Gully Rehabilitation with Stem Cuttings

• Gully rehabilitation designs can take about one year to become profitable. Initially, there are higher costs involved due to the establishment costs, which can be quite labour-intensive. 
• The durability of the check dam is determined by the size and dimensions of the gully, site conditions such as soil type and sloping, as well as the availability of suitable materials.

Material required

• 300-500 Poles 
• Seedlings
• Wheelbarrow 
• Line-level
• Tape measure
• Axe 
• Machete
• Shovel
• Hoe

Steps of implementation

1. Materials preparation: For this intervention, the most suitable material is stems with a diameter of 5-15 cm and 1.5-2.5 m long, depending on the depth of the gully. The cuttings are planted for half of their length and placed to form a semi-circular barrier. 
2. Building and positioning of dams: Dams are spaced according to the slope of the gully bed. Dams aim to reduce runoff speed and stop the eroded sediment. This way, the portions of the gully between the dams will fill up with eroded soil. In addition, over time the agricultural land that was divided by the gully will become reconnected, allowing the runoff to be further reduced.
3. Fortification: To obtain the best results, it is recommended to integrate this intervention with other Soil and Water Conservation measures on lateral slopes, such as retention trenches or live barriers along the contour. Moreover, to improve the effectiveness of the stem-cutting barriers on moderate slopes, it is recommended to combine them with stone dams.
4. Maintenance: To ensure the efficiency of stem-cutting barriers over time, it is crucial to provide for their maintenance. This might require the thinning of some trees or shrubs, which leads to the production of wood and fodder, replacement of dead poles and widening of the barriers where necessary. It is also good practice to regularly inspect the resistance of the check dam, especially after heavy rainfall.
5. Overtime cropping: Gully rehabilitation can be combined with crop cultivation by establishing ‘terraced ’-like beds that crops can eventually grow on due to trapping sediment that accumulates over time. Whenever a layer of silt builds up, it is necessary to increase the height of the check dam by approximately 0.3m until there is a nice terrace upon which crop cultivation can occur.

Click here for a good step-by-step.

Considerations for application

Ecological benefits of gully rehabilitation

• Soil conservation: Stem-cutting check dams are effective in controlling and limiting soil erosion. The dams slow down the water in the gully, retaining soil on the slopes that also prevents valuable topsoil from being washed away, preserving soil fertility and promoting healthy plant growth.
• Water retention: By obstructing the flow of water, stem-cutting check dams aid water retention, and therefore flood control, by creating small reservoirs behind the dams, allowing water to infiltrate into the ground and recharge groundwater aquifers. This improved water availability for various purposes such as drinking, agriculture, and livestock rearing. This is crucial in arid or semi-arid regions where water scarcity can be a concern.
• Habitat creation: The construction of stem dams can create diverse microhabitats. The presence of water in these structures provides opportunities for various aquatic organisms such as fish, amphibians, and invertebrates to establish habitats, whilst the damp conditions around the dams can support the growth of moisture-loving plant species, fostering biodiversity.

Socioeconomic benefits of gully rehabilitation

• Agriculture and irrigation: The stored water behind the dams can be channelled into agricultural fields through canals whilst the improved soil quality allows for the cultivation of crops throughout the year, particularly during periods of low rainfall, increasing agricultural productivity and reducing dependence on rainfall alone. Improved irrigation can lead to better crop yields, increased food security, and enhanced economic opportunities for farmers, through fodder production.
• Livestock management: In areas where livestock rearing is a significant economic activity, stem-cutting check dams can provide new water sources for animals as they create small pools of water, allowing livestock to drink and providing a reliable water supply during dry spells.
• Employment and income generation: The construction and maintenance of stem-cutting check dams can create employment opportunities for local communities. The building process typically requires labour-intensive activities, providing jobs for workers involved in activities such as gathering stem cuttings, constructing dams, and establishing vegetation. Helping alleviate unemployment and generate income for individuals and families in the vicinity.

• Other types of check dams include:
  • Stones check dams
  • Stones with spillways
  • Stones combined with intertwined green branches and poles

Here you can find a complete list of types of check dams.

This intervention contributes to:

Estimation of costs & benefits of the intervention
This example is for a 100 meter long, 2 meter wide and 1-metre-deep gully, with check dams every 4 meters, on the basis of one gully per hectare.

(Source)

1. Check dams for stem cutting, Nicaragua 

Description
The technology involves using stem cuttings from specific tree species to create check dams in gullies, which helps to slow down runoff and gradually fill up the gullies with sediment. Local species such as jinocuebo, jobo, tiguilote, pochote, jocote, and madero negro are used for this purpose. The stem cuttings are planted in a semi-circular barrier formation, with spacing between dams depending on the gradient of the gully bed. These check dams are part of a larger catchment management plan and should be supported by other soil and water conservation measures. After two to three years, the barriers are pruned, and dead poles are replaced. This approach has been implemented in semi-arid regions of Nicaragua, specifically in the Santa Teresa and Paso de la Solera regions of Carazo, covering an area of 5 square kilometres. The technology was introduced through external interventions, particularly by an NGO called 'Asociación Tierra y Vida' through farmer-to-farmer extension programs.

External sources 

• Here you can find more details on gully rehabilitation with stem cuttings, and also about the suitable species of trees that can be used.
• Check dams can be built with different materials, click here to know more about their differences.

Guides 

• Click here to have more details on how to build check dams for gully rehabilitation.

Videos

• Watch this video if you want to know more about gully rehabilitation with stones and intertwined vetiver grass.