A Rising Tide ...

While a rising tide may lift all boats, here on the coast it also floods the streets and yards. As rising sea levels make tidal flooding a larger and larger concern, several local media companies got together to sponsor a King Tide event. The king tide is the highest astronomical tide of the year. This is when the moon and sun alignment, together with their proximity, drive the tides especially high. There is no guarantee that the king tide will be the highest tide of the year as weather also plays a big part. But the king tide is predictable well in advance, unlike the weather.

So on Nov 5, hundreds of citizen scientists in Hampton Roads went out and, using our smart phones, measured the water intrusion into typically dry areas. High tide was mid-morning, nice for us non-morning people, so we went out around 9:00 am, donned our waders, and walked as close to the water's edge as we could, recording our position every few steps. This created a map of our spots that could be overlaid on predictions models, like the one below.

Mapping data from my first stop

The forecast before we went out was for there to be some wind-induced surge on top of the king tide. Below is a screenshot from a NOAA storm surge prediction site.

Tide predictions just before going out

As you can see, the prediction was for nearly 5 ft above mean lower low water. This is right about the minor flooding stage. The winds seemed to fail and we didn't get quite as much water as predicted.

The same data a few hours later

The first spot I mapped was right along a creek and gave us a pretty good line to measure. There were some trees and bushes to work around but it wasn't too hard. I was frequently stretching out my arm to get over the water line to record the data. And I could easily walk around the trees that grew on the water's edge.

The second spot my partner and I went to is a new apartment complex. It was built right on the edge of the marsh; they may have even built out into the marsh, it's hard to tell. But we could't get around to tidal areas. We did find a low spot where the water table had risen up through the ground. My wife and I see this often at our house where there will be water at low spots in the marsh that didn't flow in from the main creek. We marked that area and added some photographs.

Our final spot was a little park nearby that is bordered by a tidal creek on one side and fresh water pond on the other. The pond provides good winter habitat for ducks and for several years there was a Eurasian Widgeon that would come every winter. But that water wasn't of interest to use this day. Instead we headed over to the muddy creek bed. This is near the maximum extent of the creek, so at low tide there is usually a lot of exposed mud. Over the past several years, the city has been doing work to control run-off into the creek. In fact, one of the first projects going on when I joined the master naturalist was planting trees and shrubs along this creek. That's is all wonderful and the planting have really grown up. But for this activity, having the water's edge protected but twenty feet of brush, brambles, junipers, and other dense planting, was a real pain. Literally. I came away with several scrapes and pokes, even through my adventure pants. Our data here was much more sparse and really limited by where we could push through the plants to get close.

All of the data was collected at the Virginia Institute of Marine Science where everyone can see the mapping data. This is expected to be the first of several such mappings. We may even go out during storms to map what happens.

And since this was sponsored by several media, there was a lot of coverage like this from the Virginian Pilot.