Recent Changes to the Basic Standards
Sarah Johnson, Assessment Unit Manager,
303/692-3609
Phil Hegeman, Contact for the Lower Arkansas
303/692-3518
On the WQCC website at :
(The first bullet under “Surface Water Quality Standards and Classifications”)
Issue / Major Changes to the Basic Standards (June 2005) / Implementation in the ArkansasLow Flow calculations / For streams with rapidly rising or falling hydrographs, the Discharger can ask for an alternative procedure for calculating low flows. / no changes in Reg 32 needed.
Temperature Criteria / Place holder changes were made to the Temperature Table Value Criteria that will be effective 12/31/2007. New values will be decided at a 1/07 hearing. / The results of the 1/2007 hearing will probably be proposed for the Arkansas for the 6/2007 hearing.
Temporary Modifications /
- reduces the distinction between types of temporary modifications
- reiterates that the focus should be on re-establishing attainment either by controlling the sources or adjusting the standard to an attainable goal.
- requires an annual hearing to address temporary modifications that are due to expire in the next time period.
- clarifies how temporary modifications are to be implemented in discharge permits.
The questions will be:
- What was the original reason for a TM?
- Is the appropriate underlying standard known?
- If not, when will it be known?
- Is progress being made?
Antidegradation /
- Automatic decoupling of Cold Class 2 and UP
- Opportunity to decouple Warm Class 2 and UP
- Coupling effluent-dominated and effluent-dependent flow classes with UP
- Modify the baseline date where water quality is improving.
26 warm class 2
RG: 13 cold class 2
10 warm class 2
Recreation Use Classifications /
- converts to alphabetic class identifier to address perception of value judgment in the numeric identifier
- distinguishes between primary contact based on evidence and primary contact by default
- addresses those segments which have a secondary contact label but are assigned primary contact numeric values
- assures that site-specific standards can be adopted for classified uses other than aquatic life (such as recreation)
1a=>E: Existing Primary Contact Use
1b=>P: Potential Primary Contact Use
new U: Undetermined Use
2=>N: Not Primary Contact Use
Ammonia Criteria / The Commission adopted EPA’s 1999 Update For Ammonia
Cold = salmonids present, ELSP all year
generally relaxed standards
Warm = salmonids absent, ELSP April 1 through August 31
generally more stringent standards
(ELSP = early life stage present) / The WQCC is considering a recommendation to change the Ammonia standards for the Whole state at a Feb 2007 hearing. Discuss at the Oct Meeting.
Get data NOW so you know how it will affect you!
ELSP =>decisions made by WQCC
Aluminum / The Commission changed the aluminum table value analytical fraction from dissolved to total recoverable aluminum and the addition of a clarifying footnote that the chronic value is only applicable where there is low pH and low hardness.. / not much
Antimony / W+F => 5.6, & FI => 640
(reflects the Commission’s earlier approval of a higher fish consumption rate.) / not much
Arsenic / Water Supply =>0.02-10 ug/L,
W+F => 0.02, & FI => 7.6
(reflects changes in the fish consumption rate and a lower SDWA MCL) / could be a big deal on a site specific basis
Cadmium / Modified Cadmium criteria. (hardness equation: chronic at 50 => 0.25;
at 200=> 0.72 ug/L) / could be a big deal on a site specific basis
Uranium / Uranium domestic water supply table value (at the MCL). 50 ug/L / could be a big deal on a site specific basis
Zinc / Modified Zinc criteria (hardness equation: chronic at 50 =>69; at 200=> 224 ug/L). Now acute is higher than chronic! / this is a very slight relaxation.
How will the new ammonia criteria affect my discharge limit?
General Suggestions[1] about Data Collection to run AMMTOX
A preview of your new under the new ammonia criteria can be developed using the model AMMTOX with a relatively limited set of data. AMMTOX works in essentially the same way that CAM does, except that it has the new ammonia criteria instead of the old ones. It should be understood, however, that operating AMMTOX with a limited data set requires a number of assumptions, for which the default values tend to be conservative.
The bare-bones data set, which characterizes water quality conditions in the effluent and in the receiving water above the outfall, creates the basis for mass balance calculations and for calculating setpoint conditions. In the receiving water, paired measurements of pH and temperature should be made monthly, or more frequently, and the time of day must be recorded. In addition, the concentration of total ammonia must be measured. PH and temperature also must be measured in the effluent, but the frequency of samples may be less critical if operators expect uniformity over time.
To complete the mass balance calculations, low flow conditions must be defined in the receiving water, and design flow must be specified for the treatment facility. You can use your current low-flow estimates, or develop new ones using daily flows in the receiving water from existing gage records, with adjustments as necessary for diversions, seepage, and other tributaries.
A logical add-on to the data set is a characterization of setpoint (equilibrium) conditions with a downstream site rather than relying on data from the upstream site. Without belaboring the purpose and protocol for setpoint conditions, data from a downstream site is preferred and the data requirements are relatively simple: pH, temperature, and time of day. Selecting a location for the sampling site is more troublesome. The site should be far enough below the outfall to ensure complete mixing, but not so far that tributaries or seepage might alter substantially the chemistry of the receiving water.
A logical add-on to the data set is a characterization of setpoint (equilibrium) conditions with a downstream site rather than relying on data from the upstream site. Without belaboring the purpose and protocol for setpoint conditions, data from a downstream site is preferred and the data requirements are relatively simple: pH, temperature, and time of day. Selecting a location for the sampling site is more troublesome. The site should be far enough below the outfall to ensure complete mixing, but not so far that tributaries or seepage might alter substantially the chemistry of the receiving water.
Summary
LocationTimepHTempAmmoniaFrequencyComments
(total)
UpstreamXXXXMonthlyMore frequent in critical months
EffluentXXXMonthlyIs your effluent consistent?
DownstreamXXXMonthlyMore frequent in critical months
1.It is important to get pH, temperature at the same time and to record that sample time. The model takes into account the way temperature and pH change over a 24-hour cycle.
2.If you can, it would be helpful to sometimes take more than one set of measurements (of pH and temperature) in a day (with the time, of course) so that you can tell the model how much change occurs over the 24-hours. Before dawn and late afternoon would be best.
3.Sampling locations and record the time and the sampling location. Don’t change the location when the flow changes.
4.Frequency: It would be helpful to measure these things twice each month. In the month/months where your current limit is the tightest (hardest to meet) you might want to sample every week (get a solid data set for those months).
5.Remember, low-flows are subject to change.
6.Remember, antidegradation may apply.
7.Presence or Absence of Early Life Stages will be determined on a case-by-case basis. Evidence will have to be presented to convince the Commission that ELS are absent consistently for some portion of the year.
Once you get the data – then what? You can have it modeled to see what the resulting effluent limits are likely to be. If it is horrible, then you may want to propose a temporary modification to delay until you have a solution. You will also have an idea about what length of TM you need.
H:\GENRL\TALK\LowArk05.docpage 1Sept 21June 13, 2005
[1] Check with your consultant or expert about your specific situation. This is provided as general advice.