Artificial Recharge of aquifers is devised as a means of increasing
groundwater resources. Regulating surface flow, providing underground
storage of water and avoiding its loss in seas or in salt depressions,
also help to preserve the recharged groundwater. A number of water table
aquifers in coastal zones are being increasingly exploited and affected
[1,2]. Artificial recharge of groundwater can be used to preserve the
water resources and restore the water table aquifer which has been
threatened due to overexploitation and a fall in piezometric level. .
Artificial Recharge has been used in many countries for protecting
against predicted water shortages.
For example in India, a sustainable technology has been developed,
which consist of runoff from rooftop through PVC pipe, passed through a
filter and finally put into an aquifer formation above water table via a
recharge well. In Tunisia, a pilot programme to mobilize resources,
aimed at stormy water form winter rains, which would be used during the
dry season, was developed . The objective of artificial recharge is
to recreate a piezometric level of groundwater that is either higher
than or equal to the normal, with a better quality of aquifer water. The
objectives of groundwater recharge have been defined by Asono &
Contruvo, ; Bouwer & Pyne  and Grunheid . Artificial
recharge used in many countries has a clear correlation between the
fluctuations of water table and the recharge rate by irrigation. Also
extremely large amount of water is continuously added to the soil during
sprinkling infiltrations. It alters the flow of water and nutrients in
the soil, resulting in an increase in pH. and base cation concentration
of the uppermost soil layers and changes in nitrogen cycle. Another
study conducted in France along Seine River recorded a total elimination
of parasite between raw water used for the artificial recharge and the
water in the aquifer .
Umudike is found in Ikwuano Local Government Area of Abia State in
the south east zone of Nigeria. It is located between latitude
5[degrees]19'N and 5[degrees]30'N and between longitude
7[degrees]30'E and 7[degrees]37'E. It is within the Kwa Ibo
River watershed which has Anya River as the major tributary. The latter
is found within the premises of Michael Okpara University of
Agriculture, Umudike and flows across the National Root Crops Research
Institute, Umudike, see Figure 1.
1.2. Geology of Umudike
The geologic formation of Umudike is that of Coastal Plain Sands,
also known as the Benin Formation. It belongs to the later Tertiary to
Early Quaternary. The Formation is about 200 m thick at Umudike. The
lithology is unconsolidated fine-medium-coarse grained cross-bedded
sands occasionally pebbly with localized clay and shale that favors
1.3. Piezometric Cycle
The piezometric Cycle of the study area shows a cycle of 3 phases
which corresponds to the rainy (wet) season, when it enjoys a steady
heavy rainfall period of 3 months from May to July; a short break period
of dry weather, and a return of another copious rainfall. There are two
peak months of rainfall in a year: July and September. The mean monthly
rainfall during the wet season is 335 mm, which falls to 65 mm during
the dry season that lasts from October to April . The Anya River,
which is the main tributary of Kwa Ibo River, enjoys reasonable volume
of water during these rainfall peaks. This River serves as water
resource for the recharge of the aquifer in the study area.
[FIGURE 1 OMITTED]
The Benin Formation or the Coastal Plain Sands has high aquifer
permeability. The permeability of the study area is about 3.15 m/day.
Groundwater recharge due to rainfall takes place from the top layer. In
the normal course, the surface water goes to the ground water by natural
infiltration process after crossing different layers of clay and fine
sands. The top layer consists of 5-120 m topsoil/laterite underlain by a
sandy zone, 68-320 m thick. There is a serious groundwater abstraction
owing to the presence of Michael Okpara University of Agriculture,
Umudike (MOUAU) and the National Root Crops Research Institute.
Abstraction is through wells and groundwater pumping. The pumping rate
varies from 100 [m.sup.3] x [day.sup.-1] to 150 [m.sup.3] x
The depth of bore-hole is an important parameter that governs the
rate of recharge of groundwater. The bore hole log data is therefore
found to be of great importance in deciding the optimum depth of
recharge and hence the boring equipment required. The bore log data of
BH No. 3 at Michael Okpara University of Agriculture, Umudike indicates
that a minimum of 45 m in depth is required to reach the first aquifer
consisting of medium sands, and about 82 m-88 m for the second aquifer.
The groundwater contour map in Figure 2 clearly shows this.
Alternatively, the subsurface hydrological data can also be used in
deciding the optimum depth of recharge. It is also essential to have a
good permeability that can be obtained by going deep enough to encounter
medium sands or coarse sand strata.
To stop the groundwater depletion, the rain and surplus water from
the Anya River was stored by artificial recharging. The Artificial
recharge system consists of injecting water into the underlying water
bearing aquifer. Two recharging systems were constructed by the sides of
the drain, one at the University, (MOUAU) and the other at the center of
the village near Amawom. Following the design of Radhey Mohan et al.
; see Figure 3, a recharge well of about 3.0 m x 9.0 m were
constructed by the side of the drain. It has about 0.5 m thick layer of
fine sand, 0.5 m thick layer of coarse sand and 0.5 thick layer of 5 -
12 mm gravel. A borehole of about 50 m deep; 0.5 m diameter was drilled
with the rig machine by direct mud circulation process. A P.V.C pipe of
diameter 0.3 m length was lowered in the borehole, and the space between
the pipe and the borehole was filled with 5 - 12 mm of gravel. The
length of the perforated part of the pipe in the coarse grained sands
was about 20 m, from the aquifer. Piezometers made of PVC pipes were
installed by the sides of the drain so that the water level reading
before and after recharge could be taken. Observations were also taken
from about 6 abstraction wells within the catchments area located at
about a distance of 500 - 600 m away from each other and about 1000 to
2000 m away from the recharge well.
[FIGURE 2 OMITTED]
The rise of the water level was seen to be more at some locations
where it was initially low, especially during the peak periods of the
rainy season, i.e. July and September. During the recharge process, the
average depth of groundwater rose up to 35 m for the first aquifer
within the charging catchments area instead of the usual 45 m depth. The
maximum rise of water table was observed to be in abstraction wells
located southwards in the direction of the river flow e.g. at the
Engineering Department of MOUAU. This is located at about 1km away from
the recharging well. The direction of the velocity field vector at these
sites is from North to South. Runoff is low while recharge is here. The
maximum rise shows that the groundwater table depends on the type of
strata. Water analysis carried out at MOUAU by Ebilah et al. ,
indicates good quality water which compares well with the WHO standards
except for the pH of 5 which of course is not detrimental to health.
Hence there is no need for treatment or sedimentation of raw water of
the drain. Table 1 shows that water increases due to recharge of the
underground water at closer locations than at farther points. At Umudike
it is 85 m (above sea level) before recharge and 95 m after recharge
(Figure 2). This is due to infiltration of underground water by rainfall
and river water.
Groundwater recharge is a function of the annual average rainfall,
hydrological characteristics, geology of the area, slopes, and nature of
the soil. Increase in rainfall leads to increase in groundwater level.
Conversely, decrease in rainfall leads to groundwater depletion. Over
exploitation in the form of excessive pumping to meet the increasing
water demands was observed in the study area. The geo logy of Umudike
supports to a reasonable extent, the natural infiltration process
especially during the rainy season. Artificial recharge yields good
promising results when applied. With the rate of recharge recorded,
Umudike looks very promising for groundwater development programme in
[FIGURE 3 OMITTED]
 G. Demarsily, "Importance of the Maintenance of Temporary
Ponds in Arid Climates for the Recharge of Groundwater," Comptes
Rendus Geosciences, Vol. 335, No. 13, 2003, pp. 933-934.
 Fedrigoni, "Origin de la Mineralization et Comportment
Hydrogeochimique d' une Nappe Phreatigue Soumise a des Contraintes
Naturelles et Anthropigues Severe: Example de la Nappe de Djebenia
(Tunisie)," Earth and Planetary Science Letters, Vol. 332, 2001,
 P. Nojd, et al., "Artificial Recharge of Groundwater
through Sprinkling Infiltration: Impacts on Forest Soil and the
Nutrients Status and Growth of Scots Pine," Science of the Total
Environment, Vol. 407, No. 10, 2009, pp. 3365-3371.
 Ministere de L' Agriculture, "Rapport sur l'
etat des Nappes Phreatigues et Profondes de la Tunisie," Ministere
de l' Agriculture, Tunis, 1996.
 T. Asono and J. A. Cotruvo, "Groundwater Recharge with
Reclaimed Municipal Waste Water: Health and Regulatory
Consideration," Water Research, Vol. 38, No. 8, 2004, pp.
 H. Bouwer and R. D. G. Pyne, "Artificial Recharge of
Groundwater," National Groundwater Association, Baltimore, 2005.
 S. Grunheid, et al., "Removal of Bulk Dissolved Organic
Carbon (DOC) and Trace Organic Compounds by Bank Filtration and
Artificial Recharge," Water Research, Vol. 39, No. 14, 2005, pp.
 M. Detay and J. C. Bersillion, "La Realimentation
Artificielle de Nappes Profondes. Faisabilite et Consequences," La
Houille Branched, Vol. 366, 1996, pp. 57-61. doi:10.1051/lhb/1996040
 M. U. Igboekwe, E. E. Okwueze and C. E. Okereke,
"Delineantion of Potential Aquifer Zones from Geoelectric Soundings
in Kwa Ibo River Watershed, South Eastern Nigeria," Journal of
Engineering and Applied Sciences, Vol. 1, No. 4, 2006, pp. 410-421.
 M. Radhey, "Artificial Recharging of Groundwater from
Rain and Surplus Canal Water along Harsauli Drain, District,"
Proceedings of ISWRPM 2003, Muzaffarnagar, 11-12 October 2003.
 Ebilah-Salmon and Partners, "Investigation of the
Existing Water Supply Facilities within the University Complex,"
Geophysical Report and Recommendations for Reactivation and Future
Exploitation for Potable Water Supply, Federal University of
Agriculture, Umudike, 1994, p. 25.
Magnus U. Igboekwe *, Adindu Ruth
Department of Physics, Micheal Okpara University of Agriculture,
Umuahia, Nigeria E-mail: email@example.com
Received January 1, 2011; revised February 3, 2011; accepted April
Table 1. Depth of water table (amsl).
Water Table Water Table
S/N Location recharge (m) recharge (m)
1 Engineering Dept, MOUAU 1 km from 85 95
2 From Vice Chancellor's lodge. 1.5 80 88
km from recharge well.
3 Observation well at Research 83 87
Institute 1.7 km from recharge
4 Village open well located at 2 km 83 87
from recharge well.
5 Bore holes at Amawon 1 km from the 79 85
6 Open well at Amawon 1.5 km away 79 83
from recharge well.