course 5 groundwater investigation ina.compressed

1

Mulawarman UniversityMining Engineering Department

Faculty of Engineering

1

Teknik Pengendalian Air Tambang

Shalaho Dina Devy



2

Investigasi Airtanah

(Post Midterm-3)

2



3

Survey Permukaan dan Bawah Permukaan Airtanah

4



Kenapa diperlukan survey airtanah?

Potensi daerah untuk pengembangan airtanah

1. Akuifer produktif baik

2. Permukaan airtanah dangkal

3. Kualitas airtanah baik

4. Akuifer terjaga/terlindungi dari kontaminan/pencemaran

3

5



Objek Survey Airtanah

Objek penelitian airtanah harus jelas dari awal, seperti:

1. Pengunaan/pemanfaatan untuk apa?

2. Kualitas dan kuantitas yang diinginkan?

3. Daerah penelitian?

4. Prediksi?

6



Investigasi Airtanah

Pendahuluan dan persiapan Studi awal prakelayakan Studi kelayakan

Pilot Project (proyek percobaan) Pengembangan

Exploration

Exploitation and

Management

4

7



Skema Survey Airtanah

Surface

Investigation

Sub-Surface

Investigation

Direct Indirect

Geologic

Investigation

Hydrology

Geography

Climatology

Agriculture, etc

Supplemented by:

Remote

Sensing

Surface

Geophysic

al Method

Exploration

well

Geophysical

Logging

Drilling

Pumping Test

Groundwater

Quality Test

Resistivity

Log

SP Log

GR Log, etc

Groundwater

Survey

8



Investigasi permukaan airtanah

Metode-metode investigasi geologi

Penginderaan jauh

Geofisik

5

9



Investigasi geologi

Investigasi geologi dimulai dari:

1. Collection, analysis and hydrogeologicinterpretation of existing data data sekunder.

2. Dilengkapi dengan kondisi geologi awal.

3. Dilengkapi dengan evaluasi data hidrologi, aliran sungai dan mata air, keberadaan sumur (bor), imbuhan dan luahan airtanah, permukaan dan kualitas air

10



Lithostratigraphy

6

11



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

12



Contoh KasusStudi Hidrogeologi Sarasuta - Saraswaka

7

13



Remote Sensing (Penginderaan jauh)

• Identifikasi kondisi permukaan dari hasil penginderaanjauh yang bertujuan untuk mengevaluasi kondisiairtanah:

1. Topografi kondisi relief regional dan lokal

2. Geologi daratanseperti lapisan permeabel

3. Danau dan sungai

4. Penurunan muka air (lingkungan rawa) dan infiltrasi

5. Mata air (tergantung daerah penelitian)

6. Kondisi air (buatan) sumur, tampungan air,saluran air, pengembangan mata air

14



Satellite Image

8

15



16



9

17



Eksplorasi geofisika permukaan

Metode listrik resistivity

Metode seismic Refraction

Metode gravitasi dan magnetik

18



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

10

19



Electrical Circuit for Resistivity Determination

20



11

21



22



Resistivity value of sediments and rocks

12

23



24



FENCE DIAGRAM OF HYDROGEOLOGY SYSTEM

13

25



3-D MODEL OF AQUIFER SYSTEM

26



Other surface geophysical survey

Seismic Refraction the actual presence ofgroundwater is difficult to determine withoutsupplemental information because velocitiesoverlap in saturated and unsaturated zones.

Gravity Method indicate subsurface geologicalstructure, differences in water content insubsurface strata seldom involve measurabledifferences in specific gravity at surface, littleapplication to groundwater prospecting

Magnetic Method magnetic contrast is seldomassociated with groundwater occurrence, themethod has little relevant to groundwater studies

14

27



Seismic Velocity of Geologic Materials

28



Subsurface Groundwater Survey

Exploration Well / Drilling

Well Logging

15

29



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)

30



Geologic Log, Drilling Time Log

16

31



Geophysical Logging

32



Geophysical Logging

17

33



Geophysical Logging

34



Logging Data

18



35

Sumber: Dr. Doni Prakasa Eka Putra

36



course 5 groundwater investigation ina.compressed

Documents