ADEQ Lakes Classification ADEQ Lakes Classification ADEQ Lakes - - PowerPoint PPT Presentation

ADEQ Lakes Classification Project ADEQ Lakes Classification ADEQ Lakes Classification Project Project

Update on the Narrative Nutrient Criteria Development Project Update on the Update on the Narrative Nutrient Criteria Narrative Nutrient Criteria Development Project Development Project

Water Quality Standards Water Quality Standards

Water Quality Criterion Designated Use Antideg. Policy

Designated Uses… Designated Uses…

Aquatic & wildlife-coldwater Agricultural uses: irrigation, livestock watering Full or partial body contact Drinking water supply Aquatic & wildlife-warmwater

Nutrients most common causes of Nutrients most common causes of lake/reservoir impairment… lake/reservoir impairment…

Problems with nutrients Problems with nutrients

• Nuisance

Nuisance algal/ algal/macrophyte macrophyte growths growths

– – Unaesthetic Unaesthetic – – Toxic Toxic – – Taste & odor problems Taste & odor problems – – Low dissolved oxygen Low dissolved oxygen – – Food quality impacts Food quality impacts – – Habitat degradation Habitat degradation

USEPA’s USEPA’s National Nutrient National Nutrient Strategy Strategy

• As of 1995, most states did not have effective

As of 1995, most states did not have effective nutrient standards nutrient standards

• USEPA’s

USEPA’s National Strategy document published National Strategy document published in 1998 in 1998

• Technical guidance manuals published in 2000

Technical guidance manuals published in 2000

• Nutrient criteria in 2001

Nutrient criteria in 2001-

• 2002

2002

– – Causal variables: TN, TP Causal variables: TN, TP – – Response variables: Chlorophyll Response variables: Chlorophyll a a, and , and Secchi Secchi depth depth

• States required to adopt standards in 2004

States required to adopt standards in 2004-

• 2007

2007 timeframe timeframe

USEPA’s USEPA’s default criteria are default criteria are ecoregional ecoregional… …

AZ Narrative Nutrient Standard AZ Narrative Nutrient Standard

• R18

R18-

• 11

11-

• 108A. A surface water shall be free from pollutants (
• 108A. A surface water shall be free from pollutants (nutrients

nutrients in this case in this case) in amounts that: ) in amounts that:

– – Settle to form bottom deposits Settle to form bottom deposits that inhibit or prohibit the habitation, growth, that inhibit or prohibit the habitation, growth,

• r propagation of aquatic life;
• r propagation of aquatic life;

– – Cause objectionable odor Cause objectionable odor in the area in which the surface water is located; in the area in which the surface water is located; – – Cause off Cause off-

• taste

taste or odor in drinking water;

• r odor in drinking water;

– – Cause off Cause off-

• flavor

flavor in aquatic organisms; in aquatic organisms; – – Are toxic Are toxic to humans, animals, plants, or other organisms; to humans, animals, plants, or other organisms; – – Cause the growth of algae or aquatic plants that inhibit or proh Cause the growth of algae or aquatic plants that inhibit or prohibit the ibit the habitation or other aquatic life or that impair recreational use habitation or other aquatic life or that impair recreational uses s; ; – – Cause or contribute to Cause or contribute to a violation of an aquifer water quality standard a violation of an aquifer water quality standard…; …; – – Change the color Change the color of the surface water from natural background levels

• f the surface water from natural background levels

Project Goals Project Goals

• To help develop flexible

To help develop flexible narrative nutrient criteria narrative nutrient criteria and and associated implementation procedures associated implementation procedures for for Arizona’s lakes that will maintain a consistent, Arizona’s lakes that will maintain a consistent, scientifically scientifically-

• based means of compliance

based means of compliance assessment. assessment.

• Avoid “one

Avoid “one-

• size fits all” numeric criteria; i.e.,

size fits all” numeric criteria; i.e., consider how variability lake/watershed consider how variability lake/watershed characteristics affects characteristics affects trophic trophic responses. responses.

• Link criteria/numeric targets with

Link criteria/numeric targets with designated uses. designated uses.

Lake Pleasant

Overview of Approach Overview of Approach

Compile Lake/Reservoir Data Statistical/ Modeling Analysis Lake Classification

2005 Triennial Review for public review and comment

Implementation Procedures Numeric Targets

Project Overview Project Overview

74 Lakes in the Study 138 Sampling Sites Water Quality Data spanning 20 Years collected by:

• ADEQ,
• U of A,
• Southern Nevada Water Authority
• Game and Fish,
• Fish and Wildlife,
• EPA,
• USBR,
• USGS

Statistical Analysis Design Statistical Analysis Design

• Graphical analysis

Graphical analysis

– – Exploration of important correlations Exploration of important correlations – – Determine need for transformations Determine need for transformations

• Multivariate analysis

Multivariate analysis

– – Principal components analysis (PCA) Principal components analysis (PCA) – – Seek useful linear combination of lake/water Seek useful linear combination of lake/water characteristics variables to “explain” water quality characteristics variables to “explain” water quality

• Classification and regression tree (CART)

Classification and regression tree (CART)

– – Use most powerful variables to classify lakes. Use most powerful variables to classify lakes.

Project Status Project Status

• Water quality and GIS databases compiled and linked

Water quality and GIS databases compiled and linked (Spring 2003 (Spring 2003 -

• Winter 2004);

Winter 2004);

• Descriptive statistics, PCA, CART & phosphorus load

Descriptive statistics, PCA, CART & phosphorus load modeling performed (Spring 2004); modeling performed (Spring 2004);

• Algae species data analyzed, TSI re

Algae species data analyzed, TSI re-

• worked for AZ &

worked for AZ & project re project re-

• scoped (Summer 2004);

scoped (Summer 2004);

• Refined statistical analyses performed (Fall 2004);

Refined statistical analyses performed (Fall 2004);

• Matrix completed for implementation of narrative nutrient

Matrix completed for implementation of narrative nutrient standard for lakes & reservoirs (Spring 2005); standard for lakes & reservoirs (Spring 2005);

• Survey of recreational use attainment (Spring 2005)

Survey of recreational use attainment (Spring 2005)

• Implementation proposed in 2005 Triennial Review

Implementation proposed in 2005 Triennial Review

Modeling concept Modeling concept

Phosphorus loading (g/m2 yr) Mean depth/hydraulic residence time (m/yr)

Summer mean chlorophyll a (µg/L) 120 5 15 30 60 100

Oligotrophic zone Eutrophic zone Reservoir Category A: Unlikely to meet coldwater A&W uses Reservoir Category B: Likely to meet coldwater A&W uses

Figure 1: Conceptual application of generalized model results. Basic chart form after Rast and Lee (1978).

Preliminary results suggests that other variables Preliminary results suggests that other variables may complicate this approach… may complicate this approach…

I refuse to draw a regression line through these points.

Model Results Model Results

• Lack of a clear predictive relation between the normalized

Lack of a clear predictive relation between the normalized annual aerial phosphorus load (NAAPL) and the water annual aerial phosphorus load (NAAPL) and the water quality of Arizona’s lakes and reservoirs…why? quality of Arizona’s lakes and reservoirs…why?

– – errors in model parameter estimates and uncertainty of the true errors in model parameter estimates and uncertainty of the true seasonal average concentrations seasonal average concentrations – – Limitation by factors other than phosphorus Limitation by factors other than phosphorus – – Sequestering of nutrients by Sequestering of nutrients by macrophytes macrophytes or

• r periphyton

periphyton – – Deposition of nutrients Deposition of nutrients – – Internal recycling of nutrients Internal recycling of nutrients – – High or variable proportions of non High or variable proportions of non-

• bioavailable

bioavailable nutrients in the nutrients in the annual load annual load – – Top Top-

• down biological controls (i.e., grazing).

down biological controls (i.e., grazing).

Confirmed some expected relations Confirmed some expected relations between water quality variables between water quality variables

Chlorophyll-a v. total phosphorus

…albiet with a lot of scatter.

Chlorophyll-a v. secchi depth

Insight into how water quality Insight into how water quality varies within lakes/reservoirs varies within lakes/reservoirs

“Lakes” have more Uniform water quality “Reservoirs” display longitudinal variations

Water quality correlates with Water quality correlates with agricultural and urban land use agricultural and urban land use

TP v. percent agricultural land Secchi depth v. percent agricultural land

PCA Analysis PCA Analysis

• Significant relationship

Significant relationship between chlorophyll, TKN, between chlorophyll, TKN, and % blue and % blue-

• green algae

green algae

• Will become part of the

Will become part of the narrative nutrient narrative nutrient implementation index implementation index

chl% cry% cryp% cyn% eug% pyr% CHLA TKN TP TKN/TP SD DO

• 1.0
• 0.5

0.0 0.5 1.0 Factor 1 : 28.93%

• 1.0
• 0.5

0.0 0.5 1.0 Factor 2 : 19.06%

Effects of Lake Depth & Effects of Lake Depth & Stratification Stratification

MAX_DEPTH AVG_DEPTH grad_DO CHLA SI TKN SD TP grad_DOS grad_ORP

• 1.2
• 1.0
• 0.8
• 0.6
• 0.4
• 0.2

0.0 0.2 0.4 0.6 0.8 1.0 1.2 Factor 1

• 0.8
• 0.6
• 0.4
• 0.2

0.0 0.2 0.4 0.6 0.8 1.0 Factor 2

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 TKN (mg/L) 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 2.00 3.00 Vertical DO Gradient (mg/L-m) Potential threshold = ~0.8 mg/L 0.7 0.8 0.9 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 Chlorophyll-a (µ g/L) 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 2.00 3.00 Vertical DO Gradient (mg/L-m) Potential threshold = ~ 10 µg/L

The first component was highly loaded

• n DO gradient-related variables and

explained approximately 47-percent of the variance of the data. The second principal component was highly loaded

• n water quality variables such as TKN,

TP, chlorophyll-a, and Secchi depth, and explained about 28-percent of the variability in the data.

Potential place to “prune” tree Variables: Soils Precipitation %Ag land Average depth Watershed area to lake area ratio

Example: Using watershed/lake characteristics to classify lakes by average spring-summer chla concentration. Categories Chla Conc. (ppb) <3 3-5 5-12 12-20 >20

Note the power of adding other water quality variables (TKN, TP, ORP) to classify lakes by chlorophyll-a: Note the power of adding other water quality variables (TKN, TP, ORP) to classify lakes by chlorophyll-a: Note the power of adding other water quality variables (TKN, TP, ORP) to classify lakes by chlorophyll-a:

Preliminary Preliminary Lake Categories Lake Categories

Elevation is less than 5,000 ft. Urban land use not dominant Low-elevation, non- urban Roper Lake and Dankworth Ponds High TDS Sedimentary geology designation Sedimentary Basaltic geology designation Basaltic Elevation is greater than 5,000 ft. Soil types: FH2 (Sponseller-Ess-Gordo) FH5 (Mirabel-Baldy-Rock Outcrop) MA4 (Tours-Navajo) MH2 (Lithic Haplustolls-Lithic Argiustolls-Rock Outcrop) MH5 (Overgaard-Elledge-Telephone) High-elevation, soil- based Identified as “weed-choked” or macrophyte-dominated in Az L&R Database Macrophyte- dominated Urban land use dominant Urban Designated as a reservoir Reservoirs Description of Class Lake Class High elevation (>5,000’) lakes: May—September peak season Low elevation (<5,000’) lakes: April—October peak season

Some considerations Some considerations

• Numeric targets likely to vary between lake

Numeric targets likely to vary between lake categories categories

– – e.g., some types of lakes “expected” to be more e.g., some types of lakes “expected” to be more productive, less clear than others productive, less clear than others

• Implementation procedures must address potential

Implementation procedures must address potential conflicts between multiple uses conflicts between multiple uses

– – e.g., warm water fishery v. recreation e.g., warm water fishery v. recreation

• Implementation procedures should allow

Implementation procedures should allow consideration of non consideration of non-

• numeric information

numeric information

– – e.g., assessment of heath of fish community, user e.g., assessment of heath of fish community, user complaints complaints

Most Important Variables Most Important Variables

• Setting

Setting

• Geology/Soils

Geology/Soils

• Elevation

Elevation

• Hydraulic Retention

Hydraulic Retention Time/Flushing Time/Flushing

• Lake Morphology; Max

Lake Morphology; Max Depth, Depth, Avg Avg depth & depth & Stratification Index Stratification Index

• Internal Nutrient Cycle

Internal Nutrient Cycle

*[ *[NOT NOT Ecoregions Ecoregions] ]

What’s Ahead, 2005 & Beyond What’s Ahead, 2005 & Beyond

• Goals for 2005

Goals for 2005

– – Finalize lake classes Finalize lake classes – – Finalize matrix of endpoints by lake Finalize matrix of endpoints by lake class (numeric & non class (numeric & non-

• numeric)

numeric)

• Chlorophyll

Chlorophyll

• Secchi

Secchi

• TKN

TKN

• %

% Bluegreen Bluegreen algae/potential toxins algae/potential toxins

• Stratification index as related to DO,

Stratification index as related to DO, TKN, chlorophyll & Deep ORP TKN, chlorophyll & Deep ORP

• Trophic

Trophic response/TSI response/TSI

• Non

Non-

• numeric Designated Use

numeric Designated Use Attainment Attainment

– – Propose matrix in 2005 Triennial Propose matrix in 2005 Triennial Review

• Goals for Future

Goals for Future

– – More lakes, more data! More lakes, more data!

• Refine classes and endpoints

Refine classes and endpoints as needed as needed

• Develop phytoplankton index

Develop phytoplankton index for lakes for lakes

– – Work on narrative nutrient Work on narrative nutrient implementation strategy for implementation strategy for streams streams – – Encourage watershed Encourage watershed-

• wide

wide collaboration to protect and collaboration to protect and enhance lakes, reservoirs & enhance lakes, reservoirs & streams streams

Review