1. Total Maximum Daily Loads
High Rock Lake &
Total Maximum Daily Loads

2. Today’s Agenda
Introduction to Use-Support Methodologies and High Rock Lake
TMDL Process
Scoping Study
Future Efforts
Q & A
Courtesy CWRC

3. Basinwide Planning Program
Applies to All 17 River Basins

4. Use Support Methodology
Aquatic Life
Recreation
Drinking
Water
Based on
Stream
Classification

5. Use Support Methodology
Standards
Chl a, pH, Dissolved Oxygen, etc.
Aquatic Life
Standards Met = Supporting
Standards Not Met = Impaired
Inconclusive Data = Not Rated
No Data

6. Current Data (2003 Basin plan)

7. Current Data (2003 Basin plan)

8. High Rock Lake – Monitoring History
1974 – 1975 : EPA & DWQ determine nutrient enrichment.
1981 : UNC-CH documents elevated nutrients and chlorophylla concentrations
1989 – 1990 : DWQ intensive study
1992 – 1997 – 2002 : DWQ basinwide sampling.

9. Model History Early 1990’s : BATHTUB model Good loading information
Estimate nutrient loads
Determine Assimilative capacity
Develop predictive tool
Good loading information
Good Phosphorous Prediction
Poor Chla prediction
Not Sufficient for TMDL purposes

10. Current Data (2003 Basin plan)
High rock map

11. High Rock Lake Impairment
Upper Lake
Turbidity
Low Dissolved Oxygen
Chla

12. High Rock Lake Impairment
Lower Lake
Turbidity

13. High Rock Lake Impairment
Abbots Creek
Turbidity
Low Dissolved Oxygen

14. High Rock Lake Impairment
Second Creek
Lake Arm NOT IMPAIRED
Upstream is impaired : aquatic life

15. Everyone has an impact; Everyone must be part of the solution.
Water quality management is a shared responsibility.

16. Basinwide Planning Program Website http://h2o. enr. state. nc
Basinwide Planning Program Website or call