Project 3 (?): Interactions of Landscape Processes within Intensively Managed Watersheds

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Project 3 (?) Interactions of Landscape
Processes within Intensively Managed Watersheds
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Theme 3 Background

• Theme emerges from sustained UIUC and
  collaborators interest in IMLs
• Possibility of a hydrological observatory aimed
  at the Illinois River Basin

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Theme 3 Rationale

• Many landscapes in the US and elsewhere have been
  extensively modified by human activity
• Transformation of land-cover conditions has
  dramatically altered hydrological, ecological
  geomorphological and biogeochemical processes
  compared to pre-settlement conditions
• Altered processes in turn have produced
  environmental problems of societal importance,
  including exacerbated flooding, degradation of
  water quality, threats to ecosystems, and
  enhanced rates of erosion and sedimentation
• A holistic approach to the management of these
  problems requires understanding of interactions
  among various landscape processes
• Thus far, most research has involved
  disciplinary studies aimed at individual problems
  and processes (e.g. flooding and accelerated
  runoff), rather than integrated investigations of
  process interconnections .

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Theme 3 Research Questions

• How do anthropogenic changes in landscape
  heterogeneity and watershed processes alter the
  dynamic regimes of the coupled physical-ecological
  -biogeochemical systems at different scales?
• How do key drivers such as changes in land-use
  change and climate influence the magnitude and
  frequency characteristics of hydrological,
  ecological, biogeochemical and geomorphological
  processes?
• How sensitive are sediment and biogeochemical
  fluxes to hydrologic and land-cover changes
  associated with agricultural land use and
  urbanization?
• How do variability and changes in water quality,
  water quantity, and sediment fluxes impact
  aquatic habitats and ecosystem functions?
• What variables are important for the prediction
  of interacting processes in the water cycle for
  different regions, and what levels of
  predictability can be attained given the
  uncertainty of process understanding, the
  heterogeneity of process dynamics, and the
  complexity of interacting processes?

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My Research Interests

• Geomorphology of river systems in intensively
  managed landscapes
• Dynamic interactions among flow, sediment
  transport and channel form
• How dynamic interactions are related to aquatic
  habitat and fish communities
• Management, naturalization and restoration of
  river systems in IMLs

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Sediment Dynamics in Intensively Managed
Landscapes

• Issues of
• Scale
• Anthropogenic Influence
• Connections to Hydrological, Biogeochemical, and
  Ecological Processes

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Sediment Dynamics in Intensively Managed
Landscapes

• Scaling Issues
• Move beyond basin sediment delivery ratio
• SDR yield/production
• Event-based modeling perspective
• Lu et al. 2005 A theoretical exploration of
  catchment sediment delivery accounts for
  stores, fluxes of sediment from hillslopes and
  channels in relation to event timing, magnitude
  and duration
• Can be cast in spatially distributed form
• Emphasizes event conditioning how parts of a
  sediment system are prepared to respond to an
  event and how each part contributes to the
  overall response
• Hot spots, hot times, thresholds, and external
  controls

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Sediment Dynamics in Intensively Managed
Landscapes
Anthropogenic influences in IRB
Low-relief glaciated terrain Predominate land
use is row-crop agriculture High-density
urbanization within Chicago metro area
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Anthropogenic Influences Vary with Scale
Headwaters Scale Drainage Area 1 100
km2 Channelized Tile Drainage Periodic
Maintenance Flanked by farm fields or narrow
grass buffer Flashy Hydrologic Regimes
Erosionally Stable High Nutrient and Fine
Sediment Loads Storage of coarse load
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Major Tributary Scale Drainage Area 100 - 1000
km2 Actively Meandering (Bank Erosion) Flanked by
farm fields or narrow riparian corridor No Tile
Drainage Inputs Has higher nutrient and sediment
loads, flashier hydrological response, and
carries greater runoff volume than prior to
settlement May contain low-head dams or
water-supply reservoirs
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Illinois River Main Stem Drainage Area 10,000
km2 Not actively meandering, experiencing net
sedimentation Flanked by bottomland wetlands
within an incised, ancestral glacial drainageway
Regulated by navigation locks and dams Sediment
delivery higher and hydrological regime less
variable than prior to settlement Floodplain
groundwater regime influenced strongly by
hydraulic gradients from surrounding bluffs
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Sediment Dynamics Research Questions

• How are fluxes of sediment (wash load, suspended
  load, and bedload) at various scales within
  watersheds related to spatial and temporal
  variability in hydrological processes, especially
  the magnitude, sequencing and spatial extent of
  hydrological events?
• How sensitive are sediment fluxes to hydrological
  and land-cover changes associated with
  agricultural land use and urbanization, and how
  does this sensitivity vary with the type and
  intensity of land-use change, with geological
  materials, and with watershed topography?
• What inertial lags exist between the material
  fluxes of the hydrological and sedimentary
  systems and how are these lags manifested through
  sediment storage/mobilization within fluvial
  systems? How might anticipated changes in
  climate influence these inertial lags?
• How are changes in sediment fluxes linked to
  spatial and temporal patterns of stream-channel
  and floodplain erosion/deposition throughout
  watersheds? What influence have changes in the
  form and dynamics of stream channels and
  floodplains associated with human manipulation of
  fluvial systems and with changing sediment fluxes
  had on physical habitat and the characteristics
  of riparian/aquatic ecosystems?
• What coupling exists among hydrological,
  biogeochemical and sediment fluxes at various
  scales within watersheds?

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Sediment Dynamics Grand Challenge

• Lack of Appropriate Data!!!