Mapping the Elwha River after Dam Removal
On August 29th 2014 we made our way down the Elwha scraping the bottom of our raft and beating our oars against the gravel and cobble, barely submerged by the shallow low flowing water of a sleeping giant, the Elwha.
A little over three months later the flows in the river would peak at almost 10 times what we experienced during our arduous day of river mapping. A series of Pacific storms would sweep through the region giving the river the water it needs to remember the places it has run before. Natural river flows fluctuate according to the season, often with large spring flows corresponding to spring rains or snowmelt, and low summer flows corresponding to warm, dry summer weather.
Dams dramatically alter a river’s flow regime by blocking a river’s passage, storing water in artificial reservoirs. The Dams that blocked the Elwha river for 100 years are now completely gone. The dynamic nature of the Elwha has returned. The channel will be different in 2015. Insight into these differences can be gained by overlaying EarthViews data and imagery from one year to the next. How did the habitat change? Is there more or less wood? Is it in different locations? How did the sediment and shifting substrate alter the direction of the rivers main flow? Answering these questions using reality indexing from location based imagery will help establish a baseline and trend, recording the evolution of a rivers natural restoration process. Capturing this process is exactly what our mapping technology was designed to do.
*This blog is a re-post from the archives to celebrate the new EarthViews Blog.