Water quality and physical hydrogeology of the Amarapura township, Mandalay, Myanmar

Mandalay is a major city in central Myanmar with a high urban population and which lacks a central wastewater management system, a solid waste disposal process, and access to treated drinking water. The purpose of this study is to investigate the groundwater quality of local dug wells and tube wells, determine quantitative data on characteristics of the Amarapura Aquifer, and compare seasonal variations in groundwater flow and quality. Water samples were collected during the dry and wet seasons, then analyzed for major ion chemistry using ion chromatography to identify indicators of wastewater contamination transport to the shallow aquifer and to compare seasonal variations in groundwater chemistry. An open-source analytic element model, GFLOW, was used to describe the physical hydrogeology and to determine groundwater flow characteristics in the aquifer. Hydrogeochemistry data and numerical groundwater flow models provide evidence that the Amarapura Aquifer is susceptible to contamination from anthropogenic sources. The dominant water types in most dug wells and tube wells is Na-Cl, but there is no known geologic source of NaCl near Mandalay. Many of these wells also contain water with high electrical conductivity, chloride, nitrate, ammonium, and E. coli. Physical measurements and GFLOW characterize groundwater flow directions predominantly towards the Irrawaddy River and with average linear velocities ranging from 1.76 × 10−2 m/day (2.04 × 10−7 m/s) to 9.25 m/day (1.07 × 10−4 m/s). This is the first hydrogeological characterization conducted in Myanmar.


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Mandalay is a major city in central Myanmar with a population of 1,225,000 people that lack a wastewater management system, a solid waste disposal process, and access to treated drinking water. Myanmar only treats about 10% of its wastewater, and there is effectively no treatment in the city of Mandalay (United Nations World Water Assessment Programme, 2017).
The United Nations Development Programme reported drinking water quality and access to drinking water as one of the serious problems in Mandalay State (UNDP, 2014). The Asian Development Bank reports that there is a water point for every 80 households in Mandalay and that most of these are untreated, private supplies (ADB, 2013). Only 50% of the urban population has access to piped water in Mandalay, which consists of a mixture of untreated groundwater and surface waters (ADB, 2013). The Myanmar Water Resource Utilization Department reports that 68% of domestic water usage is from groundwater in Mandalay (Moe, 2013).
The Amarapura Township is an urban area on the south side of Mandalay surrounding Taung Tha Man Lake (TTML). No one in the Amarapura Township has access to piped water, so the people depend on tube wells, dug wells, or purchased purified bottled water (ADB, 2013).
The majority of these wells are within 1-50 meters of untreated wastewater canals that are in direct contact with the ground surface. It is important to investigate the physical and chemical properties of this groundwater system to identify indicators of wastewater contamination that pose a potential risk to the groundwater supply in the Amarapura Township.
In developing areas, such as the Amarapura Township, costs of software and licenses are major limiting factors when conducting this type of research. Programs such as Quantum Geographic Information System (2016) and GFLOW (Haitjema, 2016) were used because they are open-source programs that are easy to obtain in developing countries such as Myanmar.
QGIS provides the ability to project data spatially and GFLOW is used to assess groundwater flow throughout the study area. Digital elevation models (DEM) were chosen because of limitations on being able to conduct survey work with the proper equipment and in the time period allocated for the project. A workshop was conducted by Northern Illinois University at 3 Yadanabon University in December of 2016 for professors in Myanmar to teach the basics of hydrogeology and practice using this software.
The objectives of this first research study in Myanmar are to have a preliminary understanding of the physical and chemical hydrogeology of the Amarapura Township in Mandalay, Myanmar. This study 1) identifies drinking water contaminants and assesses water quality between dug wells, tube wells, and surface waters; 2) compares and identifies seasonal variations in groundwater flow and quality and yields quantitative data on the hydrogeologic properties of the Amarapura Aquifer using an analytical element model; and 3) uses open-source software programs that assist in educating the locals on issues in their region as they develop in the future.

CHAPTER 2: STUDY AREA AND GEOLOGY
Mandalay is in central Myanmar on the west side of Southeast Asia (Figure 1). Mandalay is the second largest city in Myanmar, containing about 1,225,000 people and a land area of approximately 160 square kilometers (UNDP, 2014). The city is about 70-80 meters above mean sea level (mamsl) in a flood plain for the Irrawaddy River between the Shan Plateau and the Sagaing Mountains ( Figure 1). The Irrawaddy River starts in the Himalayas, running north to south and cuts west on the south side of Mandalay. The Irrawaddy River is approximately 2,100 kilometers long, and its drainage basin is about 414,400 square kilometers (Kravtsova et al., 2008). Between Mandalay and Sagaing the river depth ranges between 9 and 15 meters, its width between 1,800 and 3,400 meters, and its flow rate between 2,000-17,000 m 3 /s (Kravtsova et al., 2008).
The Amarapura Township contains about 235,000 people and is located on the south side of Mandalay and is known locally for its textiles industry (UNDP, 2014). Taung Tha Man Lake (TTML) is an oxbow lake in the middle of the Amarapura Township on the south side of Mandalay (Kyi, 2005; Figure 1). Smaller streams from the Shan Plateau flow into TTML, and the Me-O Chaung is the outlet stream connecting TTML with the Irrawaddy River. The Myitnge River starts in the Shan Plateau, running east to west on the south side of the Amarapura Township. The Shwe-Ta-Chaung canal runs from Mandalay through the Amarapura region between TTML and the Irrawaddy River ( Figure 1). The Shwe-Ta-Chaung canal is one of the larger discharges of wastewater from the city of Mandalay into the Irrawaddy River.

Climate
Mandalay experiences monsoon rains and is considered to be a tropical savannah, averaging 1,161 millimeters of rain annually, with the majority (91%) of this coming during the wet season (Harris et al., 2014). Mandalay observes three seasons: a wet season (May-October), a dry season (October-May), and a cold season (October-February). Temperatures throughout the year range from 13°-39°C with an average between 20°-30°C. The wet season averages temperatures between 27°-32°C, the dry season averages temperatures between 23°-31°C, and the cold season averages temperatures between 20°-25°C. A summary of average precipitation 6 and temperature data from 1901-2014 is presented in Figure 2. Mandalay is subject to flooding during the wet season because of the intensity of the rain, its location in the Irrawaddy River flood plain, and higher rainfall rates in areas leading into Mandalay (Myitnge River/Irrawaddy River; Harris et al., 2014). Temperature and precipitation event data from the duration of the study is presented in Appendix A.

Geology and Hydrogeology
Mandalay is in an alluvial setting (Holocene Age) containing predominantly sands and gravels in a shallow aquifer, called the Amarapura Aquifer, from which most locals obtain their

Precipitation
Temperature groundwater for cooking, cleaning, and drinking (Htay et al., 2014;Moe, 2013). The Irrawaddy River is the major hydrologic feature in the area and its watershed extends into the Himalayas.
The Sagaing fault is an active strike-slip fault cutting north to south across the entire country and is located on the west side of the Irrawaddy River near Mandalay (Htay et al., 2014; Figure 3).  (Kyi, 2005).
No data on the hydrogeology of the city of Mandalay currently exists, and only one other peer-reviewed study has been conducted in Myanmar on the local hydrogeology. This was an inorganic chemistry study of groundwater quality in the Myingyan Township in Mandalay State (Bacquart et al., 2015). In this study, local groundwater samples were collected from tube wells, indicating unsafe levels of arsenic, manganese, fluoride, iron, and uranium. Other reports from the International Water Management Institute have collected basic hydrogeologic data in a region called the "Dry Zone" of Myanmar for improved water resource management practices 8 related to local agriculture strategies (Pavelic et al., 2015). This region includes Mandalay State but has focused on rural areas outside of the city of Mandalay.

CHAPTER 3: METHODOLOGY
Research was conducted during the wet and dry seasons in Mandalay, Myanmar. Wetseason sampling was conducted from July 20 th -August 12 th , 2016. Dry-season sampling was conducted from December 10 th -21 st , 2016. During the wet season the following activities were conducted: a field survey of groundwater wells in the Amarapura Township, drilling for grain size analysis, hydraulic conductivity measurements, water level measurements, groundwater modeling, geochemistry, E. coli testing, and stable isotope collection to determine δ 2 H and δ 18 O (Table 1). Geographical coordinates for tube wells, dug wells, surface-water sampling points, and other points of interest were taken using the built-in GPS of an iPhone 7. During the dry season, the following activities were conducted: water level measurements, slug tests (Tube wells YDB1, YDB2, and YDB3), water quality sampling, and E. coli testing (Table 1).
Geographical coordinates for tube wells, dug wells, surface-water sampling sites, and points of interest were taken using a hand-held Garmin GPSmap 62st system (Olathe, Kansas; Figure 4).
Pressure transducers were installed for long-term monitoring from July 25 th till December 13 th for YDB1 and YDB2.

Water Quality
During the dry and wet seasons, water from 13 dug wells, eight tube wells, and two surface-water sources were collected from TTML and the Irrawaddy River. Shwe-Ta-Chaung sewage canal was only sampled during the dry season ( Figure 4). These were tested for physico- Massachusetts) for all dug wells, tube wells, and surface-water samples. An injection volume of 13 25 μL and a five-point calibration curve were used in quantifying the results. Analysis was conducted to determine major cations including sodium (Na + ), potassium (K + ), calcium (Ca 2+ ), magnesium (Mg 2+ ), ammonium (NH4 + ), and lithium (Li + ). During major cation analysis a CS12A 4x250 mm column, a CERS 500 4 mm suppressor, and a 20 mM eluent of MSA were used. A 1 mL/minute flow rate and <60 mA current were established at room temperature during analysis.

Wastewater Indicators
Key indicators in major ion chemistry that may indicate contamination from wastewater in the subsurface are increased electrical conductivity (EC), total dissolved solids (TDS), chlorides (Cl), nitrates (NO3 2-), ammonium (NH4 + ), and E. coli (Bajjali et al., 2015;Fetter, 1999;Hassane et al., 2016;Lawrence et al., 2000;Lee et al., 2010;Nagarajan et al., 2010;Nas and Berktay, 2010). Chlorides in natural waters are typically below 100 ppm and nitrates below 10 ppm (Fetter, 1999). The presence of ammonium and E. coli are also often contributed from domestic wastewaters (Fetter, 1999;World Health Organization, 2008). Concentrations higher than these may indicate contamination from industrial discharges and/or sewage. These indicators have been used to show wastewater contamination of groundwater in other cities in Asia with similar wastewater problems, such as Hat Yai, Thailand, and Shanghai, China, where increases in many of these parameters were observed in groundwater wells towards the city center in close proximity to wastewater canals (Lawrence et al., 2000;Weng et al., 2006).
Chlorine-bromine ratios above 150 have also been shown to indicate wastewater contamination in areas without seawater intrusion (Vengosh and Pankratov, 1998).
Testing for E. coli was conducted using Aquagenx Compartment Bag Test (CBT) kits (Chapel Hill, North Carolina). This method was chosen because it did not require incubators or electricity. Water samples were collected from each sampling site in a sterile 100 mL Whirl-Pak bag ®. A chromogenic medium was added to the Whirl-Pak bag and allowed to dissolve for 15 minutes, before the water was transferred into a five-column Whirl-Pak bag. This bag separated the water into 5 mL, 10 mL, 15 mL, 20 mL, and 25 mL columns. This was allowed to sit for 24-48 hours depending on temperature. Each column would either change to a green color if positive or remain yellow if negative. A reference chart from Aquagenx was used to compare combinations to determine the most probable number (MPN) of E. coli per 100 mL (Stauber et al., 2014).

Stable Isotopes
Stable isotope samples were collected using 2.0 mL National Scientific Amber Glass I-D Target DP vials with septa caps. Vials were filled with no headspace. Rainfall samples were collected from three events during the wet season. Groundwater-well, surface-water, and rainevent samples were analyzed for δ 2 H and δ 18 O ratios using the Picarro L2130-I Cavity Ring Down Spectrometer (CRDS) by the University of Wyoming Stable Isotope Laboratory. Results were plotted on and compared to the Global Meteoric Water Line (GMWL) line. These were then used to compare sampling sites and to determine whether water was rain derived or from other sources.

Physical Hydrogeology
During the dry and wet seasons, 18 wells were examined ( Figure 4). These included 15 dug wells and three tube wells in the Amarapura Township (Table 2). Drilling was conducted at Yadanabon University to install YDB3 and to determine grain sizes. Hydraulic conductivities were determined in the three tube wells that were accessible (YDB1, YDB2, YDB3). Water level measurements were taken with a Heron Instruments 150-foot water level meter tape (Dundas, Ontario, Canada), two or three times in all dug wells and three tube wells during both field seasons. A numerical horizontal groundwater flow model, GFLOW, was used as a screening model to test the conceptual model and to determine groundwater flow velocities (Haitjema, 2016).

Drilling
Drilling for YDB3 (tube well) was done on the campus of Yadanabon University as part of a workshop. Drilling observations provided information on local tube well construction. These observations were key in analyzing and comparing chemical and physical data between seasons.
Grain size analysis was important information in understanding and confirming assumptions made about the Amarapura Aquifer. Grain size analysis was conducted for sediments collected from the drilling of YDB3. An attempt was made to identify a sediment core every foot, but the cores were sporadic and it was not always feasible to collect every foot. The samples were placed in Whirl-Pak bags and shipped to the United States for analysis. Dry-sieve grain size analysis was performed at Northern Illinois University to determine the percentage of sand, silt, and clay in each section.
Five USA ASTM-standard testing sieves were used: gravel (≥1.41 mm), course sand (0.35-1.41 mm), medium sand (0.125-0.35 mm), fine sand (0.062-0.125 mm), and silts/clays (<0.062 mm) were caught in a pan at the bottom. Porosities were estimated from Fetter (2001) using the percentages of grain size determined in the sieve grain size analysis. Hydraulic conductivities were estimated using Hazen's approximation (West, 1995). Appendix C contains the YDB3 core log.

Hydraulic Conductivity Measurements (K)
Hydraulic conductivities were determined by conducting falling and rising head slug tests in two tube wells (YDB1 & YDB2) in the Amarapura Aquifer during the wet season and three tube wells (YDB1, YDB2 & YDB3) during the dry season. Heads were measured every second during the slug test with an In-Situ, Inc. Rugged Troll 100 pressure transducer (Fort Collins, Colorado). Hydraulic conductivities in YDB1 and YDB2 were evaluated using a high hydraulic conductivity method developed by the Kansas Geological Survey because of the oscillatory behavior observed of the water level in the well during the slug test caused by the formation being highly permeable, which violated common assumptions used in the Hvorslev method (Butler et al., 2003). The Hvorslov method was used to determine hydraulic conductivity in YDB3 because it did not exhibit oscillatory behavior in the water levels during the slug test nor violate other assumptions in the Hvorslov method (Fetter, 2001).

Groundwater Level Measurements
Depth to groundwater from the top of casing was measured using a Heron Instruments 150-foot water level meter tape accurate to 0.01 decimal feet in all dug wells, as well as tube wells YDB1, YDB2, and YDB3. Depth to water, stickup, and total depth were measured in all wells (Appendix D). All other tube wells were in use and total depths provided by their owners. An In-Situ, Inc. Rugged Troll 100 (Fort Collins, Colorado) and Solinst Levelogger 3001 (Georgetown, Ontario, Canada) pressure transducers were installed in YDB1 and YDB2 to conduct long-term monitoring of water levels from July through December 2016.
Groundwater Modeling GFLOW is a 2D numerical code based on the analytical element method using line elements and the Poisson equation as the governing equation (Haitjema, 2016). Line elements represent hydrologic features, such as stream and lake boundaries. GFLOW was used to simulate steady-state groundwater flow based on head measurements taken during the dry and wet seasons in order to examine groundwater flow during these two time periods. These regional groundwater flow models were then used to test the validity of the conceptual model, simulate seasonal groundwater flow, map the location of groundwater divides, and determine average linear groundwater flow velocities (vx) across the site.
A conceptual model was created based on local hydrologic features, preliminary water level measurements, electrical conductivity measurements, and initial hydraulic conductivities.
The initial parameters for the model were 67 m/day for hydraulic conductivity (K) and 0.301 m/day for recharge (R). Hydraulic conductivity was measured on site and recharge was estimated using precipitation data from the CRU (Harris et al., 2014). Data from the International Water Resource Institute's hydrogeologic study in the dry zone of Myanmar estimated infiltration rates at 10% of annual rainfall (Pavelic et al., 2015). In the unconfined Amarapura Aquifer, connected with the Irrawaddy River, infiltration is assumed to equal recharge. Therefore, recharge was estimated as a percentage of precipitation (10%). Average linear groundwater flow velocities were calculated in each hydraulic conductivity zone from modeled data using the average linear velocity equation ( The groundwater flow model was calibrated using the head measurements from both the tube and dug wells during the dry season because the dry-season head measurements represented groundwater flow at a more steady state than in the wet season. Initial calibration was done manually by sensitivity analysis, and once approximate values were obtained, the PEST (Haitjema, 2016) module was used. Sensitivity analysis was used to determine the hydraulic conductivity zones and estimate effective porosity (ne) for the site by determining the values that 20 provided a better calibration. PEST is an automated parameter estimation algorithm that determines ideal values for parameters such as hydraulic conductivity (K) and recharge (R).
Once calibrated, average linear velocities (vx) were calculated in each hydraulic conductivity zone.
Both the initial parameters as well as those determined through sensitivity analysis and

Field Survey
The city of Mandalay has access to piped water, but many people in the outlying areas rely on old dug and tube wells for access to water resources, thus the population in the Amarapura Township obtain their water supply from groundwater by access to dug and tube wells. Dug wells are about a meter in width and range from 7-15 meters deep in mixed mediumcoarse sand and gravel layers ( Figure 5). The dug wells are lined with brick and contain concrete pads at the top, but these pads do not always direct water away from the well. The dug wells are community wells that are shared between sections of each community. The number of people that use these on a daily basis is unknown but is estimated to be from 50-100 people per well (ADB, 2013). Most often, the locals use a small bucket to extract water from the well, but a few contain pumps to bring water to the top. Dug wells are primarily used for cooking, cleaning, and bathing. These activities occur directly next to the well and the buckets are not sanitary. Buckets were usually made of excess rubber from tires or steel. From conversations with well owners, most people report their water tastes salty. They also claimed that many of these dug wells go dry during March and April (at the end of the dry season).
Many people have access to tube wells, which are shared among individual families or for private business purposes, such as the textile industry. The tube wells range from 15-60 meters deep and are usually installed by local drillers using a primitive drilling method. Often these wells were installed next to an old dug well (Table 3). Most tube wells had hand pumps, 22 but a few had compressors. Many of the owners who used hand pumps reported they could not access water during the months of March and April due to low groundwater levels.  other studies indicating anthropogenic contamination from wastewater sources (Table 5; Vengosh and Pankratov, 1998). Full water quality data is presented in Appendices E, F, G, and H.  Piper diagrams are used to classify water types (Figures 6 and 7). Major ion chemistry revealed the water types in this system to be predominantly Na-Cl. The predominant water type in dug wells, tube wells, and TTML in both seasons were Na-Cl type. Secondary water types such as Ca-Cl, Ca-HCO3, Na-SO4, and Na-HCO3 were also present in the Amarapura Township. Colors represent different regions of the study site: Blue represents wells on the east side of TTML. Pink represents the wells on the northeast side. Green represents the wells in the lower hydraulic conductivity zone around the north and west edges of the lake. Red represents the wells around the groundwater divide. Gray wells represents wells between TTML and the Irrawaddy River on the south side. Filled in yellow represent wells further north of the Amarapura Township near one of the major wastewater canals. Yellow with no filling represent wastewater from the Shwe-Ta-Chaung canal. Light blue represents surface waters. Figure 7. Piper diagram-Wet season. Colors represent different regions of the study site. magnesium (0-40%). Wastewater samples also contained high proportions of sulfate and chloride (90-95%), but contained a higher proportion of sodium (50-60%) than calcium (20-30%). TTML's water type is also Na-Cl and is very similar to groundwater samples, but contains a slightly lower proportion of carbonate and bicarbonate anions (10%) than the Irrawaddy River (20-40%). In the Irrawaddy River, a Ca-SO4 water type is observed towards the north side of the river during both the wet and dry seasons. During the dry season, sampling was extended further south, revealing a shift from sulfate to bicarbonate as the dominant anion, but was a minor shift.

Electrical Conductivities
Electrical conductivity (EC) is a common measurement used to evaluate water quality. The few that did not were the dug wells located closer to TTML (DW4, DW5, and DW11). In the region between TTML and the Irrawaddy River, a divide was noticed between higher and lower values of EC. Higher values (>1200 μS/cm) were located on the west side (closer to the Shwe-Ta-Chaung canal) and lower values (<1200 μS/cm) were observed on the east side (closer to TTML). This was identified as a potential groundwater flow divide. Data is presented in Appendix E and summarized in Table 4.

Total Dissolved Solids
Total dissolved solids (TDS) is a commonly used water quality parameter to describe the presence of inorganic salts in the water. The World Health Organization (2008)  ppm. In the dry season, 72% of groundwater samples exceed the average, and 56% exceed the range maximum. Data is presented in Appendix G and summarized in Table 5.

Nitrates and Ammonium
Nitrate and ammonium contamination has been documented in a number of areas from anthropogenic sources (Fetter, 1999). Nitrates (NO3 as N) above 10 ppm and the presence of ammonium in urban areas often indicate influences from domestic wastewater (Fetter, 1999).
Ammonium concentrations ranged from 0.05-3.14 ppm and averaged 0.15 ppm. Ammonium was present in 44% of wells during the wet season and 17% during the dry season. Nitrates ranged from 0.10-331.07 ppm and averaged 55.68 ppm; 56% of nitrates exceeded 10 ppm during the wet season, and 61% during the dry season. Data is presented in Appendix G and summarized in Table 5.

Cl/Br Ratios
Chlorine-bromine ratios (Cl/Br) have been used to determine the influence of wastewater contamination in regions without seawater influences (Vengosh and Pankratov, 1998). In this study, Cl/Br ratios from domestic wastewater are greater than 400 and 150 for groundwater contaminated with domestic wastewater (Vengosh and Pankratov, 1998). During the wet and dry seasons, 70% of dug wells exceeded the Cl/Br ratio for groundwater. In tube wells, 38% and 63% exceeded this ratio during the wet and dry seasons, respectively. Cl/Br ratios are summarized in Table 5.

E. coli
E. coli is measured in "most probable number" (MPN) per 100 mL, and detection of E.
coli at any level is considered unsafe for drinking water. During the wet season, 100% of dug wells and 33% of tube wells sampled contained unsafe levels of E. coli for drinking water.
During the dry season, 86% of dug wells and 11% of tube wells sampled contained unsafe levels of E. coli for drinking water. E. coli counts in most dug wells (>55%) exceeded 100 MPN/ 100 mL during both seasons, which is the United States Environmental Protection Agency (2012) recreational limit. Only two wells (DW7 and DW15) during the dry season did not contain any.
E. coli was only detected in one tube well (YDB1) during the dry season and two tube wells (WWTP2 and LS1) during the wet season. E. coli counts are high in most dug wells compared to tube wells, but it is difficult to draw a direct correlation between E. coli and sewage infiltration to the wells because of hygiene practices that occur around these wells every day. Either way this is most likely from anthropogenic causes. E. coli results are presented in Appendix H and summarized in Table 6. Stable Isotopes All isotopic values of δ 2 H and δ 18 O are presented in Appendix I. Figure 8 shows the local meteoric water line (LMWL) to be similar to the global meteoric water line (GMWL). All of the samples tested for δ 2 H and δ 18 O fall on the LMWL/GMWL. This shows groundwater being recharged by recent rain events, meaning this system is unconfined, supporting the conceptual model. From this we can assume the Amarapura Aquifer does not contain significant evaporite deposits that would account for the Na-Cl water type or high concentrations of these ions. It can be assumed that all waters in the Amarapura Aquifer are directly recharged by recent precipitation events, indicating all the wells are in the unconfined Amarapura Aquifer. YDB1 is the tube well plotted between most wells and precipitation events, further proving that its chemical type change between seasons is influenced by overland flow.

Drilling
Drilling was conducted to install tube well YDB3 in December 2016 using a local drilling technique similar to the cable tool method. One driller used bamboo sticks to lift and drop a steel pipe repeatedly to loosen unconsolidated material. A second driller covers and uncovers the top of the steel pipe to create suction, which helps to bring the surficial material to the top. If extra water is needed to break up aggregates stuck in the pipe, additional water is poured down the pipe (https://www.youtube.com/watch?v=bdZ2RHFOqEs&t=1s). Water poured down the pipe was not cleaned prior to use but was taken from a nearby retention pond. Typically, the annulus 33 is backfilled with material taken out of the borehole or allowed to collapse around the casing.
Development of the well was not done.  Overall, these hydraulic conductivities are in agreement with the types of sediments observed from the grain size analysis of YDB3.

Water Level Measurements
Long-term monitoring of water levels in YDB1 and YDB2 was conducted to observe changing conditions over the duration of the study. Long-term monitoring showed transient conditions of water levels between seasons (Figure 9). Water levels generally declined between the wet and dry seasons and often spiked 1-2 meters during rain events. Heads varied from approximately 66-71 mamsl.
During both seasons, heads in the Amarapura Aquifer were relatively shallow. Heads range from 64-71 meters across the Amarapura Aquifer and were approximately 2-6 meters higher during the wet season than the dry season. These heads are tremendously affected by heavier thunderstorms/prolonged rain events and additional inflow of water from the Irrawaddy River and other surface-water features in the region. The Amarapura Aquifer's high hydraulic conductivity (50-70 m/day) allows water to flow in and out of the aquifer with higher average linear velocities (9.25 m/day) causing quick water level fluctuations during rain events.
This means water levels in this alluvial aquifer are susceptible to changing weather conditions.
During the wet season water levels were transient and reflected changing weather conditions. The initial groundwater flow conceptual model of our groundwater flow system was from east to west towards the Irrawaddy River. Head measurements on the east side of TTML appeared to be rising during the wet season periodically, which suggested the system was controlled by the water level in the Irrawaddy River. A potential groundwater divide was noticed when taking electrical conductivity measurements between TTML and the Irrawaddy River. The electrical conductivities appeared to be high (>1200 μS/cm) towards the west side and low (<1200 μS/cm) towards the east side ( Figure 10). When oscillating slug test data were seen and hydraulic conductivity on the order of 67 m/day was calculated, it could be assumed there were areas of lower gradients across the site.

Initial Parameters
The infiltration percentage of 10% from the IWMI report was applied to the CRU average annual rainfall data for Mandalay of approximately 1100 mm/year (Harris et al., 2014;Pavelic et al., 2015). Therefore, recharge is 110 mm/year (3.01x10 -4 m/day). An effective porosity of 25% is assumed in calculating average linear velocities (vx) for comparison with modeling results. To express the actual velocity at which groundwater flows through the porous material of the Amarapura Aquifer, average linear groundwater flow velocities were calculated from measured heads. Average linear groundwater flow velocities ranged from 3.38x10 -2 m/day to 9.25 m/day and averaged 7.54x10 -1 m/day.     The dry season model shows a potentiometric surface map of heads across the study site.
Modeled heads in meters above mean sea level (mamsl) are represented in Figures 13 and 14  groundwater divide in the region between TTML and the Irrawaddy River (see Figure 13).

Wet Season Model
Groundwater flow was predominantly towards the Irrawaddy River during the wet season. Gradients were decreased across the site, and the groundwater divide between TTML and the Irrawaddy River was not present when heads were increased during the wet season (see

Water Quality and Wastewater
In Southeast Asia, management of wastewater, or lack thereof, has posed a major problem and contamination issue to groundwater and surface waters (ADB, 2013). In Myanmar, wastewater is considered to be the most important water quality issue in urban areas, such as Mandalay and the Amarapura Township (ADB, 2013; Moe, 2013;UNDP, 2014). In this study, the water quality of the Amarapura Aquifer was examined to determine if the main source of pollution is wastewater. Na-Cl water types have been observed in many groundwater systems that were contaminated with urban wastewaters (Bashir et al., 2015;Hassane et al., 2016;Lee et al., 2010). In our study, Na-Cl water types were observed and water quality parameters determined elevated levels of total dissolved solids, electrical conductivity, chlorides, nitrates, ammonium, and E. coli. These water quality parameters have been used to indicate contamination of groundwater from wastewater sources (Bajjali et al., 2015;Hassane et al., 2016;Lawrence et al., 2000;Lee et al., 2010;Nagarajan et al., 2010;Nas and Berktay, 2010).
Cl/Br ratios are also used as a key parameter to determine the extent of groundwater contamination from wastewater sources (Vengosh and Pankratov, 1998). From a combination of these factors, it is determined that wastewater from local sewage canals contaminates shallow wells in the Amarapura Aquifer.
Previous studies on wastewater contamination of groundwater in other regions of the world have resulted in similar water types, for example Na-Cl (Bashir et al., 2015;Hassane et al., 2016;Lee et al., 2010). Geochemistry data yields a predominant Na-Cl water type across the Amarapura Aquifer, which is most likely the result of infiltration by urban wastewaters because there is no known local source of halite. Not being in an arid environment, it is unlikely that evaporation would play a major role in the precipitation of Na-Cl. Further, stable isotope data does not show the presence of an evaporite line (see Figure 8). All stable isotope data of δ 2 H and δ 18 O plotted on the global meteoric water line (GMWL) and local meteoric water line (LMWL), suggesting these wells are all directly recharged by recent rain events (Clark and Fritz, 1997).
In sampling of the Irrawaddy River, a Ca-SO4 water type is observed towards the north side of the river during both the wet and dry seasons. During the dry season, sampling was extended farther south, revealing a change in water type to Ca-CO3. It is believed this is the dominant water type because of the local calcite deposits, and the sulfate anions are influenced in these surface waters from the weathering of barite (Adamu et al., 2014;Baldi et al., 1996). Myanmar has begun development of its industrial infrastructure with help from other countries across the region and world. The water quality data presented here will serve as a baseline prior to development. Many sources of pollution still exist within Mandalay. The water quality data and an uneven spatial distribution and high concentration of other ions such as ammonium, nitrates, and chlorides suggest that this likely results from anthropogenic wastewater sources. The presence of ammonium, nitrates above 10 ppm, and chlorides above 100 ppm typically indicates influence from domestic wastewater (Fetter, 1999). High sulfate levels are also observed but are likely from barite (BaSO4) deposits in the Shan Plateau. It is expected that calcite (CaCO3) and barite (BaSO4) would be the dominant water types in this area because they are present in the local source rocks.
Another indicator of anthropogenic waste is E. coli. The presence of E. coli is commonly related to human waste, can cause severe diarrhea, and is often associated with other waterborne pathogens (World Health Organization, 2008). In Myanmar, it is estimated that 38 children per 1000 live births (3.8%) in Myanmar die before the age of 5, which is mainly attributed by waterborne diseases and malnutrition (Pavelic et al., 2015). During the wet season, 100% of dug wells and 33% of tube wells sampled contained unsafe levels of E. coli for drinking water.
During the dry season, 86% of dug wells and 11% of tube wells sampled contained unsafe levels of E. coli for drinking water. High levels of E. coli in these wells may be due to wastewater canals, but may also just be from poor hygiene practices by those using the wells. DW10, being within 5 meters of the Shwe-Ta-Chaung sewage canal is more likely to have been contaminated by local wastewater. Locals using water from this well knew not to drink the water but still used it for cleaning dishes and taking baths, which could still potentially pose a health risk.
A few groundwater wells had different water types between seasons (YDB1, SVD, SA2, and DW4) and are likely due to contamination from other anthropogenic sources because of improper well construction. YDB1 changed water types between seasons from Na-SO4 during the wet season to Ca-CO3 during the dry season. This is likely due to overland flow of water during the wet season going directly into the well. YDB1 only has about 3 cm of stickup and is covered with a brick, which does not protect it from water flowing into it when flash floods are above 3 cm, which occurs frequently during monsoon season. CaCO3 is consistent with the dominant water type suspected to be present in this system, especially in deeper wells, because there is evidence of calcite deposits in this area. SVD changed from Na-HCO3 to Na-Cl, which may be due to changing groundwater flow directions between seasons near TTML. SA2 changed from Ca-Cl to Na-Cl between seasons, but this was a minor change that plots very close to one another on the Piper diagram and is not significant. DW4 changed from Na-Cl to Ca-Cl but was also a minor change on the Piper diagram.
Contamination of the shallow aquifer system can have a negative impact on the health of those using water from dug and tube wells in the Amarapura Township. It is possible that many of these health effects have gone unnoticed because health surveys haven't been conducted.
Local infrastructure is needed to build lined wastewater canals or underground sewers to protect water sources, and treatment plants are needed, which has been shown to reduce wastewater's impact on shallow groundwater systems (Foster et al., 2011). Numerical modeling can be used as guidance for resource management and determining protective zones for wells (Foster et al., 2011). A safe and accessible municipal supply would also reduce the number of private wells 49 being used and make management strategies more controlled (Foster et al., 2011). Other small things can be done as short-term solutions, such as building concrete pads that direct wash and wastewater next to a well away from it and into a lined canal (Schneider, 2014). Better construction of deeper tube wells can also help to improve the quality of the water people in the Amarapura Township are drinking (Schneider, 2014).

Well Construction
Well construction is often a major issue in the developing world when trying to provide clean water to those living there. Dug and tube wells both contain many issues with their construction that make them vulnerable to contamination. Variations and combinations of cable tool percussion, air rotary, mud rotary, auger, and reverse circulatory rotary are often used to manually construct groundwater wells (Schneider, 2014). Well construction is a very important aspect to supplying and maintaining clean water in these areas. With the proper information and materials, simple improvements can be made to improve the construction of tube wells and further the quality of groundwater. This change could impact 68% of domestic water usage in the Amarapura Township (Moe, 2013).
While dug wells are not usually used for drinking, dug wells had been created with brick liners over 50 years ago. Typically, the bottom of the dug wells were just naturally occurring sand layers. No cover existed for these dug wells, which left them vulnerable to debris collecting inside these wells. Additionally, the large diameter, heavy usage, and local hygiene practices left it vulnerable to surface contaminants. In two dug wells, fish were observed, which locals used to determine the water quality. Hence, if the fish died they knew not to use the water but otherwise considered it safe. Since the local population depend on dug wells, water quality could be improved by pumping water to the top in closed containers, where chlorination could be used as a treatment. Covering the wells and extending concrete pads on top to divert used water away from the well would also help to improve the water quality of dug wells. Tube wells did not contain any kind of sand pack, grouting, or annular surface seal to prevent infiltration of surface contaminants directly to the screen of the tube well (Schneider, 2014). Many of these did not contain a cap, and YDB1 had a stickup of only 3 cm, leaving it vulnerable to overland flow.
Often, during construction unfiltered/unclean water from local ponds were dumped down the well, and no well development was attempted.
The drilling techniques and bamboo tools used in Myanmar are similar to the cable tool percussion method developed by the Chinese 4000 years ago (Driscoll, 1986). While this technique is uncommon in the modern era, modified drilling techniques are common in many other developing countries (Schneider, 2014). Modern drilling techniques are costly and often require equipment that is not accessible. The lack of access to information on proper well construction and development has caused many of these wells to be more vulnerable to surface contaminant sources (Schneider, 2014).
Many locals install tube wells because they know they provide better drinking water quality. Tube wells are safer than dug wells for drinking water purposes because they are deeper and have a screened interval. They also do not have the component of human-infected buckets being dumped directly into them to retrieve water but instead have a hand or compressor pump for obtaining water from them. However, this was not always the case. Many of the wells with varying water chemistry between seasons are tube wells. This is likely due to the way in which they were constructed. Without a proper sand pack or grout in the annulus many of these wells have open space between the surficial material and the well casing. This makes these tube wells vulnerable to contamination, especially when there is a high amount of overland flow from rain or from practices of washing and cleaning directly next to the well. During the dry season, water chemistry revealed water types similar to the surrounding geology, suggesting that a higher amount of contamination occurs during the wet season.
During the workshop in December of 2016 with professionals in the field of geology and water quality in Myanmar, YDB3 was installed at Yadanabon University to discuss and point out improvements to their current methods. Guidebooks on water supply well guidelines for use in developing countries were provided to these participants to provide a reference for future construction of tube wells (Schneider, 2014). Hopefully, by providing this information to local professionals in similar fields, the information will begin to spread and standard well construction practices will improve over time. More hands-on applications with local professionals will help, but experienced drillers are still needed to further emphasize these points in Myanmar.

Groundwater Flow
The groundwater flow models of the Amarapura area are the first of any kind in the country of Myanmar. Little is known about the local groundwater flow systems and the variability that may exist between seasons or the influences from TTML and the Irrawaddy River. The physical conditions of an aquifer play a major role in the potential contamination to the groundwater from surface contaminants because this controls the wastewater's ability to penetrate the subsurface. These models were used to provide additional information in understanding this regional groundwater system. Improvements can be made, but these models provide information on key characteristics of the Amarapura Aquifer to be investigated for a better calibration in future studies of this region.
The physical hydrogeology of an area plays an important role in the potential for surface contaminants to infiltrate into the shallow Amarapura Aquifer. The Amarapura Aquifer contains predominantly coarse-medium sands with gravels, which creates a high range of hydraulic conductivities. Its high hydraulic conductivities (67 m/day) and high average linear velocity (2.10 m/day) allow water/contaminants to flow in and out of the Amarapura Aquifer. The surface water to groundwater interaction was observed by changing heads in reaction to changing weather conditions (Haitjema, 2012). Heavy thunderstorms/prolonged rain events cause additional inflow of water from the Irrawaddy River and other surface water features in the region.
The analytical element groundwater flow models showed the conceptual model to be correct, and groundwater does predominantly flow towards the Irrawaddy River. Sensitivity analysis showed hydraulic conductivity to be a key physical characteristic of this groundwater flow system. In the model calibration, four hydraulic conductivity zones were identified (see Figure 11). Sensitivity analysis also showed the lake stage of TTML to be a major factor in the model calibration. When the head of TTML was raised 1-2 meters there was an improvement in the model calibration. This could be due to the potential 2-3 meter error in our digital elevation model in assigning these head measurements. Errors in the digital elevation model have been observed in another study, especially with smaller streams (Fredrick et al., 2006). However, in general, flow directions and groundwater divides did not change significantly with this elevated head in TTML. Measurements of recharge (R), hydraulic conductivity (K), and average linear groundwater flow velocities (vx) in the model provided results within the same order of magnitude as the field measurements. This further validated our final model and assumptions provided by the sensitivity analysis and the PEST module.
Seasonal differences in groundwater flow existed between the dry and wet season models. The dry season model showed the influence of TTML on the shallow groundwater system, which creates a groundwater divide between TTML and the Irrawaddy River. However, this groundwater divide is not seen in the wet season model when heads are higher. Groundwater gradients also spread farther apart during the wet season and show slower average groundwater linear velocities (vx). This groundwater divide likely disappears because of a less permeable sediment layer at a particular head or because with such a high influx of water during the wet season the influence of TTML becomes negligible. Meaning, when more water is added to the system during the wet season, groundwater and surface water heads are more consistent across the region. This could potentially allow for rapidly rising heads in TTML and the Irrawaddy River during monsoon rain events to cause reverse flow conditions for short periods of time (2-10 days). Modeling results were also used to compare geochemical differences across the site between seasons. As presented earlier, there were very few major geochemical differences and were not suspected to be a result of physical flow differences. However, at the beginning of this project, electrical conductivity measurements were used in identifying the potential groundwater divide. During modeling, the hydraulic conductivity zones around TTML were identified and also showed similar geochemical characteristics. Wells in the low hydraulic conductivity zone (K2) near TTML typically had a lower TDS. Wells in the higher hydraulic conductivity zone (K3) near TTML typically had a higher TDS. These zones around the lake should be considered in future conceptual models of this area and tested further to determine their validity. Future models could also look into specific contaminants in specific wastewater canals to determine whether these contaminants are traveling along these groundwater flow paths and infiltrating into the local wells.
This initial model provides a general characterization of the regional groundwater flow and offers the first of its kind in the country of Myanmar. Many improvements would be needed to improve the accuracy of the calibration, such as properly surveying wells, long-term monitoring of surface water heads/stages, and a watershed model for the Irrawaddy River.
Additionally, from the transient conditions observed and fast groundwater velocities, an improved time-series monitoring system of groundwater heads, surface water heads, and velocities of the rivers/streams would be needed to accurately determine the full extent to which the Irrawaddy River influences flow conditions in the Amarapura Aquifer during the wet season. Open-Source Software Open-source software such as GFLOW and QGIS were used in this project because they are free and don't require licenses. QGIS contains numerous instructional videos and documents that give assistance on how to use the software (www.qgis.org, 2016). GFLOW contains instructional documents that assist using the software and understanding the assumptions made in the groundwater model (Haitjema, 2016). The software is just as effective as using any other software that could have been chosen for the tasks necessary in this project but contained challenges when transferring this information to local professors in Myanmar, such as Internet access and language barriers.
Many of the challenges in a country like Myanmar concern accessibility. Myanmar is still fairly secluded and updating its local infrastructure. Even when the technology is available, other services such as Internet service are not. The Internet service in Mandalay is still very slow and often not working. This makes downloading large software files difficult and often impossible.
Accessibility to Internet is only available during regular work hours at the university but is often not working due to technical reasons or blackouts. QGIS contains many help videos, but this was not an option if the 3-minute video takes 2 hours to complete loading. Open-source maps, such as Google maps, were often blocked by government Internet services or technology. QGIS is moderately technical and difficult to be taught in a short course to non-English speakers.
Instructional videos and documents are also in English, which not everyone there can understand easily. GFLOW is very technical and requires a basic understanding of groundwater modeling. However, many of the local geology professors are just receiving their first course on the basics of hydrogeology, which causes another barrier. Improved accessibility to these materials are needed to be successful for projects such as this one to start improving research and site investigations in Myanmar. This would require a reliable Internet system that does not censor simple items, such as Google maps. During our second trip many of these problems were solved by bringing flash drives pre-loaded with all of the software and materials. Open-source software is a great starting point for universities such as Yadanabon University to start producing higher quality research, but more support is needed locally. Local investment and commitment to projects such as this are needed for them to be successful in the future and to continue to improve in the field of hydrogeology in Myanamar.
The chemical and physical properties of the Amarapura Aquifer suggest that urban wastewater in the Amarapura Township is the predominant source of contamination to the shallow groundwater system. Seasonal variations occur for both physical and chemical properties of the Amarapura Aquifer, which include varying water types, higher concentrations of chemical ions during the wet season, transient water levels, changing groundwater divides, and gradients.
Its high hydraulic conductivities (67 m/day) allows for groundwater and contaminants to flow in and out of the Amarapura Aquifer with high average linear velocities (2.10 m/day). Therefore, chemical and physical data suggest wastewater plays a major role in contamination of shallow groundwater wells in the Amarapura Township. Future Research Future research should include further chemical and physical analysis. Testing for volatile organic compounds (VOC) and additional metals should be conducted because the potential for VOCs is high. Identification of potential contamination sources, such as the textiles industry, and their effect on the water quality should be analyzed in more detail. Identification of other industrial sources of wastewater and incoming industries should be conducted. This can then be used to determine additional effects on water quality as more industries move in and tourism begins to expand. Continued drilling to develop a hydrogeologic cross-section, or map, should be done to better understand the local hydrogeology. Additional slug tests or pump tests in wells in each of the K-zones should be done to provide field measurements to support or disprove the current groundwater flow model. Proper surveying of wells should be done to eliminate an additional source of error so the model can be better calibrated and key parameters narrowed. Sampling outside of the city limits, away from wastewater influences, would provide ideal background levels of various indicator chemicals to compare current and future data with.
Further, continued monitoring throughout the year of groundwater level heads, river heads, and lake heads should be conducted to further understand the seasonal variations in flow. This could also help determine if reverse flow conditions occur during intermittent times of the wet season.