Decision support system (DSS) for site selection floodwater spreading schemes using remote sensing (RS) and geographical information systems (GIS)

Most aquifers of semi-arid regions in Iran suffer from over-exploitation of groundwater for irrigation purposes. It is therefore important to augment the groundwater resource by artificial recharge, using floodwaters. Generally, the recharge schemes consist of diverting part of the flood discharges of ephemeral rivers in small to medium-size catchments into infiltration basins. Apart from recharging groundwater, and supporting food production and drinking water supplies, the schemes have other benefits, such as the mitigation of flood damage. The complexity of floodwater spreading schemes using flash floods of ephemeral rivers in semi-arid regions became evident during the task of selecting, defining and structuring criteria for the selection of suitable areas and sites for a scheme. Complexity is due to a large number of factors that play a role in the selection of the most suitable sites for deciding on investment in a scheme. These factors pertain to earth science (geology, geomorphology, soils), to hydrology (runoff and sediment yield, infiltration and groundwater conditions) and to socio-economic aspects (irrigated agriculture, flood damage mitigation, environment and so on). This paper deals with developing a DSS to assist decisions as to where suitable catchments and associated infiltration areas are located. The DSS developed relies on the combined use of remotely sensed information and GIS techniques. For implementation of the related phase of the DSS, a region (Bandar Abbas) was selected as the case study for suitable zone(s) selection. The DSS shows the great ability for selection of potential zones for floodwater spreading. It can be concluded that the interpretation results could be regarded as being more than the sum of separate ‘interpretation’ layers: i.e. geology, geomorphology and land use. The interpreter has to have a firm footing in earth science.