Do parts of Virginia become part of Maryland (or DC) during floods?

I don’t want to hijack this thread, so I thought I’d ask this question here.

Even people who aren’t local to the Washington DC area may have a passing familiarity with the regular flooding that Old Town Alexandria, VA endures. When Hurricane Isabel rolled through recently, the tired old shot looking down King St. at a flooded Torpedo Factory was shown all over the world.

Maryland owns the Potomac River “from shore to shore.” In other words, where the river starts on the Virginia side, so begins Maryland. I think the same rule applies to the border between Virginia and Washington, DC.

But the river is anything but static. It has tides, and it is subject to flooding, especially of late.

So, if the border begins at the “shore,” then any “islands” in the river created by flooding become part of Maryland (or possibly Washington, DC), right? Here’s a picture of the Four Mile Run area of Arlington/Alexandria. In the center of the photo you can clearly see a horseshoe shaped road underwater, which creates an “island” of row houses.

First question: Was that “island” part of Maryland (or DC) at the time the photograph was taken?

Okay, assuming the answer to the first question is “yes,” now say that as a Virginia resident I regularly record all of my telephone conversations without the consent of the second party. During the flood, my home becomes an “island” in the Potomac. I also record a phone conversation without the second party’s consent, which is a crime in Maryland. (And pretend I’m not Linda Tripp and for whatever reason Maryland actually wants to prosecute me.)

Second question: Can Maryland bust me?

If this hypothetical somehow doesn’t match the circumstances, help me out with a situation which does fit them, eh?

I believe that the boundary is defined at the low-level waterline (or something like that). That means that flooding or storms would not change the border.

Ah, that would settle the problem nicely acsenray. I’ll look into that.

Well in this case at least you are wrong. Maryland does not own the Potomac, the boundry line meanders from one side to the other for the length of the Potomac. I don’t know of any online maps, but if you have access to an ADC map, or another large scale map you can see how it meanders. But yes, if they claim one side then to the best of my knowledge it is at low tide.

The entire Potomac River was granted to Maryland in the 1600s under a grant. VA has access to the river through a series of compacts negotiated at Mt. Vernon and upheld in the intervening years. Maryland owns the Potomac River.

more on the VA/MD boundary:

The present case seems to revolve more around the uses permitted under the Compact of 1785 and the Black-Jenkins Award than about the actual boundary itself.

It may be Mean Lower Low Water (MLLW) and not Mean Low Water (MLW) but, yes, the line is fixed and does not move with the tide. Also, any piers or other constructions linked to the shore are considered to be in VA while anything not linked to the shore is in MD.

In the early 20th century there were gambling shacks built on stilts on the VA side. The walkway from the VA side was interrupted by a few inches of separation and there was a sign “Entering MD”. MD police officers provided security in the gambling shacks.

You could also, under these circumstances, hop in your car and legally detect radar.

“In the early 20th century there were gambling shacks built on stilts on the VA side.”

They’re still at Colonial Beach if Isabelle didn’t blow them away.

Yup."]An interesting article about the lawsuit between VA and MD regarding the water intake structure.

Then I stand corrected, but all the ADC maps are wrong then. I’ve also heard VA claim some of the islands as the Maryland Archaeological Society is not allowed to dig on them. I wonder if they use the original Potomac and not what it currently is, that would explain some of the discrepancies.

I have not seen any maps or charts which show the line anywhere else but the VA side of the river. Also, DC owns their part of the river

>> all the ADC maps are wrong then

Can you show us an example online or post a scan?

None of these are ADC maps, but I have seen the same thing on a number of different maps/charts, I even checked on the Aeronautical charts for the Washington area. I’m not saying these are correct, but what I have seen.

Lower section of DC/MD/VA

Same place different map

And again

A bit further north, but I’m not sure if that’s really a border line or not.

And the same place

However, this one does hug the VA line

Those are pretty much the ones I got by using Google’s image search for Potomac River border. I don’t know anything really about the VA/MD border, I only know how I’ve seen it shown on maps. I would have thought the NOAA Charts would show state borders but the ones that we have here do not.

They all mark the low water mark. I know that section of the river like the palm of my hand and I can assure you that whatever is on the VA side of the line will be dry at low water.

I am especially familiar with Jones Point Park and the Belle Haven marina areas. I have been left dry and high there in a dinghy when the tide went out and I had to drag the dinghy over the mud for quite a distance. Those mud flats at low tide are in VA.

My parents own a house along the Potomac, and the Maryland state line is about 200 feet out into the Potomac. Since the boundary was last surveyed, the river has eaten at Virginia and pushed the shore back, but not the boundary.

However, since Maryland controls all building on the Potomac, they had to get Maryland’s approval to build a dock, even though it’s wholly in Virginia.

I found at least one instance of what I was thinking. Patowmack Island. It can be found in the Montogery County ADC map 26 H12. I can only say what the map says though, I have no idea about anything else dealing with the river.