2020 303(d) Listing Methodology Workgroup Kick-off meeting - - PowerPoint PPT Presentation

Kick-off meeting – September 14, 2018 CDPHE - C1A, 9-11 am

2020 303(d) Listing Methodology Workgroup

Agenda

303(d) Listing Methodology 2

Time Agenda Topic Lead

9:00 am Introductions Skip Feeney 9:15 am 2020 Listing Methodology Workgroup Purpose Skip Feeney 9:30 am Scope/Introduce Topics All 10:00 am Lower Confidence Level Assessment of Iron, Manganese and Sulfate Skip Feeney / Sarah Wheeler 10:30 am Pollution vs Pollutant and M&E List Introductory Language in Regulation 93 Lorie Petersen 10:50 am Adjourn

Introductions

303(d) Listing Methodology 3

Overview of Workgroup Regulation #93

• Section 303(d) of the Clean Water Act.

– Requires states to identify waters where effluent limitations are not stringent enough to attain water quality standards.

• 303(d) List of Impaired Waters.

– Waterbodies exceeding standards and/or not attaining uses.

• Monitoring and Evaluation List Waterbodies

– where we suspect problems.

• Approved through a rulemaking hearing every 2 years.

4 303(d) Listing Methodology

Overview of Workgroup 303(d) Listing Methodology

• Framework for determining attainment.
• Establishes listing requirements.
• Explains:

– the processes for adoption of LM and 303(d) List. – how data are assessed and interpreted. – how impairments are determined. – how priorities are established for TMDL development.

• Revised every two years through a public workgroup process.
• Approved through an administrative action hearing since 2003.

5 303(d) Listing Methodology

Work Group Administration

Workgroup Chair: Skip Feeney skip.feeney@state.co.us 303.691.4928 Workgroup Coordinator: Caroline Byus caroline.byus@lrewater.com 303.455.9589 http://colowqforum.org/workgroup- 303d-listing-methodology.html

6 303(d) Listing Methodology

Overview of Workgroup Meeting Schedule

October 16, 2018 1:00 - 3:00 pm CDPHE C1A

– Topic 3 – How 303(d) and M&E listings are carried over when water body re-segmentation occurs. – Topic 4 - Update the Listing Methodology to remove the temperature excursion allowance for lakes and reservoirs.

November 16, 2018 9:00 - 11:00 am CDPHE C1A

– Wrap up on all topics and final adjustments to 2020 Listing Methodology.

7 303(d) Listing Methodology

Overview of Workgroup Important Dates

303(d) LISTING METHODOLOGY MILESTONE APPROXIMATE DATE Draft proposal deadline 2nd week in Jan. 2019 Written comments due 4th week in Jan. 2019 Rebuttal comments due 3rd week in Feb. 2019 Revised proposal due 4th week in Feb. 2019 Administrative Action Hearing (AAH) March 11th, 2019

303(d) Listing Methodology 8

Overview of Workgroup Ground Rules

Mission: To achieve solutions to Colorado water quality issues through communication and understanding, balancing use and protection

• f the resource.

Ground Rules:

– Come to each meeting prepared for the scheduled discussion, e.g. having reviewed any relevant draft documents that have been circulated prior to the meeting. – Avoid personal attacks. Be respectful of others’ perspectives and responsibilities. – Respect the process by letting others know if differences remain that will be pursued in other venues.

9 303(d) Listing Methodology

Agenda

303(d) Listing Methodology 10

Time Agenda Topic Lead

9:00 am Introductions Skip Feeney 9:15 am 2020 Listing Methodology Workgroup Purpose Skip Feeney 9:30 am Scope/Introduce Topics All 10:00 am Lower Confidence Level Assessment of Iron, Manganese and Sulfate Skip Feeney / Sarah Wheeler 10:30 am Pollution vs Pollutant and M&E List Introductory Language in Regulation 93 Lorie Petersen 10:50 am Adjourn

Update the Listing Methodology to remove the temperature excursion allowance for lakes and reservoirs

• Until 2016, Regulation #31 allowed for excursions of both the

dissolved oxygen (DO) and temperature standards if adequate refuge was available.

• In 2016, the language that allowed for temperature

exceedances, despite the presence of adequate refuge, was removed from the regulation.

• The 2018 Listing Methodology still allows for temperature

excursions and need to be updated.

11 303(d) Listing Methodology

Agenda

303(d) Listing Methodology 12

Time Agenda Topic Lead

9:00 am Introductions Skip Feeney 9:15 am 2020 Listing Methodology Workgroup Purpose Skip Feeney 9:30 am Scope/Introduce Topics All 10:00 am Lower Confidence Level Assessment of Iron, Manganese and Sulfate Skip Feeney / Sarah Wheeler 10:30 am Pollution vs Pollutant and M&E List Introductory Language in Regulation 93 Lorie Petersen 10:50 am Adjourn

Lower Confidence Limit Methodology for Secondary WS Standards

• Background information

– Mineral Creek COSJAF09 – Lower Confidence Limit Methodology – Water Supply Standards

• Issue Summary / Example
• Proposed action

– Listing Methodology Language Changes

13 303(d) Listing Methodology

Background – 2018 303(d) List Assessment

Background:

• Assessment of Mineral Creek COSJAF09 indicated exceedance
• f the dissolved iron secondary water supply standard.
• Animas River Stakeholders Group demonstrated attainment of

iron utilizing the lower confidence limit methodology (Appendix B of the Listing Methodology).

• Approved by Commission in 2018.
• Division is proposing to expand approach for all similar cases.

14 303(d) Listing Methodology

Background – Lower Confidence Limit Methodology

First developed to assess ambient-based standards

• Ambient-based standards:

– Water quality doesn’t meet standard(s)

• Natural source
• Irreversible man-induced cause
• Define standard based on ambient (existing) water quality.

For dissolved pollutants:

– Chronic std= 85th percentile – Acute std= 95th percentile

15 303(d) Listing Methodology

Background – Lower Confidence Limit Methodology

• Face value assessment approach.
• Challenges:

– Seasonal variation – Sampling and analytical error

• Expected variation in data will lead to differing attainment

conclusions.

• Wanted to improve confidence that impairment conclusions

are based on significant water quality change.

16 303(d) Listing Methodology

Background – Lower Confidence Limit Methodology

• Ambient-based standards are now assessed with lower

confidence limit (LCL) methodology.

• Exceedance indicates impairment with 95% confidence.
• 303(d) Listing Methodology Section IV.F, pg. 21.
• Listing Methodology Appendix B.
• Quantity of samples equates to a LCL percentile.
• Compare LCL percentile of current data to ambient-based

standard.

17 303(d) Listing Methodology

Background: Assessment of Iron, Manganese and Sulfate Water Supply Standards

The least restrictive of the following two options apply:

• Existing quality as of January 1, 2000; or
• Table value criteria

– Iron 300 ug/l (dissolved) – Manganese 50 ug/l (dissolved) – Sulfate 250 mg/l

• Regulation 31.11(6)

18 303(d) Listing Methodology

Background: Assessment of Iron, Manganese and Sulfate Water Supply Standards

How do we set the value for existing quality as of 2000?

• Data from 1995-2009 from available data sources.
• Compiled by segment.
• Per segment, the 85th percentile of the concentration data is

used to calculate the water quality as of the year 2000 value.

• This value is compared to TVS to determine least restrictive

value.

• All of this information is stored in WS data library.

19 303(d) Listing Methodology

Issue Summary:

• Existing quality as of the year 2000 value is created in similar

fashion as an ambient-based standard.

• Trying to capture conditions from a certain time period and

protecting against conditions becoming worse in the future.

• Variability in data used to set the standard and variability in

data used to characterize ambient conditions.

• Same challenge as assessing ambient-based standards.
• Different assessment conclusion based on expected variation

within the data.

20 303(d) Listing Methodology

Issue Summary:

• 2018 303(d) Hearing - ARSG recommended that the division

use the LCL approach for Fe, Mn and SO4 WS standards when 2000 is less restrictive.

• Commission agreed that these WS standards are similar to

ambient standards and so the LCL method is appropriate. Division’s proposal: Use the lower confidence limit approach for assessing Fe, Mn and SO4 water supply standards when existing quality from 2000 is the least restrictive value for assessment.

21 303(d) Listing Methodology

Mineral Creek COSJAF09

Real World Example

303(d) Listing Methodology 22

Parameter Existing Quality as

• f 2000

Current Water Quality (85th percentile) Number of Samples Dissolved Iron 3200 µg/L 3304.6 µg/L 73

Assessment conclusion: Impaired

• From Appendix B of the 2018

Listing Methodology.

• 85th percentile is used for

secondary water supply assessments.

• Sample size is 73.
• The LCL is 0.766 which equates

to the 76.6th percentile.

303(d) Listing Methodology 23

Lower Confidence Limit Table

Mineral Creek COSJAF09

Real World Example

303(d) Listing Methodology 24

Existing Methodology Lower Confidence Limit Method

Parameter (dissolved) Existing Quality as of 2000 Current Water Quality (85th percentile) Number of Samples Current Water Quality (76.6th percentile) Iron 3200 µg/L 3304.6 µg/L 73 3050.7 µg/L

Assessment conclusion: Attains

Lower Confidence Limit Assessment of Iron, Manganese and Sulfate WS Standards

Proposed Action: Utilize lower confidence limit assessment methodology for water supply standards when existing quality of year 2000 is the least stringent.

25 303(d) Listing Methodology

Language Change Proposed

2018 Listing Methodology (V.B.2 pg.30) language:

• 8. If the water quality as of year 2000 value is greater than the parameter’s table value

standard, a face value approach in which existing quality from the current period of record is compared to the 85th percentile of water quality data representing conditions as of the year 2000. a Lower Confidence Limit methodology will be used. If the lower confidence limit of the assessed value (85th percentile) of the current period of recorded exceeds the water quality as of the year 2000 value, the segment will be considered impaired. Appendix B, Assessing Attainment of Ambient Based Water Quality Standards in Colorado includes a detailed description of the statistical basis of this approach with examples of the assessment procedures and tables used to determine the lower confidence limit.

303(d) Listing Methodology 26

Language Change Proposed

Miscellaneous changes to sample size requirements:

• Substitute “ambient-based standards” with “ambient-based

standards and lower confidence limit assessments”.

– 2018 303(d) Listing Methodology IV.D, pg 19 – 2018 303(d) Listing Methodology IV.E, pg 20 – 2018 303(d) Listing Methodology IV.F, pg 21

Flow Chart Modifications:

• Add * to flow chart to indicate where lower confidence limit

assessment will be applied.

• 2018 303(d) Listing Methodology V.B.2., pg 31

27 303(d) Listing Methodology

Questions?

303(d) Listing Methodology 28

Agenda

303(d) Listing Methodology 29

Time Agenda Topic Lead

9:00 am Introductions Skip Feeney 9:15 am 2020 Listing Methodology Workgroup Purpose Skip Feeney 9:30 am Scope/Introduce Topics All 10:00 am Lower Confidence Level Assessment of Iron, Manganese and Sulfate Skip Feeney / Sarah Wheeler 10:30 am Pollution vs Pollutant and M&E List Introductory Language in Regulation 93 Lorie Petersen 10:50 am Adjourn

Removal of Regulation #93 Language

Outline of Discussion:

• Background information
• Summary of the issue
• Proposed action

30 303(d) Listing Methodology

Removal of Regulation #93 Language

Background:

• In the 2018 303(d) hearing, the division proposed to retain

COGULD02 on the 303(d) List due to temperature exceedances.

31 303(d) Listing Methodology

• The Dolores Water Conservancy District

questioned whether the segment qualifies for Category 4c.

Removal of Regulation #93 Language

Background:

• Category 4c - In cases where the impairment is determined to

be caused exclusively by pollution, that does not result in pollutant(s) levels in excess of state water quality standards, the impaired waterbody may be placed into Category 4c. A TMDL will not be required. (II.F of 2018 Listing Methodology)

32 303(d) Listing Methodology

Pollution - Man-made or man-induced

alteration of the chemical, physical, biological and radiological integrity of water (502(19) of CWA).

Pollutants - Dredged spoil, solid waste,

incinerator residue, sewage, garbage, sewage sludge, munitions, chemical wastes, biological materials, radioactive materials, heat, wrecked

• r discarded equipment, rock, sand, cellar dirt

and industrial, municipal, and agricultural waste discharge into water (502(6) of CWA).

Removal of Regulation #93 Language

Background:

• Numerous documents reviewed to see if Category 4c would be

appropriate for the Dolores River portions.

• Inconsistent language between the introduction to Regulation

#93 and the 2018 Listing Methodology was noticed.

33 303(d) Listing Methodology

Removal of Regulation #93 Language

Summary of Issue:

• Regulation #93 (93.2 (2) pg.1) language:

– “Colorado’s Monitoring and Evaluation List identifies water bodies where there is reason to suspect water quality problems, but there is also uncertainty regarding one or more factors, such as the representative nature of the data. Water bodies that are impaired, but it is unclear whether the cause of impairment is attributable to pollutants as opposed to pollution, are also placed

• n the Monitoring and Evaluation List. This Monitoring and

Evaluation list is a state-only document that is not subject to EPA approval.”

303(d) Listing Methodology 34

Removal of Regulation #93 Language

Summary of Issue:

• 2018 Listing Methodology (II.F pg.9) language:

– “Before placing impaired waterbody segments into Category 4c, thorough monitoring and assessment needs to be performed on the segment to confirm that no pollutants are contributing to the waterbody’s failure to meet water quality standards. If adequate monitoring and assessment is not performed to rule out pollutant(s) as a cause, then the impaired waterbody should be placed on the 303(d) List (Category 5).”

303(d) Listing Methodology 35

Removal of Regulation #93 Language

Summary of Issue:

• The 2018 303d Listing Methodology represents the most

recent policy discussions from the 2016 workgroup meetings.

• The Regulation #93 language was last updated in 2012 and the

language in question was developed in 2004.

36 303(d) Listing Methodology

Removal of Regulation #93 Language

Summary of Issue:

• Where there is a conflict between the Regulation and Listing

Methodology, the language in the Regulation would prevail.

• The commission based its decision on the language from

Regulation #93, but noted that the language in the Regulation should be changed.

37 303(d) Listing Methodology

Removal of Regulation #93 Language

Summary of Issue:

• EPA partially approved the 2018 Section 303(d) List of Impaired

Waters.

• To avoid partial approvals in the future, changes should be

made to Regulation #93 to better reflect recent policy decisions.

38 303(d) Listing Methodology

Removal of Regulation #93 Language

Summary of Issue:

• The division is not considering making

changes to the Category 4c classification language in the 2018 Listing Methodology.

• The division proposes to delete the

language in Regulation #93.

39 303(d) Listing Methodology

Proposed Action:

• Delete inconsistent language in Regulation 93

– “Colorado’s Monitoring and Evaluation List identifies water bodies where there is reason to suspect water quality problems, but there is also uncertainty regarding one or more factors, such as the representative nature of the data. Water bodies that are impaired, but it is unclear whether the cause of impairment is attributable to pollutants as opposed to pollution, are also placed

• n the Monitoring and Evaluation List. This Monitoring and

Evaluation list is a state-only document that is not subject to EPA approval.”

Removal of Regulation #93 Language

303(d) Listing Methodology 40

Questions?

303(d) Listing Methodology 41

LCL Not Applicable for TVS

– In the Division’s view, there are important differences between the two kinds of standards. – A TVS generally represents a physiological threshold above which concentrations threaten aquatic life. – In contrast, assessment of ambient-based standards hinges on detecting degradation of water quality: Have concentrations increased significantly over “existing quality”? – Thus, the Division does not recommend a change in current assessment practice for TVS.

42 303(d) Listing Methodology