Simulation of Soil Moisture Movement in a Hard Rock Watershed using SWIM Model

Technical Report , 2014 , 79 Pages

Geography / Earth Science - Geology, Mineralogy, Soil Science

A very large fraction of the water falling as rain on the land surfaces of the earth or applied irrigation water moves through unsaturated soil during the subsequent processes of infiltration, drainage, evaporation, and the absorption of soil-water by plant roots. The water movements in the unsaturated zone, together with the water holding capacity of this zone, are very important for the water demand of the vegetation, as well as for the recharge of the ground water storage. A fair description of the flow in the unsaturated zone is also crucial for predictions of the movement of pollutants into ground water aquifers.

A number of simulation models are available for investigating the soil water balance. SWIM (Soil Water Infiltration and Movement) is a physically based, isothermal, one dimensional model of water flow through the soil coupled with a simple crop water extraction model in which the growth of the canopy and of the root system is a predetermined input. SWIM is driven by rainfall and potential evaporation, and so appears to be more appropriate than few other similar models if the available meteorological data are limited.

The present study aims at modelling of soil moisture movement in Barchi watershed (Karnataka) using SWIM. Field and laboratory investigations were carried out to determine the saturated hydraulic conductivity at eight locations using Guelph Permeameter and soil moisture retention characteristics using the Pressure Plate Apparatus. The van Genuchten parameters of soil moisture retention function and hydraulic conductivity function were obtained through non-linear regression analysis. Daily rainfall and evaporation data of Barchi for the period 1996-97 to 1999-2000 were used for the simulations. Water balance components like runoff, evapotranspiration and drainage (groundwater recharge from rainfall) were determined through SWIM.

Inhaltsverzeichnis

• List of Figures
• List of Tables
• Abstract
• INTRODUCTION
• STUDY AREA
• METHODOLOGY
  • General
  • Soil Moisture Characteristics
  • Soil Moisture Retention Curves
    • Pressure Plate Apparatus
  • Saturated Hydraulic Conductivity
    • Guelph Permeameter
  • van Genuchten Parameters
• DESCRIPTION OF SWIM MODEL
  • Introduction
  • Water Movement
    • Richards' Equation
    • Hydraulic Properties
    • Initial and Boundary Conditions
  • Solute Transport
    • Advection-Dispersion Equation
    • Solute Initial and Boundary Conditions
  • Limitations of the Model
• ANALYSIS AND RESULTS
  • General
  • Soil Moisture Characteristics
  • Model Conceptualization
  • Simulation of Water Balance Components
  • Concluding Remarks
• CONCLUSION
• REFERENCES
• ANNEXURE

Zielsetzung und Themenschwerpunkte

This report, "Simulation of Soil Moisture Movement in a Hard Rock Watershed using SWIM Model," is a research project conducted by the Hard Rock Regional Centre of the National Institute of Hydrology in Roorkee, India. The study aims to simulate soil moisture movement in a hard rock watershed using a numerical model, specifically the SWIM model, to determine the groundwater recharge from rainfall. The research focuses on understanding the dynamics of soil moisture movement in a hard rock environment, a crucial aspect for managing water resources in arid and semi-arid regions.

• Soil moisture movement in a hard rock watershed
• Groundwater recharge from rainfall
• Application of the SWIM model for simulating soil moisture dynamics
• Water balance components in a hard rock watershed
• Implications for water resource management in arid and semi-arid regions

Zusammenfassung der Kapitel

The report begins with an introduction to the study, outlining the importance of understanding groundwater recharge in arid and semi-arid regions. It then delves into the study area, providing a detailed description of the Barchi watershed, including its drainage system and rainfall patterns. The methodology section outlines the approach used to collect and analyze data, including soil moisture characteristics, soil moisture retention curves, and saturated hydraulic conductivity. The report then introduces the SWIM model, explaining its capabilities and limitations in simulating soil moisture movement and solute transport. The analysis and results section presents the findings of the study, including the simulated soil moisture characteristics, water balance components, and concluding remarks. The report concludes with a summary of the key findings and their implications for water resource management in hard rock watersheds.

Schlüsselwörter

The keywords and focus themes of the text include soil moisture movement, groundwater recharge, hard rock watershed, SWIM model, water balance, arid and semi-arid regions, water resource management, numerical modeling, and hydrological processes. The study utilizes the SWIM model to simulate soil moisture dynamics in a hard rock watershed, providing insights into the complex interactions between rainfall, soil moisture, and groundwater recharge. The findings have implications for sustainable water resource management in regions with limited water availability.

• Authors: C. P. Kumar (Author), B. K. Purandara (Author), P. R. Rao (Author)
• Publication Year: 2014
• Pages: 79
• Catalog Number: V281973
• ISBN (eBook): 9783656768845
• ISBN (Book): 9783656768838
• Language: English
• Tags: simulation, soil, moisture, movement, hard, rock, watershed, swim, model