Water Quality
Water quality on TerraPulse is organized into monitoring-station Locationdexes and a set of national survey dexes — each a measured record of what was actually sampled from the water, drawn from the U.S. Environmental Protection Agency. No estimates, no forecasts.
The dexes
Two Locationdexes hold the fixed monitoring stations, one slot per site. Counts are live and grow as new sampling sites are added:
| Dex | Holds | Stations |
|---|---|---|
water_quality_station | EPA ScienceHub water-quality monitoring stations | 594 |
reservoir_cyano_water_quality | Reservoir stations tracking cyanobacteria and environmental variables | 20 |
Alongside them sit five EPA National Aquatic Resource Surveys (NARS) — statistically designed national assessments that sample the country’s waters on a rolling basis rather than at fixed sites. Each is carried as its own survey dex:
nla_water_quality— the National Lakes Assessment, a national survey of the condition of the nation’s lakes and reservoirsnrsa_water_quality— the National Rivers and Streams Assessment, a national survey of flowing watersncca_water_quality— the National Coastal Condition Assessment, a national survey of coastal and Great Lakes nearshore watersnwca_wetland_chemistry— the National Wetland Condition Assessment, a national survey of wetland chemistryacidified_surface_water— EPA Long-Term Monitoring of acidified surface waters
Because each survey is a continuous national program rather than a station roster, its coverage is best read as a rolling census of a water type, not a station count.
Provenance
Every record traces to the U.S. EPA — the ScienceHub water-quality datasets behind the monitoring stations, and the National Aquatic Resource Surveys behind the national assessments. Each source is registered against its dex, so any record on TerraPulse carries a direct line back to the originating EPA sample.
What’s in a record
A monitoring-station slot carries:
- Site — station identifier and name
- Location — latitude and longitude
- Analytes — the water-quality parameters sampled there (nutrients, chemistry, and, for reservoirs, cyanobacteria indicators)
- Program — the ScienceHub dataset or survey it belongs to
A national-survey slot carries the assessed condition of a water body sampled under the survey’s probability design, with its sampled parameters and sampling year.