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Titel |
Development of a high resolution modeling tool for prediction of waterflows through complex mires: Example of the Mukhrino bog complex in West Siberian middle Taiga Zone |
VerfasserIn |
Evgeny A. Zarov, Oliver Schmitz, Wladimir Bleuten |
Konferenz |
EGU General Assembly 2015
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Medientyp |
Artikel
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Sprache |
Englisch
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Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 17 (2015) |
Datensatznummer |
250111391
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Publikation (Nr.) |
EGU/EGU2015-11500.pdf |
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Zusammenfassung |
Water flow through peat bogs differ substantially from mineral soil landscapes. Permeability
of the peatlayers decrease dramatically with depth within the permanently watersaturated peat
layers (Catotelm), whereas the 10-60Âcm thick superficial layer (Acrotelm) has a very
high conductivity. Water flows predominantly in this acrotelm layer where an open
structure of stems of mosses and few plants hardly limit water flow. By omitting this
superficial flow infrastructures in many places block the waterflow. Moreover, the
different bog types within a complex bog have different hydrological conductivities.
Without considering the typical water-flow of bogs the construction of roads and
platforms for oil and gas production threatens downhill mire ecosystems by partly
drainage.
The objective of our study was to develop a modeling tool which can be used to
predict quantitatively spatially distributed water-flow of a bog complex. A part of
the extensive bog complex "Mukhrino bog complex" located at the left bank of
Irtysh river near the West Siberian town Khanty-Mansiysk’ was chosen as modeling
area. Water discharge from this bog catchment occurs by "waterfalls" at the East
margin where a scarp with ca. 8Âm elevation difference has been developed by
backward erosion into the bog by the Mukhrino river. From field observations it was
proven that no discharge of groundwater occurred at the margin of the bog catchment
area.
We used PCRaster-MODFLOW as modeling environment. The model area size was 3.8
km2, cell size 5Âm and the model included 3ÂAcrotelm layers and 3ÂCatotelm layers.
Thickness of Acrotelm and Catotelm have been measured by coring in transects. Input data of
rain, snow have been recorded in the study area. Evapotranspiration was measured with small
lysimeters and crop factors for different land unit types (open water, raised bog, patterned
bog, poor fens) were elaborated by water balance modeling (1-D). Land unit types
have been mapped by supervised classification of a satellite image (QuickBird).
For modeling open water type was split into shallow lakes and deep "primary"
lakes.
From the model output of water level heads and flows in three dimensions it was
concluded that 95% occurs by superficial flow through the Catotelm layers. Water flow
through the Catotelm occurs bit was of minor importance.
With the modeling tool a virtual dam was created through the modeling area and the
accumulated water-flow across this dam calculated. The tool proved to be suitable for
calculation of optimization of permeability of road constructions through mires avoiding
damaging the high valuable bog ecosystems. |
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