VII. References

VII. ReferencesVII. ReferencesDanehy, R.J., et al. 2005. Patterns and sources of thermal heterogeneity in small mountain streams within a

forested setting. Forest Ecology & Management 208:287-302.Fellers, G.M., et al. 2001. Overwintering tadpoles in the California Red-Legged Frog (Rana aurora draytonii).

Herpetological Review 32:156-157.Johnson, S.L. 2004. Factors influencing stream temperatures in small streams: substrate effects and a

shading experiment. Canadian Journal of Fisheries and Aquatic Sciences 61:913-923.Malcolm, I.A., et al. 2004. The influence of riparian woodland on the spatial and temporal variability of stream

water temperatures in an upland salmon stream. Hydrology and Earth System Sciences 8:449-459.Moore, R.D., D.L. Spittlehouse, and A. Story. 2005. Riparian microclimate and stream temperature response

to forest harvesting: A review. Journal of the American Water Resources Association 41:813-834.Rich, P.M. 1990. Characterizing plant canopies with hemispherical photography. Remote Sensing Reviews

5:13-29.Ringold, P.L., et al. 2003. Use of hemispheric imagery for estimating stream solar exposure. Journal of the

American Water Resources Association 39:1373-1384.

Steelhead, Turtles, and Frogs: Steelhead, Turtles, and Frogs: Temperature Dynamics of Stream HabitatTemperature Dynamics of Stream Habitat

Paul M. Rich1, Stuart B. Weiss2, and Alan E. Launer3

1Creekide Center for Earth Observation, paul@creeksidescience.com2Creekside Center for Earth Observation, stu@creeksidescience.com

3Stanford University, Land Use and Environmental Planning, aelauner@stanford.edu

AbstractAbstractAvailability of stream habitat with suitable temperature regimes is required by many species of conservation concern. Water temperature is determined by a complex interplay of prevailing meteorology, local riparian canopy structure and solar exposure, streambed morphology, and surface and subsurface flow patterns. We developed a technique for spatial-temporal analysis of temperature regimes for San Francisquito Creek (San Francisco Peninsula, California), which comprises habitat for steelhead (Oncorhynchus mykiss), California red-legged frog (Rana aurora draytonii) and western pond turtle (Clemmys marmorata). Steelhead requires relatively cool conditions, whereas the frog and turtle require warmer conditions. Our approach synthesized measurements of temperature from a network of inexpensive sensors (IButton Thermochron), riparian canopy structure and solar exposure from hemispherical (fisheye) photography, stream morphology from field characterization and geographic information system (GIS) analysis, stream flow and water temperature from gauging stations, and meteorology from nearby weather stations. We employed the RTemp Model (Washington State Department of Ecology) to predict time series of water temperature in response to heat fluxes. Water temperature co-varied with air temperature, diurnally with a lag of several hours, and over longer periods. Stream reaches with high solar exposure displayed relatively high temperature variability (up to 5° C differential from baseline), whereas shaded reaches displayed only modest temperature variability (0.5-1.0° C differential). Subsurface flow through gravel beds decreased temperature (2-3° C decrease). Our approach can be applied to a broad spectrum of streams for habitat characterization, for conservation management to ensure habitat heterogeneity, and for examination of potential impacts of climate change.

II. MethodsII. Methods

III. ResultsIII. Results

I. IntroductionI. Introduction

IV. Temperature ModelIV. Temperature Model

VIII. AcknowledgementsVIII. Acknowledgements

VI. PerspectiveVI. Perspective

• Nina Allmendinger• Linda Chamberlin• Nona Chiariello• Trevor Hébert• Ryan Navratil• Bijan Osmani• Brian Scoles• Pam Sturner

• Jasper Ridge Biological Preserve• National Fish and Wildlife

Foundation• San Francisquito Watershed

Council• Stanford University, Land Use and

Environmental Planning

Creek monkeys

Goal: Conserve species with different temperature requirements

• Cooler temperature: Steelhead Trout (Oncorhyncus mykiss)

• Warmer temperature: Northern red-legged frog (Rana aurora) and Western pond turtle (Clemmys marmorata)

Study Area: San Francisquito Watershed, California

• Headwaters in Santa Cruz Mountains, drains into San Francisco Bay (37°27’ N, 120°00’ W)

• 123 sq km, 3 tributaries, 24 creeks

Conservation Concerns• Changes in solar exposure: riparian

vegetation modification • Changes in runoff / flow: watershed

development and stream channel modification

• Climate change: shifts in energy balance

Our Approach• Develop sampling protocol and energy

balance model to characterize water temperature dynamics

• Analyze relationships between solar exposure and temperature regimes

• Relate temperature heterogeneity tohabitat suitability for different species

Long-Term Monitoring• Flow and water temperature from

gauging stations• Meteorology from nearby weather

stations

Intensive Field Measurements• Solar exposure using

hemispherical photography• Water temperature using sensor

network of iButton Thermochrons

Analysis and Modeling• Spatiotemporal patterns• Temperature model

A) Temperature Regimes• Water temperature co-varies with

air temperature, with lags• Variance explained by solar

exposure and flow patterns

B) Riparian Canopy Effects• Stream reaches with high solar exposure display

high temperature variability (up to 5° C differential from baseline)

• Shaded reaches display modest temperature variability (0.5–1.0° C differential)

C) Diurnal Canopy Effects• Water temperature closely tracks air

temperature when direct solar exposure• Lower diurnal variation in heavily shaded

reaches, and peak water temperature lags >4 hr after peak air temperature

D) Subsurface Flow Effects• Subsurface flow through gravel beds can decrease temperature 2 - 3° C

E) Solar Exposure• Solar radiation from hemiphotos every 2.5 m

along 100 meter transects • Insolation increases >3-fold between October

and June/July• Less riparian vegetation for “Dennis Martin”

than “Lunar Rocks” reaches, leading to higher insolation

F) Spatial Autocorrelation• Spatial autocorrelation used to calculate appropriate hemispherical photography sampling interval

• Semivariance peaks at 10-15 m, with pseudoperiodicity

• Implication: sample interval of 10-20 m

G) Simulated Tree Removal• Large California bay laurel

(Umbellularia californica) removed using image editing

• Tree removal increased solar exposure 2-3x, with effects 7.5 m downstream and 12.5 m upstream

Energy Balance• Predict water temperature based on energy balance

using modified rTemp model (State of Washington, http://www.ecy.wa.gov/programs/eap/models.html)

• Inputs: air temperature, solar radiation, canopy cover, water depth, etc.

• Output: water temperature as a function of time

Simulation of Riparian Canopy Change• Riparian canopy cover varied from 0 to 100%• Increased solar exposure leads to proportional

increase in daytime water temperature

V. Future WorkV. Future Work

Fiber-optic distributed temperature sensing network deployed in Waquoit Bay, MA

(courtesy of USGS)

Characterization and Modeling• Complete hemispherical photography and temperature sensor characterization• Characterize stream morphology (collaboration

with Balance Hydrologics)• Develop comprehensive temperature model

New Technologies• Use LIDAR for riparian canopy characterization

(collaboration with Stanford/Carnegie)• Apply fiber-optic technique for distributed temperature

sensing (collaboration with USGS)

Longitudinal temperature profile of Shenandoah River, VA (courtesy of USGS)

Water temperature key determinant of habitat• Steelhead Trout prefer cooler conditions• Red-Legged Frogs and Western Pond Turtles prefer warmer conditions

Synthetic Approach• Monitoring of flow, water temperature, meteorology,

geomorphology, etc.• Solar exposure from hemispherical photographs• Observed temperature from Thermochron sensor network• Predicted temperature from energy balance model

Applicable for broad spectrum of streams

Day

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