While working on yesterday’s Weather Watch post, I decided that it was important to know what the normal river levels were this time of year. After all, knowing the river stage is pretty useless without context. Flood stage is pretty easy to find for most sites, but that doesn’t necessarily provide context for low-water situations. For example, the Ohio River at Louisville, KY (McAlpine Lock and Dam, lower) has a flood stage of 55 feet, so being 15 feet below flood stage is normal. In contrast, 15 feet below flood stage for the Wabash River at Lafayette, IN is four feet below ground. The concept of pool stage exists, but it’s not widely used. So how can river depth be put in the proper context for low-water situations?
Like most other data meteorological, a comparison to the average value over some period of time is apt. The question then becomes “where do I find the average river height for a particular site?” Of course, the average height can vary greatly over the course of a year based on local and upstream precipitation patterns, so month-by-month data is preferable. Unlike temperature and precipitation, though, the National Weather Service does not issue daily climate summaries for rivers (at least not that I’ve seen).
Fortunately for the numerically-minded, the United States Geological Survey (USGS) has a wealth of data available for free on the Internet. It’s a little tricky to navigate, but with patience, the National Water Information System (NWIS) will surrender the desired information. With data for approximately 1.5 sites available in a variety of readable and parseable formats, there’s enough to keep even the most efficient data nerd busy for a long time. For easier-to-navigate real-time hydrologic data and forecasts, see http://water.weather.gov/ahps/.
The Community Collaborative Rain, Hail, and Snow (CoCoRaHS) project is really interesting. It is a nearly-nationwide collection of volunteers who take daily measurements of the precipitation they receive. I participate because my meteorological education has taught me that there’s always a need for more data. The side benefit is that I get to see what others around me have received in the way of falling moisture. The differences across small distances can be pretty large sometimes (although I suspect that is often due to a poor rain gauge setup), but seeing similar numbers can help you believe that you really did get that much rain.
Case in point: since Tuesday, my station has recorded 4.56″ of rain. To put that in perspective, the average rainfall for the month of May is 3.93″. On Wednesday, when I recorded 2.03″, I might not have believed it had other stations nearby not recorded very similar values. Today’s 2.35″, on the other hand, was pretty believable on it’s own. The lake that is my yard spoke volumes.
Last weekend, my wife and I hauled, mixed, and poured 3,200 pounds of concrete. Why? Because the walkway that goes from our front porch to our driveway sat lower than the ground around it, meaning when it rained, your shoes got wet. I’m very grateful we got it finished, since when we got home from a friend’s house last night, our yard was a marsh. Even now, over 12 hours after most of the rain has stopped, the ground just has nowhere to put the water.
Measuring nearly an inch of standing water in the yard.
Worms, worms, worms!
As a result of all the rain, the Wabash River has gone from 6 feet to 16 feet since 8 AM Wednesday, with a forecast crest of 20 feet at 8 PM tonight. At 20 feet, Extensive flooding increases. Flood waters begin to cover Stair Road located on the southeast side of the river just off SR 225 in NE Tippecanoe County. Low portions of Barton Beach Rd is flooded. Several river residences are nearly isolated by high water. River residences near Interstate 65 are affected by high water. River Road near Wabash Valley Hospital floods. Local roads begin to flood in the Granville Bridge area. River residents become concerned.