Field tool · Version 1.1.0
Convert lake field units without hiding assumptions.
Work across depth, area, volume, temperature, mass concentration, electrical conductance, and discharge using explicit dimensional categories and published conversion constants.
- Conversions
- Seven dimensional categories
- Precision
- 3 to 8 significant digits (default 6)
- Boundary
- No inferred chemistry relationships
Confirm the prerequisite
Review the governing method before entering or interpreting data.
Return to the source guide
Shared route boundary
Refuses empirical pseudo-conversions that require calibration, density, chemistry, or more measurements.
Exact dimensional conversions · Version 1.1.0
Convert the unit, not the meaning of the measurement.
Choose a measurement category explicitly. The tool will never infer a category or cross dimensions.
Results update only when you choose Convert. Display uses 6 significant digits (default). Do not report more precision than the original measurement supports.
Converted value...
ft → m
Conversions this tool refuses
Some familiar shortcuts are models, not unit conversions.
These relationships need density, water chemistry, field calibration, or environmental context. Entering two numbers cannot supply that missing evidence.
| From | To | Why it is refused |
|---|---|---|
| mg/L | ppm | This equivalence depends on solution density; the tool will not silently assume water density. |
| µg/L | ppb | Parts per billion by mass or volume require an explicit basis (mass/mass, volume/volume, or mass/volume) and often assume water density. |
| mg/L | ppb | Parts-per notation is ambiguous without stating whether the basis is mass or volume and whether dilute-water assumptions apply. |
| Specific conductance | TDS | The relationship uses an empirical factor that varies with ionic composition and must be selected and validated for the waterbody. |
| Conductivity (µS/cm) | Salinity (ppt) | Salinity from conductivity depends on ion ratios, temperature correction, and the chosen practical salinity scale or laboratory method. |
| Conductivity (µS/cm) | Chloride (mg/L) | Ion-specific concentration cannot be inferred from bulk conductance without a documented local or source-water relation. |
| Fluorescence (RFU) | Chlorophyll or phycocyanin concentration | A site- and instrument-specific calibration is required, and optical interference can change the relationship. |
| Fluorescence (RFU) | Cells/mL | Cell counts and pigment fluorescence respond differently to species, pigment packaging, and quenching; no universal factor exists. |
| Turbidity (NTU/FNU) | Suspended solids (mg/L) | The relationship depends on particle size, shape, color, and composition and requires local paired samples. |
| Secchi depth (m) | Chlorophyll-a (µg/L) | Light attenuation integrates algae, detritus, color, and suspended minerals; Secchi alone cannot identify the dominant attenuator. |
| Secchi depth (m) | Turbidity (NTU) | Secchi integrates multiple attenuation processes and is not interchangeable with a nephelometric turbidity reading. |
| Dissolved oxygen (mg/L) | Percent saturation | Temperature, barometric pressure or elevation, salinity, and the selected calculation method are required. |
| Dissolved oxygen (% saturation) | mg/L | Converting percent saturation to concentration requires the same environmental context used to compute saturation. |
| pH | Alkalinity (mg/L as CaCO₃) | Alkalinity is a charge-balance capacity that depends on the full carbonate/borate/hydroxide system, not pH alone. |
| pH | Free CO₂ (mg/L) | Carbon dioxide speciation requires alkalinity, temperature, and ionic strength; pH alone is insufficient. |
| Lake surface area | Lake volume | Volume requires a bathymetric depth distribution or surveyed stage-volume curve, not area alone. |
| Acre-feet | Discharge (cfs or L/s) | Storage and flow are different quantities; converting them requires a time basis and often a hydraulic model. |
| Stage (ft or m) | Discharge (cfs or m³/s) | A stage-discharge rating curve, weir equation, or hydraulic model is required. |
| Rainfall depth (in or mm) | Runoff volume | Runoff depends on watershed imperviousness, antecedent moisture, snowmelt, and routing, not rainfall depth alone. |
| Wind speed | Mixed-layer depth | Mixing depends on fetch, stratification, bathymetry, and duration; wind speed alone is not a depth conversion. |
| Total phosphorus (µg/L) | Chlorophyll-a (µg/L) | Yield varies with light, grazing, nitrogen limitation, and internal loading; field programs need local paired data. |
| Total nitrogen (mg/L) | Chlorophyll-a (µg/L) | Algal response to nitrogen depends on speciation, phosphorus co-limitation, and season. |
| BOD₅ (mg/L) | COD (mg/L) | The BOD:COD ratio is sample- and matrix-specific and must be measured, not assumed. |
| Coliform (CFU/100 mL) | Pathogen risk | Indicator organisms do not map to health risk without exposure route, organism identity, and jurisdiction-specific criteria. |
| ORP (mV) | Dissolved oxygen (mg/L) | Redox potential reflects many coupled reactions and is not a direct substitute for DO measurement. |
| Algae cells/mL | Chlorophyll-a (µg/L) | Cell pigment content varies by species and growth state; microscopy and fluorometry are not interchangeable without calibration. |
| Phycocyanin (RFU or µg/L) | Microcystin (µg/L) | Toxin production is strain- and environment-dependent; pigment is not a lawful proxy for toxin concentration. |
| Gauge height | Lake volume | Volume requires a stage-surface-area or stage-storage relationship developed for that basin. |
| Evaporation depth (mm) | Lake level change | Water level responds to inflows, outflows, seepage, and withdrawals as well as evaporation. |
| Sediment depth (m) | Sediment mass (kg) | Mass requires bulk density, water content, and compositional assumptions from cores or surveys. |
Save the work and continue
Carry the result into its governed record and broader workflow; these links do not approve the work.
Open the sample custody record Preserve as-collected and canonical units with custody and validation states.
Continue the monitoring-program path Move from unit checks into the full monitoring design and release curriculum.
Shared route boundary
Refuses empirical pseudo-conversions that require calibration, density, chemistry, or more measurements.
Exact constants, visible precision limits.
The converter uses the international foot (0.3048 m), international inch (0.0254 m), SI prefixes, the international acre and acre-foot relationships derived from those exact length definitions, the defined US liquid gallon (3.785411784 L), and standard conductance and discharge scaling through each category base unit. Display rounding does not increase the precision of the original field or laboratory result.
- NIST SP 811: Guide for the Use of the International System of UnitsPrimary unit and SI-prefix reference
- NIST SI Units InformationDefinitions and conversion resources
Controlled preview. Internal technical review is complete. Independent review is pending, so this artifact remains available for review but is excluded from search-engine discovery. Next review: 2027-01-15.