A Technologically Appropriate
Method for Measuring the Specific
Capacity of Rope-Pump Wells
John S. Gierke1, Essa L. Gross1 & Elizabeth A. Myre2
1Department of Geological & Mining Engineering & Sciences
2Department of Civil & Environmental Engineering
Michigan Technological University
Antoinette Kome
SNV Nicaragua
Outline
†
Introduction &
Objectives
†
Methodology
†
Results & Conclusions
Introduction:
Water Supply Issues
for Developing
Countries
• Practically no information
exists on the capacity of
rural wells
• Many areas suffer from
lack of water during the
dry season
• Management agencies
have no information to
develop water
management plans
• Lack of technical and
economic resources
prevents the collection of
performance and
monitoring data
Rope Pumps
† Originated in Nicaragua (1980s),
has since proliferated there
† Usage outside of Nicaragua has
been limited, can be driven
manually or with wind
† Affordable and readily maintained
† Can they be adapted for using in
pumping tests?
60’
Research Objectives
Design and test a method to characterize
the productivity of existing rope-pump
wells in rural areas of developing
countries
Monitor seasonal changes in SWLs
and specific capacities of ropepump wells in an area that
experiences distinct rainy and dry
seasons.
Study Area
Santa Rita
Regional Geology
X
X
X
X
Tpc - Coyol Group
Fractured ignimbrites,
tuff, andesite, basalt
Source: INETER
Hydrogeology
EMPRESA NICARAGUENSE DE ACUEDUCTOS RURALES Y ALCANTARILLADOS
EMPRESA NICARAGUENSE
DE ACUEDUCTOS
RURALES
Gerencia
de Acueductos
Rurales Y ALCANTARILLADOS
Gerencia
de Acueductos
Rurales
REGISTRO
DE POZOS
No de Pozo:
No de Pozo:
REVESTIMIENTO
REVESTIMIENTO
REGISTRO126/02/02
DE POZOS
PERFIL GEOLOGICO
PERFIL GEOLOGICO
126/02/02
Municipio:
Comunidad:
Comunidad:
Coordenadas:
0'-20' Basalto erocionado Gris(GR)
0'-20' Basalto erocionado Gris(GR)
20'-30 Basalto Compacto
20'-30 Basalto Compacto
30'-60' Toba Calcitica (Mr)
30'-60' Toba Calcitica (Mr)
50’
160’
0-20’
Elevacion
(msnm):
Coordenadas:
Elevacion (msnm):
Perforador:
Perforador:
Supervisor-Geologo:
Carlos Largaespada
Carlos
Luis
MezaLargaespada
Hurtado
Luis2/14/06
Meza Hurtado
2/14/06
2/15/06
20-30’
Compacted Basalt
30-60’
Tuff (cemented ash deposit)
90'-100' Toba Aglomeratica (MR)
90'-100' Toba Aglomeratica (MR)
NFA:
Caudal:
Caudal:
Metodo
de bombeo:
2/15/06
Rotativo
77/8" Rotativo
y 51/4 "
77/8"
20 y 51/4 "
200 pies
50200
piespies
160 50
piespies
pies
5160
gpm
60'-200' Basalto (Gr) con presencia de cristal
60'-200' Basalto (Gr) con presencia de cristal
20
60.96 m
60.96
15.24
m m
15.24
48.768
m m
48.768
m
1.1354
m3/h
5 gpm
60-90’
Metodo
bombeo:
Tiempo
de de
bombeo:
Profundidad
agua al final del bombeo:
Tiempo dedel
bombeo:
Profundidad del agua al final del bombeo:
Total de horas trabajadas
Total de
de perforacion
horas trabajadas
Tiempo
150'-160' Basalto Fracturado
150'-160' Basalto Fracturado
Juigalpa
Santa
Rita
Santa Rita
Weathered Basalt
Fecha de finalizacion:
Metodo(s):
Diametro(s)
de perforacion:
Metodo(s):
No Diametro(s)
de barras: de perforacion:
No de barras:
Profundidad
total:
Profundidad total:
NEA:
NEA:
NFA:
200’
Chontales
Chontales
Juigalpa
L.Oest
L.Oest
L. Nort
L. Nort
Supervisor-Geologo:
Fecha
de inicio:
Fecha
inicio:
Fecha
de de
finalizacion:
60'-90' Basalto (GR)
60'-90' Basalto (GR)
100'-150' Basalto con pigmentaciòn cristalina
100'-150' Basalto con pigmentaciòn cristalina
DATOS GENERALES
DATOS GENERALES
Departamento:
Departamento:
Municipio:
Basalt
horas
50 pieshoras
50 pies
DISTRIBUCCION DEL TIEMPO
DISTRIBUCCION DEL TIEMPO
Tuff
90-100’
Tiempo
de perforacion
Total
de Tiempo
muerto:
Total del
de Tiempo
Causas
tiempomuerto:
muerto:
Causas del tiempo muerto:
Lluvias
Lluvias y mantenimiento
Reparacion
100-150’
Reparacion
y mantenimiento
Falta
de materiales
Faltamayor
de materiales
Fuerza
1.1354 m3/h
15.24 m
15.24 m
18:19
18:19
6:57
6:57
1:34
1:34
Basalt
0:34
0:34
Fuerza
mayor
Falta
de acceso
Falta de de
acceso
Problemas
perforacion
150’-160’ Fractured basalt
Problemas de perforacion
Alimentacion
Alimentacion
Desarrollo
1:00
1:00
1:45
Desarrollo
Otras
actividades
Otras actividades
1:45
8:03
8:03
160-200’
Sonda de perforacion
Sonda de perforacion
Compresor
Compresor
Camion
Portasonda
Camion
Camion
delPortasonda
compresor
Camion del
compresor
Camioneta
de apoyo
Camioneta
de apoyo
Camioneta
supervision
Camioneta supervision
NOTAS:
NOTAS:
TOTAL
TOTAL
Basalt
CONSUMO DE DIESEL
CONSUMO
DE DIESEL
18 gal.
46 18
gal.gal.
8 46
gal.gal.
68.13 litros
68.13
litros
174.11
litros
174.11
litros
30.28
litros
8 gal.
gal.
8 gal.gal.
8 gal.
gal.
30.28
litros
0 litros
0 litros
30.28 litros
30.28
litros
0 litros
80 gal.gal.
80 gal.
0 litros
302.8 litros
302.8 litros
La perforac—n se desarrollo sin ning n problema, los tubos que se usaron para el encamisado del pozo, fueron de los
queLaseperforac—n
sacaron ense
la desarrollo
salida de Apompua
Portillo, para
mismo
un total
de 22 tubosdel
depozo,
4" x 3fueron
Mtrs. de los
sin ning El
n problema,
losel
tubos
queseseutilizaron
usaron para
el encamisado
que se sacaron en la salida de Apompua El Portillo, para el mismo se utilizaron un total de 22 tubos de 4" x 3 Mtrs.
Testing and Monitoring
Approaches
•
Monthly manual pump tests in triplicate at 3 wells
•
Each test included pumping, equilibrium, and
recovery phases
•
A conventional step-drawdown test performed in one
well
Manual Pumping Test
Regime
• Pump 60 – 90 gal
Elapsed time (min)
0.5
0.0
0
• Approximate rate
of 5 gpm
-1.0
Drawdown (ft)
• Well allowed to
recover for at
least an hour
-0.5
-1.5
-2.0
-2.5
-3.0
-3.5
• Triplicate tests
-4.0
20
40
60
80
100
120
140
160
180
200
After Gross (2007)
Straight-Line & Equilibrium
Drawdown Methods
Seasonal Change in SWLs
0
5
Static Water Level (ft bgs)
10
15
20
Well 1
Well 2
Well 3
Well 4
Average
Averagedry
dryseason
seasondrop
drop==66ftft
DRY
RAINY
25
30
35
40
45
50
10/22/06 12/11/06 1/30/07
3/21/07
5/10/07
6/29/07
8/18/07
10/7/07 11/26/07
Specific Capacity (gpm/ft)
2.0
1.8
Well 1
1.6
Well 2
1.4
Well 4
Seasonal
Changes in
Specific
Capacity
1.2
1.0
0.8
0.6
0.4
0.2
0.0
-1.0
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
Drop in SWL
(ft) from
Dec
Feet below
SWL Dec
06 2006
*Assuming 200’ well
Well
SWL
Change
(ft)
SWL Change
(% available
water column)*
% Change
Specific
Capacity
1
- 6.6
- 4.0 %
- 15 %
2
- 4.4
- 2.5 %
- 26 %
3
- 6.3
- 3.5 %
--
4
- 7.9
- 4.8 %
- 81 %
Traditional pump test profile 9/25/07
Elapsed time (hrs)
0
2
4
6
8
10
12
14
16
0
20
5 gpm
15 gpm
Drawdown (ft btc)
25 gpm
40
60
80
37 gpm
100
120
18
20
22
24
26
Comparison of Pumping Test Methods
Spec. cap values
calculated from
manual tests:
Equilibrium
Well 4
4.0
Prueba perfil
Specific Capacity (gpm/ft)
0.0
approx
equilibrium approx
-0.5
3.5
-1.0
-1.5
-2.0
-2.5
Non-equilibrium
method recovery curve
recovery curve
-3.0
3.0
-3.5
-4.0
-4.5
-5.0
0
2.5
500
1000
1500
2000
pump curve
2500
Non-equilibrium
method - pump
curve
2.0
Trad Equilibrium
approx
Spec. cap values
calculated from
Trad Nonconventional test:
equilibrium-pump
1.5
1.0
curve
equilibrium approx
0.5
Trad Nonequilibriumrecovery curve
recovery curve
0.0
35
36
37
38
39
40
SWL (ft btc)
41
42
43
44
pump curve
0.
0.
1.6
1.6
3.2
3.2
Displacement (ft)
Displacement (ft)
Curve Matching: PapadopolusCooper (1967) using AQTESOV
4.8
6.4
8. -1
10
4.8
6.4
0
1
10
10
Time (min)
2
10
8. -1
10
0
1
10
10
Time (min)
2
10
Comparison of Data
Analysis Methods
Method
JSL
(pumping)
GMS-MODFLOW Calibration
(pumping)
P-C AQTESOLV
(pumping)
JSL
(late recovery)
GMS-MODFLOW Calibration
(pumping and recovery, 1)
Equilibrium Drawdown
(equilibrium)
P-C AQTESOLV
(pumping and recovery)
GMS-MODFLOW Calibration
(pumping and recovery, 2)
Accounts for
casing storage?
T (gpd/ft)
no
296
yes
364
yes
367
no
438
yes
528
n/a
593
yes
630
yes
653
Conclusions: Method
1. Wells are currently used at 1/10th of their
maximum capacity
2. Although the manual pump rate is low, results are
representative of well behavior at high rates, at least
7X higher
3. Recovery data easiest to
collect and yields
representative well behavior,
equilibrium behavior easier
to analyze
4. Modifications of wells for
manual pump test are minor
& economical
Conclusions: Seasonal Effects
1. Changes in specific capacity were observed for
even slight changes (~ foot) in SWL
2. Current water demand
places a negligible stress
on the aquifer compared to
seasonal changes in the
static water level
3. Systematic monitoring is
needed for management
Acknowledgements
Financial Support:
• National Science Foundation PIRE 0530109
• DeVlieg Foundation
• SNV Nicaragua
• U.S. Peace Corps
• MTU d80 Center & GMES Department
We would like to acknowledge the following people for
their assistance in this study:
Gregg Bluth, Fernando Flores, Luis Meza, Denia Acuña,
Evelio Lopez , Ivan Palacios, Elisena Medrano, Luis
Palacios, and the Families of Santa Rita