Defining Geometry On Marginal Unconfined Shallow Aquifers By Using Ambient Noise Geophysical Prospecting

Joint International Convention of 8th IAHS Scientific Assembly and 37th IAH Congress
Water: A vital resource under stress – How Science can help
September 6-12, 2009, Hyderabad, India

DefiningGeometry on Marginal Unconfined Shallow Aquifers by
Using Ambient Noise Geophysical Prospecting
Francisco J. Alcala1, Manuel Navarro2, Antonio Garcia – Jerez2, Jorge Jodar3, José
Benavente4, MiguelRodriguez-Rodrigue5 and Francisco Domingo1,6
1

Estación Experimental de Zonas Áridas, CSIC, 04001 Almería, Spain, fjalcala@eeza.csic.es
2

Universidad de Almería, Departamento de FísicaAplicada, 04120 Almería, Spain

3

Instituto de Diagnóstico Ambiental y Estudios del Agua (IDAEA–CSIC), 08034 Barcelona,
Spain
4

Universidad de Granada–Instituto del Agua, 18074 Granada, Spain

5Universidad Pablo Olavide, Departamento de Sistemas Físicos, Químicos y Naturales, Sevilla,
Spain
6

Universidad de Almería, Departamento de Biología Vegetal y Ecología, 04120 Almería, SpainThe geophysical prospecting helps to define the geometry of sedimentary bodies defining
aquifers. Complex methods are used to accurate 3–D sedimentary models in large productive aquifers,
whileaquifers of local importance and small size are often poorly known in spite of their relevance to
maintain springs, river base–flow, wetlands and lakes, as well as the local water supply. This is thecase of small endorheic basins and marginal alluvial aquifers in hard rock areas, water bodies stored
in the uppermost meters of weathered or fractured crystalline bedrock, shallow freshwater bodiesin
marsh and estuarine coastal plains and deltas, and inland aquifers developed in large evaporitic
outcrops, both with brackish and salty groundwater, where the geoelectrical prospecting, currentlythrough vertical electric profiles (VEP), is used to typify the groundwater bodies geometry of low–to–
moderate salinity. Nevertheless, accuracy of VEP decreases under increasing groundwater...