1. 2014 NC Water Quality Assessment
Cam McNutt
DWR Modeling and Assessment Branch
March 2014 EMC

2. Overview Water Quality Assessment Methods Review
Summary of water quality assessments by method
Changes from 2012 water quality assessment
Summary of new Category 5 assessments
Public review process and information
EMC March 2014

3. Assessment Categories1 2 3 4 5
Meeting criteria
No info/inconclusive
Criteria exceeded
303(d) List

4. Water Quality Assessment Methods
Five 303(d) assessment methods
Numeric criteria (Dissolved Oxygen)
Biological criteria (benthos community diversity)
Pathogen criteria (fecal coliform bacteria)
Shellfish Harvesting criteria (growing area classifications)
Fish Consumption criteria (DHHS advisories)
Assessment Period
EMC March 2014

5. Numeric Criteria Assessment Methods
Applied to 88 Parameters of Interest
Must meet all three criteria to be a Category 5 or 303(d) assessment
N>9
Greater than 10% exceedance of numeric standard
Greater than 90% confidence that numeric standard is exceeded in at least 10% of samples
EMC March 2014

6. 90% Confidence
More statistical confidence that water quality criteria exceeded in > 10% of samples
Reduces chance of listing waters that actually meet criteria
Takes sample size into account
Non-parametric – most WQ data not normally distributed
EMC March 2014

7. Numeric Criteria Assessment Methods
Example-Dissolved Oxygen
Standard-….is not less than 4.0 mg/l
N=60
10 samples less than 4 mg/l or 16.7% exceedance
Confidence in 10% exceedance=92.65
AU assessed as Exceeding Criteria
EMC March 2014

8. Numeric Criteria Assessment Methods
206 Exceeding Numeric Criteria (Category 5)
Most common Parameters assessed in Category 5
Copper- 47
Dissolved oxygen- 45
Chlorophyll a – 31
Turbidity-31
pH-26
EMC March 2014

9. Biological Assessment Methods
Using benthos and fish community data
Criteria
Fair, Poor or Severe biological rating
Results in Category 5 or 303(d) list assessment
If there is another Aquatic Life Parameter in Category 5 then the biological exceedance is assessed in Category 4.
EMC March 2014

10. Biological Assessment Methods
319 Exceeding Biological Criteria (Category 5)
Fair, Poor or Severe Benthos-243
Fair or Poor Fish Community-76
EMC March 2014

11. Pathogen Indicator Assessment Methods
Based on Fecal Coliform and Enterrococci Data
Criteria
N>=5 within a 30 day period
Geometric Mean> 200 (Fecal) >35 (Enterro) or
Greater than 20% >400 (Fecal only)
Results in 5 or 303(d) list assessment
EMC March 2014

12. Pathogen Indicator Assessment Methods
67 Exceeding Pathogen Criteria (Category 5)
Fecal coliform-53
Enterrococci-14
EMC March 2014

13. Shellfish Harvesting Assessment Methods
Based on Growing Area Classification
Criteria
Not Approved for shellfish harvesting
Results in 5 or 303(d) list assessment
EMC March 2014

14. Shellfish Harvesting Assessment Methods
646 Exceeding Shellfish Harvesting Criteria
Conditionally Approved Open- 128
Conditionally Approved Open- 65
Prohibited- 453
EMC March 2014

15. Fish Consumption Assessment Methods
Based on DHHS Fish Consumption Advisories
Criteria
DHHS Consumption Advisory
Fish Tissue data present
Results in 5 or 303(d) list assessment
EMC March 2014

16. Fish Consumption Assessment Methods
37 Exceeding Fish Consumption Criteria
PCB- 36
Dioxin- 1
EMC March 2014

17. Changes from 2012 Assessment
Exceeding Criteria to Meeting Criteria
152 (120 removed from 303(d) List)
No longer exceeding in 10% of samples
Biological rating meeting criteria
Natural conditions assessments
Exceeding Criteria to Data Inconclusive
173 (138 removed from 303(d) List)
Change in assessment methods
Meeting Criteria to Exceeding Criteria
75 (70 added to 303(d) List)
EMC March 2014

18. New Category 5 Assessments
102 New Category 5 Assessements
PCB Advisories -19
Benthos 18
Fish Community 15
Enterrococcus- 13
Fecal Coliform 7
Dissolved Oxygen-7
pH-6
Turbidity 3
EMC March 2014

19. 303(d) List Public Review Information in addition to the 303(d) List
Links sent as attachment
Fact Sheets (for over 1,000 AUs)
Review period closes tomorrow
Comments received to date
EMC March 2014

20. EPA Role
DWR submits list, comments, responses to comments to EPA by April 1, 2014
EPA must approve or disapprove 303(d) list
EPA may ask for justification for not listing waters
EPA determines whether any waterbodies should be added to state’s proposed 303(d) list
EPA approves list as-is, or lists additional waters
EMC March 2014

21. (d) List Process
2016 listing methods out for public review and comment June 2014
DWR prepares response to comments and recommendations for changes
DWR presents listing methods, including any recommended changes, to EMC for approval by November 2014
EMC March 2014