Modeling Unsaturated Zone Water Movement in the Floodplain Wetlands of the Volta Basin

Benjamin Kofi Nyarko

doi:10.5539/enrr.v10n3p1

Abstract

The unsaturated zone of floodplain wetlands in the White Volta River basin provides an inextricable link between basin hydrology and the sustenance of plant growth. The HYDRUS-1D model was used to derive water budgets and to estimate fluxes to understand the hydrological complexities of these wetland systems. The model result indicates Spatio-temporal variation in the volume of vertical fluxes. In 2005, the estimate for average simulated flux was 0.29 cm/month in June and 1.23 cm/month in July. Consequently, the hydraulic head increased from 138.94 m to 139.30 m for the period from June to July 2005. For all sample sites, the increase in hydraulic head occurs within July and October, coinciding with high surface water fluxes. From the calculated water balance, the average monthly estimate of bottom flux was 0.01 cm/month for 2004 and 1.1 cm/month for 2005. The flow through the unsaturated zone and discharging into the subsurface water system has a high dependency on both the soil structure and the volume of water infiltrating through the surface; the highest discharge is within the period of highest water input.

Highlights

The unsaturated zone in floodplain wetlands in sedimentary formation with well laid down structure represents a zone of importance to ecological and hydrological processes
Despite the importance of these processes, human activities and climate change threatens floodplain wetlands. Hydrological processes such as infiltration, capillary rise, and interflow taking place in the unsaturated zone of floodplain wetlands are of importance to flow pathways and moisture dynamics
This study is to simulate the flow within the vadose zone into the subsurface for a layered soil profile using HYDRUS-1D

Summary

Introduction

The unsaturated zone in floodplain wetlands in sedimentary formation with well laid down structure represents a zone of importance to ecological and hydrological processes. It controls the interaction between vadose and saturated domains. Despite the importance of these processes, human activities and climate change threatens floodplain wetlands. Hydrological processes such as infiltration, capillary rise, and interflow taking place in the unsaturated zone of floodplain wetlands are of importance to flow pathways and moisture dynamics. The heterogeneous nature of subsurface structures makes it difficult to estimate soil water fluxes using standard hydrological methods. The protection of wetlands requires an understanding of the mechanism controlling the hydrological processes

Methods

Results

Conclusion