Steve_Reed

How Ecological Flows
Would be Applied to
NC River Basin Models
Ecological Flows Science Advisory Board
Raleigh – November 15, 2011
Steve Reed, NC Division of Water Resources
919/715-5424 [e-mail]
Ecological Flows
•Flows needed to maintain
ecological integrity
•Inclusion in models required by
Legislation
•If not included? – models will
assume any and ALL water can be
withdrawn to meet demands
Ecological Flows
•A SCREENING TOOL for river basin
models & plans
•Flag locations where offstream demands
and instream ecological flow needs
cannot be met under existing or
projected conditions
•Need to be quantified at ALL nodes of
interest throughout each basin
River Basin Models
Include
•Unaltered Hydrology
•Flow Alterations – withdrawals,
discharges, reservoirs
•Withdrawals include existing, 20- and
50-year projections
•Nodes –specific locations where
records of flows are simulated
Third Creek1
2
3
5
4
6
7
At Each Node
•Drainage Area
•Daily Flows for 80 years – unaltered,
existing, 20-year, & 50-year
projections
•So what’s the Ecological Flow?
Third Creek1
2
3
5
4
6
7
Third Creek1
2
3
5
4
6
7
How Many Nodes?
•Neuse = 84
•Cape Fear = 164
•Tar = 21
•Broad = 40
•Plus 13 more basins, eventually
The Task
•How will the ecological flow be quantified
at each node?
•Is the approach for determining the
ecological flow the same for all nodes?
•If not, how are we subdividing nodes?
stream classification
•How many different approaches/
classifications are there?
What values should be added at the yellow ovals to
prevent the streams from being dried up to satisfy the
demands at the blue squares?
Will it work with this number of nodes?