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Hydrological assessment approach for the elaboration of the hydro-agricultural infrastructure project aimed to the development of mangrove rice cultivation in Guinea Bissau

IWRA 2021 Online Conference One Water, One Health
Theme 2: How can managing water in agriculture contribute to food security and public health?
Author(s): Riccardo Torri, Alessandro Barbero, Federica Manni, Giancarlo Benacchio, Streng Cerise

Riccardo Torri*, Alessandro Barbero*, Federica Manni**, Giancarlo Benacchio**, Streng Cerise**

*   EG-Team (Engineering Geology Consultancies) – Turin (Italy) mob. +39 335 702 52 06 e-mail:
** LVIA (Lay Volunteers International Association) – Cuneo (Italy) / Bissau (Guinea Bissau) e-mail:

Keyword(s): Guinea Bissau, mangrove rice, hydrology, hydraulic engineering, climate change


(a) Purpose or objectives and status of study or research hypothesis
The project plans to increase food and nutritional security of communities concerned by the sustainable development of the mangrove rice chain in coastal areas of Guinea-Bissau. The activities carried out aim at the modernization of salt water paddies ("bolanhas") through their rehabilitation and protection. The study was developed on a catchment along the Mansoa seabranch which constitute a paddy-field of about 2'500 hectares by a multidisciplinary team to analyze technical data in relation to socio-economical aspects.

(b) Key issue(s) or problem(s) addressed.
Non-irrigated rice production is based on a delicate hydrological balance between water supplies both rain and marine to control salinity and acidity of the soil and the use of rice varieties tolerant to abiotic stresses. The critical aspects mainly concern the monsoon-type climate coupled to tide variations affecting coastal areas for tens of kilometers inland. Climate change also plays a key role on both the variation in rainfall and the rise of the average sea level hitting the hydro-agricultural infrastructures currently in operation.

(c) Methodology or approach used
In the first step a research of all available data was carried out to define the general context of the catchment. An analysis of satellite imagery and field survey allowed to collect site-specific data and information about the producers needs. In the second step a preliminary project was defined according to geotechnical and topographic detailed data. Executive Design of the hydraulic works was finally carried out in the third step. The hydrological parameters were obtained aiming at modeling flood hydrograms and lamination factors of the catchment.

(d) Results and conclusions derived from the project
In relation to (i) environmental factors, (ii) technological constraints and (iii) socio-economic context of reference, the methodological approach made it possible to carry on the design of the works with a reliable technical level and in accordance with the international technical standards of reference. Moreover, the solutions proposed met the producers needs and found a broad agreement among all the stakeholders.
(e) Implications of the project relevant to selected conference theme, theory and/or practice The project is aimed at developing a traditional agricultural technique which is facing the current crisis due to climate change. This is a real case of design and execution of hydraulic works designed with the aim of providing technologically modern tools that allow their sustainability in both the short and the long terms: in the short term, the typology of the
works allows their operative and their maintenance according to the technological constraints in the country; in the long term, the works sizing was verified considering the effects of current and future climate changes.

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