Based on the literature review, slope, land use, infiltration rate, alluvium thickness, and EC are some important factors. Is there any other important factor in these kind of studies?
see Nasiri et al., Determining the most suitable areas for artificial groundwater recharge via an integrated PROMETHEE II-AHP method in GIS environment (case study: Garabaygan Basin, Iran).
I would say that the land use plays a very important role as flood retention should not only be about the water volume that can be stored in order to lower/delay the flood peak downstream.
1. The land use determines hydrological parameters like the current velocity through its surface roughness (e.g. riparian forest vs. meadows);
2. The land use is relevant for the economic damage caused by this controlled flooding (e.g. extensively used pastures vs. intensively used farmland)
3. The land use finally determines the affect the flood has on the water quality through the potential mobilization or retention of pollutants (e.g. topsoil ersion from farmland which leads to an increased input of phosphate and other nutrients; mobilization of heavy metals from riparian sediments in regions with usptream ore mining activities; or the retention of pollutants in natural wetlands (phragmites australis) or riparian forests.
Seyed, Since you are mentioning infiltration rate, possibly you have considered the lithology and T and S values of the alluviual aquifer that would store the water..
ET rate is one of the factors you can consider I think. Densely vegetated area will have a high rate of ET besides that the root system will increase the infiltration rate.
Many researchers in flood hazard investigation proposed different models and relations to describe the physical processes that describe the phenomenon. Between the factors that are used and play important role in flooding it is the geology. The geology in combination with the topography of an area determines the hydrology, the erosion processes -sedimentation and debris material production. Impermeable rocks allow for high surface run-off, allowing water to reach the rivers quickly. Permeable rocks allow water through, leading to a much slower journey to the rivers. Sediments and floating debris such as logs reduce the active flow area of a cross section lowlands and floodplains. Sediments and floating debris are main reasons that lead to flooding (Mazzorana et al 2009, 2011). In many flood episodes transported sediments deposited in low inclination sites and silting the cross sections was the main reason of spreading the flood area.
All of the above answers are very useful from the physical processes sense. I suggest that you also consider biological processes. For example, many riverine fish species evolved to utilize floodplain habitats during high flow periods. These off-channel habitats provide refuge from high water velocities, access to food resources that are usually not accessible, and in many cases, improve survival during high flow events. From a design perspective, I would have a gentle slope leading to the low flow channel onto the floodplain to allow for a continuum of habitat availability as water surface elevation and velocities increase and also include topographic variation (i.e. dendritic channel design) on the floodplain to direct fish back to the low flow channel as the river recedes.
The research gate community has done justice to this interesting topical issues from physical, geological and biological considerations. I suggest geotechnical study involving grain size distribution, soils moisture content and local groundwater table is also important.
As researchers told below, i Will add statistical analyses of Rain. You have to know what Rain intensity can induce flood. You would link those results With Land use evolution for five years.
As researchers told below, i Will add statistical analyses of Rain. You have to know what Rain intensity can induce flood. You would link those results With Land use evolution for five years.
I would like to add an intensity of snow melt, especcially if this factor is combined with intensive rains. These factors are the mian reasons of formation of catastrofic floods on mountain rivers located in the Carpatians region of Ukraine.
For urban flood i feel the concrete structures affects the infiltration rate which automatically leads to flooding in rainy season. and drought in summer season....
I get the feeling that we are losing touch with the original question of characteristics of an area for flood spreading.
You may say that there should be no buildings in such areas. A rule in the Netherlands is that such areas should in fact not have inhabitants or that for rare inhabitants acceptable solutions should be found when asking them to move because of the new destination of the area as a flood spreading surface.