Super gages provide real-time data specifically designed to improve understanding of watershed processes and to address specific water-resource issues such as climate and land-use effects or hazardous substance spills.
Return to Water >> USGS Transboundary River Monitoring in Southeast Alaska
Super gages provide real-time data specifically designed to improve understanding of watershed processes and to address specific water-resource issues such as climate and land-use effects or hazardous substance spills. The ability to model estimates of water quality constituents based on a record of continuous data helps improve estimates of loads to downstream areas that are critical for salmon spawning and rearing habitats.
What types of equipment are used in a super gage?
Water-quality monitors for measuring water temperature, pH, dissolved oxygen, specific conductance, and turbidity.
How are data from the super gages are verified?
Representative stream-width and depth-integrated sampling verifies the super gage data and is used to develop surrogate models.
What's a surrogate model?
Measured in-stream values of a parameter and measured concentrations of a constituent are used to develop a regression model to estimate concentrations during non-sampled periods. Computed or estimated concentrations of a constituent of greater interest can be calculated from the surrogate model.
- Temperature, water, degrees Celsius [Graph]
- Specific conductance, water, unfiltered, microsiemens per centimeter at 25 degrees Celsius [Graph]
- Dissolved oxygen, water, unfiltered, milligrams per liter [Graph]
- pH, water, unfiltered, field, standard units [Graph]
- Turbidity, water, unfiltered, formazin nephelometric units (FNU) [Graph]
- Temperature, air, degrees Celsius [Graph]
Water Quality Measurements
Water quality samples are collected on each river every 6-8 weeks depending on weather and aircraft availability. Samples are collected following USGS sampling methods for surface water. The measured constituents are included in the following table and results are posted to the USGS National Water Information System.
| Constituent Group | Analytes |
|---|---|
| Physical | Specific conductance, dissolved oxygen, turbidity, water temperature, pH |
| Solids | Total dissolved solids, total suspended solids |
| Nutrients | Dissolved ammonia, dissolved nitrite+nitrate, total ammonia+organic nitrogen, total phosphorus, dissolved orthophosphorus |
| Major Ions | Calcium, iron, magnesium, sodium, potassium, chloride, suflate |
| Alkalinity | Alkalinity as CaCO3 |
| Trace Metals | Total recoverable and dissolved aluminum, antimony, arsenic, barium, beryllium, boron, cadmium, chromium, cobalt, copper, iron, lead, lithium, manganese, mercury, molybdenum, nickel, selenium, silver, strontium, thallium, uranium, vanadium, and zinc |
| Organic Compounds | Total organic carbon, inorganic carbon, total particulate carbon, total particulate nitrogen |
Below are other science projects associated with this project.
USGS Transboundary River Monitoring in Southeast Alaska
Suspended-Sediment and Solids Sampling
Unuk River
Stikine River
Taku River
Alsek River
Salmon River
- Overview
Super gages provide real-time data specifically designed to improve understanding of watershed processes and to address specific water-resource issues such as climate and land-use effects or hazardous substance spills.
Return to Water >> USGS Transboundary River Monitoring in Southeast Alaska
Super gages provide real-time data specifically designed to improve understanding of watershed processes and to address specific water-resource issues such as climate and land-use effects or hazardous substance spills. The ability to model estimates of water quality constituents based on a record of continuous data helps improve estimates of loads to downstream areas that are critical for salmon spawning and rearing habitats.
What types of equipment are used in a super gage?
Water-quality monitors for measuring water temperature, pH, dissolved oxygen, specific conductance, and turbidity.
How are data from the super gages are verified?
Representative stream-width and depth-integrated sampling verifies the super gage data and is used to develop surrogate models.
What's a surrogate model?
Measured in-stream values of a parameter and measured concentrations of a constituent are used to develop a regression model to estimate concentrations during non-sampled periods. Computed or estimated concentrations of a constituent of greater interest can be calculated from the surrogate model.
- Temperature, water, degrees Celsius [Graph]
- Specific conductance, water, unfiltered, microsiemens per centimeter at 25 degrees Celsius [Graph]
- Dissolved oxygen, water, unfiltered, milligrams per liter [Graph]
- pH, water, unfiltered, field, standard units [Graph]
- Turbidity, water, unfiltered, formazin nephelometric units (FNU) [Graph]
- Temperature, air, degrees Celsius [Graph]
Water Quality Measurements
Water quality samples are collected on each river every 6-8 weeks depending on weather and aircraft availability. Samples are collected following USGS sampling methods for surface water. The measured constituents are included in the following table and results are posted to the USGS National Water Information System.
Constituent Group Analytes Physical Specific conductance, dissolved oxygen, turbidity, water temperature, pH Solids Total dissolved solids, total suspended solids Nutrients Dissolved ammonia, dissolved nitrite+nitrate, total ammonia+organic nitrogen, total phosphorus, dissolved orthophosphorus Major Ions Calcium, iron, magnesium, sodium, potassium, chloride, suflate Alkalinity Alkalinity as CaCO3 Trace Metals Total recoverable and dissolved aluminum, antimony, arsenic, barium, beryllium, boron, cadmium, chromium, cobalt, copper, iron, lead, lithium, manganese, mercury, molybdenum, nickel, selenium, silver, strontium, thallium, uranium, vanadium, and zinc Organic Compounds Total organic carbon, inorganic carbon, total particulate carbon, total particulate nitrogen - Science
Below are other science projects associated with this project.
USGS Transboundary River Monitoring in Southeast Alaska
The USGS Alaska Science Center operates super gages on the Alsek, Taku, Stikine, Unuk and Salmon Rivers. Discrete water quality, sediment, and biological sampling are also collected at each gage location. Discrete water quality samples are also collected annually at the Canada-Alaska border crossings of the Taku, Stikine, and Unuk Rivers. Water quality data collection began in 2018 on the Unuk...Suspended-Sediment and Solids Sampling
Suspended-sediment samples are collected on each visit at both gage and border site locations.Unuk River
The Unuk River is the second smallest watershed in the transboundary study of Southeast Alaska, but has three large mining projects in development (Kerr-Sulplherets-Mitchell (KSM), Brucejack, and Eskay Creek).Stikine River
The Stikine River near Wrangell and Petersburg is the largest watershed in the transboundary study of Southeast Alaska.Taku River
Adverse water quality from a trio of historic mines in the Tulsequah River watershed, a tributary of the Taku River, have caused concern in local communities including Juneau, Alaska, and Atlin, British ColumbiaAlsek River
The Alsek River is the furthest north watershed in the transboundary study of Southeast Alaska, reaching 300 miles north of Haines Junction, Yukon Territory.Salmon River
The Salmon River, located near Hyder, Alaska, and Stewart, British Columbia, is the smallest watershed in the transboundary study of Southeast Alaska. - Multimedia