How does erosion affect rivers

Erosion always has been, and still is, a natural part of the rock cycle. Without erosion there would be no sediment and no sedimentary rock. Erosion involves the pickup of loose, unconsolidated soil and sediment, or it can involve erosion of solid bedrock. Streams and rivers erode and transport sediment. Moving water, in river and streams, is one of the principal agents in eroding bedrock and sediment and in shaping landforms.

Without streams or rivers, there would be few valleys, because streams and rivers form most valleys. The landscape would wear down much more slowly through geologic time. Also, weathering products, such as sand and dirt, would not be carried away to the ocean, so soil thickness would increase in most areas.

Comparing Rocks. Rock Abrasion. Do Rocks Dissolve? Rivers and Land. Skip to main content. K-5 GeoSource. PDF version Teaching and Learning Focus In the last two investigations students looked at weathering and how rocks break down into smaller pieces over time. Seal the hole with clay. Setting the Scene Many students have stood on the bank of a stream or river and watched its water flowing. In what ways are these rivers changing the land around them?

Presenting the Investigation Question After the scene is set, introduce your students to the investigation question: How does a river change the land? Have your students brainstorm ideas about how this investigation question could be investigated. How would you design an experiment that could be used to test the investigation question?

What materials would you need? What would you have to do? What would you measure? How long would the experiment take? Assessing What Your Students Already Know Most students will have observed the movement of water in a stream or river, but they may not be aware of the effect of moving stream or river water on the land.

Here are some initial questions that your students can discuss, in pairs, in groups, and as a whole class: During big rainstorms, water often flows across the surface of the land.

What does this water do to the soil and rock that it flows over? Where does water that flows over the land go? What causes some rivers or streams to be brownish in color? What does the water flowing in a river or stream do to the rock or soil that surrounds the river? Have your students share their ideas with the class and record them as a list on the flipchart. They will create their models in stream tables containing sand.

They will pour water into a coffee can. The water will flow through a rubber hose and into the streams. They will observe how the flowing water affects the sand and shapes of the streams. Arrange students in groups. Provide the materials to each group. Instruct students to cover their desktops with paper. Assign each group an image from the Stream and River Cards. Instruct students to draw a picture of their river systems on their observation sheets. Have them record their measurements on their observation sheets.

How can erosion affect the water in a river or stream? Sep 25, Explanation: Erosion affects waterways. It contaminates it with silt and accumulated chemical residues. Explanation: "Normal" erosion is part of the natural rock cycle.

Related questions What is beach erosion? How does ice cause erosion? How does erosion happen? What are the river processes of erosion, transportation, and deposition? See also Water Note 9 The importance of large woody debris. When waterway banks are cleared of their vegetation, banks are more vulnerable to erosion.

Floods are more likely to cause waterways to change their course and form new meanders or flood channels. Topsoil can also be stripped from the floodplain leading to the loss of valuable agricultural land.

Excess sediment can be damaging to the ecological health of waterways and reduce their environmental, social and cultural values. Mobilised coarse sandy sediment tends to accumulate in areas of slow-flow and may smother bottom-dwelling organisms and their habitats.

Deep permanent river pools, that are valuable habitats for aquatic fauna and refuges for wildlife during summer and drought, may become filled by course sediments. Large sediment accumulations can cause upstream flooding, or deflect the flow into the adjacent stream bank or even onto adjacent land, causing further erosion. In addition sediment can fill the deep permanent pools of rivers to ruin this critical refuge habitat.

Increased fine sediment suspended in the water column turbidity reduces the penetration of light and therefore the ability of algae and other aquatic plants to photosynthesize and clogs the gills of fish. Fine sediment and the nutrients it transports are also associated with seasonal blue-green algal blooms.

As a consequence, of excess sediment, the abundance and distribution of aquatic plants and animals change, natural food webs are disrupted and aquatic diversity declines. Once sediment has entered a waterway it is difficult and expensive to remove, requiring engineering solutions and heavy equipment.

Techniques for sediment management are described in Water Note Sediment in streams. See Water note WN Management of sediment in pools of the Avon River system for a case study that describes the restoration of deep permanent river pools filled by sediment.

Land use changes, including clearing native vegetation, mining, urban and other land development and road construction, need to be carefully planned and managed near waterways to prevent excessive erosion and sedimentation see Waterways and land planning.

Identifying and protecting an adequate foreshore is a key approach see Identifying and establishing waterways foreshore areas. Interference with the bed or banks of a waterway should also be planned carefully, follow best practice for stabilising banks and restoring riparian vegetation see Building Creek Crossings.

In agricultural landscapes, fencing and revegetating foreshore areas are important management actions. Restricting livestock access to waterways minimises damage to banks and protects existing riparian vegetation see Water Note Livestock management — fence location and grazing control , Waternote Flood proofing fencing for waterways , Water note 6: Livestock management — construction of livestock crossings and Waternote 7: Livestock management — watering points and pumps.

If catchment erosion is generating large amounts of sediment, farming practices that maintain vegetation cover ie. When river banks are too unstable to support vegetation, there are a number of engineered management techniques available to help secure and protect them Figure 3. See River Restoration Manual No. Large woody debris dead tree trunks and rocks are placed to stabilise an eroding bank and construct a riffle and pool to slow flow and trap sediment of the Canning River at Pioneer Park, Gosnells.

Skip to content Skip to navigation. Go to Minister for Water. Home Show Sub Nav. Planning for the future Show Sub Nav. Finding water Finding new water resources, including Royalties for Regions-funded programs and other drilling programs to explore resources across the state. Water allocation plans Information about allocation plans, which set out how much water can be reliably taken from groundwater and surface water sources for productive purposes while ensuring the sustainability of the resource and protection of the water-dependent environment.