Gravity Irrigation for enhancing Community-Based Restoration efforts in the degraded forests of Paktya
Type: Technologies
Creation: 2025-01-28 05:32 Updated: 2025-10-14 13:10
Compilers: Mohammad Wazir Ahmadzai
Reviewers: Rima Mekdaschi Studer, Illias Animon, Muhammad Ishaq Safi, Megha bajaj
Country/ region/ locations where the Technology has been applied and which are covered by this assessment
- Country: Afghanistan
- Region/ State/ Province: Paktya
- Further specification of location (e.g. municipality, town, etc.), if relevant: Ahamd Aba and Sayed Karam district
- Map: View Map
Description of the SLM Technology
Short description of the Technology
Using a gravity-irrigation system, spring water is diverted to fill reservoirs and then distributed to fields for the restoration of degraded forest areas, with the active involvement of local communities and a focus on the sustainable use of water resources (spring water).
Detailed description of the Technology
The Paktya province in Afghanistan, known for its mountainous terrain and rich forests of pine nuts deodar, cedar, and conifers, faces severe challenges. Most water in the province comes from rivers, springs, and tube wells, with high mountains acting as natural reservoirs. Unfortunately, many traditional water sources have been destroyed over decades of conflict and natural drought, forcing farmers to rely on costly tube wells for irrigation.
To support sustainable water management in the mountainous areas of Ahmad Aba and Sayed Karam districts, 60 water reservoirs with a total storage capacity of 6,000 m³ were constructed. The volume of individual reservoirs varies depending on the availability and flow of upstream spring water ranging from 36 m³ to 192 m³.
Water is diverted from a small intake near the source and delivered to the reservoir inlet through a 2-inch Polyvinyl Chloride (PVC) pipe. For irrigation of the restored areas, the outlets from the reservoirs are connected to 1-inch PVC pipes for distributing water to various plantation sites.
This technology is applied in a natural environment and is designed to support environmental sustainability by recharging the groundwater table, as water is harvested into reservoirs, it can infiltrate through the side walls and bottom. This percolation process contributes to the natural hydrological cycle, harvesting surplus water (water evaporate or percolating into atmosphere or soil) into reservoirs for irrigation of planted saplings, and extending existing forest boundaries.
The system enables the local community to sustainably manage and utilize spring water for gravity-based irrigation of restored areas, while also supporting the expansion of forested land through sapling plantation.
Before constructing the reservoirs, a feasibility survey of the water source (the spring) was conducted to verify the perennial availability of water and to determine the optimal distance between the spring and the designated reforestation sites. The preliminary selection of reservoir locations was based on key criteria including the year-round reliability of the water source, the size of the target reforestation area, and the discharge capacity of the spring. Excavation of the rocky mountain earth was carried out using a hand excavator as per the specified requirements as per technical drawing and approved design. The stone masonry work was completed using random rubble coursed stone with a cement-sand mortar mix (1:2, Type A). As per the design, Plain Cement Concrete (PCC M20) was applied to the top of the stone masonry and on all floors of the reservoirs. A 20 mm thick plastering was carried out on the internal walls using cement-sand mix (1:2). The external walls were backfilled to a height of 1.5 meters.
The benefits of this gravity-fed irrigation technique include increased reforestation rates, reduced water loss due to evaporation and runoff, achieved by using closed piping systems instead of open channels, and improved water use efficiency. These improvements have led to higher sapling survival rates and better growth. Overall, the socio-economic and environmental conditions of rural populations have been improved. Additionally, the implementation of the gravity irrigation system has reduced the cost of restoring degraded forests.
As a low-cost, environmentally friendly technology, it allows for the efficient harvesting of spring water for irrigation, supports sapling planting for carbon sequestration, and helps mitigate the severe impacts of climate change.
Photos of the Technology
- 📍 Sayed Karam
- 📷 Mohammad Wazir Ahmadzai
- 📍 Paktya , Ahmad Aba
- 📍 Ahmad Aba
- 📷 Mohammad Wazir Ahmadzai