Joshua F. Valder

Hydrogeologic framework and groundwater conditions of the Ararat Basin in Armenia

Armenia is a landlocked country located in the mountainous Caucasus region between Asia and Europe. It shares borders with the countries of Georgia on the north, Azerbaijan on the east, Iran on the south, and Turkey and Azerbaijan on the west. The Ararat Basin is a transboundary basin in Armenia and Turkey. The Ararat Basin (or Ararat Valley) is an intermountain depression that contains the Aras River and its tributaries, which also form the border between Armenia and Turkey and divide the basin into northern and southern regions. The Ararat Basin also contains Armenia’s largest agricultural and fish farming zone that is supplied by high-quality water from wells completed in the artesian aquifers that underlie the basin. Groundwater constitutes about 40 percent of all water use, and groundwater provides 96 percent of the water used for drinking purposes in Armenia. Since 2000, groundwater withdrawals and consumption in the Ararat Basin of Armenia have increased because of the growth of aquaculture and other uses. Increased groundwater withdrawals caused decreased springflow, reduced well discharges, falling water levels, and a reduction of the number of flowing artesian wells in the southern part of Ararat Basin in Armenia. In 2016, the U.S. Geological Survey and the U.S. Agency for International Development (USAID) began a cooperative study in Armenia to share science and field techniques to increase the country’s capabilities for groundwater study and modeling. The purpose of this report is to describe the hydrogeologic framework and groundwater conditions of the Ararat Basin in Armenia based on data collected in 2016 and previous hydrogeologic studies. The study area includes the Ararat Basin in Armenia. This report was completed through a partnership with USAID/Armenia in the implementation of its Science, Technology, Innovation, and Partnerships effort through the Advanced Science and Partnerships for Integrated Resource Development program and associated partners, including the Government of Armenia, Armenia’s Hydrogeological Monitoring Center, and the USAID Global Development Lab and its GeoCenter. The hydrogeologic framework of the Ararat Basin includes several basin-fill stratigraphic units consisting of interbedded dense clays, gravels, sands, volcanic basalts, and andesite deposits. Previously published cross sections and well lithologic logs were used to map nine general hydrogeologic units. Hydrogeologic units were mapped based on lithology and water-bearing potential. Water-level data measured in the water-bearing hydrogeologic units 2, 4, 6, and 8 in 2016 were used to create potentiometric surface maps. In hydrogeologic unit 2, the estimated direction of groundwater flow is from the west to north in the western part of the basin (away from the Aras River) and from north to south (toward the Aras River) in the eastern part of the basin. In hydrogeologic unit 4, the direction of groundwater flow is generally from west to east and north to south (toward the Aras River) except in the western part of the basin where groundwater flow is toward the north or northwest. Hydrogeologic unit 6 has the same general pattern of groundwater flow as unit 4. Hydrogeologic unit 8 is the deepest of the water-bearing units and is confined in the basin. Groundwater flow generally is from the south to north (away from the Aras River) in the western part of the basin and from west to east and north to south (toward the Aras River) elsewhere in the basin. In addition to water levels, personnel from Armenia’s Hydrogeological Monitoring Center also measured specific conductance at 540 wells and temperature at 2,470 wells in the Ararat Basin using U.S. Geological Survey protocols in 2016. The minimum specific conductance was 377 microsiemens per centimeter (μS/cm), the maximum value was 4,000 μS/cm, and the mean was 998 μS/cm. The maximum water temperature was 24.2 degrees Celsius. An analysis between water temperature and well depth indicated no relation; however, spatially, most wells with cooler water temperatures were within the 2016 pressure boundary or in the western part of the basin. Wells with generally warmer water temperatures were in the eastern part of the basin. Samples were collected from four groundwater sites and one surface-water site by the U.S. Geological Survey in 2016. The stable-isotope values were similar for all five sites, indicating similar recharge sources for the sampled wells. The Hrazdan River sample was consistent with the groundwater samples, indicating the river could serve as a source of recharge to the Ararat artesian aquifer. 2 Hydrogeologic Framework and Groundwater Conditions of the Ararat Basin in Armenia Introduction Armenia is a landlocked country located in the mountainous Caucasus region between Asia and Europe. It shares borders with the countries of Georgia on the north, Azerbaijan on the east, Iran on the south, and Turkey and Azerbaijan on the west (fig. 1). Armenia has an area of about 29,700 square kilometers (km2). Its population in 2015 was approximately 3 million (U.S. Census Bureau, 2016). Approximately onethird of the population lives in the capital city of Yerevan (World Population Review, 2016). Groundwater supplies 96 percent of the water used for drinking water purposes, and about 40 percent of all water withdrawn in the country is from groundwater (Yu and others, 2014). Agriculture depends heavily on groundwater irrigation and more than 80 percent of the gross crop production is from irrigated lands (Yu and others, 2014). The Ararat Basin lies between the Caucasus Mountains to the north and the Armenian Plateau to the south. The Aras River divides the basin into northern and southern regions and also forms Armenia’s border with Turkey (fig. 1). Elevations within the Ararat Basin range from 800 to 1,000 meters (m) (fig. 2, table 1). The Ararat Basin occupies an area of about 1,300 km2 (Armenian Branch of Mendez England and Associates, 2014). About 8 percent of the population of Armenia lives in the Ararat Basin (U.S. Agency for International Development, 2008). The Ararat Basin supports the largest agriculture and fish farming zones in Armenia (Yu and others, 2014). Table 1. Lithologic descriptions, land-surface elevations, geologic layer thicknesses, and hydrogeologic units of the Ararat Basin, Armenia (available online at https://doi.org/10.3133/ sir20175163). Since 2000, aquaculture demands and other uses have increased groundwater withdrawals in the Ararat Basin. Increased groundwater withdrawals resulted in decreased springflows, reduced well discharges, lower well water levels, and a reduction of the number of flowing artesian wells in the southern part of Ararat Basin (Armenia Branch of Mendez England and Associates, 2014; Yu and others, 2014). In 2013, groundwater use by aquaculture alone exceeded the sustainable level of groundwater resources, and the total groundwater use for all purposes in the Ararat Basin was 1.6 times the sustainable level (Yu and others, 2014). Increased groundwater withdrawals have also affected other water uses. Flowing artesian wells supplying drinking and irrigation water to 31 communities have ceased flowing. The Armenian Nuclear Power Plant at Metsamor (fig. 1) cannot meet water requirements (Yu and others, 2014). Streamflows and lake levels have diminished as a result of aquifer depletion (Armenia Branch of Mendez England and Associates, 2014). Additionally, there are numerous abandoned flowing wells in the Ararat Basin and some continue to discharge water to the land’s surface, creating environmental hazards and continued depletion of the artesian aquifers in the basin (Nalbandyan, 2012; Carter and others, 2016). In 2016, the U.S. Geological Survey (USGS) and the U.S. Agency for International Development (USAID) began a cooperative study with Armenia to share science and field techniques to increase the country’s capabilities for groundwater study and modeling (Carter and others, 2016). This study is in partnership with USAID/Armenia in the implementation of its Science, Technology, Innovation, and Partnerships effort through the Advanced Science and Partnerships for Integrated Resource Development (ASPIRED) program and associated partners, including the Government of Armenia, Armenia’s Hydrogeological Monitoring Center, and the USAID Global Development Lab and its GeoCenter. These techniques can be used by groundwater-resource managers, such as those in Armenia’s Ministry of Nature Protection, to understand and predict the consequences of their resource management decisions. One of the objectives for this study was to characterize the hydrogeologic framework and groundwater conditions in the Ararat Basin. Purpose and Scope The purpose of this report is to describe the hydrogeologic framework and groundwater conditions of the Ararat Basin study area in Armenia. Specifically, the report describes the lithology and hydrogeologic units in the study area. The hydrogeologic framework and groundwater conditions are characterized through existing geologic maps, lithologic data from drilled wells, remote sensing imagery, well records and logs, and groundwater-level measurements and other field data collected across the basin. For the artesian units that underlie the Ararat Basin study area, the hydraulic properties, discharge, and changes in hydraulic head and storage through 2016 are described. Description of Study Area The Ararat Basin (also known as the Ararat Valley) is an intermountain depression that contains the Aras River and its tributaries (Armenian Branch of Mendez England and Associates, 2014). The Aras River has a drainage area of approximately 31,500 km2, of which 14,900 km2 is in Armenia and 16,600 km2 is in Turkey (Armenian Branch of Mendez England and Associates, 2014). The study area includes the Ararat Basin in Armenia (fig. 2) and is slightly larger than the “Ararat artesian basin” defined by Armenian Branch of M

Conceptual model to assess water use associated with the life cycle of unconventional oil and gas development

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Quality-assurance plan for groundwater activities, U.S. Geological Survey Dakota Water Science Center

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Building groundwater modeling capacity in Mongolia

Suggested Citation: Valder, J.F., Carter, J.M., Anderson, M.T., Davis, K.W., Haynes M.A., and Dechinlhundev, Dorjsuren, 2016, Building groundwater modeling capacity in Mongolia: U.S. Geological Survey Open-File Report 2016– 1096, 1 sheet, http://dx.doi.org/10.3133/ofr20161096. Prepared in cooperation with U.S. Army Corps of Engineers; U.S. Pacific Command; United Nations Educational, Scientific and Cultural Organization (UNESCO) and International Center for Integrated Water Resources Management under the auspices of UNESCO; Government of Mongolia Ministry of Environment, Green Development, and Tourism; and Freshwater Institute, Mongolia

Construction of a groundwater-flow model for the Big Sioux Aquifer using airborne electromagnetic methods, Sioux Falls, South Dakota

The city of Sioux Falls is the fastest growing community in South Dakota. In response to this continued growth and planning for future development, Sioux Falls requires a sustainable supply of municipal water. Planning and managing sustainable groundwater supplies requires a thorough understanding of local groundwater resources. The Big Sioux aquifer (fig. 1) consists of glacial outwash sands and gravels and is hydraulically connected to the Big Sioux River (Niehus and Thompson, 1998), which provided about 90 percent of the city’s source-water production in 2015 (Jeff Dunn, City of Sioux Falls, written commun., 2016). Managing sustainable groundwater supplies also requires an understanding of groundwater availability. An effective mechanism to inform water management decisions is the development and utilization of a groundwater-flow model (fig. 2). Anderson and others (2015) stated that a groundwater-flow model provides a quantitative framework for synthesizing field information and conceptualizing hydrogeologic processes. These groundwaterflow models can support decision making processes by mapping and characterizing the aquifer. Accordingly, the city of Sioux Falls partnered with the U.S. Geological Survey (USGS) to construct a groundwater-flow model. Model inputs will include data from advanced geophysical techniques, specifically airborne electromagnetic (AEM) methods.

The Occurrence of Volatile Organic Compounds in Aquifers of the United States

Study basics The U.S. Geological Survey’s National Water-Quality Assessment (NAWQA) Program recently completed a national assessment of volatile organic compounds (VOCs) in ground water (Zogorski and others, 2006). As part of this assessment, samples of ambient ground water collected from 3,498 wells during 1985–2002 were selected for characterizing the occurrence of 55 VOCs in 98 aquifer studies. The 55 VOCs were assigned to the following groups on the basis of their primary usage (or origin): (1) fumigants, (2) gasoline hydrocarbons, (3) gasoline oxygenates, (4) organic synthesis compounds, (5) refrigerants, (6) solvents, and (7) trihalomethanes (chlorination by-products). The samples were collected throughout the conterminous United States as well as Alaska and Hawaii. The sampled wells had a variety of uses including domestic supply (61 percent), public supply (15 percent), monitoring (10 percent), other (13 percent), and unknown (1 percent).

Volatile Organic Compounds in Samples from Domestic and Public Wells, 1985-2002

Large-scale high-speed mass-storage systems account for a large part of the energy consumed at data centers [1]. To save energy consumed by these storage systems, we propose a high-speed tiered-storage system with a power-aware method of storage-tiering management with minimum loss of performance, which we have called the energy-efficient High-speed Tiered-Storage system (eHiTS). Our proposed method has two distinct features. The first is that eHiTS consists of a tiered-storage system with high-speed online storage as a first tier and lowpower nearline storage with high capacity as the second tier. All files are always stored in nearline storage when it is created, in which the HDDs are usually left powered off. Only the volume that has stored the accessed files is copied from nearline to online storage before access. In our proposed method, data movement and its timing are managed inversely against ILM [2] where files are stored in online storage when it is created and relocated to the nearline storage when utilization becomes lower than a predetermined threshold based on user’s policy. Even though the first-tier’s online storage is used as a data cache in eHiTS, file requests in our proposed method are hit in online storage (cache storage) even during the first access, unlike in ordinary cache management. Moreover, the accessed files are copied back soon after the access period ends. This leads to the capacity of online storage being minimized with minimum loss of performance, resulting in energy savings. The second feature is its ability to complete copying the volume that has stored the accessed files from nearline to online storage before access. The timing to start copying is predicted based on queueing theory with information about job-queue status in a batch-job scheduler of a batch-processing application. We selected an HPC system as the first target among the batch-processing applications to evaluate eHiTS. Figure 1 outlines the architecture of eHiTS with an HPC system for scientific calculations. eHiTS is equipped with another feature where the HDD enclosure is powered off when there is no access to gain larger energy savings than in MAID systems [3]. By exploiting the features of job control in the HPC system, the accessed files and the timing to start copying them to online storage are predicted in eHiTS for each user-submitted job. A simple method of completing the copying of an accessed volume to online storage before access is to start the volume copy when the job is submitted into the job-queueing system. However, we found from the simulation results of the jobqueueing system that there was not enough waiting time in the job queueing system to complete volume copy before access for lower utilization factor of the queueing system. To complete volume copy before access even in shorter waiting time cases, we propose a delayed method of job execution, where if the waiting time for the job to start to execute is shorter than a certain time, job execution is delayed. Figure 2 compares an eHiTS’s energy consumption with an ordinary tiered-storage system with ILM for system capacities of 256, 512, and 1024 TB. The preliminary results obtained from analytical studies with the measured parameters in our testbed revealed that the eHiTS’s energy consumption decreased by as much as 46 % of that of the ordinary tiered-storage system for a system capacity of 1024 TB. We also found that the proposed method of delayed job execution could achieve a miss-prediction probability less than 10. We have been developing a testbed for eHiTS on which we intend to evaluate its energy conservation and predictable probability to demonstrate its effectiveness in conserving energy with minimum loss of performance in a real HPC environment.