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Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, [email protected] King County Water and Land Resources Division July 13, 2010 HydroFutures: Water Science, Technology, and Communities
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Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, [email protected]@kingcounty.gov King.

Dec 26, 2015

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Page 1: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Identification of King County Streams with Declining Summer

Flows

Curtis DeGasperi, [email protected]

King County Water and Land Resources Division

July 13, 2010

HydroFutures: Water Science, Technology, and Communities

Page 2: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Motivation

• Wastewater Treatment Division Reclaimed Water Comprehensive Planning Process– What are the potential volumes

of reclaimed water that would be needed to serve the potential uses for reclaimed water?

http://www.kingcounty.gov/environment/wastewater/ReclaimedWater/CompPlan.aspx

Page 3: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Human Impacts on Water Cycle• Land cover change

– Forest clearing/Development

~1880

Page 4: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

~1880

“Trends in Qmean and Qmin were not consistent in urban streams and, in fact, trends in these statistics were observed for some suburban and rural streams lacking extensive changes in land use atthe scale of a drainage basin over the entire period of record. Although urban development may affect Qmean or Qmin in some streams, relations between development and these statistics were not consistent.” p. 35

- Konrad and Booth (2002)

Page 5: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Human Impacts on Water Cycle

Water management– Surface water and groundwater extraction– Consumptive uses (Irrigation)– Septic vs Wastewater conveyance– Pipeline infiltration/exfiltration

Page 6: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Water Management

Basin Water Resources Streamflow

Water Supply System

Wastewater Disposal

Withdrawals

ExportsImports

Exports

Return via septic system disposal

Precipitation

I & I

Evaporation/Transpiration

Page 7: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Weight-of-Evidence Approach

• Review previous studies and reports

• Evaluate long term stream flow data for trends

Page 8: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Previous Studies/Reports

Page 9: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Selected Stream Gauges

Page 10: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

General Approach

• Conduct trend analysis on mean annual and summer (7-day) low flow

• Include consideration of trends in precipitation and temperature (Sea-Tac)

• Attempt to provide some explanation for observed trends

King County. 2009. Working Draft. Identification of Streams Likely to Benefit from Additional Water Inputs. Prepared by Curtis DeGasperi and Jeff Burkey. Water and Land Resources Division, Seattle, WA.

Page 11: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Trend Analysis• Non-parametric “distribution free” method

– Mann-Kendall Trend test

http://pubs.usgs.gov/sir/2005/5275/

Page 12: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Trend Analysis

• p between 1.0 and 0.1 (weakest evidence)

• p between 0.1 and 0.05 (weak evidence)

• p between 0.05 and 0.01 (strong evidence)

• p <0.01 (strongest evidence)

Page 13: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

“Nothing is certain, but I think some things are more nearly

certain than others”- Bertrand Russell (paraphrased)

Page 14: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Trend AnalysisCreek basin 7-Day Low Flow Mean Annual Flow p-value TRENDBear Creek ↓ ↑ <0.01 Very Strong EvidenceBig Soos Creek ↓ ↓ 0.01-0.05 Strong Evidence INCREASINGCanyon Creek ↑ ↓ 0.05-0.10 Weak EvidenceCovington Creek ↑ ↓ >0.10 Weakest EvidenceDes Moines Creek ↓ ↑ 0.05-0.10 Weak EvidenceDes Moines Creek ↓ ↑ 0.01-0.05 Strong Evidence DECREASINGEvans Creek ↓ ↑ <0.01 Very Strong EvidenceIssaquah Creek near Hobart ↑ ↑Issaquah Creek near mouth ↓ ↓Issaquah Creek, North Fork ↓ ↓Jenkins Creek ↑ ↓Laughing Jacobs Creek ↑ ↑May Creek at mouth ↓ ↓May Creek at Coal Creek Pkwy ↓ ↑Mercer (Kelsey) Creek ↑ ↑Miller Creek Detention Fac. ↓ ↓Miller Creek near mouth ↑ ↑Newaukum Creek ↓ ↓Patterson Creek ↓ ↑Raging River ↓ ↓Sammamish River ↓ ↓Taylor Creek ↓ ↑

Page 15: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Trends in Summer Low Flow

Page 16: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Big Soos Creek (example)

Page 17: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Precipitation Trends

Page 18: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Newaukum Creek (example)

Page 19: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Air Temperature Trends

Page 20: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Potential influence on ET

• Model with temperature trend

• Model without temperature trend

?

Sea-Tac (Jensen-Haise)

0

5

10

15

20

25

1940 1960 1980 2000 2020

Po

ten

tia

l E

T (

inc

he

s)

Page 21: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Big Soos Creek (example)

Page 22: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Water Conservation

Page 23: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Additional Explanation?

• To what extent can the effect of land cover change and water management activities be ascribed to these changes?

King County. 2009. Working Draft. Preliminary Estimates of Summer Environmental Restoration Flow Targets in Streams Identified as Likely to Benefit from Additional Water Inputs. Prepared by Curtis DeGasperi. Water and Land Resources Division, Seattle, WA.

Page 24: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Land Cover Effect

• HSPF model unit flow predictions by Hydrologic Response Unit– Forested Till– Disturbed Till– Forested Outwash– Disturbed Outwash– Saturated Soils– Effective Impervious Area

Page 25: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Water Management

Basin Water Resources Streamflow

Water Supply System

Wastewater Disposal

Withdrawals

ExportsImports

Exports

Return via septic system disposal

Precipitation

I & I

Evaporation/Transpiration

Page 26: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Water Management

• Sammamish-Washington Basin – King County (2001)

• Green River Basin– Northwest hydraulic consultants (2005)

King County. 2001. Screening level analysis of 3rd order and higher WRIA 8 streams for change in hydrologic regime. Draft report prepared by David Hartley for the WRIA 8 Technical Subcommittee on Flow Regime. King County Department of Natural Resources, Water and Land Resources Division: Seattle, WA.

Northwest Hydraulic Consultants, Inc. 2005. Assessment of current water quantity conditions in the Green River basin. Prepared for WRIA 9 Steering Committee. Northwest Hydraulic Consultants, Inc., Seattle, WA.

Page 27: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Human Influence

Big Soos Creek (12112600)

July – October 2007

ManagementWaterofEffectChangeCoverLandofEffect

FlowBaseCurrentFlowBaseSummerNatural

QQ

QQ

FlowBaseCurrentFlowBaseSummerNaturalFlowstorationtalEnvironmen QQQ Re

Page 28: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Human Influence

• Environmental Flow Targets (cfs)

- 0.9 to 5 cfs

- 5 to 10 cfs

-10 to 25 cfs

Page 29: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Human Influence

• Reduction in natural flow (%)

- 14 to 37 %

- 38 to 59 %

- 60 to 82 %

Page 30: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Human Influence

• Relative importance of land cover vs water management?– Depends on basin

• Highly urbanized basin with external water sources• Suburban basin with local water sources• Modified by type of wastewater disposal system

and/or irrigation practices

Page 31: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Evidence for Potential Human Influence?

Mercer/Kelsey Creek in Bellevue, WA

Page 32: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Evidence for Potential Human Influence?

Bellevue, WA

Page 33: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

Conclusions

• Well designed long-term gauging network

• Compilation and access to up-to-date water management data

• Good models to synthesize information and extrapolate to ungauged basins

Page 34: Identification of King County Streams with Declining Summer Flows Curtis DeGasperi, curtis.degasperi@kingcounty.govcurtis.degasperi@kingcounty.gov King.

“No amount of sophistication is going to allay the fact that all your knowledge is about the past and all your decisions are about the

future”- Ian E. Wilson (former chairman of GE)