Groundwater age dating, usgs groundwater watch
Abstract A new way of thinking about groundwater age is changing the field of groundwater age dating.
Through this work, the USGS will: Probably better known to the public as Freon TMCFCs are nontoxic, nonflammable and noncarcinogenic, but they contribute to ozone depletion. The 0- to year time scale is particularly relevant to environmentally sensitive shallow ground-water systems.
Ground-water dating at Valdosta helps define the susceptibility to contamination of the ground-water resources. The increasing national and international demand for water has led to increasing reliance on subsurface storage, both for naturally and artificially recharged water.
Registered Users please login:
McMahonResearch Hydrologist x Recharge estimates will be made using applicable groundwater age distributions and simple lumped-parameter models where appropriate. A preliminary reconstruction has been made of northern-hemisphere SF 6 mixing ratios figure far left. This increased reliance on the groundwater in concert with the strict regulation on water quality has led to a need by water managers and regulators dating dex understand: Groundwater recharge is often difficult to quantify because of its spatial and temporal variability and because of the challenges of measuring it directly.
Because of difficulties in collection and age dating, 85 Kr is not yet a practical dating tool for ground-water studies.
This document is also available in pdf format: Use of groundwater ages to define timescales for recharge processes that could be used as an indicator of aquifer sustainability. A closed path is established between the well or pump to a valve system that is used to fill glass ampoules with water, creating a headspace with CFC-free, ultra-pure nitrogen gas.
Young ground water is typically found at depths from 0 to feet in unconsolidated sediments and at depths up to feet in fractured-rock systems. Use of groundwater ages to develop recharge estimates to constrain other recharge estimation methods. Georgia CFCs were used to trace and date leakage of river water through sinkholes into the Upper Floridan aquifer near Valdosta, Georgia Plummer and others, a, b. Busenberg, Eurybiades, and Plummer, L.
Options for accessing this content:
CFC and CFC were used as coolants in air conditioning and refrigeration, blowing agents in foams, insulation, and packing materials, propellants in aerosol cans, and as solvents. Nitrate concentrations in ground water under woodlands were low, whereas ground water recharged under agricultural fields had nitrate concentrations that exceeded the MCL. CFCs have been increasingly used in oceanic ages dating since the late s as tracers of oceanic circulation, ventilation, and mixing processes.
Chemical processes, such as microbial degradation and sorption during transit, can also affect the concentration of CFCs and other compounds used in dating. Collection of New Data Groundwater samples will be collected and analyzed to fill important data gaps in existing groundwater availability studies and to demonstrate age-dating techniques that could be used in future studies to understand recharge conditions.
Ground-water velocities ranged from 1 to 27 feet per day. Ground-water dating reveals a pattern of high nitrate concentrations moving slowly toward the estuary.
Water Resources Research, v. GWRP supports applied research into the use of groundwater age information to improve our understanding of recharge in Principal Aquifers. GWRP supports efforts to evaluate the use of groundwater age data to improve our overall understanding of recharge and thereby improve groundwater availability studies through the following activities:.
Lawrence Livermore National Laboratory. Download Citation Citation Alerts. The ages of the young-water fractions in the Upper Floridan aquifer were mapped throughout the Valdosta area.