CHAPTER 4 HYDROGEOLOGY - JICA報告書PDF版(JICA Report PDF) · 2011-06-01 · Final Report...

The Development study on water resources development and management for Lake Kyoga Basin Final Report -Supporting- Chapter 4 Hydrogeology

4-1

CHAPTER 4 HYDROGEOLOGY

4.1 Collection of Existing Data

Existing data about hydrogeology managed by Directorate of Water Resources Management (DWRM)

are Groundwater Database, Mapping Project data, and Groundwater Monitoring data. Others are the

MIS database which is water supply facilities database managed by Directorate of Water Development,

including the items of location, water source, functionality, and so on.

4.1.1 National Groundwater Database (NGWDB)

This database was established by DWRM with contracting to a local consultant in 2000. DWRM had

been compiled database based on the “Borehole Completion Report” which is submitted by drilling

company after completion of drilling. In 1990s, it was managed by database software on MS-DOS,

and before 1990s, it was borehole ledger described on paper book. Now it was compiled by Microsoft

Access database management software on the Windows base again. Figure 4-1 shows the initial

display of the database. The database

has been input the data based on the

completion report submitted by

drilling company every year. It is

including the well specification,

geological information, pumping test

data, water quality test result, and so

on. This database is very

sophisticated.

DWRM gave to the study team the

data which are related to the Lake

Kyoga Basin. In the obtained data, the

number of data which described the registered well number is 11,880, the number of data which

described the well construction information is 9,672, the number of data which described the

hydrogeological information is 5,902, the number of data which described the pump information is

1,095, and the number of data which described the water quality is 2,293. However, the position

data which is necessary for analysis have many mistakes. Some position data are input by

Latitude-Longitude system, and others have UTM coordinates. Latitude-Longitude system were used

in old data mainly. In this study, these data were used after correcting the position data to adequate

position from referring to the location name, e.g. Sub-county name or parish name or village name.

Problem of this database is as follows:

1) Borehole positions have many mistakes,

2) It is difficult to correct the administrative structure,

3) There are some duplicated data.

Figure 4-1 Initial Display of National Groundwater DatabaseSource: DWRM


4-2

4.1.2 Groundwater Mapping Project

DANIDA has supported this project. This is compiling

several maps for districts about groundwater

development. Now, in 47 districts in total, mapping

was completed or is going on .

In addition to NGWDB data, re-measurement of the

position of borehole which was unclear in NGWDB

was conducted, and shallow well and spring data were

collected from district office in this project. Final

results are providing useful maps for administrators of

each district.

Several kinds of maps are provided as follows; 1)

Groundwater potential map, 2) Hydrogeological

characteristic map, 3) Groundwater Quality map, 4)

Hydrochemical characteristic map, 5) Water sources

location map, 6) Water coverage per parish map, 7)

Water services area and population density map, 8)

Population per parish and distance to water source map, and 9) Water supply technology option map.

However, Since data management of DWRM is poor, all data is not available even in published paper

maps or digital data, now.

Status of Groundwater Resources Mapping in Uganda

Legend

lakes

Districts with complete Groundwater resources maps

Districts where groundwater resources mapping activities have been initiated

Districts with draft groundwater resources maps

¹

Figure 4-2 Progress of Mapping Project

Source: DWRM

Figure 4-3 Example of Groundwater Potential Map on the Mapping Project

(former Mbale district, it was divided to Mbale, Bududa, and Manafwa district)

%[

Rivers

Major permanent river

Minor permanent river

Open Water

Seasonal wetlands in secondary valleys

Permanent wetlands (papyrus) in main valleys

Water resources

Administrative BoundariesInternational boundaryDistrict boundaryCounty boundarySubcounty boundaryParish boundary

InfrastructureAll weather tarmac road

All weather murram roadDry weather murram road

Motorable trackRailway

DATA SOURCES

PUBLISHERCompiled and published by the Water Resources Management Department and the RUWASA project, Uganda. Funded by the Government of Uganda and DANIDA. Technical assistance by Wellfield Consulting Services Ltd (E-mail : [email protected]),a COPYRIGHT: Government of Uganda ,2002.

For any comment or error, please contact Water Resources Management DepartmentDirectorate of Water Development:P.O. Box 19,Entebbe.Tel: (+256) 041 321342Fax : (+256) 041 321368 E-mail : [email protected]

N O T E

LEGEND

This map is to be used as a guideline for detailed groundwater investigations.

The data density (inset map) indicates the data points used in the construction of the groundwater potential map. The map is more accurate where the data density

NOTE

Inferred Borehole Yields (cubic metres per hour)

Poor (0.01-0.5)

Moderate (0.5-0.7)

Good (0.7-1)

Very good (>1)

Water qualityAbove Guideline Values and below Maximum Acceptable Values (MAV)Above Maximum Acceptable Values

Inferred borehole yields and water quality: Based on analysis of data from RUWASA and Directorate of Water Development ( as per May, 2001).

Administrative boundaries, rivers, landcover and infrastructure: National Biomass Study proje

The potential of an area to supply water is dependant on the supply being of adequate quality and quantity.

The quantity of water is represented by the colours from white to dark brown. The quality of water

is represented by the green lines.

Main District Town%[

Groundwater Potential MapMBALE DISTRICT

R e p u b l i c o

f K e n y a

First Edition , July 2002.

GROUNDWATER POTENTIAL

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National park

3 0 3 6 9 12151.5 キロメートル 56,000 0 56,00028,000 キロメートル

THIS MAP MUST NOT BE CONSIDERED AN AUTHORITY ON DELIMITATION OF INTERNATIONAL AND OTHER BOUNDARIES

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Scale 1: 750,000

Data Density

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Scale 1 : 100,000

.Grid Projection Spheriod Meridian of Origin Latitude of Origin Scale Factor of Origin False Eastings False Northings Datum

: UTM, Zone 36: Transverse Mercator: Clark 1880 (modified)

: 33 deg. East of Greenwich: Equator: 0.9996: 500,000m: 10,000,000m: New Arc (1960): Metre

Scale 1 : 5,000,000

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100

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Location of Mbale in Uganda

Source: DWRM


4-3

4.1.3 Groundwater Monitoring

DWRM is monitoring the

groundwater levels by using the

monitoring wells in Uganda. Although

32 monitoring wells were constructed

in whole Uganda. Now functioning

monitoring wells are only 11 locations,

because some boreholes have been

already demolished, or some facilities

are not functioning yet. Three wells of

11 monitoring wells are in Lake

Kyoga Basin; they are at Soroti,

Pallisa, and Nkokonjeru. Figure 7-4

shows the location of monitoring

wells in and around Lake Kyoga

Basin. Figure 4-5 shows the

relationship between groundwater

level and rainfall, as an example of

the monitoring data. According to

this data, it is recognized that water

level is rising after rainfall. The time

lag can be estimated approximately 0.5 to 1 month.

Soroti Otucopii Network StationWater Level and Rainfall Data

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6

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ater

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Figure 4-5 Relationship between Groundwater Level and Rainfall Source: DWRM

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Bombo

Pallisa

Apac DWO

Loro CPAR

Nkokonjeru

Soroti Otucopii

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Lake Kyoga Basin

!> Monitoring_BH_Location

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Figure 4-4 Location of Groundwater Monitoring StationSource: DWRM


4-4

4.1.4 Borehole Completion Report

Borehole Completion Report is submitted from drilling contractors 4 times a year. The data of

NGWDB is based the reports. However, boreholes which were conducted the pumping test are not

very much. The reports which were conducted pumping test properly were selected from whole reports.

This purpose was to grasp the hydrogeological condition conducted by pumping test analysis

ourselves, because these reports have no analysis result of pumping test. The number of report

collected was 204, after exception of the data which the location was not clear and pumping test data

was not good, the number of analyzable data was 158. Figure 4-6 shows the location of borehole

which the pumping test data was analyzed.

Most of the data are conducted constant rate pumping test and recovery test, however, step drawdown

test data were very few. Most of pumping period of constant rate pumping test was 3 hours (180

minutes), few are 24 hours (1,440 minutes). However, there are some data which changed pumping

rate in the period of constant rate test.

Step number of step drawdown test is 3 to 5 times.

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Figure 4-6 Location of Boreholes Analyzed Pumping Test


4-5

4.2 Hydrogeological Analysis

Data from NGWDB were used for hydrogeological analysis mainly. Since the data have many mistake

on the position data, correction of position data was necessary. First, unification of position data was

necessary, because both of Latitude - Longitude system and UTM system are used as position data in

the database. The numbers of data for each coordinate system are shown below.

UTM coordinate system: 4,736

Latitude – Longitude system: 2,564

UTM system would be used in this study, because the number of UTM is more than Latitude –

Longitude system, UTM is used for managing data in NGWDB now, and latest data is input by UTM.

Then after checking of coordination data, mistaken data which are wrong ordering and mixing up east

and North are corrected. Finally, the numbers of data which were used for analysis are shown below.

Drilling Depth data: 4,709

Static Water Level Data: 4,094

Pumping Test Data: 4,416

Depth to Bedrock: 3,834

Water quality (TDS) data: 1,530

Table 4-1 shows the summarized table of drilling depth, static water level, well yield, and depth to bedrock.

Additionally, Table 4-2 is summarized by districts.

Table 4-1 Drilling Depth, Static Water Level, Well Yield and Depth to Bedrock

in Each Geological Unit

Average Average

(m) (m)

1 Quaternary P1 2 190 66.1 166 16.2 178 1.9 151 26

2 Alkali volcanics T 49 64.6 47 15.9 46 2.3 32 28

3 Carbonatite TC 17 58.7 16 19.4 15 2.2 11 35

4 Karoo System KR 5 78.9 3 16.0 3 4.6 5 28

5 Aswa Shear Zone CM 53 64.9 51 8.0 53 2.5 50 26

6 Karasuk serise KS 15 78.8 15 29.4 14 1.7 7 11

7 Kyoga Series B-K 65 69.4 58 20.9 62 4.0 50 39

8 Granite G 75 55.2 71 12.6 72 1.9 57 31

9 Buganda-Toro System B-T 338 69.9 238 19.5 302 1.8 284 35

10 Nyanzian System NZ 98 55.1 86 13.7 92 2.5 69 32

11 Aruan Series A 77 85.2 64 23.3 71 2.0 62 24

12 Watian Series W 75 71.4 63 21.7 66 2.7 49 34

13 Gneiss-Granulite Complex GC 3551 62.5 3127 13.9 3345 1.9 2946 28

14 Granitoid GZ 101 56.1 89 15.3 97 2.0 61 28

4709 63.5 4094 14.7 4416 2.0 3834 29

Depth to Bedrock

Data No. Data No. Data No.Average (m3/h)

Data No.Average

(m)

Formation Name Symbol

Drilling Depth Static Water Level Well Yield


4-6

Table 4-2 Drilling Depth, Static Water Level, Well Yield and Water Quality (TDS) by District

No. District Drilling Depth Static Water Level Well Yield TDS

Sample Number

Average(m)

Sample Number

Average(m)

Sample Number

Average (m3/h)

Sample Number

Average (mg/L)

1 ABIM 49 67.43 38 18.92 47 2.86 15 255.5

2 AMOLATAR 46 76.58 37 29.39 42 2.52 4 456.0

3 AMURIA 103 66.11 98 9.47 98 2.12 39 201.9

4 APAC 221 76.50 201 18.92 211 2.26 66 507.3

5 BUDAKA 136 61.54 121 9.61 120 1.51 35 268.3

6 BUDUDA 3 43.30 3 17.33 3 1.60 1 185.0

7 BUGIRI 89 56.26 82 14.20 79 2.28 22 471.3

8 BUKEDEA 67 78.05 63 10.97 67 2.44 16 444.8

9 BUSIA 121 54.50 110 12.13 118 2.16 35 313.4

10 BUTALEJA 46 66.15 27 6.60 41 1.27 5 256.8

11 DOKOLO 42 70.64 40 8.18 41 2.12 17 476.5

12 IGANGA 306 55.43 272 13.64 282 2.63 51 225.8

13 JINJA 171 54.52 157 17.10 160 2.07 24 241.7

14 KAABONG 48 79.85 42 30.85 39 1.54 25 495.0

15 KABERAMAIDO 70 58.10 68 11.86 67 2.13 27 397.5

16 KALIRO 149 52.88 146 12.79 147 2.44 47 536.4

17 KAMULI 274 60.12 266 17.50 264 1.73 66 376.5

18 KAPCHORWA 13 92.44 13 28.48 13 1.81 1 451.0

19 KATAKWI 85 69.97 80 12.19 79 1.64 32 273.8

20 KAYUNGA 243 66.27 224 20.44 235 1.28 26 202.3

21 KOTIDO 32 80.17 20 28.92 32 2.48 14 308.9

22 KUMI 145 80.42 139 9.15 145 1.58 23 243.2

23 LIRA 195 70.96 190 8.86 190 2.10 93 186.5

24 LUWERO 335 64.01 182 17.28 318 1.69 78 195.6

25 MANAFWA 74 62.21 74 14.81 72 1.48 21 238.1

27 MBALE 95 64.10 87 11.22 93 1.86 10 254.3

28 MOROTO 50 77.77 47 25.77 47 2.81 15 483.7

29 MUKONO 111 63.69 102 17.97 107 2.20 22 117.2

30 NAKAPIRIPIRITI 49 83.23 45 19.32 41 2.22 20 463.2

31 NAKASONGOLA 120 70.94 85 31.05 111 1.23 47 465.2

32 NAMUTUMBA 154 52.53 146 9.82 148 1.73 55 243.9

33 PALLISA 330 57.29 307 9.90 307 1.80 73 382.7

34 SIRONKO 51 58.86 46 11.39 49 1.93 12 402.4

35 SOROTI 112 55.74 110 8.87 105 2.93 51 277.9

36 TORORO 149 56.60 122 7.55 137 1.81 46 268.1

37 WAKISO 246 66.89 185 19.54 198 2.09 5 120.8


4-7

4.2.1 Drilling Depth Distribution

The Drilling depth distribution map of existing boreholes is shown in Figure 4-7. Although each

borehole has different condition, this distribution seems to indicate the actual depth of the aquifer

which was needed to secure particular amount of water.

Average depth of drilling is 64m. It is tend to show that the depth is relatively shallow in the central

and southern part of the Basin. On the other hand, the drilling depth is deeper in Karamoja area in the

north-eastern part of Lake Kyoga Basin, Apac district, Nakasongola district, and Kumi district around

the Lake Kyoga, and Kapchorwa district in the northern part of Mt. Elgon.

Drilling depth is a parameter for estimation of the cost of the well construction.

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Sub BasinDistrict BoundaryLake, Water body

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Drilling Depth

　　　　　(m)

- 15

15 - 30

30 - 50

50 - 75

75 - 100

100 - 125

125 -

Figure4-7 Drilling Depth Distribution Map


4-8

4.2.2 Static Water Level Distribution

Static water level distribution of existing boreholes is shown in Figure 4-8.

I It is recognized that belt-like zone from north-northwest to south-southeast in the central part of Lake

Kyoga Basin has shallow static water level. On the other hand, deep static water level zones are in

Karamoja area in the north-eastern part of Lake Kyoga Basin, Apac district, Amolatar district,

Nakasongola district, Kayunga district, and Kamuli district around the Lake Kyoga.

Static water level is the parameter to decide a capacity of pump.

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Static Water Level

(m)

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5 - 10

10 - 15

15 - 20

20 - 25

25 - 30

30 -

Figure4-8 Static Water Level Distribution Map


4-9

4.2.3 Well Yield Distribution

Distribution of the well yield of existing wells is shown in Figure 4-9. Constant pumping test results

are used for this analysis as well yield data, because this parameter has relatively many data in

NGWDB.

The areas which show large yield per well are in Karamoja area in the north-eastern part of Lake

Kyoga Basin, and Soroti district, Amolatar district, Apac district, Dokolo district, and Kaberamaid

district in the northern shore of Lake Kyoga. Southern area of Lake Kyoga has relatively low yield.

Well yield is the parameter to estimate groundwater potential and necessary number of wells at the

target area.

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Yield

(m3/hr)

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0.6 - 1.0

1.0 - 1.5

1.5 - 2.0

2.0 - 3.0

3.0 - 5.0

5.0 -

Figure4-9 WellYeild Disribution Map


4-10

4.2.4 Water Quality Distribution (TDS)

Distribution map of Total Dissolved Solid (TDS) is shown as water quality map in Figure 4-10. TDS is

recognized as a good indicator to judge water quality comprehensively, for example salinity, iron

content, and so on.

Surrounding to Lake Kyoga, especially, Apac district, amolatar district, and Kaliro district shows high

value. It means the groundwater seems to be saline water.

Water quality is the parameter to judge the possibility of potable water and the necessity of water

treatment facility.

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District Boundary

catchment_subbasin

Lake, Water body

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TDS - 150

150 - 200

200 - 300

300 - 400

400 - 500

500 - 700

700 - 1,000

1,000 - 1,500

1,500 -

Figure4-10 Total Dissolved Solid Distribution Map

CHAPTER 4 HYDROGEOLOGY - JICA報告書PDF版(JICA Report PDF) · 2011-06-01 · Final Report...

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