How Are Flow Recommendations Determined?

The procedure for determining an instream flow recommendation for a water project is dictated by federal and state statutes. Specifics of the water project are used as guidance towards a recommendation: proposed or existing? water withdrawal with a dam or without a dam? hydropower or water supply? federal jurisdiction or state jurisdiction or no jurisdiction? a compliance issue or riparian rights issue? Some flow recommendations may be a percentage of a low flow value while others may be variable, seasonally dependent flows based on field work and consensus among numerous stakeholders. The dichotomous key provided below is an attempt to illustrate the process the Division of Water Resources uses to determine the appropriate procedure.

(Please be aware that although the Dam Safety Law (G.S. 143-215.31) establishes the policy of the State of North Carolina for determining and recommending flow requirements for non-hydropower and "small hydropower producer", as defined by G.S. 62-3(27a), dams, federal agencies are not subject to this Law.)

[View as a flow chart (1127kb)]

Steps Toward A Flow Recommendation:

Step 1. Receive and review:

A). Proposal (Go to Step 2)

 

B). Complaint (Go to Step 17)

 

 

Step 2. Proposal for:

 

 

A). Run-of-river project (Go to Step 3)

 

 

B). Impoundment (Go to Step 5)

 

Step 3. Does the run-of-river project proposal require the use of a dam or weir?

 

A). No (Go to Step 4)

 

 

B). Yes (Go to Step 8)

 

Step 4. Will the proposed run-of-river project withdraw from a stream:

 

A). less than 20% of the 7Q10 ; or, when combined with other withdrawals in the watershed, will reduce the stream 7Q10 by less than 20% at the proposed project site?

 

 

Therefore:  No field study; no flow requirement.

 

 

B). 20% or more of the 7Q10; or, when combined with other withdrawals in the watershed, will reduce the stream 7Q10 by 20% or more at the proposed project site?

 

 

Therefore:  Field visit and Aquatic Habitat Evaluation with flow recommendation from desktop model or field study.

 

Step 5. Is the impoundment proposal for an existing dam? [Back to Step 2]

 

A). Yes (Go to Step 6)

 

 

B). No (Go to Step 8)

 

Step 6. Does the dam have an existing flow requirement which was developed with environmental review and documentation?

 

A). Yes (Go to Step 7)

 

 

B). No (Go to Step 8)

 

Step 7. Will the proposal alter the existing flow conditions from the dam?

 

A). No.

 

 

Therefore:  No action.

 

 

B). Yes.

 

 

Therefore:  Field visit and permit revision consideration.

 

Step 8. Is generation of hydroelectric power the sole {a} purpose of the project?  [Back to Step 5]

 

A). No (Go to Step 9)

 

 

B). Yes (Go to Step 10)

 

Step 9. Will the dam or weir associated with the proposed impoundment be subject to the N.C. Dam Safety Law - Exempt Dams (GS_143-215.25A) or Section 401 or 404 of the federal Clean Water Act?
(Not sure? Forms are provided by Dam Safety and U.S. Army Corps of Engineers.)

 

A). Yes.

 

 

Therefore:  Field visit and Aquatic Habitat Evaluation with flow recommendation from desktop model or field study, or Section .0502(b) if the average annual stream flow is less than or equal to 3.0 cubic feet per second (cfs) .

 

 

B). No (Go to Step 15)

 

Step 10. Will the hydroelectric project be a small power producer, i.e. a facility that does not exceed power generation of 80 megawatts, and the owner is not engaged in generation or sale of electricity from other than small power producing facilities? {Reference: Dam Safety Law GS 143-215.31}  [Back to Step 8]

 

A). No.

 

 

Therefore:  Field study to determine flow requirement in Federal Energy Regulatory Commission (FERC) license and/or Certificate of Public Convenience and Necessity (CPCN (Article 11)).

 

 

B). Yes (Go to Step 11)

 

Step 11. Will the small power producer divert water from more than 4000 feet of natural streambed (bypassed reach) and return it to the same stream?

 

A). Yes.

 

 

Therefore:  Field visit and Aquatic Habitat Evaluation with flow recommendation from desktop model or field study .

 

 

B). No (Go to Step 12)

 

 

Step 12. Does the bypassed reach have a permitted wastewater discharge from a treatment plant, or include any part of a river or stream which is designated as a component of the State Natural and Scenic Rivers System or the national Wild and Scenic Rivers System?

 

 

A). Yes.

 

 

Therefore:  Flow recommendation through Section .0503 of the N.C. Administrative Code.

 

 

B). No (Go to Step 13)

 

 

Step 13. Does the small power producer have a bypassed reach of 2500 feet or more, and is located on a stream where there were six or more dams operated by small power producers on 1/1/1995?

 

 

A). Yes.

 

 

Therefore:  The minimum flow, as legislated by the 1995 N.C. General Assembly, is 28 cfs. (See Section 143 - 215.31 of the Dam Safety Law.)

 

 

B). No (Go to Step 14)

 

Step 14. Did the small power producer, prior to 1/1/1995, have a license from the FERC or a CPCN (Article 11) from the N.C. Utilities Commission?

 

A). Yes.

 

 

Therefore:  The minimum flow, as legislated by the 1995 N.C. General Assembly, is the 7Q10, or 10% of the average pre-dam stream flow, whichever is less. (See Section 143 - 215.31 of the Dam Safety Law.)

 

 

B). No.

 

 

Therefore:  The minimum flow, as legislated by the 1995 N.C. General Assembly, is the 7Q10, or 10% of the average pre-dam stream flow, whichever is greater. (See Section 143 - 215.31 of the Dam Safety Law.)

 

 

Step 15. Will the proposed structure be used for public water supply?  [Back to Step 9]

 

 

A). No.

 

 

Therefore:  No flow recommendation can be required.

 

 

B). Yes (Go to Step 16)

 

Step 16. Is the withdrawal less than 20% of the 7Q10 for the stream, or when combined with other withdrawals in the watershed, does not reduce the 7Q10 flow by more than 20% at the site?

 

A). Yes.

 

 

Therefore:  No flow requirement

 

 

B). No.

 

 

Therefore:  Field visit and Aquatic Habitat Evaluation with flow recommendation from desktop model or field study . The negotiated recommendation is a condition for issuing a Finding of No Significant Impact (FONSI) or the Record of Decision (ROD) after review of the Environmental Assessment (EA) or an Environmental Impact Statement (EIS), respectively, under the Environmental Policy Act. The FONSI/ROD conditions are then rolled into whatever permits or certificates are required.

 

 

Step 17. Does the subject of the complaint have a flow requirement?  [Back to Step 1]

 

 

A). Yes.

 

 

Therefore:  Compliance issue--contact regulatory authority: FERC , DLR , DWQ

 

 

B). No (Go to Step 18)

 

Step 18. Is the activity subject to Section 401 or 404 of the federal Clean Water Act, the N.C. Dam Safety Law - Exempt Dams (GS_143-215.25A), or Federal Energy Regulatory Commission (FERC) authority?

 

A). No.

 

 

Therefore:   Riparian rights issue.

 

 

B). Yes (Go to Step 19)

 

Step 19. Is the activity subject to FERC authority?

 

A). No (Go to Step 20)

 

 

B). Yes.

 

 

Therefore:   Refer complaint to FERC staff

 

Step 20. Is the activity a dam operated by a small power producer as of 10/13/1994?

 

A). No.

 

 

Therefore:  Field visit and Aquatic Habitat Evaluation with flow recommendation from desktop model or field study, or Section .0502(b) if the average annual stream flow is less than or equal to 3.0 cubic feet per second (cfs).

 

 

B). Yes.

 

Therefore:   Riparian rights issue.