Saturday, May 4, 2013

Oxbow on the Columbia

Columbia River & Wetlands April 29,2013 - by Larry Halverson

One of the best examples of an Oxbow on the Columbia River can be seen from the view points on the mile hill at Radium Hot Springs.
Oxbows are formed when a river creates a meander by river's eroding the bank through hydraulic action. After a long time, the meander becomes very curved, and eventually the neck of the meander will become narrower and the river will cut through the neck usually at flood time.
After the river finds a different, shorter, course. The meander becomes an oxbow lake along the side of the river.
It would make an interesting photo story if pictures were taken of this process over time.

Friday, May 3, 2013

Columbia Spotted Frog Eggs

Columbia Spotted Frog egg mass in the Columbia Valley near Brisco - by Larry Halverson
Hatchlings on top of egg mass by Larry Halverson
Females lay eggs in communal masses at the water surface, either freely floating or loosely tangled around emergent vegetation. You can tell that these eggs just hatched because the tadpoles have no eyes and the gills are visible.  The hatchling stage of clinging to the egg mass only last a day or two before they become tadpoles. 
Water temperature was 22 degrees C which likely why the hatching is earlier in the Columbia Valley than Kootenay National Park where the water temp was 0 degrees C on May 1.