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APPLICATION OF GROUNDWATER DATA LOGGERS TO MONITOR DYNAMIC AND STATIC

WATER LEVELS IN A TEST PUMPING WELLCASE STUDY: NAKOROS AREA, TURKANA

COUNTY KENYA.

11/19/2015

PresentedBy

Bernard Omwenga-Geologist

Bernard_mageto@yahoo.com/bomwenga@kengen.co.ke

GEOEACE CONFERENCE 2015

04/28/2023 MBA-COMPUTING FOR MANAGEMENT 2

Outline

IntroductionMaterials and methodsResults and interpretationDiscussionConclusion and recommendations

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INTRODUCTION

Nakoros well located in Kakuma area region in Turkana County, Kenya.

Study area lies in the northern terminus of the eastern arm of the African Rift system.

Its aquifer was struck along fractured basalt and weathered trachyte. Borehole’s TD= 70m, Q= 1.2 m3/hr.

Static and dynamic water levels recorded using both the water level deeper and groundwater data logger diver.

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Study area

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Introduction..cont

The data loggers were used in constant rate

pumping. Other well testing

stages such as step-drawdown and

recovery were done manually using

electronic sounder.

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Definition of termsStatic water level -level of water in a well under normal, undisturbed, no-pumping conditions.

Dynamic water level -level of water drawn from a pumped well.

Data loggers - used to automatically measure the water levels in monitoring wells and boreholes.

Test pumping (well test) - field experiment for evaluating amount of water that can be pumped from a water well.

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Materials and equipments used

Electronic deeper to measure real static water level.2 sets of data logger divers; baro diver and cera diver.Corrosion free aluminum cable (30m long).USB cable data downloader.A laptop computer for data downloading.Diver office 2012.1 software for data modelling.

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Equipments used (Pictorial illustration)

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Baro diver-measure barometric pressure of water

Cera diver-measure barometric pressure of water

Electronic sounder

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Computer Laptop

USB down loader

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Equipments used..cont

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Schematic representation of data logger in a well

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RESULTS AND INTERPRETATIONObtain the water column given by:i.). WC=k(Pcera-Pbaro)/ᵖg Where WC=Water Column=Water Head, PCera=Cera diver Pressure ,

Pbaro=Baro Diver Pressure ,ᵖg=Density of Water*Acceleration due to gravity= 9810 and K=Constant=9806.65

Calculate the SWL as follows: ii.). WL=CL (WC+h1).Where:WL= water Level (both SWL and DWL), CL=Cable Length h1=Length of casing above ground level.

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Deriving the Water level formula

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Results and interpretation..cont

Measured swl by electronic sounder-20m.Static Water level measured by groundwater data logger is 21m. The average dynamic level in the first 10 minutes is 21.7m.

The static water level deeper is 12.27m. The average dynamic level by electronic sounder for the first 10 mins is 24.7m.

The pumping water level data logger is 35.08m compared to 36.54m for electronic sounder.

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Date/time Water head[cm] water head (m) Temperature[°C]k pg Water Column (m) Cable length(CL)h1 (m) Static Water level (m)4/30/2014 20:50 311 3.11 33.61 9806.65 9810 3.108937971 30 0.51 26.381062034/30/2014 20:50 929 9.29 33.68 9806.65 9810 9.286827574 30 0.51 20.203172434/30/2014 21:40 841 8.41 33.94 9806.65 9810 8.407128084 30 0.51 21.082871924/30/2014 21:41 749 7.49 33.94 9806.65 9810 7.487442253 30 0.51 22.002557754/30/2014 21:41 705 7.05 33.94 9806.65 9810 7.047592508 30 0.51 22.442407494/30/2014 21:42 703 7.03 33.94 9806.65 9810 7.027599337 30 0.51 22.462400664/30/2014 21:42 702 7.02 33.93 9806.65 9810 7.017602752 30 0.51 22.472397254/30/2014 21:43 705 7.05 33.93 9806.65 9810 7.047592508 30 0.51 22.442407494/30/2014 21:43 709 7.09 33.93 9806.65 9810 7.087578848 30 0.51 22.402421154/30/2014 21:44 713 7.13 33.93 9806.65 9810 7.127565189 30 0.51 22.362434814/30/2014 21:44 718 7.18 33.94 9806.65 9810 7.177548114 30 0.51 22.312451894/30/2014 21:45 724 7.24 33.95 9806.65 9810 7.237527625 30 0.51 22.252472384/30/2014 21:45 729 7.29 33.96 9806.65 9810 7.28751055 30 0.51 22.202489454/30/2014 21:46 735 7.35 33.97 9806.65 9810 7.347490061 30 0.51 22.142509944/30/2014 21:46 747 7.47 33.98 9806.65 9810 7.467449083 30 0.51 22.022550924/30/2014 21:47 772 7.72 33.99 9806.65 9810 7.71736371 30 0.51 21.772636294/30/2014 21:47 802 8.02 34 9806.65 9810 8.017261264 30 0.51 21.472738744/30/2014 21:48 828 8.28 34.02 9806.65 9810 8.277172477 30 0.51 21.21282752

Results and interpretation_Water level data

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Discussion..cont

0 2 0 0 4 0 0 6 0 0 8 0 0 1 0 0 0 1 2 0 0 1 4 0 0 1 6 0 00

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10

15

20

25

30

35

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Dynamic Water Level (m)

elapsed time (minutes)

dyna

mic

wat

er le

vel (

m)

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Graphical representation of well data

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Discussion

Water level fluctuation occurs at different stages of pumping. High pressure differences are noted at the third hour.

Similarity occurs between data collected by the electronic deeper sounder.

Negative static water level values were obtained between 0-30 mins, implying that the cera diver was placed above water level.

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Conclusion and recommendations

• Slight variation noted between data collected by data loggers and electronic sounder.•Data collected by the divers tend to be more accurate

compared to those collected by electronic sounder. However variation occurred at stages of pumping.• It is applicable to monitor events of poor workmanship by test

pumping crew- they enables us to detect instances where data has been manipulated by the test pumping personnel.• It is advisable that the data loggers be adopted in test pumping

measuring exercise because they are cheap, relatively accurate compared to ordinary electronic sounders. They are also Ideal for long-term monitoring in saline environments

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Thank you!

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