The potential application of regional hydrogeological maps to engineering geology: Fid-Bau Portal

The potential application of regional hydrogeological maps to engineering geology

Shephard-Thorn, E. R. / Moseley, R.

Summary Hydrogeological maps are designed to present a visual summary of the major features of the surface and groundwater hydrology of the areas they portray. The maps can yield valuable background information to the engineering geologist engaged with major linear or point construction projects. A selection of the regional maps procedured by the Hydrogeology Unit of IGS over the past decade will be exhibited at the Symposium. On a small scale base map (normally 1: 100,000) simplified geology is shown, and the aquifers depicted by coloured lithological ornaments, while aquicludes are left blank. The superficial deposits and landslipped areas are omitted in the interests of clarity, but alluvium and the extensive glacial and associated deposits are usually shown. On this geological base structural and minimum groundwater level contours for the major aquifers are depicted together with the sites of springs, river intakes, licensed groundwater abstractions, observation boreholes, river gauging stations and overflowing artesian areas. Smaller scale insets illustrate rainfall and relief, groundwater chemistry and groundwater schemes of special interest within the area. Brief notes describe the hydrogeological characteristics of the formations present. With their large content of interpreted data hydrogeological maps provide much more than the standard 1: 50 000 Geological Survey maps in evaluating regional conditions. Although their small scale limits their application in specific site investigation work, their use at the planning stage of large-scale projects, such as pipelines or motorways should eliminate potential conflicts between groundwater and engineering interests.