Real-time water quality data
The U.S. Geological Survey now offers real-time maps and data on surface water quality across the U.S. We had a heavy downpour this morning, which is visible on one of the many graphs offered by the service:
The USGS explains:
Real-time water quality is in-stream water-quality measurements made available on the web in real-time. Water-quality measurements are recorded in time intervals as small as 5 minutes to hourly and often are referred to as continuous. These time-dense (continuous) stream data are made available on the Web in near real-time (updated 4-hour intervals or less) (available at http://waterdata.usgs.gov/nwis). Providing these data in real-time informs the user of stream conditions for various uses and public safety.
Real-time water quality is made possible because of improvements in sensor and data recording technology since the first in-stream sensors were developed in the 1950-60s to directly measure or compute concentrations of many water-quality constituents. Sensors that measure water-quality properties or constituent concentrations are available for specific conductance, pH, water temperature, turbidity, and dissolved oxygen, and ion-specific electrodes (for chloride or nitrate). Sensors also are available that measure portions of the electromagnetic spectrum (light) that indicate adsorption or scatter (turbidity, chlorophyll, and fluorescence) or sound (acoustic Dopler technology,). In-stream chemical analyzers and portable field laboratories for nitrate and phosphorus also are available. Many additional new sensors are being developed as the need for these data increase.
