Groundwater search by remote sensing: A methodological approach

Groundwater search by remote sensing: A methodological approach

Descripción

In the framework of the technical assistance provided to the Groundwater Unit (GWU) of the FAO-implemented IRAQ/SCR/986 "Three-year Agricultural Programme" for the three Iraqi Northern Governorates, a comprehensive remote sensing/GIS methodology was developed to identify potential sites for groundwater exploitation. The approach used in the study was a development of the traditional standard sequence of drainage, landforms, cover and lineaments analyses, to which several improvements and addit ions were made, such as: (1) all data were in digital format and stored in a geo-database as GIS layers; (2) all analyses and interpretations were performed directly from the computer screen; (3) on the basis of a previous positive experience, thermal lineaments analysis was performed; (4) a comprehensive geo-database was created including all GIS layers which were considered of interest for the study; (5) by using the potentiality of GIS software, which allows stacking of georeferenced data f or comparison and integration and data query for subsetting the needed information, selected layers of the database were superimposed on the Landsat image kept as background and a logical series of observations was made, leading to a well-substantiated set of interpretation assumptions. The creation of a GIS database, including the data format and entry, is a time-consuming and laborious exercise, as high accuracy is definitely mandatory. However, once the database is complete, interpretation of features leading to selection of promising sites for groundwater search is carried out easily and quickly. This as a result of data availability of all needed information in a GIS environment. Thirty test areas, selected by the field team, were investigated and 198 promising sites were identified for further ground survey and subsequent drilling.