Revealing groundwater discharge to a lowland wetland by combining temperature and vegetation surveys

House, Andrew; Sorensen, James; Gooddy, Daren; Marchant, Benjamin; Newell, Andrew; Old, Gareth ORCID: https://orcid.org/0000-0002-4713-1070; Roberts, Colin; Scarlett, Peter. 2013 Revealing groundwater discharge to a lowland wetland by combining temperature and vegetation surveys. [Lecture] In: Wetland Hydrology: BHS National Meeting, Birmingham, UK, 13 Sept 2013. (Unpublished)

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Abstract/Summary

Understanding of wetlands is vital for conservation management and evaluating the impacts of climate change and groundwater abstraction. The Lambourn Observatory at Boxford comprises a 10 ha SSSI designated water meadow. A layer of up to 2.7 m of peat covers up to 7.5 m of coarse-grained gravel alluvium, underlain by Chalk. Previous investigations using an arbitrary piezometer array and chemistry have suggested a northern dependency on river stage and southern dependency on groundwater contributions. However, groundwater inflows to wetlands can be discrete and easily missed. Spatial surveys are necessary to ensure sites are adequately conceptualised. We rapidly characterised the site using temperature and vegetation over 2 weeks. Temperature data were collected in winter at multiple depths down to 0.9 m at over 1000 locations. Temperature ranged from ~10 °C to ~2 °C, with anomalous warm hotspots and relatively constant temperature gradients indicating areas of groundwater contribution. Botanical indicators of groundwater were identified from a vegetation survey and available literature. The distribution of Carex paniculata (Greater tussock sedge) corresponded to temperature anomalies, whilst Alisma plantago-aquatica (Water plantain) matched areas of constant surface flow fed by springs. Hydraulic heads and groundwater chemistry from a new targeted piezometer array provided corroborating information which supported designation of the temperature anomalies as zones of groundwater discharge.

Item Type:	Publication - Conference Item (Lecture)
UKCEH and CEH Sections/Science Areas:	Acreman
Additional Keywords:	GroundwaterBGS, Groundwater, Surface water interaction, Groundwater thermometry
NORA Subject Terms:	Hydrology
Date made live:	11 Nov 2013 11:42 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/503673

Item Type:

Publication - Conference Item (Lecture)

UKCEH and CEH Sections/Science Areas:

Acreman

Additional Keywords:

GroundwaterBGS, Groundwater, Surface water interaction, Groundwater thermometry

NORA Subject Terms:

Hydrology

Date made live:

11 Nov 2013 11:42 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/503673