CUAHSICUAHSI FallFall 20042004 VisionVision PaperPaper CyberseminarCyberseminar SeriesSeries www.cuahsi.orgwww.cuahsi.org

LealLeal MertesMertes Coming to you from Santa Barbara, CA October 5th, 2004 To begin at 3:05 ET

FloodplainsFloodplains WelcomeWelcome toto thethe 33rd SemesterSemester ofof CUAHSICUAHSI EducationEducation andand OutreachOutreach DistinguishedDistinguished LecturesLectures

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„ ScalingScaling andand HydrologicHydrologic ModelingModeling-- GeoffGeoff ThyneThyne,, CSM.CSM. OctoberOctober 1414th „ IntensivelyIntensively ManagedManaged LandscapesLandscapes BillBill Simpkins,Simpkins, ISU.ISU. OctoberOctober 1919th „ EcohydrologyEcohydrology ofof SemiSemi--AridArid EnvironmentsEnvironments BrentBrent Newman,Newman, LANL.LANL. OctoberOctober 2121st

GoGo toto CUAHSICUAHSI websitewebsite forfor completecomplete calendar,calendar, linkslinks toto papers,papers, presentations,presentations, andand discussiondiscussion forumsforums FLOOD TEAM: FLOODPLAINS Jean Bahr - UWisc CUAHSI Cyberseminar: Martin Doyle - UNC October 5, 2004 Leal Mertes - UCSB Noon – Pacific Time Andrew Miller - UMaryland Geoff Poole - UGA Ken Potter - UWisc Leal A.K. Mertes Department of Geography Jim Smith - Princeton UCSB Rip Sparks - UIllinois Emily Stanley - UWisc [email protected]

Landsat OUTLINEOUTLINE z 1st Principles – Scale – Geomorphology – Hydroclimatology – Habitat z Human Impact z Research Agenda – Flood Discharge ƒ Urban Watersheds – Flood Frequency – Inundation Hydrology ƒ Water Distribution – Floodplain Capacity & Modelling ƒ Perirheic Mixing - Sediment ƒ Hyporheic Exchange – Thermal – Geomorphic Template – Heterogeneity & Landscape Arrangement – Biogeochemistry – Nitrogen Cycle – Biology – Flow Reversals z Summary – Societal Importance – Enoughness? – Function Compression 11stst PRINCIPLESPRINCIPLES -- SpatialSpatial Scale:Scale: RiverineRiverine GeomorphologyGeomorphology && EcologyEcology z Watershed 101 km2-106 km2 z Valley/Reach 100 m-104 m z Channel Unit 100 m-103 m z Stream Bed 100 cm-105 cm

(Poff, 1997) 11stst PRINCIPLESPRINCIPLES –– Hydroclimatology:Hydroclimatology: SpatialSpatial && TemporalTemporal ScalesScales

z Watershed 101 km2-106 km2

z Valley/Reach 100 m-104 m

z Channel Unit 100 m-103 m

z Stream Bed 100 cm-105 cm

(after Hirschboeck, 1988) 11stst PRINCIPLESPRINCIPLES -- FloodFlood HydroclimatologyHydroclimatology && BiomesBiomes

(hydroclimatology after Hayden, 1988 - as published in Poff et al. 2001) HUMANHUMAN IMPACTIMPACT -- DamsDams

Rate of rise Duration “Ideal” (1887)

Rate of fall Reversal

0 100 200 300 Day of the year

Indicators of Hydrologic Alteration (IHA, Richter et al. 1996): 42 biologically meaningful hydrologic parameters for eight gage sites along the Illinois River. HUMAN IMPACT – Geomorphic simplification of floodplains – Willamette River and floodplain

1854 1910 1967

(Sedell and Froggatt, 1984) RESEARCHRESEARCH AGENDAAGENDA

– Flood Discharge ƒ Urban Watersheds – Flood Frequency – Inundation Hydrology ƒ Water Distribution – Floodplain Capacity & Modelling ƒ Perirheic Mixing - Sediment ƒ Hyporheic Exchange – Thermal – Geomorphic Template – Heterogeneity & Landscape Arrangement – Biogeochemistry – Nitrogen Cycle – Biology – Flow Reversals FLOODFLOOD DISCHARGEDISCHARGE -- QuestionsQuestions z What is the relationship between the channel – floodplain system and the history of storm events in an urban drainage basin? z What are the dynamic processes associated with flooding at the watershed scale, how do floods respond to the interplay between hydrometerology, geology, topography, and anthropogenically modified features of the landscape? FLOODFLOOD DISCHARGEDISCHARGE -- AssertionsAssertions z Floods are both spatially and temporally complex and notoriously difficult to measure z Stage/discharge relationships are not necessarily single-valued; can get looped or hysteretic rating curves when following rising and falling limbs of the same event z Can get substantial lateral water-surface gradients across the floodplain with changing stage during a flood z Can also get backwater effects, sometimes including reverse flow at confluences and constrictions; or associated with transient obstructions like debris jams FLOOD DISCHARGE – Urban Watersheds Extreme conditions in small watersheds FLOOD DISCHARGE – Urban Watersheds Urban channel/floodplain systems are not necessarily simple; channels and riparian zones may exhibit strongly heterogeneous characteristics over short distances.

5000 Flood of June 13, 2003 4500

4000

3500

/s 3000 3 t f e in

g 2500 r a h sc i 2000 Whitemarsh Run at Fullerton D Whitemarsh Run at White Marsh 1500

1000

500

0 6/13/03 15:00 6/13/03 17:00 6/13/03 19:00 6/13/03 21:00 6/13/03 23:00 6/14/03 1:00 6/14/03 3:00 6/14/03 5:00 (Whitemarsh in Baltimore region watershed) TheThe UrbanUrban HydrologicHydrologic SystemSystem (courtesy(courtesy ofof KenKen Belt,Belt, U.S.U.S. ForestForest Service)Service)

Impervious Surfaces

Stormdrains Water Supply Pipes

Septic Systems Groundwater Flow Paths Artificial Channels Wastewater Conduits INUNDATIONINUNDATION HYDROLOGYHYDROLOGY -- WatershedWatershed StructureStructure && thethe FloodplainFloodplain PatchPatch z Variable contributions from sources can produce different inundation patterns.

SOURCES of WATER IN = main channel input TR = major tributary L = local tributary GW = groundwater/hyporheic water P = local precipitation INUNDATIONINUNDATION HYDROLOGYHYDROLOGY -- FloodplainFloodplain Capacity:Capacity: DistributionDistribution ofof FloodplainFloodplain WaterWater z How much water in a stream ever resides on the floodplain? z What is the frequency distribution of inundation depths and areas? z What is the frequency distribution of residence times of water that reaches floodplain surfaces? z How is this residence time distributed across a watershed? INUNDATIONINUNDATION HYDROLOGYHYDROLOGY-- DistributionDistribution ofof recurrencerecurrence intervalsintervals asas aa measuremeasure ofof capacitycapacity forfor riverriver reachesreaches ((WoltemadeWoltemade 1993)1993) INUNDATION HYDROLOGY - Modelling Floodplain Flows INUNDATION HYDROLOGY - GW & HW Model Results for Flathead River

radius = degree of variation in GW vector over 6-month simulation

direction & magnitude of GW flow vector upwelling (white) & downwelling (black); radius = vertical flux INUNDATIONINUNDATION HYDROLOGYHYDROLOGY -- SurfaceSurface WaterWater Mixing:Mixing: PerirheicPerirheic INUNDATIONINUNDATION HYDROLOGYHYDROLOGY -- SurfaceSurface Mixing:Mixing: MonitoringMonitoring SedimentSediment

Landsat 321 = RGB August 15, 1988 R. Negro + R. Solimões = Amazonas INUNDATIONINUNDATION HYDROLOGYHYDROLOGY -- PerirheicPerirheic MixingMixing onon AmazonAmazon FloodplainFloodplain

~2 km

perirheos INUNDATIONINUNDATION HYDROLOGYHYDROLOGY -- SubSub--SurfaceSurface WaterWater Mixing:Mixing: HyporheicHyporheic

Riparian Zone Channel

Alluvial Aquifer Phreatic Streambed Hyporheic Paleochannel INUNDATION HYDROLOGY – Hyporheic Exchange: Thermal Monitoring Temperature patterns from data loggers (Arrigoni 2004)

river (downwelling) 28 ground water (upwelling) downwelling g n i l 27 mp

sa 26 ss

ro 25

ac ° d o i C) r 24

° e ( r pe u t 23 era

mp upwelling

e 22 t an

e 21 M 20 1 3 5 7 9 11131517192123 Time (hours)

° INUNDATION HYDROLOGY – Hyporheic Exchange: Thermal Monitoring Fine Temporal Monitoring with Field Instruments (Arrigoni 2004)

31 Downwelling Predicted Upwelling Predicted 29 Rain

C) 27 ° ( e r 25 u at er 23 mp e 21 T r e t 19 a W 17

15 20-Jul 22-Jul 24-Jul 26-Jul 28-Jul 30-Jul 1-Aug 3-Aug 5-Aug 7-Aug 9-Aug 11-Aug 13-Aug INUNDATION HYDROLOGY – Thermal Monitoring with Forward- Looking Infrared Radiometer (FLIR) (Torgersen et al. 2001 as published in Mertes et al. 2004) GEOMORPHICGEOMORPHIC TEMPLATETEMPLATE GEOMORPHIC TEMPLATE – Fine resolution data – LiDAR - Upper Gwynns Falls GEOMORPHIC TEMPLATE – Measuring Heterogeneity, i.e. Landform Variability Jökulhlaup on Skeiðarársandur, Iceland

November 5-7, 1996 (Guðmundsson & Sigurðsson, 1996) GEOMORPHIC TEMPLATE – Measuring Heterogeneity, i.e. Landform Variability Jökulhlaup on Skeiðarársandur, Iceland Iceberg Landforms

(Guðmundsson & Sigurðsson, 1996) GEOMORPHIC TEMPLATE – Measuring Heterogeneity, i.e. Landform Variability Jökulhlaup on Skeiðarársandur, Iceland Channel Landforms

(Iceland Calendar 1997) GEOMORPHIC TEMPLATE – Measuring Heterogeneity, i.e. Landform Variability Sandur Variability Map Based on Digital Elevation Map from Airborne Radar Altimetry (Smith et al. 2000)

(J. Mason) GEOMORPHICGEOMORPHIC TEMPLATETEMPLATE –– HumanHuman Impact:Impact: MesopotamianMesopotamian MarshesMarshes ChangingChanging thethe TemplateTemplate

Mesopotamia GEOMORPHIC TEMPLATE – Landscape Re – Arrangement Mesopotamian Marshlands From 1970s to present, marshlands re-engineered and drained. White areas on 3 images (Landsat – 77 & MODIS – 02 & 04) show location of open water during “flood” season. Grey tones show wetland vegetation. Renewed water releases due to 2003-2004 Iraqi conflict show impact of drainage engineering on geomorphic template &, therefore, inundation pattern. BIOGEOCHEMISTRY – Nitrogen Cycle

(Figure courtesy of Bruce Peterson) BIOGEOCHEMISTRY – Nitrogen Cycle: Watershed Scale (Seitzinger et al. 2001) BIOGEOCHEMISTRY – Nitrogen Cycle Nitrate transport and transformation in groundwater beneath floodplains z How can floodplain preservation and restoration contribute to reducing nitrogen export from agricultural lands? z What combinations of subsurface hydrostratigraphy, surface topography, vegetation, and inundation patterns create conditions that promote subsurface denitrification? z What field monitoring strategies are necessary for and most effective at identifying zones of denitrification and quantifying denitrification rates in the subsurface? BIOGEOCHEMISTRY – Nitrogen Cycle Basic requirements for denitrification a) Microbial population of denitrifiers b) Suitable Redox conditions (low Dissolved Oxygen - DO) c) Electron donor (organic carbon or other reduced species) Floodplain zones in which these conditions are expected include shallow wetland soils and zones of hyporheic exchange

Shallow wetland soils Hyporheic Zone BIOGEOCHEMISTRY – Nitrogen Cycle Can floodplain complexity generate additional zones of denitrification?

Local topography creates complex flow paths

Transient water levels may create deeper mixing zone in which organic carbon moved downward with infiltrating water serves as electron donor for reduction of nitrate from upland agricultural areas. BIOGEOCHEMISTRY – Nitrogen Cycle z Greater potential for denitrification in groundwater beneath floodplains with complex topography and frequent inundation compared to those with more uniform topography and steady water levels or flowpaths z RESEARCH STRATEGY – Comparative studies in floodplains with varying degrees of physical and hydrologic complexity and affected to varying degrees by human or other disturbance – Integration of stratigraphic, hydrologic, geochemical, vegetation and microbiologic data – Monitoring over sufficient time to characterize effects of variations in flow paths and nitrogen sources at seasonal and inter-annual scales. BIOGEOCHEMISTRY – Scale Issues

? Need for understanding nutrient dynamics at the scale of the problem versus -Characteristic small-scale variation of floodplains -Small-scale of measurement

100 300

250 75 200

50 150

100 25 # of samples 50 Denitrification 2000

0 0 0 5 10 15 20 25 30 40 50 75 100 150 0 25 50 75 100 125 150 DEA (ng N/g soil/hr) Denitrification 1999 BIOLOGYBIOLOGY BIOLOGY – Human Impact: Flow reversals Effects on Plants Rate of rise Duration Moist soil plant growing season

Spikes

Rate of fall Reversal

0 100 200 300 Day of the year BIOLOGY – Human Impact: Flow reversals 136 Altered Water Regime Pre-dam (1887)

Post-dam (1987) 134

132

natural dry season

River Level (meters above msl) River Level (meters 130 0 100 200 300 Day of Year From Technical support of public decisions to restore floodplain ecosystems: a status report on the Illinois River project, 2000 BIOLOGY – Human Impact: Flow reversals BIOLOGY – Human Impact: Flow reversals

Biomass

g

End of growing season

Plant height

With pre-dam (1887) hydrograph BIOLOGYBIOLOGY –– Human Impact: Flow reversals

Biomass g

End of growing season

Plant height

With post-dam (1987) hydrograph SUMMARYSUMMARY –– SocietalSocietal ImportanceImportance

– Enoughness? – Function Compression SocietalSocietal Importance:Importance: StrikingStriking aa BalanceBalance

EngineeredEngineered NaturalNatural GoodsGoods SystemSystem ServicesServices && ServicesServices

Transportation Drinking Water Hydropower Nutrient Retention Agriculture Fisheries Recreation Flood Mitigation Wildlife Habitat SUMMARY – Societal Importance The value of nature and the nature of value.

“Identify the production functions” (Daily et al.)

z N removal/uptake z Flood reduction z Production of fish, wildlife z Maintenance of biodiversity z “Serenity”

“Enoughness” questions – How much (e.g., in- stream flow)? Arrangement on landscape – Upstream- downstream; lateral SUMMARY – Societal Importance

“Function Compression” Doing more with less -- Providing equivalent ecosystem services on smaller area.

(Firth, Galat, Sparks -- Water Environment Research Foundation (WERF) Workshop)