There are six categories of data collected and used to calculate sub index scores:
- Water Quality
Collected at the surface and bottom of the lake
- Nutrients (Nitrate-N, Ammonia-N, and Orthophosphorus)
Collected only at the surface
- Total Suspended Solids
- E coli bacteria
Collected along a depth profile
- Conductivity
- pH, temperature and dissolved oxygen are also collected but are not part of scoring
2. Sediment Quality
Sediment Chemistry
- Sampled at the deepest point of each lake near the lower dam.
- Shows the accumulation of material from the lake’s watershed
- Metals, PAHs, pesticides and herbicides
3. Habitat Quality-
Visual assessment based on EMAP protocol
- Riparian zone plant density, community structure, and width
- Shoreline characteristics
- Aquatic cover and substrate characteristics
4. Aquatic Life
Benthic Macroinvertebrate Community
- 7 metrics assessing: Diversity, Pollution Tolerance, and Community Structure
- Evaluates lake health beyond single ‘snapshot’ of water chemistry sample
5. Vegetation
Surveys performed by Texas Parks and Wildlife Department
- 3 metrics assessing: Percent coverage, Diversity, and Community Structure, including invasive species cover
- Total acreage of all plant species
6. Eutrophication
Phytoplankton community
- 3 metrics assessing: Phytoplankton abundance, Pollution Tolerance, and Community Structure
- Evaluates lake health and nutrient loading beyond single ‘snapshot’ of water chemistry sample
A more complete description of the parameters and methods are provided in the Lake Index Methodology.