Rocks sculpted by ceaseless river flow are popular materials for landscaping and nature study. Especially in regions of heavy vegetation and deep soils, rivers are also some of the likeliest places to find rocks above ground: They tumble actively into stream channels, spill from eroding banks and originate from bedrock and huge boulders molded by alluvial flow and abrasion.
Instructions
1. Consult the appropriate party for regulations. If you're collecting on your own land, that may be one thing, but you should always check with the proper individual or agency if heading for other private land or public acreage, such as a national forest or Bureau of Land Management-administered area. Collecting rocks in many areas, like national parks and monuments, is strictly prohibited.
2. Clarify for yourself what type of rock you're looking for. Think about not only the size but also the shape. Do you want smooth pebbles, or rough boulders? Is there a particular color you're after? In all these cases, you'll be considering local geology and hydrology.
3. Look for likely spots of deposition along the river course. Generally this occurs where river flow decreases, gradient diminishes or the channel widens or shifts course. The upper reaches of rivers and their adjoining tributaries will often have larger rocks in their channels; these streams have a high gradient that lends them erosive vigor and---especially during high flow---particular capacity for toting heavier stones. On lower stretches, and along big, mature rivers in a well-established floodplain, you may have the best luck seeking out point bars---the inside contour of a riverbend, opposite the incised, actively eroding bank, where lazier flow results in sediment accumulation. River mouths also offer rich pickings, as the current slows on a gentling gradient and loses carrying strength. So do the gravel bars of braided rivers.
4. Pry larger rocks with screwdrivers or other flattened, sturdy tools. Wearing gloves or using slings will assist in hauling slippery rocks.
Tags: larger rocks, river flow
