As a marina managers, one of our most frequently asked questions is, “How much water do you have?” This has nothing to do with drinking water. Instead, it’s about depth. Sailors and larger power boats with deeper drafts, struggle to get information to help them decide where they can safely tie up. Or, they just need to know ahead of time if they can get through that section of waterway.
The very best resource for this information is the United States Army Corps of Engineers. Yeah right – the Army?? Yes. For over 150 years the Corps has been involved in maintaining our navigable waterways. As part of their mission, they also do surveys and publish the results for mariners to use.
We’ve all seen this guy before. If ever a bloke seemed confused, it was this one. The boat will travel back and forth out in front of OTYC for hours. Then, run up and down the channel while we ask “is this guys not the most LOST captain ever?” Nope. He’s mapping the bottom of the area he’s traveling. Creating a detailed map of what lies below. His equipment is so precise that when he’s done, a color coded map with perfect coordinates will be the result. These maps are priceless to mariners who depend on up-to-date information about shifting channels and hazards along the waterway.
The maps created are updated periodically to keep pace with our fast changing environment. Storms, currents and nearby construction all impact how the rushing tidal currents affect the shifting sands below our waterways. Keeping up with this dynamic ebb and flow means the Corps can effectively make use of their limited dredging budgets. These maps give the dredge Captains important information on where the currents are tending to maintain deeper water while also showing them what areas are prone to shoaling. Below is an example. This is a recent map of Bulkhead Channel, the area right outside our marina.
Above, you see the survey data overlaid on a Google Earth image. This is possible by downloading the KMZ file (as long as you have the Google Earth app on your PC) from the Corps web site. The darker the blue, the deeper the water. You can see the sandbar that is encroaching into the channel just off Pivers Island.
In this second image, we see the same area, this time populated with actual depth readings and US Coast Guard navigation aid information. Again, up by Green 9, right out in front of OTYC, we can see the encroachment of the sandbar. These maps are priceless to mariners. So what kind of VooDoo does one need to get your own copy? It’s easy. three clicks and you’re there!
First, visit the Corps website here. This will get us to the menu page where we can select the proper area where maps exist. I chose Morehead and Beaufort Harbors. From there one can select the area to display. PDF files look like the one above. The “range numbering” scheme is used by the Corps to section maps into bite size pieces. Play with the images until you find the one you’re most interested in.
Now the little white boat and the larger black boat who look sooooooooo lost make sense!