New Hampshire Estuaries Project September 30, 2005 Estuarine Nutrient Criteria Presentation to New Hampshire Estuaries Project Technical Advisory Committee.

New Hampshire Estuaries ProjectSeptember 30, 2005

Estuarine Nutrient Criteria

Presentation to New Hampshire Estuaries Project Technical Advisory Committee

Matthew Liebman, EPA New England


“We have a lot of problems,so let’s get started”

• EPA’s Nutrient strategy– Nutrients are a problem– Identify nutrient and biological levels below which nuisance or

impaired conditions are unlikely to occur; thus designated uses are protected

– Apply ecoregional reference condition approach, or effects based approach

– Adopt criteria into state water quality standards

• Examples from lakes and streams• Factors to think about in developing nutrient criteria• Expectations from EPA, a national perspective, and

examples from regional/state workgroups


Fortunately, there’s a lot of good work in developing lakes and streams

ecoregional-based criteria• Lakes and streams ecoregional-based criteria (reference

conditions) published in 2000 and 2001

• EPA established RTAGS to gather data and develop criteria with states, federal agencies and academics

• EPA/NEIWPCC published more specific recommended ecoregional criteria for lakes and streams in New England www.neiwpcc.org

• States have developed nutrient criteria plans (mutually agreed to with EPA), they are currently being updated to include estuarine criteria

http://www.neiwpcc.org/



The statistical reference condition approach assumes that the reference condition protects uses

35 30 25 40 Low water quality High water quality

TP (ug/L)

Reference rivers distribution

All rivers distribution

75%

25%

1

2

2

1


States can adjust the reference condition with additional information, such as “use impairment”, or effects information

0

10

20

30

40

50

60

[TP]

Final State/Tribal Criterion

State/Tribal Refinements Through RTAG Progression from Reference Condition to Criterion

Reference Conditions

Expert Judgment

ModelingHistorical

InformationDownstream

Effects


Example of effects-based approach for streams:literature nutrients and periphyton biomass regression

equations

General nutrient-periphyton regression equations were backcalculated to provide TP and TN levels resulting in <100 mg/m2 chl a biomass:

TP = 47 ug/L

TN < 0.97 mg/L


.1

1

10

100

1000

open

closed

Reference ModeratelyImpaired

Impaired

Mil

lig

ram

s p

er m

eter

sq

uar

edExample of effects-based approach for streams:

Periphyton chlorophyll a

(10)

(10)

(10)

(10) (10)

(10)

(10) Number of samples

(Source: USGS, EPA)


0

.1

.2

.3

.4

.5

.6

0

1

2

3

4

5

6

7

8

Mil

lig

ram

s p

er l

iter

Mil

lig

ram

s p

er l

iter

10th 25th 50th 75th 90th

Percentile

10th 25th 50th 75th 90th

Percentile

Subecoregion 59 .024 mg/L

Subecoregion 59 0.57 mg/L

0.037 mg/L0.75 mg/L

Total PhosphorusImpaired Sites

Total NitrogenImpaired Sites

(Source: USGS, EPA)


Factors to consider in development of nutrient criteria

• Identify nutrient and biological levels below which nuisance or impaired conditions are unlikely to occur; thus designated uses are protected

• Criteria should be developed for different uses, e.g. aquatic life, recreation

• Consider both causal and response variables• Consider an index period, such as summer June to September• Classify estuaries to reduce variance, develop criteria for each class • Consider concentration or loading based approaches• Reference condition approach or effects-based approach• Availability of current or historical data• Apply modeling results or literature values• Develop consensus criteria


National perspective of estuarinenutrient criteria

• Estuarine guidance manual published in 2001 proposes several approaches to criteria development HQ has set up a national workgroup with academics, feds and state scientists to assist in development of estuarine nutrient criteria.

• One of first tasks is to select a “pilot” group of estuaries for criteria development, including 10 from the Gulf of Mexico, and 10 other estuaries (including Delaware Bay and Peconic Bay)

– uses a classification scheme of nutrient susceptibility developed by NOAA– approach depends on availability of data

• Will select other “pilot” estuaries in near future– Selection factors include availability of data, approach for criteria development, whether

systems are multi-state or effluent dominated systems, degree of nutrient enrichment– Goal is to publish criteria for these systems by 2007

• Coastal (not estuarine) nutrient criteria workgroup meeting in Delaware October 24 and 25 to review coastal nutrient criteria manual


There are several ongoing work groups or efforts to develop estuarine nutrient criteria in

New England• Massachusetts Estuaries Project

– Contact Brian Dudley, MA DEP, [email protected], 508/946-2753, http://www.oceanscience.net/estuaries/index.htm

– Using a combination of modeling and effects based approach, nitrogen concentrations related to eelgrass habitat, residence time is a normalizing factor

• EPA NHEERL –AED– Contact Jim Latimer

• CT Long Island Sound embayments– Contact Paul Stacey CT DEP

• New Hampshire Estuaries Project– Contact Phil Trowbridge

mailto:[email protected]

http://www.oceanscience.net/estuaries/index.htm


89 Embayments for Massachusetts Estuaries Project


FT and Volume Normalized Loading, mgN m-3 (Emperical)

y = 7.3129x-1.1865

R2 = 0.7172

y = 7.3129x-1.1865

R2 = 0.7172

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 50 100 150 200 250

Load

SA

V %

of

shor

elin

e

DRAFT DO NOT CITEFor informational purposes onlyContact Jim Latimer

FT and Volume Normalized Loading, mgN m-3 (Emperical)

y = 7.3129x-1.1865

R2 = 0.7172

y = 7.3129x-1.1865

R2 = 0.7172

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 50 100 150 200 250

Load

SA

V %

of

shor

elin

e

DRAFT DO NOT CITEFor informational purposes onlyContact Jim Latimer

NHEERL Effects-based approach


Classification and comparison among estuaries in Long Island Sound

River dominated

Small embayment

Small embayment


Can you choose a reference condition in Great Bay?


Factors to consider in development of nutrient criteria

• Identify nutrient and biological levels below which nuisance or impaired conditions are unlikely to occur; thus designated uses are protected

• Criteria should be developed for different uses, e.g. aquatic life, recreation

• Consider both causal and response variables• Consider an index period, such as summer June to September• Classify estuaries to reduce variance, develop criteria for each class • Consider concentration or loading based approaches• Reference condition approach or effects-based approach• Availability of current or historical data• Apply modeling results or literature values• Develop consensus criteria

New Hampshire Estuaries Project September 30, 2005 Estuarine Nutrient Criteria Presentation to New Hampshire Estuaries Project Technical Advisory Committee.

Documents

epa new england slide

epa slide

nutrient criteria expectations

estuarine criteria

protected criteria

effects based approach

impaired conditions

streams factors