Technologies

Gully plug [Jordan]

السدات

technologies_5862 - Jordan

Completeness: 88%

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)

co-compiler:
SLM specialist:

Strohmeier Stefan

International Center of Agriculture Research in the Dry Areas (ICARDA)

Jordan

SLM specialist:
SLM specialist:

Evett Steve

USDA Agricultural Research Service

United States

Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)
International Center for Agricultural Research in the Dry Areas (ICARDA) - Lebanon

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:

Ja

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?

Nee

2. Description of the SLM Technology

2.1 Short description of the Technology

Definition of the Technology:

Gully plugs aim at rehabilitating active gullies in dryland watersheds, which are prone to erosion through concentrated surface runoff. Multiple gullies plugged in succession dissipate runoff energy, foster local water retention and infiltration, encourage sedimentation, assist in the stabilization of gully bed and side banks, and stimulate revegetation of flow paths; the channel measures must be combined with proper SLM in the catchments upstream.

2.2 Detailed description of the Technology

Description:

Characteristics: Multiple gully plugs positioned sequentially within a gully system interrupt concentrated surface runoff and reduce its erosive power. The plugs are each made of multiple cobbles/stones mostly ranging between 10 and 30 cm diameter and constructed to ensure a stable structure. The plugs started at the head of the gully (upstream) and ranges from 1.5 - 3.7 m in width with an average of 2.5 m. For heavily eroded and very unstable sections, gabions can be used also. The structures are around 1.0 to 1.5-m high, anchored into the sidewalls, and around 0.20 to 0.35 m deep into the gully bed, built up to around 1/3 to max. 1/2 of the gully depth - ensuring the concentrated flow stays within the channel and does not overflow the side banks. The top of the plug is U-shaped, with the sides built higher than the centre. Upslope, the plugs are packed with soil to trap sediments (stopping it flowing through the structure), and downslope the plugs have an apron to dissipate the energy of overflowing water, into a micro stilling basin. The downslope side of the gully plug is sloped rather than vertical. The large stones add roughness to the slope, creating a rough spillway that dissipates erosive energy. In the direction of gully flow, several gully plugs are placed such that the upper gully apron is set at approximately the height of the following downstream gully crest.

Environment: The technology is used in a watershed close to Al Majeddyeh village, located in the Middle Badia zone, approximately 30 km south-east of Amman. The climate is arid and warm (Palmer, 2013). The average annual rainfall is around 130 mm. The natural environment is labelled as steppe, “BSh” in the köppen classification. The human environment is characterized by agropastoralists. They are semi-nomadic and live in villages around the watershed, for example, Al Majeddyeh village.

Purpose: The measure interrupts the concentrated flow, reduces velocity, and dissipates energy. Multiple structures along the gully decrease the erosive power of runoff, retaining a fraction of the runoff, inducing sedimentation (upstream of the plug), thus protecting the gully bed from further deep-scouring, and strengthening the gully side banks, especially when this is linked with re-vegetation. Over time, the establishing vegetation (roots and surface cover) stabilizes the soil and protects it from concentrated flow erosion. To be effective, gully plug emplacement requires SLM in upland areas. These measures then jointly mitigate peak runoff generation and accordingly reduce downstream flooding.

Major activities: Upland SLM is essential. In the specific watershed rehabilitation context, upland SLM was achieved through micro water harvesting and re-vegetation through native shrubs (the “VALLERANI” method). Gully morphology assessment is required for gully plug design, and positioning and earthwork excavation is necessary for foundation preparation in the gully bed and wall anchors. Proper layering of various size stones and shaping of gully plugs is necessary as is the addition of a packed soil pack upstream of the stone structure, to semi-seal the surface and to pond water. Then gully walls are revegetated through native seedlings: these benefit from the water ponding upstream prior to sedimentation upstream of the gully and enhanced soil water storage in the sediments once the gully is filled.

Benefits: Stops ongoing land degradation and gully deepening, and achieves a certain degree of rehabilitation; retains a fraction of runoff water and sediments in the watershed – water mainly infiltrates and provides moisture to the gully vegetation; gully vegetation serves various purposes including livestock fodder, reduction of flow velocities in the gully, and retention of further sediment.

Land user's opinion: Land users benefit from the vegetation (e.g. fruit trees can potentially be out-planted), as well as ponded water for livestock; however, the technology is labor-intensive, and therefore costly, and landowners (at the local target site) require incentives to carry out the work.

2.3 Photos of the Technology

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

Country:

Jordan

Region/ State/ Province:

Amman governorate/Al Jizza/Al Majeddyeh village

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

Indicate year of implementation:

2017

2.7 Introduction of the Technology

Specify how the Technology was introduced:
  • during experiments/ research
  • through projects/ external interventions

3. Classification of the SLM Technology

3.1 Main purpose(s) of the Technology

  • reduce, prevent, restore land degradation
  • 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:

Ja

Specify mixed land use (crops/ grazing/ trees):
  • Agro-pastoralism (incl. integrated crop-livestock)

Grazing land

Grazing land

Extensive grazing:
  • Semi-nomadic pastoralism
Waterways, waterbodies, wetlands

Waterways, waterbodies, wetlands

  • Drainage lines, waterways
Main products/ services:

To convey and drain: Wd

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

Has land use changed due to the implementation of the Technology?
  • Yes (Please fill out the questions below with regard to the land use before implementation of the Technology)
Land use mixed within the same land unit:

Nee

Grazing land

Grazing land

Extensive grazing:
  • Nomadism
  • Semi-nomadic pastoralism
Animal type:
  • goats
  • sheep
Is integrated crop-livestock management practiced?

Nee

Products and services:
  • meat

3.4 Water supply

Water supply for the land on which the Technology is applied:
  • rainfed
Comments:

The measure mitigates the effect of surface runoff in concentrated flow areas - as a consequence of heavy rainfall events

3.5 SLM group to which the Technology belongs

  • improved ground/ vegetation cover
  • minimal soil disturbance
  • cross-slope measure
  • water harvesting; surface water management (spring, river, lakes, sea, riparian zone, riverbanks, seashore, lakeshore, spring shed); ecosystem-based disaster risk reduction

3.6 SLM measures comprising the Technology

vegetative measures

vegetative measures

  • V2: Grasses and perennial herbaceous plants
structural measures

structural measures

  • S6: Walls, barriers, palisades, fences
other measures

other measures

Specify:

Specify tillage system: no tillage
Specify residue management: grazed and retained

3.7 Main types of land degradation addressed by the Technology

soil erosion by water

soil erosion by water

  • Wg: gully erosion/ gullying
  • Wo: offsite degradation effects
physical soil deterioration

physical soil deterioration

  • Pk: slaking and crusting
  • Pu: loss of bio-productive function due to other activities
water degradation

water degradation

  • Hs: change in quantity of surface water
  • Hw: reduction of the buffering capacity of wetland areas

3.8 Prevention, reduction, or restoration of land degradation

Specify the goal of the Technology with regard to land degradation:
  • reduce land degradation
  • restore/ rehabilitate severely degraded land

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

4.1 Technical drawing of the Technology

Technical specifications (related to technical drawing):

Emplacement in gully morphological system and watershed context: Determine the downstream starting point for the gully plugs and then extend upstream. The basic design is to keep the structure height maximum half the gully depth regardless of structure type. The spacing between structures is set as a gully depth function, structure crest height above the gully bed, and slope of the gully bed between structures. Additionally, the structure's final location will be shifted either upstream or downstream of the calculated gully bed level to place the structure in a more stable point if required. Following this methodology ensures variable spacing between structures to cope with both slope and depth of gully to ensure the sediment filling in between these structures occurs. In the case of distinct gully morphology and side banks that are very unstable, gabion structures can also be used/instead of a single stone pack.

Design of the Structure: Gully plugs must be anchored strong enough to resist water flow and prevent bypass from the side banks. A foundation is also required for all structures, depending on their dimensions and the bed's nature. At the specific site, the foundation depth for the planned structures ranges between 0.2 to 0.35 meters. The anchoring of gully plugs ranges between 1 and 1.5 meters. This depends on the existing condition of the banks at each structure location. Gully plugs have a downstream apron with a length of around 3 to 4 times the height of structures. The apron starts from below the bottom level of the foundation and gradually level halfway down. All gully plugs were designed to have a height maximum of 0.5 the depth of the gully. So each structure will pass water flow downward but keeping it inside the gully. Gabion structures have a sort of spillway from the top but at the same time protecting the banks. The configuration slightly differs from the normal stone structure, but the idea is to protect the sides and a spillway in the middle. The upstream front of each gully plug has a side slope of 1:1, while the downstream front of the plug has a side slope of 2:1 (not counting the apron). The slopes at the two sides greatly increase the base width of the plug and improve their stability. The gully plugs are provided with an amount of soil resulting from the foundation to form a triangle of soil fill against the structure at the upstream side; this improves the function of the gully plugin holding more water and trapping sediments. On the other side of each structure, the downstream side's slope is meant to tackle the overflow of water along the drop to safely return to the gully bed level without causing additional erosion. The rock-filled apron catches the flow and acts to dissipate erosive energy.

Author:

Steve Evett

Date:

15/08/2017

4.2 General information regarding the calculation of inputs and costs

Specify how costs and inputs were calculated:
  • per Technology unit
Specify unit:

Gully plug

Specify currency used for cost calculations:
  • USD

4.3 Establishment activities

Activity Timing (season)
1. Implement upland watershed SLM (reference VALLERANI)
2. Gully system/morphological assessment
3. Determine plug design and implementation in the watershed
4. Excavation earthworks for anchors and foundation At least 2 months prior rainy season onset
5. Stone made construction of gully plugs (occasionally with gabions) At least 1 month prior rainy season onset
6. Soil pack at upstream front At least 1 month prior rainy season onset
7. Revegetation of gully side banks At the onset of the rainy season
Comments:

Gully plugs require proper SLM in the uplands. Revegetation of gully side banks is optional – depending on the recovery potential of the area.

4.4 Costs and inputs needed for establishment

Specify input Unit Quantity Costs per Unit Total costs per input % of costs borne by land users
Labour Field technician (design and oversight) Labour Day (LD) per structure 0.2 50.0 10.0
Labour Workers (excavation/earthworks) LD 4.0 35.0 140.0
Labour Workers (stone layering/construction) LD 4.0 35.0 140.0
Labour Worker (out-planting of seedlings) LD 1.0 35.0 35.0
Equipment Shovel, Pickaxe, buckets, ruler Lump sum 1.0 10.0 10.0
Plant material Seedlings per item 10.0 0.5 5.0
Construction material Stones m3 4.0 10.0 40.0
Other Logistics (seedling transport, local stone transport) lump sum 1.0 10.0 10.0
Total costs for establishment of the Technology 390.0
Total costs for establishment of the Technology in USD 390.0
If land user bore less than 100% of costs, indicate who covered the remaining costs:

International research for the development project.

Comments:

Design is tailored for implementation through local workers (rural agro-pastoral community) and local materials. The engagement of local community workers as part of the specific project; if a professional contractor is hired costs can be significantly reduced.

4.5 Maintenance/ recurrent activities

Activity Timing/ frequency
1. Inspect damage/status After severe storms and runoff events
2. Maintain/repair/improve After inspection
Comments:

If optimally designed and connected with proper upland SLM the gully plug technology would not require maintenance; the measure induces nature-based (vegetation) protection of vulnerable gully zones over time.

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 Expert (investigation) LD 0.1 50.0 5.0
Labour LD 0.5 35.0 17.5
Labour LD 1.0 35.0 35.0
Construction material stones m3 0.5 10.0 5.0
Total costs for maintenance of the Technology 62.5
Total costs for maintenance of the Technology in USD 62.5
If land user bore less than 100% of costs, indicate who covered the remaining costs:

It is 100% covered by the research project

Comments:

Maintenance might be needed in case of improper implementation and/or extreme event occurrence. Maintenance should be minimal - mostly after initial 1-2 rainy seasons. Thereafter, revegetated and rehabilitated gully system – and most importantly, the rehabilitated uplands - would take on hydrological buffering functions and withstand the erosive force of surface runoff.

4.7 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

The most distinct cost factor is labor – which is especially significant when using local (community) labor; some technical training is required.

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:

130.00

Specifications/ comments on rainfall:

Jordan has a rainy season from September to May – but locally, the effective rainy season sets on later (November or December) and lasts until April.

Indicate the name of the reference meteorological station considered:

Queen Alia international airport reference station reports long term average annual rainfall of about 150 mm A rainfall tipping bucket installed in the site in 2016.

Agro-climatic zone
  • arid

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
Comments and further specifications on topography:

Gully slope is 3.4% on average.

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:
  • low (<1%)
If available, attach full soil description or specify the available information, e.g. soil type, soil PH/ acidity, Cation Exchange Capacity, nitrogen, salinity etc.

Soil depth is varying throughout the gully areas. At some points (mostly upstream) the gully bed reaches the bedrock

5.4 Water availability and quality

Ground water table:

> 50 m

Availability of surface water:

medium

Water quality (untreated):

for agricultural use only (irrigation)

Water quality refers to:

surface water

Is water salinity a problem?

Nee

Is flooding of the area occurring?

Ja

Regularity:

frequently

5.5 Biodiversity

Species diversity:
  • high
Habitat diversity:
  • medium
Comments and further specifications on biodiversity:

Gully plugs with out-planted vegetation create micro-climates; after recruitment and emergence of seed material, biodiversity increases.

5.6 Characteristics of land users applying the Technology

Sedentary or nomadic:
  • Sedentary
  • Semi-nomadic
Off-farm income:
  • less than 10% of all income
Relative level of wealth:
  • very poor
  • poor
Individuals or groups:
  • individual/ household
  • groups/ community
Level of mechanization:
  • manual work
Gender:
  • men
Age of land users:
  • youth
  • middle-aged

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
Comments:

The entire watershed area affected by gully plugs is 160 hectares.
The total constructed plugs are 55.

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

Land ownership:
  • individual, titled
Land use rights:
  • individual
Are land use rights based on a traditional legal system?

Ja

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

Production

fodder production

decreased
increased

fodder quality

decreased
increased
Water availability and quality

water availability for livestock

decreased
increased

Socio-cultural impacts

food security/ self-sufficiency

reduced
improved
Comments/ specify:

Some herbs (and fruits (trees) in the future)

recreational opportunities

reduced
improved
Comments/ specify:

enhanced biodiversity, shade and shelter

SLM/ land degradation knowledge

reduced
improved
Comments/ specify:

Through training/community participation

Ecological impacts

Water cycle/ runoff

water quality

decreased
increased
Comments/ specify:

Certain degree purification through infiltration in the sediment accumulation zone

harvesting/ collection of water

reduced
improved

surface runoff

increased
decreased
Comments/ specify:

Effect on hydrology (distinctness of runoff peak)

groundwater table/ aquifer

lowered
recharge
Comments/ specify:

Certain deep-infiltration

evaporation

increased
decreased
Comments/ specify:

more open water ponding – but also deep-infiltration and beneficial use for vegetation (transpiration)

Soil

soil moisture

decreased
increased

soil cover

reduced
improved

soil loss

increased
decreased
Comments/ specify:

Side banks stabilized

soil accumulation

decreased
increased
Comments/ specify:

sediments trapped

soil crusting/ sealing

increased
reduced
Comments/ specify:

sediment crust increased in the ponding area – but better soil structure at the side banks (revegetation) – overall positive impact.

Biodiversity: vegetation, animals

Vegetation cover

decreased
increased

biomass/ above ground C

decreased
increased

plant diversity

decreased
increased

animal diversity

decreased
increased

beneficial species

decreased
increased
Climate and disaster risk reduction

flood impacts

increased
decreased

landslides/ debris flows

increased
decreased
Comments/ specify:

Through side bank stabilization.

micro-climate

worsened
improved

6.2 Off-site impacts the Technology has shown

downstream flooding

increased
reduced

downstream siltation

increased
decreased
Comments/ specify:

especially when combined with upland measure: reference VALLERANI

damage on neighbours' fields

increased
reduced
Comments/ specify:

Less tributary channel development (connectivity of upland areas); less downstream siltation

damage on public/ private infrastructure

increased
reduced
Comments/ specify:

less runoff peakiness and siltation

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

Gradual climate change
Season increase or decrease How does the Technology cope with it?
annual temperature increase moderately
annual rainfall decrease well

Climate-related extremes (disasters)

Meteorological disasters
How does the Technology cope with it?
local rainstorm well
Hydrological disasters
How does the Technology cope with it?
flash flood very well
Biological disasters
How does the Technology cope with it?
epidemic diseases well

Other climate-related consequences

Other climate-related consequences
How does the Technology cope with it?
extended growing period very well

6.4 Cost-benefit analysis

How do the benefits compare with the establishment costs (from land users’ perspective)?
Short-term returns:

negative

Long-term returns:

positive

How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?
Short-term returns:

negative

Long-term returns:

slightly positive

Comments:

During the initial stage potential benefits through vegetation do not materialize; main effects are on water and sediment retention. Long-term, the technology fosters the rehabilitation nature-based retention functions (very limited long-term maintenance required).

6.5 Adoption of the Technology

  • single cases/ experimental
If available, quantify (no. of households and/ or area covered):

1

Of all those who have adopted the Technology, how many did so spontaneously, i.e. without receiving any material incentives/ payments?
  • 0-10%

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
Gully side bank vegetation useable as (livestock) fodder source; some herbs (later fruit tree benefits) for human consumption.
Gully is stable and does not expand e.g. tributaries. Uplands remain connected and productive.
Ponded water for livestock watering (during the rainy season).
Shelter and shade through vegetation.
Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
Sediments from the uplands are trapped; relatively fertile soil remains in the watershed.
Increased local soil moisture and consequential vegetation quantity and bio-diversity enhancement; increase carbon storage and other ecosystem services such as pollination.
Smoothened watershed hydrology is beneficial for downstream agriculture – especially when applied in a watershed context with downstream flood irrigation (MARAB)
Protection of downstream infrastructure (flooding and sediments).

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?
implementation costs Incentives (e.g. governmental) for communities to implement SLM; regulations and enforcement on environmental management – especially connected with entitlements of natural resources facilitation
Tensions between upstream and downstream watershed users (watershed hydrology) – especially affected through wrong design and failure (e.g. gully breakage) Community-based and holistic watershed management – the share of benefits and commitment for maintenance.
Additional fodder supply might attract other foreign herders (overgrazing) Community-based and holistic watershed management – and protection.
Technical skills needed for implementation Rural communities’ capacity building programs
Weaknesses/ disadvantages/ risks in the compiler’s or other key resource person’s view How can they be overcome?
Expert design and implementation support required Governmental and environmental organizations in control of design and support to local communities (training).
Requires upland SLM Integrated watershed management and empowerment of local communities to manage and facilitate – provision of support (e.g. government and/or international projects).
Increased vegetation in a fragile ecosystem can lead to local pressure Integrated watershed management and empowerment of local communities – especially sustainable grazing plans
Risk of wrong lessons learned: large water harvesting in gully systems (dams) created by locals Capacity development programs; regulations and enforcement on environmental management.

7. References and links

7.1 Methods/ sources of information

  • field visits, field surveys

The number of field visit is 5.

  • interviews with land users

The number of land users that were interviewed is 10.

  • interviews with SLM specialists/ experts

The number of SLM experts who were interviewed is 5.

When were the data compiled (in the field)?

09/08/2020

7.2 References to available publications

Title, author, year, ISBN:

Steven, E. (2017). Report on Majiddya Watershed Rehabilitation Project - Gully Plugs Plan /August 2017.

Title, author, year, ISBN:

Strohmeier, S. (2017). Dimensioning of Marab in Majidyya.

Title, author, year, ISBN:

SEA. 1974. Les ouvrages en gabions – techniques rurales en Afrique. Secretariat d’Etat aux Affaires Etrangeres, Republique Francaise, 20, rue Monsieur, 75007 Paris.

Title, author, year, ISBN:

FAO. 1977. Guidelines for watershed management. FAO Conservation Guide 1. Food and Agriculture Organization of the United Nations. Rome, 1977

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