Rwanda: Civil Engineer Consultant with Expertise in Hydraulics/Hydrology at Global Green Growth Institute (GGGI): (Deadline 1 November 2021)

Based in Seoul, the Global Green Growth Institute (GGGI) is an intergovernmental organization founded to support and promote a model of economic growth known as “green growth”, which targets key aspects of economic performance such as poverty reduction, job creation, social inclusion, and environmental sustainability. GGGI works with countries around the world, building their capacity and working collaboratively on green growth policies that can impact the lives of millions. The organization partners with countries, multilateral institutions, government bodies, and private sector to help build economies that grow strongly and are more efficient and sustainable in the use of natural resources, less carbon intensive, and more resilient to climate change.

Since 2012, GGGI has worked with Rwanda as one of Africa’s premier models of green growth, evident in its ability to embed green growth and sustainability elements into national policies, strategies, and action plans. GGGI has supported Rwanda’s green growth and sustainable urbanization goals, examining green development solutions including capacity development in hydrological and hydraulic modelling and analytical studies focusing on critical urban watersheds in the capital city and secondary cities.

The City of Kigali (CoK) is one of the most vulnerable areas to flooding in Rwanda and experiences extreme flooding on an annual basis. The magnitude of this flooding problem is expected to increase because of climate change. As data has shown, Rwanda is highly vulnerable to adverse effects of climate change as evidenced by the 2018 and 2019 heavy rainfalls. Within the next few decades climate change is expected to greatly increase the frequency, severity, and extent of flooding in Rwanda. This will in turn result in a considerably greater damage to infrastructure, greater loss of lives, livestock and of crops. The impact of these increasingly extreme rainfall events will be exacerbated by Kigali’s rapid rate of urbanization and the city’s hilly and mountainous relief.

Current approaches to flood risk management such as traditional drainage systems have proven insufficient to accommodate the increased runoff resulting from recurrent high intensity rainfall triggered by climate change. The ongoing rapid urbanization, therefore, requires a paradigm shift towards integrated development that applies nature-based solutions to manage floods; and reduce, retain, and attenuate runoff at the source as opposed to focusing only on increasing the conveyance capacity of the drainage systems.

To contribute to making the city and communities sustainable, livable and resilient, GGGI and ENABEL, in collaboration with the City of Kigali, Rwanda Forestry Authority, and MININFRA are designing and developing a project proposal to catalyze access to climate finance, aiming at building urban resilience in the City of Kigali, with a focus on selected sub-catchments within Nyabugogo catchment, including Gisozi-Mukindo. To respond to this challenge, there is a need to establish scientific and technical basis from a climate perspective and other available evidence and data collection.

The objective of the assignment is to conduct detailed flooding risk modelling and design nature-based solutions to reduce flood risks in Gisozi-Mukindo sub-catchment in the City of Kigali (CoK).

The study area is a small sub-catchment known as Gisozi-Mukindo within the City of Kigali with area of about 100 ha. The sub-catchment is highly urbanized and the downstream part of the sub-catchment which is the most flood prone zone is a very busy commercial area known as AGAKIRIRO mostly occupied by small scale businesses.

Some studies related to flood mitigation have been undertaken within the City of Kigali that can inform this study. These include:

• • • Storm water and wetland management model for delineated flood prone areas in Kigali city including Gisozi-Mukindo sub-catchment using wflow software for hydrological modelling and hydraulic models for some sections using SOBEK 2 software.
    • A landscape analysis and pre-feasibility study of urban based nature-based solutions to reduce flood risks and strengthen resilience in the city of Kigali
    • Detailed study on flood and landslide risks assessment and mitigation measures in some sub-catchments within the city of Kigali and secondary cities
    • Run off reduction guidelines in an urban set up.

The above-mentioned studies will serve as a reference for the Gisozi-Mukindo sub-catchment study.

The key tasks will include:

• • • Hydrological modelling for the sub-catchment and hydraulic model for the main river channel as highlighted under Figure 1 which is about 1 KM.
    • Detailed topographic survey for the channel section to be covered for hydraulic modelling under this study (1 KM).
    • Assessment of impacts of flood events over the last ten years (loss of life, livelihoods, physical assets, etc.)
    • Description of the catchment area at risk to inform a cost-benefit assessment: population at risk and estimated value of existing and planned physical assets at risk. This is to estimate the cost of not investing in the proposed measures (BAU)
    • Detailed assessment and design of Nature Based Solutions to reduce the runoff in the entire sub-catchment building on the developed run off reduction guidelines
    • Simulation of the contribution of the proposed nature-based solutions to reduce flood risks within the sub-catchment
    • Preliminary design of required hydraulic structures to manage the excess run off
    • Estimated investment costs and bill of quantities for the proposed measures

The assignment will be undertaken over a period of two months with a total of 40 working days. The expected outputs of the Consultant are as follows (however, the Consultant may be required to produce additional output(s) as deemed reasonably necessary by GGGI). All reports and outputs must be in English, in accordance with GGGI’s formatting requirements, and submitted in electronic formats along with complete sets of raw data, models and any other material.

Deliverables and Timeline

The assignment is expected to be completed by December 2021

i) Inception report: Revised methodology, detailed work plan and initial description of the study areas

ii) Interim report: Topography investigation report, detailed hydrological and hydraulic models, assessment of impacts of flood events and description of the catchment areas at risk to inform a cost-benefit assessment

iii) Draft final report: Design of Nature-Based Solutions to reduce the runoff in the study area and required hydraulic structures and their costing

iv) Final report :covering all the required tasks under the study

Payment modalities

The consultant will invoice at each task milestone according to the contract fractions listed below. Invoices will be paid against the delivery of acceptable outputs for each task in the fractions of the total contract value listed below: