IJERD – International Journal of Environmental and Rural Development (2012) 3-1

Research article
erd

Assessment of the Groundwater Quantity Resulting fromArtificial Recharge by Ponds at Ban Nong Na, Phitsanulok
Province, Thailand
SIRIRAT UPPASIT*
Faculty of Technology, Khon Kaen University, Khon Kaen, Thailand
Email: sirirat_upp@hotmail.com

KRIENGSAK SRISUKFaculty of Technology, Khon Kaen University, Khon Kaen, Thailand

PHAYOM SARAPHIROM
Faculty of Technology, Khon Kaen University, Khon Kaen, Thailand

PAUL PAVELICInternational Water Management Institute, Hyderabad, India
Received 19 December 2011

Accepted 18 April 2012(*: Corresponding Author)

Abstract Ban Nong Na Phitsanulok Province, has been facing continuous groundwaterlevel decreases, from 1-2 m below ground surface in the past 25 years to 7-8 m in thepresent due to overexploitation for irrigation. This area was selected as a pilot site toconstruct and conduct the recharge experiment. The objective of this research is toquantify groundwater mound resulting from the recharge experiment using
MODFLOW2000. Two recharge ponds A and B, which have an area of 660 and 600 m2,respectively, were constructed in the selected site of the study area. The experiment
duration was July to November, 2010 using raw water with turbidity less than 100 NTU.
The total recharge amount is 25,797 m3. The results showed that under the experimentconditions the designed recharge pond can provide a moderately good analysis of therecharge water. The mounding results of the simulations were compared with the fieldobservation; both were found to be compatible. After 5 days of the fifth test, themaximum rise of the mound was 3.33 m and covers an area of approximately 6,000 m2.
Keywords artificial recharge, groundwater mound, Phitsanulok

INTRODUCTION
The Groundwater Research Center (GWRC), Khon Kaen University, was invited by theDepartment of Groundwater Resources (DGR), Ministry of Natural Resources and Environment, toconduct the research on “Pilot   Study   and   Experiment   on   Managed   Aquifer   Recharge   Using  Ponding System in the Lower North Region River Basin, Phitsanulok, Sukhothai, and Pichit
Provinces”   to  test  the  feasibility   of   using   artificial   groundwater recharge to reverse the declining
trend. The project duration was between April 2009 and April 2011. The project area was identified
from the Lower North Region River Basin areas of about 21,300 km2 covering the areas ofPhitsanulok, Sukhothai, and Pichit Provinces using a zooming-in technique ultimately focusing inon the Ban Nong Na pilot area of approximately 4.12 km2, and a construction site for the artificial
recharge pond system of about 0.01 km2. Ban Nong Na pilot project area is suitable for theconstruction site of recharge pond system because it fits various suitability indices such as; (i)hydrogeological suitability, which include thin top clay layer of less than 3 m thick, thick shallowstrata (10-15 m) of sands and gravels with good continuity of strata; (ii) there are about 100
agricultural wells for target water user; (iii) suitable distance from raw surface water source; (iv)availability of electricity and access road; and (v) availability of land and good cooperation fromⒸISERD196

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local people and local organization (DGR, 2011). Uppasit et al (2011) described the sitecharacterization for the ponding recharge system at Ban Nong Na and used the finite differencegroundwater flow model, MODFLOW2000, (Harbergh et al, 2000) in order to assess thegroundwater flow and groundwater balance.
The objective of this study is to quantify the groundwater mound resulting from the recharge
experiment using numerical modeling technique in the study area.
STUDY AREA
General description
The study area covers Ban Nong Na, Tambon Nong Kula, Amphoe Bang Rakham, Phitsanulok
Province. Topographic elevations range between 43-50 meters above mean sea level (m amsl).
Low elevations are found in the central and northern part and to the southeast of the study area
which are mainly dominated by paddy fields. High elevations are found in the southwestern part,
where landuse is mainly dominated by villages and sugarcane fields. Soil types of the study area
consist of loamy sand, clay, and loamy clay (Fig. 1). Important sources of surface water are Klong
Lan Ba and a drainage canal. Klong Lan Ba is located in the northern part of the study area andflows from West to East with a total catchment area of 30.38 km2. The canal is used to drain waterfrom paddy fields. It flows from west through the central part, and drains into Klong Lan Ba in
northern part with a catchment area of 6.54 km2. Average runoff of the drainage canal is about 0.75
million (M) m3/y. Surface water quality is good and with no contamination of chemical fertilizers
under the standard of notification of the national environmental board No. 8. Surface water
turbidity  frequently  exceeded  the  “recharging  waste  water  into  groundwater  wells  regulation”  of  50  NTU established by the Ministry of Industry, Thailand. Manganese concentration ranges from 5-8
mg/L (the standard is 1 mg/L; DGR, 2011). The water of the canal is used to recharge the aquifer
using the pond system.
Hydrogeology
Detailed hydrogeological characteristics of the study area were obtained from the field
investigation. Forty seven wells were drilled and installed in the main directions of groundwaterflow since June, 2009 to explore geology, and monitor the groundwater level and quality. These
include 32 wells for shallow depths of less than 15 m and 15 wells for depths greater than 15 m.
Uppasit et al (2011) described the hydrogeology of the study area, underlain by alluvial fandeposits (Qaf) consisting of sand, gravel and clay; and flood plain deposits (Qff) composed of sandand gravel (Fig. 2). The area is overlain with clay layer of varying thickness of 0-3 m. Shallow
aquifers deposited at the depth of 6 to 20 m below ground level. Thin clay layer of 2 to 7 m
separates the shallow and deeper aquifers. The deep aquifer consists of gravelly sand and is foundat 17-27 m depth (Fig. 3). The shallow aquifer has a transmissivity (T), hydraulic conductivity (K),and storativity (S) of 2,000-3,400 m2/d, 2.43x10-3 - 3.90x10-3 m/s, and 0.001-0.090, respectively.
The deep aquifer has T and S values of 30-150 m2/d, and 0.001-0.040, respectively. The main
groundwater moves from the southern part area with a head of 38.5-39 m amsl to the northern part
area with a head of 36-36.50 m amsl (Fig.2). Shallow groundwater depths range from 7-9 m below
the ground surface. The groundwater recharge of the study area is about 6 to 21% of annual rainfall(1,300 mm). The groundwater balance study using mathematical groundwater model simulationsin the study area showed that the total groundwater recharge rates, use and deficit are about 1.2, 1.5 and0.23 Mm3/y, respectively. Groundwater level in the current condition showed a declination of 0.25 m/y.

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Fig. 1 Map of the study area showing topography and landuse

Fig. 2 Hydrogeological map of the study area

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The thirty nine groundwater samples from the groundwater wells were monitored prior andduring the recharge experiments and analyzed for physicals, chemicals, and toxic elements
following the standard of characteristics discharged into deep wells of the Notification of theMinistry of Industry, No. 5 B.E. 2521 (1978) and analyzed for volatile organic compounds, heavymetals, and pesticides following the groundwater quality standards of the Notification of theNational Environmental Board No. 20, B.E. 2543 (2000). It was indicated that the samples are ofgood quality and do not show signs of contamination from fertilizers or pesticides (DGR, 2011).
METHODOLOGY
The methods used in this paper consist of (1) data compilation including climate, physiography,hydrology and hydrogeology from the literature review and field investigation of DGR (2011) andUppasit et al (2011); (2) recharge pond experiment, groundwater level and quality monitoring; and(3) numerical modeling of groundwater flow, balance and mound prior and resulting from therecharge experiment.
Recharge pond system and experiments
The recharge pond system was constructed in the central part of the study area closely to thedrainage canal (Fig. 3). The construction site consists of two main systems; four constructedwetlands for raw water quality treatment, and two recharge ponds. The constructed recharge ponds
A and B have ground surface areas of 1,250 and 1,160 m2 and the bottom floor areas of 660 and
600 m2, respectively. The depths of the ponds A and B are 2.66 and 2.75 m with the maximum
storage capacity at the storage level of 2 m of 1,830 and 1,690 m3, respectively. The side slope of
the ponds was designed at 1.5:1 to ensure slope stability. The bottom floor of the ponds werecovered with filter sand layer of 0.5 m thick and the side walls and bottom floors were lined withsynthetic filtering blankets for sediments filtering and protection of erosion (DGR, 2011).
The twenty two shallow groundwater wells situated along the major groundwater flow
direction were installed to monitor the water level fluctuation during experimental of artificial
recharge. The recharge pond experiment was made 5 times for 55 days during July to November
2010, the recharge vary from 3,953-4,439 m3 using surface water with the average turbidities
varying from 27.2 to 89.9 NTU. The total recharged water is 25,797 m3 as shown in Table 1 (DGR,2011). During the longest experiment of 30 days in the fifth test, the groundwater level underneaththe recharge ponds rises to the highest level of 3.33 m from normal immediately after 5 days ofartificial recharge operation and after that gradually lowers to normal level (Fig. 3). The
groundwater flows from the recharge pond area to the surrounding region and the north withaverage flow velocity of 0.07 m/day. The results of the physical, chemical and biochemical
groundwater quality monitoring show no indications of groundwater quality changes (DGR, 2011).
Groundwater numerical modeling
The simulation area is 2.6 km in width and 2.7 km in length. The size of the grid cells increase
from 5 m x 5 m at the recharge pond area to 20 m x 20 m at the remainder of the model. The model
height ranges from 0-50 m amsl. Model was divided into three layers; shallow aquifer, deep
aquifer, and confining layer. For the shallow aquifer, the southern side was selected as groundwater
divided boundary, eastern and western boundaries as parallel with groundwater flow line, andnorthern side set as river boundary. For the deep aquifer, western and eastern sides are designed asprescribed flux, and southern and northern boundaries as parallel with groundwater flow line.
Ponds A and B were assigned as recharge boundaries.
The recharge from rainfall and the pilot experiment was assigned using recharge boundary.
Groundwater usage was simulated by the well package. The hydraulic property values are assigned
based on the range of field hydrogeological testing results. The model was calibrated with the waterlevel data both in prior and during the recharge experiment. In current condition, the water level
data of 59 monitoring wells observed during monthly basis since December 2009 to NovemberⒸISERD199

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2010. During the recharge test, water level data in daily basis of 22 monitoring wells werecalibrated.

Fig. 3 Cross sections showing groundwater mound during the fifth experiment.
Table 1 Field data of the recharge pond experimentNo.

Pond

Duration (days)

12

BA
B
ABA
B
AB

345Total

Recharged water
Turbidity (NTU)

Artificial recharge(m3)Jul 13-15, 2010 (2)52.6

Aug 3-8, 2010 (5)27.2

Aug 25-Sep 8, 2010 (14)71.9

Sep 19-23, 2010 (4)65.5

Oct 23-Nov 22, 2010 (30)

89.9

814
4,439
896
1,918
4,157
2,835
1,901
4,884
3,953

Jul 13-Nov 22, 2010 (55)

25,797

RESULTS AND DISSCUSSION
Groundwater flow pattern in natural condition shown that groundwater flows from the southernpart of the study area or at Ban Nong Na with recharge rates of 6 to 21% of rainfall to the cone ofdepression area in the northern region nearby Klong Lan Ba and is characterized by low recharge
rates of 3 to 5%. Groundwater heads surrounding the recharge ponds A and B were 36.70-36.30 m
amsl (Fig. 4a). Groundwater balance during the recharge experiment can be summarized as thefollowings: the total recharges to the study area were 1.37 Mm3 including the total of artificial
recharge of 25,735 m3, and seepage from the river was 0.17 Mm3. The total annual draft throughpumpage was 1.40 Mm3. The subsurface horizontal inflows and outflows were 0.17 Mm3. The
result shows a deficit balance of 0.20 Mm3. A continuous trend of groundwater decline of 0.22 m/ycan be found for the study area. The mounding results of the numerical model simulations werecompared with the field observation; both were found to be compatible with the Root Mean Square(RMS) of 0.48 m.
During the recharge experiment, it was found that groundwater mounded underneath therecharge ponds as shown in Fig. 4b and Fig. 4f. Groundwater flows from the central part of theⒸISERD200

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mound to the surrounding area. The mound geometry that develops in the unconfined aquifer
beneath the recharge ponds depends on several factors including the aquifer hydraulic properties,aquifer thickness, duration and quantity of the artificial recharge.

(a)  before the recharge
experiment   (July 2010)(b)  First recharge experiment(July 15, 2010)(c)  Second recharge experiment(August 8, 2010)(d)  Third recharge experiment(September 7, 2010)(e)  Fourth recharge experiment  (September 22, 2010)(f)  Fifth recharge experiment(November 22, 2010)

Fig. 4 Simulations of groundwater levels before and during the recharge pond experiment
CONCLUSIONS AND RECOMMENDATIONS
Groundwater recharge mound from the recharge experiment can be quantified using numericalmodeling technique. It can provide a clarification of recharge mechanism, water balance, andmounding characteristics. Results from the simulations indicated that groundwater deficit in Ban
Nong Na could be controlled by constructing an artificial recharge system in the highly abstractionof groundwater areas. Based on the results of pilot experiments, to keep the water table in Ban
Nong Na area as the current condition, the volume of artificial recharge in this area have to be
increased to not lower than 0.23 Mm3/y, which indicated that more than 6 six recharge systems
need to be implemented in this area.
ACKNOWLEDGEMENTS
This  study  was  carried  out  as  part  of  the  research  project,  “Pilot  Study  and  Experiment  on  Managed  Aquifer Recharge Using Ponding System in the Lower North Region River Basin, Phitsanulok,Sukhothai,  and  Pichit  Provinces”  financed  by  the  Department  of  Groundwater  Resources,  Ministry  of Natural Resources and Environment, Thailand. The authors also acknowledge the participating
research staff from the Groundwater Research Center (GWRC), Khon Kaen University, for theirfield technical support, and graphic preparation.
REFERENCES
Department of Groundwater Resources (DGR) 2011. Pilot study and experiment on managed aquifer
recharge using ponding system in the lower north region river basin, Phitsanulok, Sukhothai, and PichitProvinces. Groundwater Research Center, Khon Kaen University, Thailand.
Harbaugh, A.W., Banta, E.R., Hill, M.C. and McDonald, M.G. 2000. MODFLOW-2000. The U.S. geological survey modular gound-water model-user guide to modularization concepts and the ground-waterflow process, U.S. Geological Survey. Open-File Report 00-92.
Uppasit, S., Srisuk, K., Phongsatitpat, A. and Nadee, S. 2011. Site characterization for ponding recharge
system at Ban Nong Na, Phitsanulok Province, Thailand. The International Conference   on   “Geology,  Geotechnology  and  Mineral  Resources  of  Indochina”, Khon Kaen Province, Thailand.
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