Assessment of Water Infiltration in the Three (3) Most Vulnerable LGAs to Flooding of Rivers State Before and After Flooding

Abstract

Water infiltration is the process by which water enters the soil surface and moves downward through the soil profile. The inability of water to infiltrate the soil often results in increased surface runoff, which can lead to flooding. Water infiltration is a key component of the hydrological cycle, influencing groundwater recharge, soil moisture availability, crop production, and the flow of surface runoff. To understand water infiltration rates in the three vulnerable LGAs (Ahoada East, Ahoada West, and Ogba/Egbema/Ndoni) in Rivers State, water infiltration was measured using the double-ring infiltration method. This was done at 12 locations, both before and after the flood. The mean values of infiltration rate ranged between 0.69-2.45 and 0.79 -2.07cm min-1 before and after flooding, respectively, with a high (>35%) coefficient of variation. Control (unflooded) stations showed higher results for Ahoada East and Ogba/Egbema. The highest infiltration rate was observed in Ahoada East, while the lowest was in Ahoada West during the sampling period. Water infiltration was generally lower after flooding, likely due to the initial moisture content before the infiltration tests. Generally, the water infiltration in the study area revealed moderate to high water infiltration rates, indicating that water infiltration is not the primary cause of flooding in the study area. However, further enquiries revealed that an overflow of river banks and the failure of dams, as experienced in 2012 and 2022, are the major causes of flooding in the study area.