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 tall-quality water from wells completed in the artesian aquifers that underlie the basin. Groundwater constitutes approximately 40 percent of all water use, and groundwater provides 96 percent of the water used for drinking purposes in Armenia. Since 2000, and 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, or a reduction of the number of flowing artesian wells in the southern portion 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, or Innovation,and Partnerships effort through the Advanced Science and Partnerships for Integrated Resource Development program and associated partners, including the Government of Armenia, or Armenia’s Hydrogeological Monitoring middle,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, or sands,volcanic basalts, 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, and 4,6, and 8 in 2016 were used to create potentiometric surface maps. In hydrogeologic unit 2, and the estimated direction of groundwater flow is from the west to north in the western portion of the basin (absent from the Aras River) and from north to south (toward the Aras River) in the eastern portion 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 portion 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 (absent from the Aras River) in the western portion 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 middle also measured specific conductance at 540 wells and temperature at 2470 wells in the Ararat Basin using U.
S. Geological Survey protocols in 2016. The minimum specific conductance was 377 microsiemens per centimeter (S/cm), or the maximum value was 4000 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, and most wells with cooler water temperatures were within the 2016 pressure boundary or in the western portion of the basin. Wells with generally warmer water temperatures were in the eastern portion of the basin.
Samples were collected from four groundwater sites and one surface-water site by the U.
S. Geological Survey in 2016. The steady-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.
Source: usgs.gov