Search

The tropical mountainous environments of the Northern-western provinces of Rwanda in Africa are often referred to as the breadbasket of the country and are also densely populated. This high demographic pressure is associated with significant land management practices. In particular, agricultural practice of terracing has been promoted as soil and water conservation measure on the steep hillslopes of the region. However, the region is also landslide prone and the potential effect of terracing on landslides occurrence has never been considered in the land management strategy. In this work, we assess this potential effect through the analysis of more than 4000 recent landslides that were triggered by intense rainfall events. Exploring the role of slope, lithology, regional landslide susceptibility patterns and the types of terraces (typology, age), we show that, overall, terracing increases the odds of landsliding when compared to non-terraced hillslopes. Although the terraces are implemented as soil and water conservation measures in the region, we find that they result into higher hillslope hazard.

Monitoring of environmental parameters is one of the highest priorities in the evaluation of environmental status of water resources and in environmental protection policy. The main objectives are to understand and evaluate the water quantity and quality in order to provide water of appropriate quality to various water users. The water quantity was assessed by the measurement of runoff or discharge at specific river cross sections using floating method for surface water and bucket and stopwatch method for springs and boreholes. The quality of river water and spring was identified in terms of its physical, chemical, and biological parameters. The analyzed data were compared with standard values recommended by WHO. Macroinvertebrates were collected in the rivers using a plankton nets and 10 minutes of sampling. Identification was made at the laboratory of Malacology. Results revealed that the quality of water obtained from sampling points is generally good to use for different domestic purposes except the Idanta River and Rwembwe borehole, which need an appropriate treatment before use. All sampling points are located far from houses and latrines, which can contribute to fecal contamination. On the different sampling points, bathing and washing clothes were observed and could constitute the source of pollution of drinking water. In Idanta and Kamira Rivers animals used water for drinking while also people use this water for domestic and drinking. In the two sampling points high values of Escherichia coli were found. No pollutant-taxa tolerant were found in the two monitored rivers for macroinvertebrates. Since water quality and quantity remain a major challenge in rural areas, the government should provide safe water to the population around Mikeno sector after treatment using suitable techniques.