Technologies

Coarse woody debris to slow streamflow [Hungary]

Creation: 03/29/2022 4:10 nm.
Update: 03/28/2023 9:17 vm.
Compiler: Brigitta Szabó
Editors: Piroska Kassai, Zoltan Toth
Reviewers: William Critchley, Rima Mekdaschi Studer

Durva fatörmelék

technologies_6197 - Hungary

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Completeness: 92%

1. General information

2. Description of the SLM Technology

2.1 Short description of the Technology

Definition of the Technology:

Accumulating coarse woody debris in stream beds reduces flow velocity and levels of flood peaks. As a consequence the speed and energy of water flow is reduced, allowing greater deposition of sediments. In addition the technology has ecological advantages.

2.2 Detailed description of the Technology

Description:

Allowing the accumulation of coarse woody debris in streambeds reduces flow velocity and levels of peak floods. This technology is applied in sloping landscapes, where runoff flows into streams/ gullies. The main function is to break the energy and reduce the speed of flow. Riparian trees or their branches are allowed to fall naturally into streams – through deliberate placement of wooden debris can contribute to the process. This may even create dams on steeper sections of the watercourses. Sediment loss will be reduced from the catchment area by deposition (sedimentation) of soil particles along the watercourses and on the plains lower in the valleys. In addition, slowing the flow results in a larger surface area of water and infiltration is increased. Wet spots created this way improve aquatic biodiversity and wildlife. A downstream benefit is that land users at a lower elevation are less affected by runoff, floods and sediment deposition. However a disadvantage is the risk of damage to surrounding fields - caused by wild animals attracted to the wet conditions and increased biodiversity.

2.3 Photos of the Technology

Media Gallery

2.4 Videos of the Technology

Comments, short description:

No video available

Location:

Name of videographer:

2.5 Country/ region/ locations where the Technology has been applied and which are covered by this assessment

Country:

Hungary

Region/ State/ Province:

Zala County

Further specification of location:

The site where the technology is applied is situated within the catchment of Felső-Válicka stream, which belongs to the Balaton catchment area in western Hungary.

Specify the spread of the Technology:

applied at specific points/ concentrated on a small area

Is/are the technology site(s) located in a permanently protected area?

Nee

2.6 Date of implementation

If precise year is not known, indicate approximate date:

more than 50 years ago (traditional)

2.7 Introduction of the Technology

Specify how the Technology was introduced:

as part of a traditional system (> 50 years)

3. Classification of the SLM Technology

3.1 Main purpose(s) of the Technology

reduce, prevent, restore land degradation
conserve ecosystem
protect a watershed/ downstream areas – in combination with other Technologies
preserve/ improve biodiversity
reduce risk of disasters

3.2 Current land use type(s) where the Technology is applied

Land use mixed within the same land unit:

Nee

Waterways, waterbodies, wetlands

Drainage lines, waterways

3.3 Has land use changed due to the implementation of the Technology?

Has land use changed due to the implementation of the Technology?

No (Continue with question 3.4)

3.4 Water supply

Water supply for the land on which the Technology is applied:

rainfed

3.5 SLM group to which the Technology belongs

natural and semi-natural forest management
surface water management (spring, river, lakes, sea)

3.6 SLM measures comprising the Technology

vegetative measures

V1: Tree and shrub cover

3.7 Main types of land degradation addressed by the Technology

soil erosion by water

Wt: loss of topsoil/ surface erosion
Wg: gully erosion/ gullying
Wr: riverbank erosion
Wo: offsite degradation effects

water degradation

Hs: change in quantity of surface water

3.8 Prevention, reduction, or restoration of land degradation

Specify the goal of the Technology with regard to land degradation:

prevent land degradation

4. Technical specifications, implementation activities, inputs, and costs

4.1 Technical drawing of the Technology

Technical specifications (related to technical drawing):

Coarse woody debris (CWD) can be a feature in any water course but will probably have the highest water retention and biodiversity benefits in forest headwater streams. There are no space requirements for this measure and there are no site or slope stability limitations. Riparian forest buffers are natural inputs for this measure: when the trees in the riparian area fall into the stream, they will immediately become coarse woody debris

Author:

Piroska Kassai

Date:

13/03/2023

4.2 General information regarding the calculation of inputs and costs

Specify how costs and inputs were calculated:

per Technology unit

Specify unit:

watercourse

Specify currency used for cost calculations:

Indicate average wage cost of hired labour per day:

4.3 Establishment activities

	Activity	Timing (season)
1.	No activity needed, the technology is a fully natural process

4.5 Maintenance/ recurrent activities

	Activity	Timing/ frequency
1.	Cleaning (debris caught up behind the structure)	yearly

4.6 Costs and inputs needed for maintenance/ recurrent activities (per year)

	Specify input	Unit	Quantity	Costs per Unit	Total costs per input	% of costs borne by land users
Labour	Cleaning (debris caught up behind the structure)	watercourse	1.0	50.0	50.0	100.0
Total costs for maintenance of the Technology					50.0
Total costs for maintenance of the Technology in USD					50.0

4.7 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

5. Natural and human environment

5.1 Climate

Annual rainfall

< 250 mm
251-500 mm
501-750 mm
751-1,000 mm
1,001-1,500 mm
1,501-2,000 mm
2,001-3,000 mm
3,001-4,000 mm
> 4,000 mm

Specify average annual rainfall (if known), in mm:

725.00

Agro-climatic zone

sub-humid

5.2 Topography

Slopes on average:

flat (0-2%)
gentle (3-5%)
moderate (6-10%)
rolling (11-15%)
hilly (16-30%)
steep (31-60%)
very steep (>60%)

Landforms:

plateau/plains
ridges
mountain slopes
hill slopes
footslopes
valley floors

Altitudinal zone:

0-100 m a.s.l.
101-500 m a.s.l.
501-1,000 m a.s.l.
1,001-1,500 m a.s.l.
1,501-2,000 m a.s.l.
2,001-2,500 m a.s.l.
2,501-3,000 m a.s.l.
3,001-4,000 m a.s.l.
> 4,000 m a.s.l.

Indicate if the Technology is specifically applied in:

concave situations

5.3 Soils

Soil depth on average:

very shallow (0-20 cm)
shallow (21-50 cm)
moderately deep (51-80 cm)
deep (81-120 cm)
very deep (> 120 cm)

Soil texture (topsoil):

medium (loamy, silty)
fine/ heavy (clay)

Soil texture (> 20 cm below surface):

medium (loamy, silty)
fine/ heavy (clay)

Topsoil organic matter:

medium (1-3%)

5.4 Water availability and quality

Ground water table:

< 5 m

Availability of surface water:

good

Water quality (untreated):

poor drinking water (treatment required)

Water quality refers to:

surface water

Is water salinity a problem?

Nee

Is flooding of the area occurring?

Nee

5.5 Biodiversity

Species diversity:

high

Habitat diversity:

high

5.6 Characteristics of land users applying the Technology

Sedentary or nomadic:

Sedentary

Market orientation of production system:

commercial/ market

Off-farm income:

10-50% of all income

Relative level of wealth:

rich

Individuals or groups:

individual/ household

Level of mechanization:

mechanized/ motorized

Gender:

Age of land users:

elderly

5.7 Average area of land used by land users applying the Technology

< 0.5 ha
0.5-1 ha
1-2 ha
2-5 ha
5-15 ha
15-50 ha
50-100 ha
100-500 ha
500-1,000 ha
1,000-10,000 ha
> 10,000 ha

Is this considered small-, medium- or large-scale (referring to local context)?

large-scale

5.8 Land ownership, land use rights, and water use rights

Land ownership:

individual, not titled

Land use rights:

leased
individual

Water use rights:

communal (organized)

Are land use rights based on a traditional legal system?

5.9 Access to services and infrastructure

health:

poor
moderate
good

education:

poor
moderate
good

technical assistance:

poor
moderate
good

employment (e.g. off-farm):

poor
moderate
good

markets:

poor
moderate
good

energy:

poor
moderate
good

roads and transport:

poor
moderate
good

drinking water and sanitation:

poor
moderate
good

financial services:

poor
moderate
good

6. Impacts and concluding statements

6.1 On-site impacts the Technology has shown

Socio-economic impacts

Water availability and quality

irrigation water availability

decreased

increased

Ecological impacts

Water cycle/ runoff

harvesting/ collection of water

reduced

improved

Comments/ specify:

Woody debris slows the water during high flows. It does not collect water in a specific place, just keeps it longer in the upper area of the watershed.

surface runoff

increased

decreased

Comments/ specify:

Since the water moves more slowly, the rate of runoff also decreases.

Biodiversity: vegetation, animals

animal diversity

decreased

increased

habitat diversity

decreased

increased

Comments/ specify:

Natural dams provide a new habitat for water wildlife.

Climate and disaster risk reduction

flood impacts

increased

decreased

drought impacts

increased

decreased

impacts of cyclones, rain storms

increased

decreased

Comments/ specify:

Fallen trees are the basis of natural dams, they are no longer destroyed by storms, and new dams can be built from the newly fallen trees.

emission of carbon and greenhouse gases

increased

decreased

wind velocity

increased

decreased

micro-climate

worsened

improved

Comments/ specify:

The natural dams can increase humidity in the forest.

6.2 Off-site impacts the Technology has shown

water availability

decreased

increased

Comments/ specify:

As water is coming slower from the watershead upper part, water availability is much more balanced

reliable and stable stream flows in dry season

reduced

increased

downstream flooding

increased

reduced

buffering/ filtering capacity

reduced

improved

Comments/ specify:

Natural dams play a filtering role in the forest. Waste and debris must be regularly cleaned behind the structures.

damage on public/ private infrastructure

increased

reduced

6.3 Exposure and sensitivity of the Technology to gradual climate change and climate-related extremes/ disasters (as perceived by land users)

Gradual climate change

	Season	increase or decrease	How does the Technology cope with it?
annual temperature		increase	well
seasonal temperature	summer	increase	well
seasonal rainfall	summer	decrease	moderately

Climate-related extremes (disasters)

Climatological disasters

	How does the Technology cope with it?
heatwave	moderately
drought	moderately
forest fire	not well

Hydrological disasters

	How does the Technology cope with it?
general (river) flood	moderately

6.4 Cost-benefit analysis

How do the benefits compare with the establishment costs (from land users’ perspective)?

Short-term returns:

positive

Long-term returns:

positive

How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?

Short-term returns:

positive

Long-term returns:

positive

6.5 Adoption of the Technology

1-10%

Of all those who have adopted the Technology, how many did so spontaneously, i.e. without receiving any material incentives/ payments?

91-100%

6.6 Adaptation

Has the Technology been modified recently to adapt to changing conditions?

Nee

6.7 Strengths/ advantages/ opportunities of the Technology

Strengths/ advantages/ opportunities in the land user’s view
Land users having fields in the sloping area at a lower elevation are not affected by runoff water, floods and sediment deposition as much as without the technology.

Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
Sediment transport will be reduced from the area reducing in smaller deposition (sedimentation) of soil particles at the valleys or in the municipalities.
The retention of water results in larger area covered by water. Wet spots created this way improve aquatic biodiversity and wildlife.

6.8 Weaknesses/ disadvantages/ risks of the Technology and ways of overcoming them

Weaknesses/ disadvantages/ risks in the land user’s view	How can they be overcome?
The risk of damage caused by wild animals in the surrounding arable fields are higher.

Weaknesses/ disadvantages/ risks in the compiler’s or other key resource person’s view	How can they be overcome?
The goal of water management can be to improve fast downward flow in the stream which is an opposite process than the result of coarse woody debris.

7. References and links

7.1 Methods/ sources of information

field visits, field surveys

interviews with SLM specialists/ experts

compilation from reports and other existing documentation

When were the data compiled (in the field)?

19/05/2021

7.2 References to available publications

Title, author, year, ISBN:

Harmon M.E. et al. 1986. Ecology of coarse woody debris in temperate ecosystems. Advances in Ecological Research 15: 133-276

View sections

1. General information

1.2 Contact details of resource persons and institutions involved in the assessment and documentation of the Technology

Key resource person(s)

SLM specialist:

Name of project which facilitated the documentation/ evaluation of the Technology (if relevant)

Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)

1.3 Conditions regarding the use of data documented through WOCAT

The compiler and key resource person(s) accept the conditions regarding the use of data documented through WOCAT:

1.4 Declaration on sustainability of the described Technology

Is the Technology described here problematic with regard to land degradation, so that it cannot be declared a sustainable land management technology?

2. Description of the SLM Technology

2.1 Short description of the Technology

Definition of the Technology:

2.2 Detailed description of the Technology

Description:

2.3 Photos of the Technology

Media Gallery

2.4 Videos of the Technology

Comments, short description:

Location:

Name of videographer:

2.5 Country/ region/ locations where the Technology has been applied and which are covered by this assessment

Country:

Region/ State/ Province:

Further specification of location:

Specify the spread of the Technology:

Is/are the technology site(s) located in a permanently protected area?

2.6 Date of implementation

If precise year is not known, indicate approximate date:

2.7 Introduction of the Technology

Specify how the Technology was introduced:

3. Classification of the SLM Technology

3.1 Main purpose(s) of the Technology

3.2 Current land use type(s) where the Technology is applied

Land use mixed within the same land unit:

Waterways, waterbodies, wetlands

3.3 Has land use changed due to the implementation of the Technology?

Has land use changed due to the implementation of the Technology?

3.4 Water supply

Water supply for the land on which the Technology is applied:

3.5 SLM group to which the Technology belongs

3.6 SLM measures comprising the Technology

vegetative measures

3.7 Main types of land degradation addressed by the Technology

soil erosion by water

water degradation

3.8 Prevention, reduction, or restoration of land degradation

Specify the goal of the Technology with regard to land degradation:

4. Technical specifications, implementation activities, inputs, and costs

4.1 Technical drawing of the Technology

Technical specifications (related to technical drawing):

Author:

Date:

4.2 General information regarding the calculation of inputs and costs

Specify how costs and inputs were calculated:

Specify unit:

Specify currency used for cost calculations:

Indicate average wage cost of hired labour per day:

4.3 Establishment activities

4.5 Maintenance/ recurrent activities

4.6 Costs and inputs needed for maintenance/ recurrent activities (per year)

4.7 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

5. Natural and human environment

5.1 Climate

Annual rainfall

Specify average annual rainfall (if known), in mm:

Agro-climatic zone

5.2 Topography

Slopes on average:

Landforms:

Altitudinal zone:

Indicate if the Technology is specifically applied in:

5.3 Soils

Soil depth on average:

Soil texture (topsoil):

Soil texture (> 20 cm below surface):

Topsoil organic matter:

5.4 Water availability and quality