How to mitigate debris flow?

How to mitigate debris flow?

To reduce the hazards from debris flows in drainage basins burned by wildfire, erosion control measures such as construction of check dams, installation of log erosion barriers (LEBs), and spreading of straw mulch and seed are common practice.

How does climate affect debris flow?

Climate also affects geomorphic processes that supply sediment to slopes susceptible to debris flow activity, such as solifluction, freeze-thaw activity, and glaciation. Warm and dry weather can also predispose slopes to debris flows.

What causes a debris flow?

Debris flows can be triggered by intense rainfall or snowmelt, by dam-break or glacial outburst floods, or by landsliding that may or may not be associated with intense rain or earthquakes.

What factors make Southern California so susceptible to debris flows?

Southern California is susceptible to debris flows12,13, partly because its winter wet season (November–April) encourages plant growth. If the following dry season (May–October) extends into the wet season and strong winds occur, the soil and vegetation both dry out.

How can you reduce the risk of landslides?

There are also various direct methods of preventing landslides; these include modifying slope geometry, using chemical agents to reinforce slope material, installing structures such as piles and retaining walls, grouting rock joints and fissures, diverting debris pathways, and rerouting surface and underwater drainage.

How can we stay safe from landslides?

Tips for Staying Safe During a Landslide

1. Adhere to local land-use regulations.
2. Put property protections in place.
3. Add sandbags in exposed areas.
4. Do not build your home in places that may be in the path of a landslide.
5. Do your research.
6. Look for new cracks.

What are the causes of climate change?

The main causes of climate change are:

• Humanity’s increased use of fossil fuels – such as coal, oil and gas to generate electricity, run cars and other forms of transport, and power manufacturing and industry.
• Deforestation – because living trees absorb and store carbon dioxide.

How are landslides caused by climate change?

Current research is consistent in projecting an increase in the frequency and intensity of heavy rain events. 9 These changes could result in greater erosion, higher sediment transport in rivers and streams, and a higher likelihood of landslides, primarily as a result of higher soil water content.

What is debris flow in geography?

Debris flows are fast-moving landslides that are particularly dangerous to life and property because they move quickly, destroy objects in their paths, and often strike without warning. Debris flows generally occur during periods of intense rainfall or rapid snowmelt and usually start on hillsides or mountains.

Where are debris flows common?

Areas where surface runoff is channeled, such as along road- ways and below culverts, are common sites of debris flows and other landslides. Debris flows commonly begin in swales (depressions) on steep slopes, making areas downslope from swales particularly hazardous.

Why is Southern California prone to mass wasting?

Like the northern part of the state, southern California is well known to be susceptible to landslides (see Preliminary soil-slip susceptibility maps, southwestern California – Open-File Report 2003-17). Some are triggered by earthquakes, but more frequently landslides are caused by intense and/or prolonged rainfall.

Why is Southern California prone to mass wasting events?

The problem is exacerbated by California’s climate, in which most of the rainfall is concentrated into a winter season which typically lasts from November through April. Those sudden torrents of water further destabilize the loose material on the slopes, causing it eventually to give way.

How is Forestry involved in debris flow mitigation?

Forestry has played an important role in hazard mitigation associated with debris flows. Most forest mitigation measures refer to the experience of soil and water conservation, which disregard the destructive effect of debris flows, causing potentially serious consequences.

How are debris flow mitigation measures in China?

The debris flow mitigation measures constructed in the Xiaogangjian Gully effectively resisted a debris flow with a 50-year return period that was triggered by rainfall on July 26, 2012. Specifically, these measures effectively protected a highway and minimized debris flow damage.

What are the engineering measures for debris flow?

This system of engineering measures is based on the main river’s transport capacity and consists of five check dams with various opening sizes, a drainage channel with sidewalls constructed of prefabricated reinforced concrete boxes, and a debris flow basin at the base of the main gully.

How are deflection walls used to control debris flow?

Deflection walls are commonly constructed as the last element of a systematic debris flow mitigation measures (Huebl and Fiebiger, 2005), regulating and directing the debris flow towards areas of low consequences, such as the main river channel.