Hawaii Administrative Rules
Title 11 - DEPARTMENT OF HEALTH
Subtitle 1 - GENERAL DEPARTMENTAL PROVISIONS
Chapter 54 - WATER QUALITY STANDARDS
Section 11-54-12 - Intake credits

Universal Citation: HI Admin Rules 11-54-12

Current through February, 2024

(a) An intake credit is an NPDES implementation tool that applies to the implementation of water quality standards through NPDES permits only.

(b) As used in this section:

"Background pollutant concentration" means the . water body concentration immediately upstream/upcurrent of a permitted discharge, regardless of whether those pollutants are natural or result from anthropogenic upstream activity.

"Intake pollutant" means the background pollutant concentration that is present in the intake water body, which must be the same water body as the receiving water for the discharge at the time it is withdrawn from such waters.

"Same body of water" means an intake pollutant is considered to be from the 'same body of water" as the discharge if the department finds that the intake pollutant would have reached the vicinity of the outfall point in the receiving water within a reasonable period of time had it not been removed by the permittee. This finding may be deemed established if:

(1) The background pollutant concentration in the receiving water (excluding any amount of the pollutant in the facility's discharge) is similar to that in the intake water; and

(2) There is a direct hydrologic connection between the intake and discharge points; and

(3) Water quality characteristics (e.g. temperature, pH, hardness) are similar in the intake and receiving waters.

The department may consider other site-specific factors relevant to the transport and fate of the pollutant in deciding whether a pollutant would or would not have reached the vicinity of the outfall point in the receiving water within a reasonable period had it not been removed by the permittee.

(c) The director may, upon request of the discharger, adjust water quality-based effluent limitations or standards to reflect credit for intake pollutants in the discharger's intake water only:

(1) To the extent necessary to meet the applicable limitation or standard, up to a maximum value equal to the intake pollutant value; and

(2) If there is no net increase in the concentration of the intake pollutant for which the credit is given. A discharger may add to the mass of the background pollutant concentration if an equal or greater mass is removed prior to discharge, so there is no net addition of the pollutant in the discharge compared to the intake water.

(d) Intake credit is not applicable to any pollutant for which a Total Maximum Daily Load (TMDL) and waste load allocation (WLA) have been developed and have been approved by the U.S. Environmental Protection Agency unless the TMDL and WLA provide for such an intake credit.

(e) The director shall grant credit for water quality-based effluent limits only if:

(1) One hundred per cent of the intake water containing the intake pollutant is withdrawn from the same body of water into which the discharge is made;

(2) The facility does not chemically or physically alter the intake pollutant in a manner that would cause adverse water quality impacts to occur that would not occur if the pollutant was left in-stream;

(3) The timing and location of the discharge would not cause adverse water quality impacts to occur that would not occur if the intake pollutant were left in-stream; and,

(4) The director finds that the discharge of intake pollutants into the same body of water will not adversely impact narrative or numeric water quality criteria specified in this chapter.

(f) Effluent limitations must be established so that they comply with all other applicable state and federal laws and regulations including water quality-based requirements and anti-degradation policies.

(g) All requests for the establishment of credit for intake pollutants shall be made on forms furnished by the department and shall be accompanied by:

(1) Documentation showing a complete and detailed description of present conditions and how present conditions do not conform to standards; and

(2) Documentation showing that the intake and discharge waterbodies are the 'same body of water;" and

(3) Documentation showing that pollutant(s) for which credits are being request actually come(s) from the intake water.

(h) Credit for intake pollutants shall be specified in the discharger's NPDES permit and shall become effective with the department's issuance of the permit for the specified permittee.

(1) All permits that include intake credits issued by the department shall include monitoring of all influent, effluent, and ambient water to demonstrate that the conditions in this section are maintained during the permit term.

(2) All credit for intake pollutants developed under this section shall be re-evaluated upon permit renewal.

(i) Credit for intake pollutants established under this section apply in the vicinity of the discharge for purposes of establishing permit limits for a specified pollutant for the specified permittee.

(j) All other water quality criteria established under this chapter continue to apply.

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