Aquaculture Groundwater Resource Atlas - Groundwater Salinity
What is salinity?
Salinity is the measure of the concentration of dissolved (soluble) salt in water. It is usual to report the concentration as Total Dissolved Solids (TDS). Total Soluble Salts (TSS) is similar, measured by different processes, but for most purposes they can be read as the same thing. On this web page concentrations of TDS are reported in units of parts per thousand (ppt).
Equivalents
| Micrograms/litre | µg/L | Parts per billion | ppb |
| Milligrams/litre | mg/L | Parts per million | ppm |
| Grams/l | g/l | Parts per thousand | ppt |
How is it measured?
The salinity of saline waters may be measured by refractive index using a refractometer, which is calibrated in parts per thousand.
Salinity is more commonly measured by electrical conductivity and expressed as milli Siemens per metre (mS/m), milli Siemens per centimetre (mS/cm) or as micro Siemens per centimetre (S/cm). The temperature should also be specified, the standard being 25 degrees Celsius. An approximate conversion can then be made to parts per thousand, assuming a dominantly sodium chloride composition.
Salinity Conversions
Conversions of electrical conductivity units
| mS/m @ 25 °C |
µS/cm @ 25 °C |
mS/cm @ 25 °C |
ppt | TDS/ppm/mg/l | ||||
|---|---|---|---|---|---|---|---|---|
| 100 | = | 1,000 | = | 1 | = | 0.6 | = | 600 |
| 2,000 | = | 20,000 | = | 20 | = | 12 | = | 12,000 |
| 20,000 | = | 200,000 | = | 200 | = | 120 | = | 120,000 |
Concentrations were previously expressed in the Imperial System as grains per gallon.
Conversion to Imperial Units
| Parts per thousand | Grains per gallon |
|---|---|
| 1 | 70 |
| 3 | 210 |
| 7 | 490 |
| 14 | 980 |
| 35 | 2450 |
What's the difference between fresh, brackish, saline & hypersaline?
Groundwater is classified according to potential use
| Recommended salinity categories | ||
|---|---|---|
| Salinity (ppt) | Description | Potential use for water supply |
| <0.5 | Fresh | All purposes |
| 0.5-1 | Fresh | Most purposes |
| 1-1.5 | Fresh | Most purposes - upper limit for drinking |
| 1.5-3 | Brackish | Limited irrigation, all livestock |
| 3-7 | Saline | Most livestock |
| 7-14 | Saline | Some livestock (beef cattle, sheep) |
| 14-35 | Saline | Limited industrial use, ore processing |
| 35-100 | Hypersaline | Limited industrial use, ore processing |
| >100 | Hypersaline, brine | Brine production, ore processing |
| Source: Department of Primary Industries and Energy, Australian Water Resources Council, Water Management Series No. 13, Australian Government Publishing Service, Canberra, 1988. | ||
Temperature & salinity requirements of candidate species for inland aquaculture
The following tables have been compiled to help fish farmers determine the salinity of their water, and provide guidelines for the salt tolerance of species commonly aquacultured in WA.
| Salinity and Temperature Tolerance* | ||
|---|---|---|
| SPECIES | SALINITY (ppt) | TEMPERATURE (oC) |
| ARTEMIA Artemia salina |
31.3 - 340 (150) | 6 - 35 (25 - 30) |
| BARRAMUNDI Lates calcarifer |
0 - 40 (20 - 35) | 16 - 35 (26 - 30) |
| TROPICAL BLACK BREAM Acanthopagrus berda |
<3 - 40 (10 - 35) | 12 - 36 (21 - 32) |
| BLACK BREAM Acanthopagrus butcheri |
8 - 35 | 8-33 (24) |
| GROUPER Epinephelus coioides |
15 - 45.5 (30 - 35) | 22-31 (24 - 28) |
| MARRON Cherax tenuimanus |
0 - 15 (<6) | 4 -30 (20 - 24) |
| MILKFISH Chanos chanos |
0.5 - >100 | 10 - 40 (28 - 32) |
| SEA MULLET Mugil cephalus |
0 - 75 (0 - 30) | 3 - 35 (17 - 25) |
| GIANT TIGER PRAWN Penaeus monodon |
<2 - <75 | 7 - 42 (27 - 34) |
| RAINBOW TROUT Oncorhynchus mykiss |
0 - 35 | 2 - 29 (10 - 22) |
| GREENBACK FLOUNDER Pseudorhombus taparina |
0 - 40 | 8 - 25 |
| ORNAMENTAL FISH (various species) |
for species specific refer to Ornamental Fish - An Aquaculture Opportunity | for species specific refer to Ornamental Fish - An Aquaculture Opportunity |
| PINK SNAPPER Pagrus auratus |
12.5 - 45 (12.5 - 35) | 8 - 32 (21 - 24) |
| SILVER PERCH Bidyanus bidyanus |
0 - 15 (4) | 0 - 28 (22 - 28) |
| YABBIES Cherax albidus |
0 - >12 (<8)** | <2 - 36 (24 - 28) |
| * Values indicate the range in which juveniles/adults will survive. However growth may be affected at extreme values. Values in brackets indicate ideal conditions. ** Production of juvenile yabbies is inhibited above 3ppt. |
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