August 19, 2009 Agenda Aquatic Life Use Refinement Nutrient - - PowerPoint PPT Presentation

August 19, 2009

Agenda

 Aquatic Life Use Refinement  Nutrient Criteria – Rivers and Streams  Nutrient Criteria – Lakes and Reservoirs  Nutrient Criteria – Direct Use Water Supply Res  CMA issues

Recap – rivers and streams

 Refined Aquatic Life Uses (and Nutrient Criteria for Rivers

and Streams) depend on bioassessment tools and

biocriteria

 Bioassessment tools

 methods of quantifying the biological condition of an

aquatic community

 Biocriteria

 Describe the biological condition that must be present

to support the use

 Serve as the threshold against which assessment results

are compared

Bioassessment Tools

 How to describe the

condition of the elephant height weight temperature blood pressure

Bioassesment Tools

 A method of

quantifying the biological condition

• f an aquatic

community

Multi-Metric Bioassessment Tool

 Statistical analysis of stressed and reference sites  Select metrics that discriminate well between the

good and bad sites

 MMI

 Macroinvertebrates  Recalibration complete (see website for report)

Biocriteria

Setting thresholds Are any of these elephants “impaired” ?

Longterm view…

 Embarking on new

territory

 Incremental Progress  Refinement in the

years to come

 The thresholds we are

about to discuss are the Division’s preliminary thresholds.

 We are still in the process of

checking our math and making sure the logic and concepts are sound.

 The thresholds will change.

August 19, 2009

Topics

 Terminology  WQCC Policy 2010-1  Tool Limitations  Determining MMI Score  Threshold Development  Decision Framework Approach  Next Steps

Terminology

 Reference and Stressed

 The ID of reference and stressed was a scientific exercise

using anthropogenic influences.

 Attained and Impaired

 The ID of attained and impaired is a regulatory exercise based

• n direct measurement of aquatic community.

 Biotype

 Refers to the conceptual biological groupings defined by

cluster analysis.

 Class

 Refers to Aquatic Life Use Classifications Cold and Warm I

and II.

WQCC Policy 2010-1

 Division will not propose revisions to the aquatic life

use classification descriptions in the Basic Stds.

 The Division’s proposal will be made in WQCC Policy

2010-1 titled “Aquatic Life Use Attainment, Methodology to Determine Use Attainment for Wadeable Rivers and Streams”.

 This document will:

 Provide a description of methodology  Record the WQCC’s policy decisions for MMI

thresholds for use attainment

Tool Limitations

 The Division is defining “wadeable streams” as streams

with a natural drainage less than 7,000 km2 or 2,700 mi2.

 The limit on stream size is driven by practical concerns

related to:

 Sampling methodology  Data treatments in MMI development (“limitations of

the model”)

 Examples:

 South Platte River at Waterton = 2,621 mi2  Arkansas River at Canon City = 3,117 mi2

Tool Limitations cont.

 The MMI tool was calibrated and validated with data

treatments for consistency in analysis.

 Therefore, not all samples will match this data

treatment.

 Tool Usage Criteria:

 Drainage area must be less than 7,000 km2 or 2,700 mi2  Sample must include 150 or more total individuals1  Sample must include 10 or more taxa1

1 Target sub-sample size is 300 individuals.

Determining MMI Score

High or Low Elevation MMI

Primary Biotype “Ingredients to Determine MMI Score”

MMI Score (0-100)

Metrics Germane to Hi

• r Lo Index

Initial Threshold Development

 Thresholds for each biotype developed based upon the

reference dataset distribution of MMI scores.

Step 1

 Example – Biotype 2 (Reference Sites):

 25th percentile=66, IQR=14.4  Midpoint = 66 – 1.5 x 14.4  Midpoint = 66 – 21.6 = 44.4 or 44

Inter-Quartile Range 25th Percentile

Step 1 Illustrated

Midpoint=44

Step 2

Midpoint=44 Upper Bound (+6) Lower Bound (-6) Yellow Zone

Initial Thresholds

Initial Thresholds for Aquatic Life Use Classification Colorado Biotype (MMI Group) MMI Index Threshold MMI score Impaired Attainment High Mountains (biotype 2) High elevation, steeper slopes, moist High <38 >50 Mountains (biotype 1) Mid-elevation, flatter slopes, moderate precipitation High <34 >46 Mountain Edges (biotype 3) Mid-elevation, steeper slopes, drier High <26 >38 Transition (biotype 4) Low elevation, flatter slopes, drier Low <22 >34 Plains and Xeric (biotype 5) Low elevation, flatter slopes, drier Low <16 >28

Decision Framework Approach

 The distinction between Class 1 and Class 2 relies on

the phrase “a wide variety of warm/cold biota including sensitive species”.

 The Division proposes using a decision framework

approach that relies upon auxiliary metrics that measure diversity and sensitivity.

Example of Class 1 Water

Attainment Threshold Impairment Threshold 38 50

Example of Class 1 Water

Attainment Threshold Impairment Threshold

• MMI Score
• f 46.5

38 50

Example of Class 2 Water

Impairment Threshold 38

Example of Class 2 Water

Impairment Threshold

• MMI Score
• f 46.5
• MMI Score
• f 20.0

38

Next Steps

 The Division is still investigating auxiliary metrics and

their potential thresholds.

 The Division is still examining the issue of secondary

biotype membership and will be assessing its implications for threshold development.

 The Division will start exploring other options for

streams/rivers that don’t meet the Tool Usage Criteria.

Questions?

RIVERS AND STREAMS NUTRIENT CRITERIA UPDATE

Sabin Room--CDPHE 1:30pm--August 19, 2009

BACKGROUND

 2001 304(a) Criteria  Colorado’s use-based approach to numeric

nutrient criteria for rivers and streams

 Recreation—150 mg/m2 Chla (attached)

 Based on recreational user surveys

(http://www.umt.edu/watershedclinic/algaesurveypix.htm)

 Aquatic Life—numeric values to be determined

 Based on Colorado’s Multimetric Index (MMI) thresholds

and Total Phosphorus/Total Nitrogen

COLORADO’S AQUATIC LIFE USE LINKAGE

MMI Scores Nutrient (ug/L)

TABLE VALUE STANDARDS

 Nutrient criteria will be adopted into the Basic

Standards (Reg. 31) via numeric table value standards (TVS)

Nutrient Criteria for Rivers and Streams

Total Phosphorus (ug/L) Total Nitrogen (ug/L) Cold water biota AA BB Warm water biota CC DD

RIVERS AND STREAMS 304(a) CRITERIA

Summary of the 2001 304a Nutrient Criteria for Rivers and Streams by Subecoregion That Would be Applicable to Colorado

EPA Ecoregion Designation Portion

• f

Colorado Total Phosphorus (ug/L) Total Nitrogen (ug/L) Chlorophyll a (ug/L) Turbidity (FTU) Xeric Wyo Basin Plateau (III.18) westslope, north

21.87 368 1.78 4.2

Xeric Colo Plateau (III.20) westslope, west

20 553 1.78 2.79

Xeric Az/NM Plateau (III.22) westslope, south

15 228 1.78 5.13

Mountains So Rockies (II.21) central mountains

6.34 90 1.08 0.8

So Great Plains W High Plains (V.25) eastern plains, northeast

90 840 2.5 9.01

Great Plains SW Tablelands (IV.26) eastern plains, southeast

25 450 3.4 4.96

CURRENT NUTRIENT DATABASE

 + 51,000 total

phosphorus records

 +35,000 total

nitrogen records

 911 MMI Scores

(Colorado EDAS)

 Includes data from  Storet  NWIS 

Riverwatch

 23 other 3rd party

sources

INITIAL RESULTS

10 20 30 40 50 60 70 80 90 100 0.01 0.1 1 10

MMI Score TP (mg/L)

Total Phosphorus

INITIAL RESULTS

10 20 30 40 50 60 70 80 90 100 0.02 0.2 2

MMI Score TN (mg/L)

Total Nitrogen

MOVING TOWARDS NUMERIC CRITERIA

 Explore various statistical methods to define the

linkage between biological thresholds (MMI) and nutrient concentrations in order to develop numeric nutrient TVS

 LOWESS  Change-point analysis  Break-point analysis  Quantile regression  Conditional probability

http://n-steps.tetratech-ffx.com/statisticalTool-method.cfm

LOWESS EXAMPLE (f = 0.8)

10 20 30 40 50 60 70 80 90 100 0.01 0.1 1

MMI Score TP (mg/L)

Total Phosphorus

ATTAINMENT THRESHOLD EXAMPLE

NEXT STEPS

 Data  Complete nutrient database  Pair remaining EDAS MMI sites and nutrient data  Process 3rd party macroinvertebrate data  Table Value Development  Explore methods for use in defining linkage between

biological community and nutrients

 Develop thresholds for nutrient concentrations  Propose numeric nutrient table values

QUESTIONS

AND

COMMENTS

Blake W. Beyea blake.beyea@state.co.us 303.692.3656

BREAK

WQ Impacts of High Chlorophyll

 Transparency  pH  DO demand  Cyano-toxins  DBPs  Fish species

Chlorophyll and Transparency

 Transparency high

• nly at low

chlorophyll

 Transparency also

may be reduced by factors other than chlorophyll

1 2 3 4 5 6 7 8 9 1 10 100 1000 Secchi Depth, m Chlorophyll, ug/L

Warm Lakes

Chlorophyll and pH

 pH>9 much more

likely when chlorophyll >30

 At low chlorophyll,

high pH values are from shallow lakes with abundant macrophytes

6.5 7.5 8.5 9.5 10.5 0.5 1 2 4 8 16 32 64 128256512 pH Chlorophyll, ug/L

Warm Lakes

Trophic State and Fishery Type

Trophic State (OECD) Chlorophyll , ug/L Secchi Depth, m Oligotrophic <2.5 >6 Mesotrophic 2.5 – 8 6 – 3 Eutrophic 8 – 25 3 – 1.5 Hyper- eutrophic >25 <1.5

 Salmonids do better in

low productivity lakes

 Transition to walleye  Warmwater fishes in

eutrophic lakes

 Highest productivity

lakes dominated by carp and bullheads

General Strategy

 Balance potentially competing interests (high clarity

for swimming vs. high yield for fishery) without compromising support for other uses

 Develop meaningful thresholds for non-toxic

constituents

 Focus on algal abundance (chlorophyll concentration)

as the response variable with direct impact on uses

 Support with data from Colorado lakes

Swimming and Chlorophyll

 Perceptions – When is it too green?

 Texas user surveys: Recreational experience diminished

when chlorophyll approaches 30 ug/L

 Other states with plains lakes

 Iowa: 25 ug/L (and Secchi of 1.0m)  Minnesota: up to 30 ug/L

 “severe nuisance bloom” = 30 ug/L  “nuisance bloom” = 20 ug/L

 Instantaneous vs. summer average thresholds

Linking Blooms and Averages

 After Walker (1985)  Capitalizes on log-

normal distribution: std deviation increases with mean

 Defines exceedance

frequency of grab sample based on summer avg

 250 lake-years of data

from Colorado

y = 0.3043x1.2184 R² = 0.8547 0.1 1 10 100 1000 0.1 1 10 100 1000 Standard Deviation, ug/L Seasonal Average Chlorophyll, ug/L

Warm Lakes Overview

 Summer average – 20 ug/L

 Optimal for warmwater game fish - eutrophic  Prevents hyper-eutrophic conditions  Exceedance frequency – once in 5 yrs

 Bloom threshold – 30 ug/L

 Link with Walker’s method  Exceedance frequency <15% when avg < 20 ug/L  Acceptable risk of cyano-toxins (> 50 ug/L once in 6

weeks)

Cold Lakes Overview

 Summer average – 8 ug/L

 Optimal for most salmonids  Similar to cold water fishery thresholds in other states

 MN: 6 ug/L  VA: 10 ug/L

 Exceedance frequency – once in 5 yrs  May need site-specific for lake trout

 Bloom threshold – 20 ug/L

 Exceedance frequency ~1% when summer avg < 8 ug/L (i.e., 1

day in summer)

 No risk of cyano-toxins (no measurable risk of chlorophyll

>50 ug/L)

Link Chlorophyll to Phosphorus

 13 lakes with sufficient data (multiple years)  Compare 80th percentile summer averages  Strong linkage

y = 0.7894x0.7331 R² = 0.8839 1 10 100 1000 1 10 100 1000 80% Summer Avg Chl, ug/L 80% Summer Average Phosphorus, ug/L

Link Chlorophyll to Nitrogen

 6 lakes with sufficient data (multiple years)  Compare 80th percentile summer averages  Strong linkage

y = 0.0021x1.3364 R² = 0.9969 1 10 100 1000 100 1000 10000 80% Summer Avg Chl, ug/L 80% Summer Average Nitrogen, ug/L

N and P from same set of lakes

y = 0.5512x0.777 R² = 0.9784 y = 0.0021x1.3364 R² = 0.9969 1 10 100 1000 1 10 100 1000 10000 80% Summer Avg Chl, ug/L 80% Summer Average Nutrients, ug/L TP TN

Summary and Comparison

EPA 304(a) Nutrient Criteria Table Values for Lakes Ecoregion Spectrophot. Chlorophyll (ug/L) Total Phosphorus (ug/L) Calculated Total Nitrogen (ug/L) Mountains, So Rockies (II.21) 1.7 15 180 Xeric, Wyo Basin Plateau (III.18) 1.4 10 380 Xeric, Colo Plateau (III.20) 1.4 3 150 Xeric, AZ, NM Plateau (III.22) 2.0 15 230 Plains, So Great Plains (V.25) 2.4 24 500 Plains, Great Plains (IV.26) 1.2 20 390 Initial Table Values: Nutrient Criteria for Lakes Classification Recreation1 Aquatic Life2 Chlorophyll (ug/L) Chlorophyll (ug/L) Total Phosphorus (ug/L) Total Nitrogen (ug/L) Cold water biota 20 8 24 490 Warm water biota 30 20 82 960 1 – 85th percentile of summer measurements 2 – 80th percentile of summer average

Previous presentations are on the website

Domestic Water Supply

 31.13(1)(d) These surface waters are suitable or

intended to become suitable for potable water

• supplies. After receiving standard treatment (defined

as coagulation, flocculation, sedimentation, filtration, and disinfection with chlorine or its equivalent) these waters will meet Colorado drinking water regulations and any revisions, amendments, or supplements thereto.

Necessity of proposed changes

 31.6(1)(e) Classifications should be for the highest

water quality attainable.

 Must protect the most sensitive use.  Nutrient criteria based on protection of aquatic life

may not be protective of public health.

Proposed Regulatory Revisions

31.13 STATE USE CLASSIFICATIONS (1) Classifications (d) Domestic Water Supply These surface waters are suitable or intended to become suitable for potable water supplies. After receiving standard treatment (defined as coagulation, flocculation, sedimentation, filtration, and disinfection with chlorine or its equivalent) these waters will meet Colorado drinking water regulations and any revisions, amendments, or supplements thereto.

(i) Class DUWS – Direct Use Water Supply. A plant intake is located on these lakes and reservoirs in order to provide raw water directly to a water treatment facility. .

Proposed Regulatory Revisions (cont.)

31.5 DEFINITIONS (31) “Plant Intake” means the works or structures at the head of a conduit through which water is diverted from a source (e.g., river or lake) into the treatment plant. Note: This is the same definition as contained in the Colorado Primary Drinking Water Regulations (5 CCR 1003.1).

How are these reservoirs different?

 Most are off channel  Highly managed, both inputs and outputs  Aquatic life and recreation are not the driving factors

for use protection

 Human health consequences for non-attainment

What water treatment managers really care about: compliance and customer satisfaction

 Taste and odor  Disinfection byproducts  Filter clogging algae  Release of metals from anoxic sediments  Contaminants of concern/pharmaceuticals

pH, 25 µg/L taste and odor, 10 µg/L prevalence of blue- green algae, 10 µg/L disinfection by- products, 5 µg/L dissolved oxygen, 6 µg/L transparency, 5 µg/L Chlorophyll a 304(a) criteria, 1-2 µg/L

Initial Proposal Table Values for Direct Use WS

 Chlorophyll a = 5 ug/L

 Annual average  1 in 5-yr allowable exceedance frequency

 DUWS sub-classification would be

applied by the WQCC on a case-by- case basis

Next Steps

 Averaging period  Monitoring concerns  Discussion

Future Meetings

 September 21, 2009

 Reservoir DO  Antidegradation (WQCD)  Economic Reasonableness (Regulated Community)  Update on thresholds as they are refined

 October 19, 2009

 Antidegradation (others)  Temperature issues  Discharger Specific Variance  Update on Thresholds as they are refined

Future Dates

 November 9, 2009 – IFH  November 16, 2009



Implementation issues

 December 16, 2009  January 15, 2010 –

 Proposals due to WQCC office

More meetings on Aq Life or Nutrient Criteria?

 Intensive refresher on Bioassessment Tools?  Focus on Lake Nutrient Criteria?  Focus on Rivers and Streams Nutrient Criteria?

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