What is meant by the term overland flow?

What is meant by the term overland flow?

Overland flow is defined as water that flows over the land surface as either diffuse sheet flow (laminar or mixed laminar flow) or concentrated flow (turbulent flow) in rills and gullies (Ward and Robinson, 2000).

What is the difference between runoff and surface runoff?

Surface runoff is precipitation runoff over the landscape. Impervious areas cause excessive runoff. Still, it is true that much of the water in rivers comes directly from runoff from the land surface, which is defined as surface runoff. When rain hits saturated or impervious ground it begins to flow overland downhill.

What is meant by surface runoff?

Surface runoff can be described as water flowing over soil, vegetation or other ground cover instead of infiltrating to the underlying soil. Surface runoff may be caused by imperviousness of the underlying material, or because the underlying material is already being saturated, i.e. at capacity.

What causes overland flow?

1. when the intensity of precipitation that reaches the surface exceeds the infiltration capacity of the soil. This process is known as Hortonian overland flow. when the combination of precipitation intensity and duration (and run-on from higher areas) saturates the soil and raises the water table to the surface.

Where does runoff end up?

And now when it rains, the water (often called runoff or stormwater) runs off roofs and driveways into the street. Runoff picks up fertilizer, oil, pesticides, dirt, bacteria and other pollutants as it makes its way through storm drains and ditches – untreated – to our streams, rivers, lakes and the ocean.

How can we control runoff?

You can do a lot to help minimize stormwater problems

1. Maintain your car or truck.
2. Wash your car at a commercial car wash rather than in the street or in your driveway.
3. Drive less.
4. Cut down on fertilizers, pesticides and herbicides.
5. Remove part or all of your lawn.
6. If you are on a septic system, maintain the system.

What are examples of runoff?

Runoff is defined as excess water draining away from land or buildings. The overflow of water that drains off of your driveway is an example of runoff. Dissolved chemicals, etc, included in such water. The runoff of nitrates is poisoning the lake.

How do you deal with rainwater runoff?

1. Add plants. Incorporate plantings, especially in areas where runoff collects.
2. Protect trees. Like other plant roots, tree roots help absorb and filter runoff.
3. Break up slabs.
4. Go permeable.
5. Catch runoff.
6. How to Divert Water Runoff from Driveway.
7. Plant a rain garden.
8. Cover soil.

Where does runoff go after it leaves the ground?

Runoff and water quality A significant portion of rainfall in forested watersheds is absorbed into soils (infiltration), is stored as groundwater, and is slowly discharged to streams through seeps and springs.

Why does surface runoff occur in semi-arid regions?

This is called flooding excess overland flow, Hortonian overland flow (after Robert E. Horton ), or unsaturated overland flow. This more commonly occurs in arid and semi-arid regions, where rainfall intensities are high and the soil infiltration capacity is reduced because of surface sealing, or in paved areas.

What are the effects of surface runoff in urban areas?

Surface runoff. In addition to causing water erosion and pollution, surface runoff in urban areas is a primary cause of urban flooding which can result in property damage, damp and mold in basements, and street flooding.

Where does the runoff from the mountains come from?

In high mountain regions, streams frequently rise on sunny days and fall on cloudy ones for this reason. In areas where there is no snow, runoff will come from rainfall. However, not all rainfall will produce runoff because storage from soils can absorb light showers.