Utah's Approach to New Water Quality Criteria for Ammonia, published by the Utah Division of Water Quality. For more information, please visit waterquality.utah.gov
Utah's Approach to New Water Quality Criteria for Ammonia
1. Utah’s Approach to New
WQ Criteria for Ammonia
Utah Division of Water Quality
Water Quality Standards Workgroup
July 21, 2014
2. Slide 2
Utah’s Approach
Receiving Waters with
Current UPDES permits
Evaluate whether new
ammonia criteria would be
exceeded
(informational only)
Phase I: Determine
whether sensitive
species are present
(genus level)
Present – adopt new
ammonia criteria
Not present – discuss
phase 2 research to
determine if present
historically
Historical presence or
probability of
occurrence using
spatial statistical
models; Potential
teaming with other
states
Non-Receiving
Waters
Evaluate whether new
ammonia criteria
would be exceeded
(informational only)
Adopt new
ammonia
criteria
New UPDES
permitees
could do
research in
support of site-
specific
standard
when/if
necessary
Scoping
Recalculation scenarios for presence/absence of sensitive species
Presence of families with sensitive species using existing data
Potential impacts on POTWs
3. Slide 3
Recalculated Acute
Ammonia Criteria Scenarios
Criteria1
(mg TAN/L)
Final Acute Value
(mg TAN/L)
Scenario Species Used for
Final Acute Value
17 33.85
Sensitive mussels and snails
present and salmonids absent
per USEPA (2013)
24 48
Salmonids and snails present
and sensitive mussels absent
per USEPA (2013)
29 58.43
Salmonids and sensitive snails
present but no sensitive
mussels2
Golden Shiner, Pebblesnail,
Lost River sucker, Mountain
whitefish
30 60.23
Salmonids present but no
sensitive mussels or snails2
Shortnose sucker, Golden
Shiner, Lost River sucker,
Mountain whitefish
38 74
Snails present but no sensitive
mussels or salmonids per
USEPA (2013)
2These were recalculated by DWQ by backing out the described species to show the potential impact of sensitive
snails on the ammonia criterion. The difference observed between the values provided in the USEPA criteria document
and these recalculated values requires further evaluation. The recalculations assume 7 pH and 20o C and that all
genus mean acute values are above the 5th percentile
1Current acute standard is 24 mg/L at 7 pH for Class 3A
5. Slide 5
2013 (new)maximum (acute) ammonia criteria compared to existing
criteria at pH=7 and 8
0
1
2
3
4
5
6
7
8
9
10
10 15 20 25 30
AcuteCriteria(mg/l)
Temperature (˚C)
2013, Sensitive species
not present
2013, sensitive species
present
Existing, Classes 3B-3D
Existing, Class 3A
@pH=8
6. Slide 6
2013 (new)chronic ammonia criteria
compared to existing criteria at pH=8
0
1
2
3
4
5
6
10 15 20 25 30
ChronicContinuousCriteria(mg/l)
Temperature (˚C)
2013, sensitive species
not present
2013, sensitive species
present
Existing, no early life
stages present
Existing, early life
stages present
7. Slide 8
Gastropod families in Utah that
include sensitive species
Hydrobidae: mud snails/spring snails
Valvatidae: valve snails Found in streams and lakes in northern Utah
Ancylidae (tribe in family Planorbidae):
snails/limpets
8. Slide 9
Bivalve families in Utah that
include sensitive species
Unionidae: mussels
Corbiculidae: Asian clamsFound in streams and lakes in northern Utah
Pisididae: pill clams
Photo courtesy of CA Dept of Fish and Wildlife, Aquatic Bioassessment Laboratory
Photo courtesy of CA Dept of Fish and Wildlife, Aquatic Bioassessment Laboratory
9. Slide 10
Utah’s Approach
Receiving Waters with
Current UPDES permits
Evaluate whether new
ammonia criteria would be
exceeded
(informational only)
Phase I: Determine
whether sensitive
species are present
(genus level)
Present – adopt new
ammonia criteria
Not present – discuss
phase 2 research to
determine if present
historically
Historical presence or
probability of
occurrence using
spatial statistical
models; Potential
teaming with other
states
Non-Receiving
Waters
Evaluate whether new
ammonia criteria
would be exceeded
(informational only)
Adopt new
ammonia
criteria
New UPDES
permitees
could do
research in
support of site-
specific
standard
when/if
necessary
Scoping
Recalculation scenarios for presence/absence of sensitive species
Presence of families with sensitive species using existing data
Potential impacts on POTWs
10. Slide 11
Determining Presence
of Sensitive Mollusks
Species occur at site if…
Are usually present at the site.
Are present at the site only seasonally due to migration.
Are present at the site intermittently because they
periodically return to or extend their ranges into the site
Were present at the site in the past, are not currently
present at the site due to degraded conditions, but are
expected to return to the site when conditions improve.
Are these sensitive mollusks present today?
Historical records
Field surveys
eDNA