The friction factor is affected by variations of fluid physical properties caused by variations in temperature and by the action of buoyancy forces. In rough channels the hydraulic resistance increases due to formation of vortices at the roughness elements leading to additional loss of flow specific energy. Three types of roughness can be distinguished: Natural roughness, which is formed as a result of long operation of pipelines.
Erosion by Glaciers. Like flowing water, flowing ice erodes the land and deposits the material elsewhere. Glaciers cause erosion in two main ways: plucking and abrasion. Both are illustrated at this link: [Insert a link to an animation showing how glaciers cause erosion by plucking and erosion.] Plucking is the process by which rocks and other sediments are picked up by a glacier.
Over watering kills marijuana plants. Water once the top few inches of the soil dry out. Hydroponics is harder to over water because rockwool has such excellent drainage properties. As long as the rockwool cubes are not sitting in liquid it is virtually impossible to over water a hydroponic setup.