final report on development of deep aquifer database and...

87Final Report on Development of Deep Aquifer Database and Preliminary Deep Aquifer Map

5.4.1.3 Hydrostratigraphic Model

Figure 5.57 presents the complete hydrostratigraphic model for Satkhira district generated by the RockWorks 2004

software. The model presents a predominantly six-layer hydrostratigraphy. The topmost layer is the upper clay and

silt layer that exists all over the district with some variations in the thickness. The second layer is the shallow aquifer,

which is the most prolific aquifer of the district. This third layer is the aquitard separating the shallow aquifer from

the deep aquifer. The fourth layer the upper deep aquifer, which is also a good aquifer with uniform thickness. The

fifth layer is the deep aquitard that separates the two deep aquifers. The sixth layer is the deeper deep aquifer,

which is a relatively thin aquifer. Figure 5.58 presnts the fence diagram for the district.

Figure 5.57: Hydrostratigraphic model for Satkhira district

Figure 5.58: Fence diagram of Satkhira district

88 Final Report on Development of Deep Aquifer Database and Preliminary Deep Aquifer Map

5.3.2 Khulna

As there is sufficient data (and DPHE is planning to undertake a project of deep aquifer abstraction in the

area), Khulna district is also selected for the mapping exercise using the RockWorks 2004 software. The

locations of borelogs and orientations of the section lines is shown in Figure 5.59.

Figure 5.59: Location map of borelogs included in the database from Khulna district

5.4.2.1 Hydrostratigraphic Cross Sections

A number of NS and EW hydrostratigraphic sections have been drawn using the RockWorks software. All the

sections, Figure 5.60 to 5.61, show the presence of two deep aquifers in the area. The sections also

demonstrate prominent changes in the thickness of the aquifers and aquitards in the NS directions.


Figure 5.60: NS Hydrostratigraphic cross sections from Khulna district along the line AB (Top diagram showing the

lithology; bottom diagram shows the section generated by the RockWorks software)

Figure 5.61: NS Hydrostratigraphic cross sections from Khulna district along the line CD (Top diagram showing the

lithology; bottom diagram shows the section generated by the RockWorks software)


Figure 5.62: EW Hydrostratigraphic cross sections from Khulna district along the line (Top diagram showing the lithology;

bottom diagram shows the section generated by the RockWorks software)

5.4.2.2 Aquifer Models

As demonstrated by the cross sections, the aquifer models also confirm the presence of three aquifers in the

system. The first aquifer is the shallow aquifer whereas the second and third aquifers are the deep aquifers as

shown in Figure 5.63 and 5.64.

Figure 5.63: Aquifer model for Khulna district


Figure 5.64: Aquitard model for Khulna district


The hydrostratigraphic model for the district is presented in Figure 5.65 that shows a six-layer

hydrostratigraphy. The model also picks the thickness variations of the different aquifers and aquitards. Figure

5.66 presents the fence diagram for Khulna district.

Figure 5.65: Hydrostratigraphic model for Khulna district


Figure 5.66: Fence diagram of Khulna district

5.4.3 Jessore

Figure 5.67 shows the location of borelogs included the in the database from Jessore district. The figure also shows the

orientation of the hydrostratigraphic cross sections.

Figure 5.67: Map showing locations of borelogs included in the database and orientation of hydrostratigraphic cross sections



Figures 5.68 to 5.71 presents the hydrostratigraphic sections generated with the RockWorks 2004 software.

The sections show distinct shallow and deep aquifer in the area with pronounced thickness variations in the

north south directions. However, from JICA (2002) deep aquifer investigations it was shown that there was no

clay aquitard present up to a depth of 300m. JICA borelogs are included in the database and used for

generation of the sections. The software makes generalized sections by statistical averaging methods. In such

situations, the software may not be useful. To overcome such difficulties sections has to be drawn manually

by picking up the section line and plots of the logs (as demonstrated later for Chandpur Sadar Upazila).

Figure 5.68: Hydrostratigraphic cross section along the line AA (Top diagram showing the lithology; bottom diagram

shows the section generated by the RockWorks software)


Figure 5.69: Hydrostratigraphic cross section along the line BB (Top diagram showing the lithology; bottom diagram


Figure 5.70: Hydrostratigraphic cross section along the line CC (Top diagram showing the lithology; bottom diagram



Figure 5.71: Hydrostratigraphic cross section along the line DD (Top diagram showing the lithology; bottom diagram



Figure 5.72 and 5.73 presents the aquitard and aquifers of the Jessore district. Both the models show

pronounced variations in thicknesses of the aquitards and aquifers in the north-south directions. The shallow

aquifer becomes very thick in the north and consequently the aquitard separating the deep and shallow

aquifers becomes very thin. However, as mentioned in the earlier section, the aquitard does not exist in some

places in the north and the models are unable to demonstrate this, may be due to lack of enough data.


Figure 5.72: Different views of the aquitards of Jessore district


Figure 5.73: Different views of the aquifer models of Jessore districts



Figure 5.74 is the hydrostratigraphic model for Jessore district. The model presents 4 to 6 layers in different

parts of the modeled area. The model shows that the top clay layer becomes thicker towards south. The

shallow aquifer extends to a much larger depth in the north than in the south. The aquitard separating the

shallow and deep aquifers varies significantly in thickness, i.e. very thick in the south and very thin in the

north. The deep aquifer seems to exist all over the district but covered by varying thickness of aquitard.

Figure 5.74: Hydrostratigrahic Model of Jessore district


Figure 5.75: Fence diagram of Jessore district


5.4.4 Comilla

Figure 5.76 shows the location of borelogs from Comilla district along with the orientation for the

hydrostratigraphic section lines.

Figure 5.76: Location map of borelogs in the database and hydrostratigraphic section lines from Comilla district


The north south and east west section line show the aquifer and aquitard configurations from Comilla

district. There are considerable variations in aquifer disposition in Comilla district in NS directions as

demonstrated by figures 5.77 to 5.82.


Figure 5.77: NS Hydrostratigraphic cross section along line AA/ in Comilla district (Top diagram showing the lithology;


Figure 5.78: NS Hydrostratigraphic cross section along line BB' in Comilla district (Top diagram showing the lithology;



Figure 5.79: EW Hydrostratigraphic cross section along line CC' in Comilla district (Top diagram showing the lithology;


Figure 5.80: EW Hydrostratigraphic cross section along line DD' in Comilla district (Top diagram showing the lithology; bottom diagram shows the section generated by the RockWorks software)


Figure 5.81: EW Hydrostratigraphic cross section along line AA/ in Comilla district (Top diagram showing the lithology; bottom diagram shows the section generated by the RockWorks software)

Figure 5.82: EW Hydrostratigraphic cross section along line FF' in Comilla district (Top diagram showing the lithology; bottom diagram shows the section generated by the RockWorks software)



Figure 5.83 presents the aquifer and aquitard models for Comilla district. The models show wide variations in

the thickness of the aquifers and aquitards of the area.

Figure 5.83: Models of aquitard and aquifers of Comilla district



Figure 5.84 presents the hydrostratigraphic model for Comilla district. The model deciphers a six-layer

hydrostratigraphy for the Comilla district. The top clay and aquitard layer becomes significantly thicker

towards the east while the shallow aquifer is very thick southwest. The aquitard separating the shallow and

deep aquifer varies in thickness and depth. The first deep aquifer occurs at around 200m. Figure 5.85 presents

the Fence diagram for Comilla district.

Figure 5.84: Hydrostratigraphic model for Comilla district

Figure 5.85: Fence diagram for Comilla district

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