Water info
Here are some quotes.....
Oxygen and hydrogen stable isotope data indicate that all
water samples from Big Bend are of meteoric origin (have participated
in an atmospheric cycle) and generally enter the surface
and subsurface water cycle as rainfall.
Water samples collected from BBNP show a large range of chemical compositions and complex histories of subsurface flow and reaction. Helium-tritium data show that most drinking water sources in BBNP are mixed waters with both young and older components. Exceptions are K-Bar water, which predates nuclear bomb testing (>50 yr), and Cottonwood well water, which is mostly young (0?5 yr). Noble gas solubility calculations show that RGV well water and Oak Spring water are recharged at higher elevations in surrounding mountains. Hot spring water found at RGV has a relatively long residence time during subsurface flow and is geothermally heated along the flow path, which probably follows N-S trending fault zones.
KBAR and PJ
Water from production wells at Panther Junction and K-Bar is produced from subsurface aquifers in tuffaceous sandstone of the Tertiary Chisos Formation (Abbott, 1983; Gibson, 1983); this water has reacted mainly with rhyolitic ash. Helium-tritium data indicate that K-Bar water is mostly older than 50 yrs and Panther Junction water is mixed water with roughly equal proportions of old water and young water. Panther Junction and K-Bar waters have some of the lowest dissolved solids in BBNP and are sources of good quality water.