To solve this problem sustainably, an integrated approach using agroforestry and grey infrastructure using civil engineering methods at the micro-catchment level might be the solution. Starting in 2017, APFNet funded two phases (2017-2019, 2020-2022) of the project “Development of participatory management of a micro-catchment in the Bengawan Solo Upper Watershed”, which have now both been successfully completed. The project selected the Naruan Micro Catchment (NMC) in the upstream area of Bengawan Solo River as a pilot site to showcase participatory measures to tackle soil erosion. In order to make sure that the needs of the local community and existing knowledge were sufficiently considered, this project used a participatory approach that involved local farmers in decision-making during planning, implementation and subsequent monitoring.
Controlling Erosion while Benefitting People
The upstream watershed, where the project was located, plays a crucial role in erosion control as slopes there are often steep and unsuitable land use causes erosion, affecting not only the local population but all downstream areas. Unfortunately, due to the complex interaction between topography (steep slopes, insufficient land cover) and hydrology (rainfall and run-off), soil erosion and land degradation in the NMC are difficult to fully halt and reverse on a large scale in the short term. Complicating this, most of the people living in this rural area depend on farming for their livelihoods, inevitably causing soil erosion. As such, it was the task of the APFNet project to find measures that can control erosion while also allowing people to earn a living sustainably. For this, a practical and operational plan was developed and demonstration sites were established.
Fig.1: Agroforestry demonstration site established by APFNet project in Naruan Micro Catchment, Central Java, Indonesia
In addition to those vegetative measures, erosion was addressed through the construction of grey infrastructure that used civil engineering measures. These included check dams and gully plugs for erosion control, built from various materials, like cemented stones, gabion (Fig.2), or bamboo. By installing a series of these in gullies, the project was able to stabilize them and prevent them from further deterioration.
Fig.2: Before and after construction of a gully plug for controlling water erosion in fields along steep slopes
The APFNet-project has just been completed and therefore it is impossible to already see the long-term impacts of project activities. However, the analysis of data generated in Phase I already shows the advantages of using agroforestry (compared to tree monocultures or traditional agriculture) as it offers the best cost-benefit ratio to farmers. In this project phase, a policy brief on village-based participatory micro-watershed management addresses potential improvements in watershed management planning regulations, e.g. concerning the size definitions of managed areas and integration into village development programs. Moving forward, the NMC and its watershed management will function as a model for participatory watershed management in Indonesia. The methods for community participation and participatory intercropping designs are further shared through upcoming scientific papers and publications. The approach of agroforestry in combination with physical barriers, such as gully dams, will provide long-term erosion control and reduce the sediment load in rivers in downstream areas.
Overall, the project has already made a positive impact in the area and beyond and is expected to continue to do so.
For more information see https://www.apfnet.cn/plus/view.php?aid=4325