Ask LCRA How fast will you float down river? Here are some guidelines when planning a river trip
Q. I'm planning a trip down river from Austin to La Grange and possibly to Matagorda. I want to estimate how fast I will travel. I read LCRA's daily reports of the flow of the river — measured in cubic feet per second (cfs) — at Bastrop, Smithville and La Grange. Is it possible to translate cfs into miles per hour? I would like to leave when the current is moving at more than 3 mph.
--Bill Perkins, Austin
LCRA river gauges measure the height of the water (or stage) at each location, and LCRA uses various measurements to convert the number into flow. Keep in mind that cubic feet per second is a measure of the volume of the water, not speed. Water speed is affected by many things, such as boulders, sandbars, manmade obstructions and wind.
While LCRA doesn't continuously measure the speed of the water, hydrologists periodically perform measurements to calibrate the gauges and obtain the mean velocity across the river at these locations.
During the summer, LCRA releases water below Austin for about 10 to 12 hours per day, said Geoff Saunders, supervisor of LCRA's River Operations Center. This translates to flow rates ranging from about 100 to 4,000 cfs at the Highway 183 bridge near Austin.
This flow tends to level off as the water moves downstream, with summer flow rates ranging from 1,500 to 2,000 cfs at La Grange.
The river moves about 2 mph based on an average flow rate of 1,500 cubic feet per second, according the Lower Colorado River User's Guide, which contains 32 pages of valuable information for anyone traveling the river.
"That's a good rule of thumb," said Keith Ging, LCRA hydrologist who is on the team that rates and analyzes data from the gauges. "It all depends on the channel because you are going to travel faster if the channel is narrow than if you are in the middle of a big pool of water."
Skill is one factor
With some paddling, the average canoeist will travel 3 to 4 mph, depending on skill level, wind and other factors.
"Water speed towards the middle of the channel will be faster," Ging said.
The summer months are the best time for a Colorado River trip. That's because during the fall and winter months, release rates slow to about 300 to 400 cfs — which makes for a very slow moving river of less than 1 mph.
For more information:
See guide for river users or plan out your trip by looking at where the different river access points are located by going to the following link: Lower Colorado River access points.
Call the LCRA park information line at 512-473-3366 for more information.