Surface and

Sub-Surface

Survey of

Groundwater

Dr. Doni Prakasa Eka Putra

Why groundwater survey?

The potential area for groundwater development

(1). Good productive aquifer

(2). The groundwater level is not too deep

(3). The water quality is good

(4). The aquifer is protected from contamination

Objective of Groundwater Survey

The objective of groundwater survey should be

clear from the beginning, such as:

- domestic/irrigation/industrial use ?

- quantity and quality needed ?

- area of survey ?

- Prediction ?

Groundwater Investigation

Preparation & Reconnaisance

Prefeasibility Study

Feasibility Study

Pilot Project

Development

Exploration

Exploitation and

Management

Scheme of groundwater survey

Surface

Investigation

Sub-Surface

Investigation

Direct Indirect

Geologic

Investigation

Hydrology

Geography

Climatology

Agriculture, etc

Supplemented by:

Remote

Sensing

Surface

Geophysical

Method

Exploration

well

Geophysical

Logging

Drilling

Pumping Test

Groundwater

Quality Test

Resistivity Log

SP Log

GR Log, etc

Groundwater Survey

Surface Investigation of

Groundwater

Geologic Investigation Methods

Remote Sensing

Geophysical Exploration

Geologic Investigation

Enable large areas to be rapidly appraised to their potential for groundwater development.

A geologic investigation begins with

(1). Collection, analysis and hydrogeologic interpretation of existing data.

(2). Supplemented by geologic field reconnaisance.

(3). Supplemented by evaluation of hydrologic data on; streamflow and springs; well yields; groundwater recharge and discharge, levels and water quality.

Lithostratigraphy

Hydrostratigraphy

Sand & Gravel

Sand

Shale / Mudstone

Till

Clay

Stratigraphic Lithologic Hydrostratigraphic

Surficial Deposits Surficial Aquitard

Floral Aquifer

Floral Fm

Floral Aquitard

Empress Gp Empress Aquifer

Bearpaw Fm Bedrock Aquitard

Contoh Kasus

Studi Hidrogeologi Sarasuta -

Saraswaka

Remote Sensing

Surficial Features Identified on Aerial Photographs thatAid in Evaluating Groundwater Conditions:

Topography regional relief setting and local reliefsetting

Geologic Landform likely to contain relativelypermeable strata

Lakes and Streams

Moist depressions (marshy environment) and seepages

Springs (tentatively inferred from aerial photograph)

Artificial water features Wells, Reservoirs, Canals,Developed Springs

Satellite Image

Surface Geophysical Exploration

Electric Resistivity Method

Seismic Refraction Method

Gravity and magnetic Method

Electric Resistivity Method

Resistivity of rocks depend on:

1. The water content (porosity)

2. The resistivity of the water

3. The clay content

4. The content in metallic mineral

Electrical Circuit for Resistivity

Determination

Resistivity value of sediments and rocks

FENCE DIAGRAM OF HYDROGEOLOGY SYSTEM

3-D MODEL OF AQUIFER SYSTEM

Other surface geophysical survey

Seismic Refraction

the actual presence of groundwater is difficult to determinewithout supplemental information because velocities overlap insaturated and unsaturated zones.

Gravity Method

indicate subsurface geological structure, differences in watercontent in subsurface strata seldom involve measurabledifferences in specific gravity at surface, little application togroundwater prospecting

Magnetic Method

magnetic contrast is seldom associated with groundwateroccurrence, the method has little relevant to groundwater studies

Seismic Velocity of Geologic Materials

Subsurface Groundwater Survey

Exploration Well / Drilling

Well Logging

Test Drilling

Test drilling of small diameter holes to ascertain

geologic and groundwater condition.

The choice of method (cable tool, hydraulic

rotary method, auger method, jetting, etc)

depends on the type of material encountered,

drilling depth and location.

Important result Geologic Log, Drilling-Time Log (Hydraulic Rotary Method), Water

Level Measurement (electric water level

sounder)

Geologic Log, Drilling Time Log

Geophysical Logging

Geophysical Logging

Geophysical Logging

Logging Data