A conversation on Caledon state chat yesterday raised the question of whether a certain body of water in Caledon was fresh, brackish, or seawater.
Fortunately, a prior field expedition which surveyed waterways around the Independent State had also collected surface salinity data. These results had been unpublished (and not updated after recent cataclysmic tectonic activity), but seeing as how at least one of our citizens would find the information useful, I exercised my editorial powers to publish the data without their as-yet-unfinished analysis.
This illustration shows the surface salinity in parts-per-thousand, mapped on a spectrum from green (fresh water) to blue (sea water). Brackish water is defined as having a salt concentration of 0.5 to 30 parts per thousand.*
A cursory view shows that the Independent State is fresh-water replete in areas with higher elevation. The Firth tends toward mild brackishness towards the east, and more pronounced to the west and the open sea. Lower-lying areas show a more-rapid increase in salinity as a function of distance from shore.
Limitations of these results include a lack of sampling at depth, no correction for water temperature, and a lack of readings across time (meaning that any diurnal or seasonal variations are unknown. The Winterfallen waters north of Caledon remain unstudied.
Readers wishing some advice on which fish ought to be introduced to a nearby stream, which plants may flourish at a given location, or simply where to refill one's canteen may find this map useful.
Regrettably, a lack of grant funding current prevents further data collection or analysis, at least at present.
* The actual phenomenon being measured is not salinity but rather halinity, a measure of the halide content of water. This should not be confused with conductivity (measuring the ionic content of water), or turbidity (measuring the particulate matter content), though each of these measurements overlap to some degree.