Floodspotting

Most people hate the rain. Not me. Give me a good thunderstorm and you're likely to find me in a wet T-shirt and bare feet, splashing happily down the street to unfoul the rain gutters and bust the leaf dams.

Once upon a time, being a river rat meant heading north to huge wilderness watersheds in Canada. These days, I stick closer to home, eagerly tracking the latest precipitation event online, and planning my next floodspotting field trip.

If you want to see whitewater inside Route 128, you had better move fast--most flood events last only a matter of hours, as we are so close to sea level and the terrain is relatively low. But if you get your skates on, you can see a roaring waterfall in Greater Boston with a little floodspotting.

Real-Time Stream Gauge Data for Massachusetts

Want to be a floodspotter? Start with the USGS real-time stream gauge data for your local state. I start paying attention when the dots turn dark blue, but the real fun starts when a dot turns black. Blue dots mean the river is higher than the 90th percentile for that day of the year, and a black dot simply means "High." Hovering over a dot will show you some of its statistics, and clicking on it will take you to the real-time data page for that gauging station, with spiffy graphs.

How Fast? How High? How Full?

Stream gauge graphs will show you how full the river is (volume in cubic feet per second, or CFS), how fast it's flowing (velocity in feet per second), and how high the water is (gage height in feet). If the river has reached flood stage, a red line appears on the graph at the flood stage. Red triangles show the mean, or average flow, so you can see how much fuller, higher, or faster the river is than usual.

I especially love finding a log graph, where the horizontal lines get closer together at the top. That means the river is SOOO much bigger than normal that it can't be graphed on a linear scale, so they've had to use a logarithmic scale.

Log graphs have abounded this month on rivers I've never seen them on before. Alewife Brook usually runs about 1-2 CFS this time of year. On May 15, it was running at 100 CFS - two orders of magnitude more than usual! Alewife crested at 6 feet above sea level on May 15, before subsiding to its normal 2 feet. That translated into water nearly over the road on the back streets around Alewife Marsh--excellent for splashing about.

Chasing Waterfalls
Once you've marveled at the data in real-time, it's time to go see it live! Use your trusty local watershed map, Google Maps and/or Yahoo! Maps, and the indispensable Delorme Massachusetts Atlas & Gazetteer to locate the gauging station, plan your route, and find nearby parking or public transit. Never mind the rain--get yourself a serious raincoat, a waterproof hat, and knee-high boots. A Ziploc bag or a small dry bag lets you bring your camera along in a pocket, and presto! You're a floodspotter.

Most Accessible Waterfall Award: Lower Falls on the Charles River

From Route 128, take the Route 16W exit and turn towards Newton Lower Falls. Immediately, turn in to the Arthur T. Gregorian parking lot (map). A small iron bridge just behind the parking lot runs across the falls, providing excellent viewing both upstream and downstream. Footpaths are accessible for a short distance on either side of the river.

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