Vol.:(0123456789) 1 3 Modeling Earth Systems and Environment https://doi.org/10.1007/s40808-021-01146-z ORIGINAL ARTICLE Hydrological and hydraulic model for food forecasting in Rwanda Gisele Icyimpaye 1  · Chérifa Abdelbaki 1,2  · Khaldoon A. Mourad 3 Received: 30 December 2020 / Accepted: 15 March 2021 © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2021 Abstract This paper aims to forecast the Nyabugogo River food risk and to propose mitigation measures that can reduce food impacts using hydrological and hydraulic models. The annual Nyabugogo River foods that have led to human and economic losses are mainly due to the high topography, rainfall, soil texture and urbanization. It was found that the medium to high food vulnerability is located in cropland, open grassland, open shrubland, settlement, sparse forest and wetlands. The results for 10-, 30- 50- and 100-year return periods show a slight increase in the food inundation area and in water depth. The simula- tion shows that the 100-year return period gives a water depth of 3.24 m. Therefore, food mitigation measures are needed, which can include the construction reservoirs upstream, relocation of infrastructures within the food plain area, bufer zoning around the river, rainwater harvesting and raising public awareness. This paper provides basic support for decision-makers and can help in land use planning and food management within the basin. Keywords Flood risk · Modelling · HEC-RAS · HEC-HMS · Nyabugogo River Basin Introduction Flooding Floods are considered the most harmful natural hazards, which are likely to be more frequent, dominant and serious due to climate change, population growth, urbanization and other factors related to watershed characteristics and human activities (Bahar 2010). Floods losses can be divided into direct losses such as the number of people killed and the damage to buildings, infrastructure and natural resources, and indirect losses such as the deterioration of water quality and some socio-economic activities (Queensland Govern- ment 2011). Globally, more than 3060 foods disasters were recorded between 1995 and 2015 that afected 2.3 billion people, 157,000 deaths and economic losses of 662 Billion USD (UNISDR 2015). In Rwanda, fooding, erosion and landslides afect the northern and western regions including Kigali city due to the abundant rainfall, overexploitation of the natural resources, deforestation, inappropriate farming practices and housing systems (Habonimana et al. 2015; Nsengiyumva 2012). Tor- rential rain causes high-level fooding in Kigali causing an annual average loss of an estimated 200,000 USD (NTR 2016; Munyaneza et al. 2013). The food of 2011 in the North-Western part of the coun- try killed 10 people, destroyed 354 houses, and damaged 3000 ha of the farmland (Nsengiyumva 2012). In 2012, some districts of the North-Western part of the country got fooded and as a result, fve deaths were recorded, 2232 households with 11,160 peoples had been afected, 348 houses were totally destroyed, 446 were partly damaged, 1000 ha of cul- tivated areas were inundated in addition to huge damage to the water networks. In April 2015, Rubavu and Nyamasheke districts in the Western Province of Rwanda experienced heavy rainfall that led to severe fooding and landslides, which inundated 206 ha of crops and afected 685 house- holds. In May 2016, the heavy rainfall in the Gakenke dis- trict in the Northern province killed 49 people and afected the quality of the water resources. Recent fooding, on May * Khaldoon A. Mourad khaldoonmourad@yahoo.com Gisele Icyimpaye icyimpaye992@gmail.com Chérifa Abdelbaki cherifa.abdelbaki@pauwes.dz 1 Pan-African University Institute for Water and Energy Sciences (PAUWES), Tlemcen, Algeria 2 Laboratoire EOLE, Université de Tlemcen, Tlemcen, Algeria 3 The Centre for Sustainable Visions, 22643 Lund, Sweden Content courtesy of Springer Nature, terms of use apply. Rights reserved.