Holden, Jospeh

McKendrick-Smith, Kathryn

Parry, Lauren E.

English

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Geophysical Research AbstractsVol. 18, EGU2016-9898, 2016EGU General Assembly 2016© Author(s) 2016. CC Attribution 3.0 License.Impact of mesh tracks and low-ground-pressure vehicle use on blanketpeat hydrologyKathryn McKendrick-Smith (1), Joseph Holden (1), and Lauren Parry (2)(1) School of Geography, University of Leeds, Leeds, United Kingdom (gy08ks@leeds.ac.uk), (2) School of InterdisciplinaryStudies, University of Glasgow, United KingdomPeatlands are subject to multiple uses including drainage, farming and recreation. Low-ground-pressure vehicleaccess is desirable by land owners and tracks facilitate access. However, there is concern that such activity mayimpact peat hydrology and so granting permission for track installation has been problematic, particularly withoutevidence for decision-making. We present the first comprehensive study of mesh track and low-ground-pressurevehicle impacts on peatland hydrology. In the sub-arctic oceanic climate of the Moor House World BiosphereReserve in the North Pennines, UK, a 1.5 km long experimental track was installed to investigate hydrologicalimpacts. Surface vegetation was cut and the plastic mesh track pinned into the peat surface. The experimentaltrack was split into 7 treatments, designed to reflect typical track usage (0 – 5 vehicle passes per week) and varyingvehicle weight. The greatest hydrological impacts were expected for sections of track subject to more frequentvehicle use and in close proximity to the track. In total 554 dipwells (including 15 automated recording at 15-minintervals) were monitored for water-table depth, positioned to capture potential spatial variability in response.Before track installation, samples for vertical and lateral hydraulic conductivity (Ks) analysis (using the modifiedcube method) were taken at 0-10 cm depth from a frequently driven treatment (n = 15), an infrequently driventreatment (0.5 passes per week) (n = 15) and a control site with no track/driving (n = 15). The test was repeatedafter 16 months of track use.We present a spatially and temporally rich water-table dataset from the study site showing how the impactsof the track on water table are spatially highly variable. Water-table depths across the site were shallow, typicallywithin the upper 10 cm of the peat profile for > 75% of the time. We show that mesh track and low-ground-pressurevehicle impacts on water-table depth were small except for directly under and close to the track. Where the trackruns parallel to the contours, water-tables were found to be deeper downslope of the track and shallower upslope.However in the no track/driving treatment; water table was significantly shallower downslope than upslope.Strong anisotropy was found in both ‘before-track’ and ‘after-track’ Ks, with horizontal Ks significantly greaterthan vertical Ks. No significant difference was found in vertical Ks before and after driving (medians 8.6 x 10-5and 6.6 x 10-5 cm s-1 respectively). Horizontal Ks was significantly greater after driving (median 2.2 x 10-3cm s-1) than before (median 3.7 x 10-4 cm s-1). Post-hoc testing highlights variability in response to treatmentand topographic position. We suggest that this surprising result is related to rapid regrowth of new vegetation(particularly Sphagnum) through the mesh of the track, which was more dominant on horizontal Ks than thecompression from low-ground-pressure vehicle use. Our results indicate that mesh tracks have a significant impactupon hydrology; however response is variable dependent upon topographic and seasonal factors. These findingscan be used to inform land-management decision-making for the use of mesh tracks in peatlands.

Impact of Mesh Tracks and Low-Ground-Pressure Vehicle Use on Blanket Peat Hydrology

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http://eprints.gla.ac.uk/119152/7/119152.pdf

Impact of Mesh Tracks and Low-Ground-Pressure Vehicle Use on Blanket Peat Hydrology

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