How deep is the river?
Ask any ranger or river guide how deep the river is and they’ll probably roll their eyes. Aside from being a common question, it’s a very difficult one to answer accurately. The reason? The Colorado and Green rivers have serpentine channels that change constantly as the current and the sediment it carries act upon each other. Along both rivers, sand bars move continually. Add runoff from storms and spring snowmelt to the mix, and one could argue that few places in the river ever have the same depth for very long. But what’s below all this shifting sediment? The Colorado and Green rivers carry and traverse millions of tons of sand, mud and rocks, but at some point their channels must encounter bedrock. At what depth? Scientists studying this question in Cataract Canyon have found some unexpected answers. Cataract Canyon contains roughly 14 miles of closely spaced, large rapids. These noise makers stand in stark contrast to the calmer conditions upstream on both the Green and Colorado ri
My last post mentioned the water fluctuations that can affect one’s paddling experience on rivers in Florida. (Thanks to Becky Bragg for the update on current water levels on the Peace River.) Word of mouth is a reliable way to find out about water levels, but other options are available. The United States Geological Survey (USGS) posts measurements on the Internet through its National Water Information System. The data is surprisingly detailed and current. You can check water readings in three categories – discharge, gage height (that’s “gauge” in non-technical language) and precipitation – for any of countless specific locations. And the Web site allows you to get information for various time periods, from annual statistics to real time listings. I checked levels for the Alafia River at Lithia, requesting gage height for the past 31 days (the longest period allowed, unfortunately). The resulting graph showed how much water levels fluctuate on the river, ranging from a low of about 3
