normative flow studies

King County DNRP/Parametrix 1

Normative Flow Studies

Small Streams Biology-Hydrology Analyses

King County DNRP/Parametrix 2

Project Goals

• Analytical and decision tools for managers– Understand relationships:

flows ecological condition

– Evaluate effects:

management actions flows ecology

King County DNRP/Parametrix 3

Human Actions

Flow Regime

Habitat Structure

Biologye.g., salmon conservation

Water Quality

Arrows indicate relationships that are important to the technical questions at hand. The weight of the arrows indicates the degree of this project’s focus

on the indicated relationship – not their overall importance or the merit of studying them in a

different project.

MagnitudeFrequency

Duration

Seasonality

Rate of Change

Biological Interactions

Energy Flow

Issues/Challenges - Science

Several Possible Approaches….• Indicator-based approach – inform management

Conceptual Model

Define Metrics to Describe System Condition

Test Metrics

Inform ManagementActions

5

Bio

logy

Met

ric

(rec

epto

r)Indicator Response

Hydrology Metric(Stressor)

Metric Relationships

King County DNRP/Parametrix 6

Linking Biology and Hydrology

• Watersheds with both data types– Urbanization gradient

• Pair biology and hydrology– “Subbasins “ – Distinct hydrology – One or more BIBI sites

• Small data set

King County DNRP/Parametrix 7

Available Data: Hydrology

• Few long term gauge records• Modeled flow data (HSPF) available for

some watersheds• Developed flow for 50 years

– Original forested land cover - Baseline– Current land cover (1995/1998) - Scenario

• Computed metrics for both conditions– M, D, F, T, rates of change

King County DNRP/Parametrix 8

Available Data: Biology• Macroinvertebrate data

– Raw data for Benthic Index of Biotic Integrity (BIBI)• BIBI - general indicator of ecosystem integrity• Not designed to assess effects of flow• Only “calibrated” for 2nd and 4th order streams• No long term records (1995-2001 longest

period)– Tested BIBI metrics plus other life

history/richness metrics

King County DNRP/Parametrix 9

King County DNRP/Parametrix 10

Working Biological Data Set

• Issaquah (8/35;34)• Bear/Evans (19/63;51)• Little Bear (5/18)

• Swamp (7/12;11)• Madsen (2/6;2)• Miller (1/0)• Thornton (5/15/9)

Sample size = 125

King County DNRP/Parametrix 11

0

10

20

30

40

50

60

70

80

90

100

10/1/1989 1/9/1990 4/19/1990 7/28/1990 11/5/1990

Flow

(cfs

)

-

1

2

3

4

5

6

7

8

9

10

Pre

cip

(inch

es)

Example Hydrograph

King County DNRP/Parametrix 12

y = 1.02x

0

20

40

60

80

100

120

0 20 40 60 80 100Forested

Cur

rent

y = 1.89x

0

20

40

60

80

100

120

0 20 40 60 80 100Forested

Cur

rent

Non-urbanized Watershed Urbanized Watershed

Forested Rise Count vs. Current Rise Count

King County DNRP/Parametrix 13

Annual Scenario - High Pulse Count (count)

30.020.010.00.0

Plec

opte

ra (

# Ta

xa)

10.0

8.0

6.0

4.0

2.0

0.0

-2.0

Basin

Swamp

Miller

Madsen

Little Bear

Issaquah

Evans

Big Bear

King County DNRP/Parametrix 14

Annual Scenario - Fall Count (10% Rule) (count)

300.0200.0100.00.0

Clin

ger

(# T

axa)

30.0

20.0

10.0

0.0

Basin

Swamp

Miller

Madsen

Little Bear

Issaquah

Evans

Big Bear

King County DNRP/Parametrix 15

BIBI Score vs. Q2:Q10 in sites with similar local land cover (within 100m of BIBI site)

King County DNRP/Parametrix 16

Canonical Discriminant Functions

Annual Ratio Hydrology Metrics normalized

Function 1

210-1-2-3-4-5

Func

tion

2

3.0

2.0

1.0

0.0

-1.0

-2.0

-3.0

BIBI group

Group Centroids

35 - max

20 - 35

min - 20

35 - max

20 - 35

min - 20

King County DNRP/Parametrix 17

Uni+semi voltine taxa groups

Func1: longer LPD, runoff duration, and decreased Q2:Q10, LPC, HPR, Power, FC, & reversals

King County DNRP/Parametrix 18

Func1: increased LPD, later onset fall flows and later date annual min, & lower Q2:Q10, fewer LPC and fewer reversals

King County DNRP/Parametrix 19

Length of High Pulse Period vs. BIBI Groups

King County DNRP/Parametrix 20

Time (in days) Between Low Pulse Events vs. BIBI Groups

King County DNRP/Parametrix 21

Number of Low Pulse Events/Yr vs. BIBI Groups

King County DNRP/Parametrix 22

Ratio of current 2-yr discharge to historic 10-yr discharge vs. BIBI

groups

King County DNRP/Parametrix 23

Potential Hydrology Indicators

• Stream Power• Q2:Q10• LP/HP counts,

duration, range• Onset fall flows• % time above 2-yr

baseflow

• Date minimum flow• Runoff event counts• Runoff event duration• Reversals

King County DNRP/Parametrix 24

Conclusions

King County DNRP/Parametrix 25

Relationships between biology and hydrology metrics

• ‘Worst’ and ‘best’ biological sites can be separated based on hydrology metrics

• Life history and richness metrics significantly correlated with specific hydrology metrics

• Measures of hydrologic ‘disturbance’ and biological resistance/resilience to disturbance may be most productive

King County DNRP/Parametrix 26

Next Steps

• Document analyses/report• Validate relationships with separate data

set(s)• Test relationships with other biological data

(e.g., fish)• Summarize findings for managers – what

general guidance can be derived from preliminary analyses?