The seasonal flooding of the Inner Niger Delta is the lifeline for communities and biodiversity in this flood-dependent ecosystem and economy. Fishermen, rice farmers and pastoralists time their (socio-)economic activities to the flooding pattern in time and space. For local communities therefore, it is crucial to be informed about the seasonal flooding pattern.
The timing and extent of flooding are both related to the discharge of the Niger and the Bani at the entrance of the delta. Local rainfall may be important for rice farmers (rice planting), but hardly has impact on the flooding level. In the past, and even partly up to now, people in the delta relied and rely on collective memory about the flooding in the past. Although information about the amount of rainfall upstream and the behaviour of the flood may travel fast – through radio and people who move through the delta – there are no clear-cut cues in the early season what the flood extent and height of the flood will be.
The analysis of water levels and the first flooding model developed by Zwarts & Grigoras (2005: Niger, a lifeline) clearly showed that the raise of water levels at the different hydrological stations in the delta was telling about the height of the flood later in the season. This led to the idea of develop a simple tool which enables the people in the delta to forecast the flooding. The basic idea was, that by using the water levels at the quay in Mopti from August onwards should be enough to foretell the height of the flood and the related extent of flooding.
The initial development of the tool by Altenburg & Wymenga, Wetlands International Mali and the Direction National Hydraulique was very much supported by the Dutch Embassy in Mali. Ultimately, this led to the development of a forecast model, finally translated in the tool OPIDIN. Many workshops were held from 2009 onwards with stakeholders in Mopti and Bamako to improve the tool to the current level. The management of the tool and input of data is done by the Direction National Hydraulique in Mali.