The National Eutrophication Survey: lake characteristics and historical nutrient concentrations
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Joseph Stachelek - Michigan State University - stachel2@msu.edu
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Chanse Ford - Michigan State University
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Dustin Kincaid - Michigan State University
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Katelyn King - Michigan State University
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Heather Miller - Michigan State University
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Ryan Nagelkirk - Michigan State University
Historical ecological surveys are an important source of baseline information to provide context for contemporary research, yet many of these records are not preserved in a way to ensure their long-term usability. The National Eutrophication Survey database is currently only available as portable document files (PDF) scanned from printed records with no embedded character information. This limits its searchability and the ability of current and future scientists to systematically evaluate its contents. The data was collected by the United States Environmental Protection Agency between 1972 and 1975, as part of an effort to investigate eutrophication in freshwater lakes and reservoirs. Although several studies have hand-transcribed portions of the database in support of specific studies, there have been no systematic attempts to transcribe and preserve the database in its entirety. Here we use a combination of automated optical character recognition and manual quality assurance to make this data available for analysis. The performance of the optical character recognition procedure was highly variable depending on scan quality. For each of the four archival pdf files, we found an error rate of between 5.9 and 17%. The goal of our approach was to strike a balance efficiency and data quality by combining hand-entry of data with digital transcription technologies. The finished database contains information on the physical characteristics, hydrology, and water quality of about 800 lakes in the continental United States. This database could be combined with more recent data to generate meta analyses of water quality trends and spatial variation across the continental United States.
Nov 1972
Dec 1975
Continental United States
Lat/long coordinates for the northwest corner and southeast corner of spatial coverage
49 23 3.7 - 124 43 32.88
24 29 53.27 - 66 56 59.6
NES Methods
| variable name | description | units |
|---|---|---|
| pdf identifier (474 - 477) | integer | |
| pagenum | page number of the pdf (not the report page number) | integer |
| storet_code | identifier which links measurement to coordinate locations | character |
| state | state where the water body resides | character |
| name | name of the water body | character |
| county | county where the water body resides | character |
| lake_type | natural or impoundment | character |
| drainage_area | the total drainage area | square kilometers |
| surface_area | the area of the water surface | sq km |
| mean_depth | the volume of the water body divided by the surface area in square meters | meters |
| total_inflow | the mean of the inflows of all tributaries and the immediate drainage | cubic meters per second |
| retention_time | a mean value determined by dividing the lake volume, in cubic meters, by the mean annual outflow in cubic meters per unit cof time | years or days |
| retention_time_units | the units of time for each retention entry | years or days |
| alkalinity | alkalinity | milligrams per liter |
| conductivity | conductivity | microohms |
| secchi | secchi | meters |
| tp | total phosphorus | milligrams per liter |
| po4 | orthophosphate | milligrams per liter |
| tin | total inorganic nitrogen | milligrams per liter |
| tn | total nitrogen | milligrams per liter |
| p_pnt_source_muni | municipal point source phosphorus loading | kilograms per year |
| p_pnt_source_industrial | industrial point source phosphorus loading | kilograms per year |
| p_pnt_source_septic | septic point source phosphorus loading | kilograms per year |
| p_nonpnt_source | nonpoint source phosphorus loading | kilograms per year |
| p_total | total phosphorus loading | kilograms per year |
| n_pnt_source_muni | municipal point source nitrogen loading | kilograms per year |
| n_pnt_source_industrial | industrial point source nitrogen loading | kilograms per year |
| n_pnt_source_septic | septic point source nitrogen loading | kilograms per year |
| n_nonpnt_source | nonpoint source nitrogen loading | kilograms per year |
| n_total | total nitrogen loading | kilograms per year |
| p_total_out | total phosphorus outlet load | kilograms per year |
| p_percent_retention | percent phosphorus retention | percent |
| p_surface_area_loading | phosphorus surface area loading | grams per square meter per year |
| n_total_out | total nitrogen outlet load | kilograms per year |
| n_percent_retention | percent nitrogen retention | percent |
| n_surface_area_loading | nitrogen surface area loading | grams per square meter per year |
| lat | latitude | decimal degrees |
| long | longitude | decimal degrees |
Inland lakes of the continental United States.
Most parameters are reported as annual means computed form measurements taken on a monthly basis.
United States Environmental Protection Agency. 1975a. National eutrophication survey methods, 1973-1976. Working Paper Number 175. Office of Research and Development, United States Environmental Protection Agency, Washington, D.C., USA.
Digital
No restrictions