creek flooded following a severe storm, presumably its buoyancy caused it to float out of its hiding place as the water rose and was carried out to sea. To solve that, I visited the local fishing supplies shop and bought some of the largest lead sinkers they had. Experimenting in the kitchen sink, I ended up needing three of them glued into the bottom of the container to stop it from floating. I also upgraded the container to a Duratech ABS instrument case as they withstand total submersion a lot better than Sistemas.

 

 

I just checked on it this morning and there was a fair bit of silt on top of the container, so it's been fully submerged at some time since my last visit in November, but the interior and logbook were still bone dry.

[raubana]

I didn't know that location was off limits. I did think it was strange no one had put one there already. I guess I better disable it and remove the cache

[+kunarion]

5 hours ago, raubana said:

https://www.geocaching.com/geocache/GCB3QKP

This is placed under a bridge with a river running underneath it. It is in a floodplain and my container is hollow, so it would float away for sure if the water level gets high enough. What should I do?

 

A river that floods is carrying debris that will scour a container away. One hide similar to yours that I know of, is a match tube cache, where the river floods at least once a year. The Cache Owner waits til there are several DNFs after a flood before he goes to check on it, then verifies it was washed away and places a new one. I would not treat cachers like that in a million years, I'd check it immediately after the flood subsides. But that means a lot of checking and a lot of container replacement, so I won't place a cache like that in the first place.

 

My flood-prone caches are at a lake that slowly rises when it floods. So the caches are a few feet above the highest water level. One was a lock-n-lock with an attached cord, and it hung from a tree branch. That kept it high and dry. Another was a 50ml tube clipped to a tree branch. There were DNFs during a flood because Cachers weren't prepared to wade out into the flooded lake. But at that point, someone could then kayak to the cache. The best case scenario is, as CO, providing flood water level updates. Even with a secure cache, that can be a lot of work.

 

A weighted water-tight container might be good, as barefootjeff mentioned. But it could instead become buried in muck (or washed away in the torrent), so you'd still need to check on it. Flooding cache spots are a challenge. I guess your new plan is to archive the one under a bridge? A place higher up, out of the water danger is a good idea.

[+kunarion]

4 hours ago, barefootjeff said:

 

In 2016 I placed a cache in a cavity inside a rock retaining wall alongside a creek, about a metre and a half above the normal water level:

 

 

My original container, a regular-sized Sistema, disappeared after the creek flooded following a severe storm, presumably its buoyancy caused it to float out of its hiding place as the water rose and was carried out to sea. To solve that, I visited the local fishing supplies shop and bought some of the largest lead sinkers they had. Experimenting in the kitchen sink, I ended up needing three of them glued into the bottom of the container to stop it from floating. I also upgraded the container to a Duratech ABS instrument case as they withstand total submersion a lot better than Sistemas.

 

 

I just checked on it this morning and there was a fair bit of silt on top of the container, so it's been fully submerged at some time since my last visit in November, but the interior and logbook were still bone dry.

 

I once found an ammo box cache that was weighted and placed into a stump in a creek.  So in that case, it was hidden submerged.  It worked for a few years, til the stump rotted away.

 

There was a cache on a lake shore that would float during the floods.  Maybe it would have fared better if weighed down.  That's an interesting idea.

[raubana]

Oh crap.

[raubana]

There was a sort of bridge of ice I could walk here, but it was covered in dirt. I didn't realize the whole thing would melt in just a day or two since I last checked on it. Currently the temperature is below freezing, and I am not equipped for wading.

[raubana]

12 hours ago, kunarion said:

 

I once found an ammo box cache that was weighted and placed into a stump in a creek.  So in that case, it was hidden submerged.  It worked for a few years, til the stump rotted away.

 

There was a cache on a lake shore that would float during the floods.  Maybe it would have fared better if weighed down.  That's an interesting idea.

I did want to do an ammo box originally, but it's just not in the budget at the moment. I settled for an old plastic container for instant coffee that I'd cleaned out and covered with camo tape.

 

I think I'll just have to relocate it. Probably a different location altogether.

[+Viajero Perdido]

Wind, kids hanging out, and especially animals will all move caches.  Combine with a river, and your cache could reach the nearest ocean.  Coyotes and the like will chew holes in containers that smell even the tiniest bit interesting, so beware with old food containers.  Even fresh camo paint smells for a while, and hungry animals aren't fussy, chew first and digest later.

 

This one might've gone through an animal, hard to tell:

 

Edited March 6 by Viajero Perdido

[raubana]

Gross. Okay, I will keep that in mind.

[raubana]

Ok I had to do some barefoot wading in some nasty ice-cold water, but I got it. I knew I had to get it sooner than later, since the weather isn't supposed to be at nor below freezing often enough going forward and I expect the water level to continue to rise. I'll go ahead and archive the listing.

[+cerberus1]

18 hours ago, raubana said:

I didn't know that location was off limits. I did think it was strange no one had put one there already. I guess I better disable it and remove the cache

When you asked for permission to hide it, no one mentioned the area was questionable?   Thanks.

[+JL_HSTRE]

You can try tethering the container to a bolt or girder, depending on the container and bridge design. 

 

Very few bridge hides I've encountered (mostly pedestrian bridges) were not at risk from flooding except in the most extreme conditions.