| Section 1 | Overview | |||
| Originator | Natural Resources Research Institute, Minnesota Pollution Control Agency | |||
| Title | Lake water quality - Chlorophyll, Phosphorus, and Transparency | |||
| Abstract | This data layer indicates lake chlorophyll-a levels in micrograms per liter, lake phosphorus levels in micrograms per liter, and lake clarity based on Secchi disk measurements in meters from the surface. It was developed by the Natural Resources Research Institute using data from the Minnesota Pollution Control Agency. The concentration of chlorophyll, total phosphorus, and Secchi depth are the three components used to assess lake trophic status or health. Chlorophyll-a is the green pigment that is found in plants and algae. Because all algal cells contain this pigment, its concentration provides an estimate of algal biomass. Phosphorus is often the nutrient in most limited supply and thus the nutrient most likely to limit the productivity of plants and algae in lakes and streams. A Secchi disk measures water transparency or clarity and indicates the depth of light penetration into a lake. Secchi depth also provides an indirect measure of the amount of suspended material, algae or sediment in the water. Metrics were calculated using the 10 year average for samples collected from May through September. The average is recalculated annually. | |||
| Purpose | ||||
| Time Period of Content Date | ||||
| Currentness Reference | ||||
| Progress | ||||
| Maintenance and Update Frequency | Annually | |||
| Spatial Extent of Data | ||||
| Bounding Coordinates | -97.141765 -89.915627 49.404474 43.440014 | |||
| Place Keywords | ||||
| Theme Keywords | Water Quality, Surface Water, Lakes, Chlorophyll, Algae, Clarity, Transparency, Nutrients, Phosphorus | |||
| Theme Keyword Thesaurus | ||||
| Access Constraints | ||||
| Use Constraints | ||||
| Contact Person Information | Kristi Nixon,
GIS Specialist University of Minnesota, Natural Resources Research Institute 5013 Miller Trunk Highway Duluth, MN 55811 Phone: 218-788-2645 Email: knixon@d.umn.edu | |||
| Browse Graphic | None available | |||
| Associated Data Sets | ||||
| Section 2 | Data Quality | |||
| Attribute Accuracy | ||||
| Logical Consistency | ||||
| Completeness | ||||
| Horizontal Positional Accuracy | ||||
| Lineage | ||||
| Section 3 | Spatial Data Organization (not used in this metadata) | |||
| Section 4 | Coordinate System | |||
| Horizontal Coordinate Scheme | Universal Transverse Mercator | |||
| UTM Zone Number | 15 | |||
| Horizontal Datum | NAD83 | |||
| Horizontal Units | meters | |||
| Section 5 | Attributes | |||
| Overview | ||||
| Detailed Citation | ||||
| Table Detail: | ||||
| lake_data_CTF | |||
| Field Name | Valid Values | Definition | Definition Source |
|---|---|---|---|
| FID | Internal feature number. | Esri | |
| Shape | Feature geometry. | Esri | |
| fw_id | |||
| dowlknum | |||
| pw_basin_n | |||
| pw_parent_ | |||
| pw_sub_nam | |||
| sub_flag | |||
| wb_class | |||
| lake_class | |||
| acres | |||
| shore_mi | |||
| center_utm | |||
| center_u_1 | |||
| cty_name | |||
| dnr_region | |||
| LAKE_ID | |||
| HUC_8 | |||
| ECOREGION | |||
| BASIN | |||
| Total_phos | Total phosphorus in micrograms per liter | ||
| Water_tran | Water transparency Secchi disk measurement in meters from water surface | ||
| Chlorophyl | Chlorophyll-a level in micrograms per liter | ||
| DOWstr | |||
| ObjectID | |||