Figure six Noticeable CFC demand schedules intended in the event that: (a) more youthful h2o for the equilibrium that have 1993 heavens brings together which have water recharged into the 1940; and (b) younger water inside the balance having 1993 air combines having liquid recharged from inside the 1975. Data on 10°C and 1 automatic teller machine. total tension.
Hydrodynamic dispersion
From the smooth and usually expanding nature of your own atmospheric mixing ratios, hydrodynamic dispersion is not expected to provides a life threatening effect on CFC levels otherwise apparent CFC years inside groundwater. Playing with a-one-dimensional logical option to the latest advection-dispersion equation for the steady state circulate career (van Genuchten and you can Alves, 1982), Plummer ainsi que al. (1993) simulated the fresh transportation and you can resulting age uncertainties to have CFC-eleven and you can CFC-several getting liquids energized of 1940 owing to 1991 (Figure 7).
Shape seven Problems inside CFC-11 and you can CFC-12 obvious decades computed for starters-dimensional disperse, which have dispersivities away from 0 in order to 2 yards (regarding Plummer ainsi que al., 1993).
on the 1975 should are available somewhat avove the age of the brand new advective years. Water energized before on 1970 seems to be quite more youthful compared to advective years. A beneficial dispersivity out-of 0.step one yards has actually little or no effect on CFC-eleven and you may CFC-twelve density across the dating list of the brand new tracers. If dispersivity are step one.0 yards, h2o billed from inside the 1960 you’ll appear younger prior to the brand new advective age by as much as five years having CFC-11 and you can on three-years centered on CFC-a dozen.
The outcome out of dispersion toward obvious years will change to own tracers which have various other shapes on their atmospheric type in properties, rather step three H/ step 3 He (Solomon and you may Prepare, Part 13). The theory is that, it may be you can easily to make use of differences in obvious age derived regarding some other tracers to spot surroundings where tracer density are firmly affected by hydrodynamic dispersion (Plummer ainsi que al., 1993; Ekwurzel mais aussi al., 1994), regardless if used such quick variations can be disguised by the most other procedure. An assessment out of CFC and you can 3 H/ step 3 He visible decades getting oceans co-old on the mud aquifers of your own Delmarva Peninsula (Ekwurzel et al., 1994) suggests little evidence to own tall effects of hydrodynamic dispersion in these tracers. Likewise, Szabo et al. (1996) receive a good contract anywhere between step 3 H/ 3 He and you can CFC years into the a sand aquifer inside south New jersey, more than an age range off almost forty years spanning both sides of one’s step 3 H bomb peak, showing you to definitely dispersion did not have a serious influence on groundwater decades obtained with the tracers about research town. Reilly et al. (1994) utilized CFC matchmaking to refine a groundwater flow design getting good low sandy aquifer with the Delmarva Peninsulaparison regarding counted tritium having tritium concentrations modelled playing with a beneficial solute transport model corroborated the fresh new flow design and you may displayed one to negative effects of hydrodynamic dispersion have been negligible inside the newest sand aquifer.
Occupation Advice
Though most of the analysis with CFC relationships have worried about comparison the latest accuracy of the strategy (come across, instance 
, Dunkle et al., 1993; Ekwurzel mais aussi al., 1994; Szabo et al., 1996), addititionally there is a growing literature regarding successful applications of CFCs inside hydrologic assessment. It area summarises particular is a result of chose career knowledge, and you can presents short term interpretations from CFC analyses out of 10 liquid products selected off a wide range of industry sites.
Katz et al. (1995) made use of CFCs to learn leaks regarding a beneficial sinkhole river within the north Florida and you will test forecasts from a beneficial around three-dimensional groundwater circulate model getting transient and you can steady state move requirements. To help with new evaluation away from Yucca Slope, Las vegas, once the a prospective web site having a high-height radioactive spend databases, Thorstenson et al. (1998) put CFC sized unsaturated-zone sky over the slope crest to display your travelling duration of low, advecting fuel is actually =five years.