S.C. Code Regs. § § 61-119.E.4

Current through Register Vol. 48, No. 11, November 22, 2024

Section 61-119.E.4 - Operations and Contingency Plan Requirements

Anytime the flow at the point of the permitted withdrawal is less than or equal to the minimum instream flow and taking into consideration natural and artificial replenishment of the surface water and existing or planned consumptive and nonconsumptive uses affected by the withdrawal downstream, the permitted surface water withdrawer must implement applicable portions of its water contingency plan and, excepting public water systems addressed in Section 49-4-150(A)(6), will discontinue facility consumptive water uses from the surface water source such that continued withdrawals will result in no net decrease in flow below the facility's discharge.

a. Each permittee must prepare and maintain on site, available for inspection, an operational and contingency plan to promote an adequate water supply from the surface water during times when the actual flow of the surface water is less than the minimum instream flow, plus any flow necessary to protect downstream permitted and registered withdrawals, taking into account natural and artificial replenishment of the surface water, for that particular surface water segment. The existence of a plan is deemed to be an enforceable part of the permit under which the permittee is withdrawing surface water and shall be deemed to control a permitted surface water withdrawal in situations where the actual flow of the surface water is less than the minimum instream flow for that particular stream segment.

b. For applicable new or expanding surface water withdrawers, the plan must identify actions to be taken to address low flow conditions, including: water conservation, use of supplemental water supplies, use of off-stream water storage, operational changes, seasonal water flow fluctuation withdrawals, or hydroelectric operations in controlled surface waters. For expansion of permits initially issued under section D above, the requirements of this section only apply to the permitted amount over and above the permitted quantity of the initial permit.

c. Public water systems must develop operational and contingency plans consistent with E.4.b. above and implement their plan, applicable to their service territory, commensurate with the drought level declared by the State Drought Response Committee and in accordance with any drought response plan required by the owner of a licensed impoundment that they use as a water source.

d. Non-public water withdrawers must develop operational and contingency plans consistent with E.4.b. above and implement them consistent with the requirements of this section and act in accordance with any drought response plan required by the owner of a licensed impoundment that they use as a water source.

e. For surface water withdrawers with an operational and contingency plan requiring one or more supplemental sources of water to be used for continued facility operations during minimum instream flow conditions, the supplemental water supply needed will be addressed as follows.

i. For a surface water withdrawer proposing to use surface water as all or a portion of the supplemental water supply:

(A) Where only surface water will be used as a supplemental supply, the volume of water required to be stored is set forth in Section 49-4-150(A)(2)(c), and the following used as an aid to such determinations.

(1) Using an appropriate USGS or Department approved gaging station, historical flow at the withdrawal point will be determined. Factors to be considered in determining an appropriate index station include but are not limited to drainage area, flow characteristics, physiographic province, period of record, and land use.

(2) Using the flow record at the appropriate index station, a daily flow record for the longest period of record feasible will be determined at the proposed withdrawal point. All years experiencing periods of flow below the minimum instream flow for the months July through November will be determined and evaluated, up to and including the drought of record. For the purposes of this section, the drought of record will be considered the July through November period, within the period of record, having the largest number of days with flows equal to or less than the minimum instream flow.

(3) Using the flow records of July through November periods experiencing flows equal to or less than the minimum instream flow, including but not limited to the drought of record, the Department will determine a supplemental water volume for inclusion in any permit to be issued for the withdrawal. The supplemental water volume is not required to be any larger than the quantity that allows for facility operations during twenty percent mean annual daily flow conditions, based upon a review of historical low flow data and projected facility consumptive water uses during low flow periods. Facility consumptive water uses means the amount of water that is lost and not returned to the source waterbody during normal operations.

(4) If an appropriate index station with an appropriate period of record is not available, the Department, in consultation with the applicant, will determine an appropriate storage volume using the best information available. The USGS and/or SCDNR may be consulted as needed.

(B) For a surface water withdrawer proposing to utilize surface water in conjunction with other supplemental sources to satisfy contingency plan requirements, the volume of supplemental supply needed will be determined as in item E.4.e.i(A) above with due consideration given to the volume of water to be supplied by sources other than surface water when determining drought contingency pond size.

(C) A permitted surface water withdrawer utilizing a drought contingency pond as all or some of its supplemental water source may withdraw the entire volume of water from the pond during low flow periods requiring supplemental water source usage. Water withdrawn from drought contingency ponds is not subject to environmental and permitting restrictions unless or until it is discharged to state waters. The Department will designate drought contingency ponds, a type of supplemental water source, as part of an approved operational and contingency plan.

(D) For withdrawals where the withdrawal point is not located on a licensed or otherwise flow controlled impoundment, a permitted surface water withdrawer may withdraw water from the permitted surface withdrawal point in order to refill its supplemental water source, or other drought contingency water supply vessels, anytime the river flow exceeds the minimum instream flow, provided the total amount withdrawn for daily operations and for refilling the supplemental water source or other drought contingency water supply vessel does not cause the flow downstream of the withdrawal point to go below the minimum instream flow plus any flow necessary to protect downstream permitted and registered withdrawals.

(E) For withdrawals where the withdrawal point is located on a licensed or otherwise flow controlled impoundment, the permitted withdrawer may withdraw water to refill his supplemental water source or other drought contingency water supply vessel anytime the total amount withdrawn for daily operations and for refilling the supplemental water source does not cause the reservoir water level to drop below its minimum water level or to be unable to release the lowest minimum flow specified in the license for the impoundment as issued by the appropriate government agency.

ii. For a surface water withdrawer proposing to utilize groundwater obtained on its site as a supplemental source, the applicant must document the availability of groundwater of sufficient quantity to provide for the withdrawer's daily needs for a period of time at least equal to the period of time the surface water will be unavailable as determined in item E.4.e.i(A) above. Any permits or approvals required to extract groundwater for use as a supplemental source must be obtained prior to issuance of a surface water withdrawal permit.

iii. For a surface water withdrawer proposing to utilize as their supplemental source water purchased from: another surface water withdrawer; a permitted discharger; a supplier using groundwater as its source; or other source approved by the Department, the withdrawer must demonstrate via contract or other legally binding commitment the availability of a sufficient quantity of water to provide for the withdrawer's daily needs for a period of time at least equal to the period of time the surface water will be unavailable as determined in item E.4.e.i(A) above.

iv. New surface water withdrawers are not required to engineer the supplemental water source identified in their contingency plan any larger than the quantity that allows for facility operations during twenty percent mean annual daily flow conditions, based upon a review of historical low flow data and projected facility consumptive water uses during low flow periods.

v. A new surface water withdrawer may not return to the withdrawal source when its supplemental water source is exhausted unless the supplemental water source has been engineered to meet the specifications of this section.

vi. If after all reasonable contingency plans have been implemented, and the surface water withdrawer is within fifteen (15) days of exhausting the usable water supply from its supplemental water source, a new surface water withdrawer may give notice to the Department that he is exhausting his supplemental water sources and that he intends to return to the withdrawal source in amounts up to his permitted amount. Notification must be made in writing as expeditiously as possible, to include electronic communication, to the address provided in the permit. Upon receiving notice, the Department must determine whether all or any portion of the withdrawal for facility consumptive water uses will result in a significant negative impact to an existing user or the environment if the permitted withdrawal is resumed. If the Department does not make its determination within ten (10) days of receipt of notice, the permittee may make withdrawals up to the permitted amount and do so until notified by the Department whether all or any portion of the withdrawal for facility consumptive water uses will result in a significant negative impact to an existing user or the environment during this low flow period. Upon notification by the Department, the permittee will cease withdrawals for facility consumptive water uses that will result in any significant negative impact.

f. The Department must consult with the SCDNR to determine which, if any, existing stream gaging station should be utilized to quantify the stream flow at the point of the proposed withdrawal. The Department may also seek the input of the applicant in determining a suitable means to measure or extrapolate the stream flow at the point of the proposed withdrawal. If no existing stream gage is suitable for measuring or extrapolating the flow at which the applicant's water withdrawal must be reduced due to inadequate stream flow, the SCDNR will recommend the location of a new stream gage.

g. The Department must consult with the SCDNR to quantify the stream flow measured at the specified measuring device that will require a reduction in the applicant's water withdrawal because of inadequate stream flow at the point of withdrawal.

S.C. Code Regs. § 61-119.E.4