Trail_Balloon_(Barwick)

Trial Balloon
NC Ecological Flows Science
Advisory Board
June 18, 2013
Concerns
Biological-Environmental Classifications
(BEC) do not appear to be a viable tool for
stream classification
Biological data used in the BEC were from
wadeable streams
Potential for future water withdrawals
appears greater for streams larger than
those sampled and analyzed in the BEC
80% flowby appears overly protective 2
Trial Balloon Objectives
To present an alternative method of
developing ecological flows somewhat
based on a water withdrawal permitting
program currently used in SC
To suggest how these flows might be
used by the NCDWR for planning
purposes3
Attributes Needed for a Desirable
Ecological Flow Planning Tool
Specific for physiographic regions
Accounts for seasonal needs of the
aquatic resources
Based on the needs of specific stream
biota
Relatively easy to understand and use
Balances the needs of humans and
aquatic resources4
Physiographic Regions
Lower Coastal Plain Streams (tidally
influenced and not part of this trial balloon)
Upper Coastal Plain Streams
Piedmont Streams
Mountain Streams
5
Upper Coastal Plain Streams
(Anadromous fish)
High flow (Jan-April) – 50%*
Transition flow (May, June, and Dec) – 40%*
Low flow (July-Nov) – 30%*
* Percentage of Annual Mean Flow (cfs) or Percentage of Monthly Mean
Flows
6
7
Neuse River Flows
8
Neuse River Flows
Piedmont Streams
(Cyprinids and Catostomids)
High flow (Feb-April) – 40%*
Transition flow (May, June, and Jan) – 30%*
Low flow (July-Dec) – 20%*
* Percentage of Annual Mean Flow (cfs) or Percentage of Monthly Mean
Flows
9
Deep River Flows
10
Deep River Flows
11
Mountain Streams
(Trout)
High flow (Dec-April) – 40%*
Transition flow (May, Oct, and Nov) – 30%*
Low flow (June-Sep) – 20%*
* Percentage of Annual Mean Flow (cfs) or Percentage of Monthly Mean
Flows
12
Linville River Flows
13
Linville River Flows
14
15
Benefits of Percentage Based
Ecological Flows
Appears to provide adequate protection for
aquatic resources when compared to drought
flows
Appears to balance the needs for humans
and the aquatic resources
Thought to be easily incorporated into
NCDWR models for planning purposes
Does not preclude site specific studies