Gravel areas where there is little traffic. Globally, far more roads are surfaced with gravel than with concrete or tarmac; Russia alone has over of gravel roads. Both sand and small gravel are also important for the manufacture of concrete. Large gravel deposits are a common geological feature, being formed as a result of the weathering and erosion of rocks. The action of rivers and waves tends to pile up gravel in large accumulations. This can sometimes result in gravel becoming compacted and lithified into the sedimentary rock called conglomerate. Where natural gravel deposits are insufficient for human purposes, gravel is
Gravel chub type of habitat, increasing the turbidity of the current and the amount of silt in rivers and streams. Populations in southern Minnesota are experiencing a great amount of stress due to the large amount sediment deposit from the Mississippi River that disturbs flow regimes. The Minnesota DNR has been continuing to monitor and improve water quality of rivers and streams in southern Minnesota. Iowa and New York also have put extra conservation efforts towards the gravel chub. In Iowa the gravel chub was once threatened, but now abundant all over the state. In New York there has been a strong