HomeMy WebLinkAboutRTI_USGS_presentationRECOMMENDED FRAMEWORK FOR
EVALUATING ECOLOGICAL FLOWS IN
THE STREAMS AND RIVERS OF NORTH
CAROLINA
Conducted by: RTI and USGS
Funded by: Environmental Defense Fund, NC DENR, and NC WRC
COMPONENTS
•Flow Alteration – Biological (i.e., flow-biology)
response curves for fish and benthos
–Ecological Flow (EF) Categories and Thresholds
•Based on “Working Rivers” concept
–Examples within the Upper Neuse River Basin
•Where do these curves apply?
FLOW – BIOLOGY CURVES
Bi
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Benthic EPT Richness
Riffle-Run Fish Guild
(Shannon Diversity Index)
Summer Ecodeficit (%)
ECOLOGICAL FLOW (EF) CATEGORIES AND
THRESHOLDS
-EF Category = Current biological condition that determines
EF Threshold
-EF Threshold = Change in biological condition (caused by
flow alteration) that triggers a “red flag”
-“Working Rivers” approach
EF Category (current biological
condition of stream/river (%))
EF Threshold (% change in biological
condition before “red flag”)
100 – 80 5
80 – 60 10
60 – 35 15
<35 Other or minimum flows standard
-----------40%
?
BENTHIC EPT RICHNESS IN RESPONSE TO SUMMER
ECODEFICIT - EF CATEGORIES AND THRESHOLDS
-------27.4%
15 %
EF Category: 0 --------
EF Categories
(Biological Condition)
80 – 100%
60 – 80%
35 – 60%
< 35%
•Current Biological
Condition = 85.8%
•EF Category:
- 80-100%
-----16.8%
10 %
8.4%
5 %
Example:
•Current Ecodeficit
= 6%
Bi
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%
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Summer Ecodeficit (%)
•EF Threshold:
- 5% change in
biological
condition
- 8.1%
Ecodeficit (2.1%
additional
Ecodeficit)
RIFFLE-RUN FISH GUILD WITH EF CATEGORIES
--------------38%
?
RIFFLE-RUN FISH GUILD SHANNON DIVERSITY IN RESPONSE TO
SUMMER ECODEFICIT - EF CATEGORIES AND THRESHOLDS
------23.5%
15 %
EF Category: 0 ------
EF Categories
(Biological Condition)
80 – 100%
60 – 80%
35 – 60%
< 35%
-----14.5%
10 %
7.2%
5 %
Bi
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%
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Summer Ecodeficit (%)
APPLICATION EXAMPLES – UPPER NEUSE BASIN
•Locations:
–Eno River State Park stream segment
–Goldsboro river segment
•Scenarios (flow metrics and associated biological
condition):
–Current Condition = WaterFALL PNV – 2006
–Projected 2050 Condition = OASIS current – 2050
–EF Category and Threshold = determined by flow-biology curve
•Flow metrics and Million Gallons per DAY (MGD)
BENTHIC EPT RICHNESS IN RESPONSE TO SUMMER
ECODEFICIT - EXAMPLE
(WaterFALL)
Current Condition (WaterFALL)
Goldsboro Eno
Projected 2050 Condition (OASIS)
Goldsboro Eno
Ecological Flow Category
Goldsboro (15%) Eno (5%)
5.4%
1.1 MGD
3.1%
27 MGD
2.1%
0.43 MGD
6.2%
54 MGD
Summer EcoDeficit (%)
Bi
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%
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“red flag”
FISH EXAMPLE RIFFLE-RUN FISH GUILD SHANNON DIVERSITY IN
RESPONSE TO SUMMER ECODEFICIT - EXAMPLE
(WaterFALL)
Current Condition (WaterFALL)
Goldsboro Eno
Projected 2050 Condition (OASIS)
Goldsboro Eno
Ecological Flow Category
Goldsboro (15%) Eno (5%)
5.4%
1.1 MGD
3.1%
27 MGD
1.8%
0.37 MGD
5.4%
47 MGD
Summer EcoDeficit (%)
Bi
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“red flag”
ENO RIVER AND GOLDSBORO EXAMPLES – SUMMARY
OF FLOW METRICS: BENTHIC EPT RICHNESS
Eno River
Goldsboro
%MGD %MGD Current 2050
Winter 121 12.8%278 2.5%57 67.6 61.1
Spring 91 12.5%142 2.5%32 69.2 63.1
Summer 92 17.1%175 3.1%27 59.4 52.0
Fall 61 21.1%220 4.1%23 52.5 43.3
30 Day Min Flow 30 NA NA NA NA NA NA
Metric Number
of Days Current EcoDeficit
Projected 2050 EcoDeficit -
[Oasis]
Benthic Biologic
Condition (%)
%MGD %MGD Current 2050
Winter 121 2.5%2.0 4.2%3.4 93.7 83.0
Spring 91 3.7%1.6 2.8%1.4 90.9 83.9
Summer 92 5.3%0.9 5.4%1.1 87.4 74.7
Fall 61 3.5%1.1 3.0%0.5 92.1 85.4
30 Day Min Flow 30 1.7%0.0 13.1%1.0 97.7 79.5
Metric Number
of Days Current EcoDeficit
Projected 2050 EcoDeficit -
[Oasis]
Benthic Biologic
Condition (%)
ENO RIVER AND GOLDSBORO EXAMPLES – SUMMARY
OF FLOW METRICS: RIFFLE-RUN GUILD
Eno River
Goldsboro
%MGD %MGD Current 2050
Winter 121 2.5%2.0 4.2%3.4 96.6 91.0
Spring 91 3.7%1.6 2.8%1.4 93.9 89.2
Summer 92 5.3%0.9 5.4%1.1 85.4 70.6
Fall 61 3.5%1.1 3.0%0.5 92.7 86.4
30 Day Min Flow 30 1.7%0.0 13.1%1.0 97.3 76.3
Metric Number
of Days Current EcoDeficit
Projected 2050 EcoDeficit -
[Oasis]
Fish Biologic Condition
(%)
%MGD %MGD Current 2050
Winter 121 12.8%278 2.5%57 82.7 79.3
Spring 91 12.5%142 2.5%32 79.3 75.3
Summer 92 17.1%175 3.1%27 52.8 44.1
Fall 61 21.1%220 4.1%23 55.9 47.4
30 Day Min Flow 30 NA NA NA NA NA NA
Metric Number
of Days Current EcoDeficit
Projected 2050 EcoDeficit -
[Oasis]
Fish Biologic Condition
(%)
COMPONENTS
•Flow alteration – Biological (i.e., flow-biology)
response curves for fish and benthos
–Ecological Flow (EF) Thresholds
–Examples within the Upper Neuse River Basin
•Where do these curves apply?
WHERE DO THE FLOW-BIOLOGY RELATIONSHIPS
APPLY?
River Class
Drainage Area
(sq miles) # Fish Sites % Fish Sites
# Benthic
Sites
% Benthic
Sites
# of Biological
Monitoring Sites
% Biological
Monitoring Sites
Headwater < 39 701 81.7 1,124 65.3 1,825 70.7
Creek & small rivers >= 39 < 200 154 17.9 409 23.7 563 21.8
Medium rivers >= 200 < 1,000 3 0.4 130 7.6 133 5.2
Mainstem rivers >= 1,000 < 3,861 0 0.0 42 2.4 42 1.6
Large rivers >= 3,861 0 0.0 17 1.0 17 0.7
Totals 858 100 1,722 100 2,580 100
River Class
Drainage Area
(sq miles) Count % NC catchments
Headwater < 39 59,803 86.7
Creek & small rivers >= 39 < 200 5,377 7.8
Medium rivers >= 200 < 1,000 2,210 3.2
Mainstem rivers >= 1,000 < 3,861 1,106 1.6
Large rivers >= 3,861 509 0.7
Totals 69,005 100
RECOMMENDATION: Apply framework for fish and benthos to all
rivers and streams in NC until more data become available
QUESTIONS?