This week: The lunar landscape behind the former Elwha Dam and the sediment getting transported below it, good thoughts on the risk increase potential from the CVFPP, more landslides at Three Gorges, update coming for USLE, and the productivity killer known as email.
The river below former Elwha Dam is carrying about 50 times more sediment than usual, according to Tim Randle at the U.S. Bureau of Reclamation, who is directing the management of the sediment in the Elwha River restoration project. The spike is sediment is due to the disappearance of Lake Aldwell, which used to settle out some of the material that’s cut loose as the dams have been demolished. Most of the sediment in the river right now is coming from behind the former Elwha Dam. Much of what is coming out now is fine silt and clay.
The sediment behind the dams is one of the factors that makes the $325 million Elwha restoration the largest dam removal project ever anywhere, with some 24 million cubic yards of sediment to manage.
Much of the material will remain behind in the watershed, distributed along the river’s middle and lower run. But a lot of it is also rinsing out to the Strait of Juan de Fuca, where it is expected the material will help rebuild the near shore and beaches eroded to ankle-turning cobble.
Increasing protection levels actually increases risk where it induces urbanization and increases the valuable life and property exposed in areas that would otherwise remain undeveloped. That levees induce urban development where it was formerly discouraged by nuisance flooding is well documented.
Landslides were identified as being a major hazard of the Three Gorges project more than a decade ago, and several years ago I wrote that although a Vaiont style event was unlikely, landslides would probably be a major problem. To give an indication of the concerns, the image below is the Qianjinangping landslide, which I visited on my recent trip. It occurred as the water level was being raised in July 2003. The landslide killed 24 people, destroyed 346 houses and caused the loss of four factories.
About 50 years ago, scientists at the U.S. Department of Agriculture (USDA) devised the Universal Soil Loss Equation (USLE), a formula farmers could use to estimate losses from soil erosion. Agricultural Research Service (ARS) scientists will soon release a version that integrates models generated by cutting-edge computer technology, an updated soils database, and new findings about erosion processes.
When You’re Constantly Checking Your Email, You’re Putting Your Needs Behind Everyone Else’s (Lifehacker)
Chances are you’ve got a few tasks you plan to complete during the day, ranging from pieces of a project at the office to folding laundry at home. When you stop what you’re doing to look at your email, you’re putting a priority on what other people want from you. You’re making the tasks in your life less important by constantly checking to find out what everyone else needs. This issue is at the root of why email can kill your productivity when you don’t use it correctly.