TMDL Lakes

The Clean Water Act Section 303(d) establishes the Total Maximum Daily Load (TMDL) program. The purpose of the TMDL program is to identify sources of pollution and allocate pollutant loads in places where water quality goals are not being achieved. This layer shows the list of waters for which technology-based or other required pollution controls are not stringent enough to meet water quality standards. The TMDLs themselves specify a pollutant budget that must be achieved to meet state water quality standards and allocates pollutant loads among pollution sources in a watershed, e.g., point and nonpoint sources. This layer represents lakes with TMDL associated with them. Lakes have characteristics that differentiate TMDLs from other waters. Lakes are not free-flowing like streams, but are contained waters that trap pollutants for long periods. Most lake impairments are from high nutrient or sediment loads. Wherever possible, lake TMDLs are developed with the information in the lake study reports that were sponsored by local watershed groups or other local interests. Target acceptable pollutant loads are set at the level of a watershed largely unaffected by human induced impacts. Load allocations are given to the pollutant sources using the same methods as nonpoint source TMDLs. Other indicators of water quality are also considered in the evaluation of a lake. One indicator is the Trophic Status Index (TSI), which refers to the degree of nutrient enrichment in the lake. Nutrient enrichment causes growths of algae that consume oxygen and interfere with the health of the aquatic organisms in the lake. The TSI is affected by factors such as lake volume, water residence time and nutrient loads to the lake. After target loads are set, the TSI is evaluated under reduced nutrient load conditions to assure that the pollutant reductions will bring the TSI into an acceptable range. Implementation of lake TMDLs is best accomplished though local participation. This layer is based on the High Resolution National Hydrography Dataset (NHD).

Data and Resources

Field Value
access_constraints ["Use Constraints: Commonwealth of Pennsylvania Department of Environmental Protection Disclaimer for Data The user shall save the Commonwealth harmless from any suits, claims, or actions arising out of the use of the data files or accompanying documentation, or arising out of any defects in the datafiles or accompanying documentation. The Commonwealth excludes any and all implied warranties and makes no warranty or representation with respect to the data files or accompanying documentation, including quality, performance, merchantability, or fits for a particular purpose. These data files and documentation are provided \"as is\" and the user assumes the entire risk as to their quality and performance.", "Access Constraints: None"]
bbox-east-long -74.744705
bbox-north-lat 41.663657
bbox-south-lat 40.003513
bbox-west-long -80.531309
coupled-resource []
dataset-reference-date [{"type": "publication", "value": "2012-01-01"}]
frequency-of-update continual
licence ["The USER shall indemnify, save harmless, and, if requested, defend those parties involved with the development and distribution of this data, their officers, agents, and employees from and against any suits, claims, or actions for injury, death, or property damage arising out of the use of or any defect in the FILES or any accompanying documentation. Those parties involved with the development and distribution excluded any and all implied warranties, including warranties or merchantability and fitness for a particular purpose and makes no warranty or representation, either express or implied, with respect to the FILES or accompanying documentation, including its quality, performance, merchantability, or fitness for a particular purpose. The FILES and documentation are provided \"as is\" and the USER assumes the entire risk as to its quality and performance. Those parties involved with the development and distribution of this data will not be liable for any direct, indirect, special, incidental, or consequential damages arising out of the use or inability to use the FILES or any accompanying documentation."]
metadata-date 2012-10-03
metadata-language eng; USA
metadata_type geospatial
progress completed
resource-type dataset
responsible-party [{"name": "PA Department of Environmental Protection", "roles": ["pointOfContact"]}]
spatial {"type": "Polygon", "coordinates": [[[-80.531309, 40.003513], [-74.744705, 40.003513], [-74.744705, 41.663657], [-80.531309, 41.663657], [-80.531309, 40.003513]]]}
spatial_harvester true
Groups
  • AmeriGEOSS
  • National Provider
  • North America
Tags
  • amerigeo
  • amerigeoss
  • ckan
  • geo
  • geoss
  • national
  • north-america
  • united-states
isopen False
metadata_created 2025-11-20T01:30:44.329470
metadata_modified 2025-11-20T01:30:44.329474
notes The Clean Water Act Section 303(d) establishes the Total Maximum Daily Load (TMDL) program. The purpose of the TMDL program is to identify sources of pollution and allocate pollutant loads in places where water quality goals are not being achieved. This layer shows the list of waters for which technology-based or other required pollution controls are not stringent enough to meet water quality standards. The TMDLs themselves specify a pollutant budget that must be achieved to meet state water quality standards and allocates pollutant loads among pollution sources in a watershed, e.g., point and nonpoint sources. This layer represents lakes with TMDL associated with them. Lakes have characteristics that differentiate TMDLs from other waters. Lakes are not free-flowing like streams, but are contained waters that trap pollutants for long periods. Most lake impairments are from high nutrient or sediment loads. Wherever possible, lake TMDLs are developed with the information in the lake study reports that were sponsored by local watershed groups or other local interests. Target acceptable pollutant loads are set at the level of a watershed largely unaffected by human induced impacts. Load allocations are given to the pollutant sources using the same methods as nonpoint source TMDLs. Other indicators of water quality are also considered in the evaluation of a lake. One indicator is the Trophic Status Index (TSI), which refers to the degree of nutrient enrichment in the lake. Nutrient enrichment causes growths of algae that consume oxygen and interfere with the health of the aquatic organisms in the lake. The TSI is affected by factors such as lake volume, water residence time and nutrient loads to the lake. After target loads are set, the TSI is evaluated under reduced nutrient load conditions to assure that the pollutant reductions will bring the TSI into an acceptable range. Implementation of lake TMDLs is best accomplished though local participation. This layer is based on the High Resolution National Hydrography Dataset (NHD).
num_resources 1
num_tags 8
title TMDL Lakes