Landscape influence on small-scale water temperature variations in a moorland catchment

Abstract

6We monitored temperatures in stream water, groundwater and riparian wetland surface 7 water over 18 months in a 3.2 km 2 moorland catchment in the Scottish Highlands. The 8 stream occupies a glaciated valley, aligned west-east and has three main headwater 9 tributaries with northerly, southerly and westerly aspects. Much of the stream network is 10 fringed by riparian peatlands. Stream temperatures are mainly regulated by energy 11 exchanges at the air-water interface. However, they are also influenced by inflows from the 12 saturated riparian zone, where surface water source areas are strongly connected with the 13 stream network. Consequently, the spatial distribution of stream temperatures exhibits 14 limited variability. However, there are significant summer differences between the 15 headwaters, despite their close proximity to each other. This is consistent with aspect (and 16 incident radiation), with the south and west facing headwaters having higher temperatures. 17The largest, north-facing sub-catchment shows lower summer diurnal temperature 18 variability, suggesting that lower radiation inputs dampen temperature extremes. Whilst 19 stream water temperature regimes in the lower catchment exhibit little change along a 1km 20 reach, they are similar to those in the largest headwater; probably reflecting size and 21 comparable catchment aspect and hydrological flow paths. Our results suggest that 22

Using high‐resolution isotope data and alternative calibration strategies for a tracer‐aided runoff model in a nested catchment

“…The slightly better performance of the BB parameter set on HW1 during Jul was possibly due to the greater area of peatland in HW1 and therefore a more marked non‐linearity in flow response, which is better captured in the BB calibration. Field observations in both HW1 and BB have shown subtle discrepancies in hydrological responses caused by differences in percentage riparian peatland (Tunaley et al, ), GW influence (Blumstock et al, ) and solar radiation (Dick, Tetzlaff, & Soulsby, ). One difference evident from the isotope measurements was the more enriched isotope values during summer in HW1 compared to the BB, likely due to enhanced evaporation fractionation in the peatland pools.…”

Evaporation fractionation in a peatland drainage network affects stream water isotope composition

“…For our study, we used a nested experimental design, where we monitored a 0.73 km 2 headwater catchment (HW1) of the BB (green boundaries in Figure ). HW1 is characterized by an extensive raised peat bog [ Blumstock et al ., ; Dick et al ., ]. The bog is surrounded by a groundwater‐fed fen area, receiving groundwater seepage from the surrounding steep hillslopes [ Lessels et al ., ].…”

Characterization of contrasting flow and thermal regimes in two adjacent subarctic alpine headwaters in Northwest Canada

“…Stream temperature in BB was generally characterized by less variability (daily and sub-daily) than in GC. This is probably the result of a greater groundwater/discharge flow ratio (within the reach investigated), that could more effectively buffer non-advective flux troughs and peaks Dick et al, 2015;Johnson, Wilby, & Toone, 2014;Snyder, Hitt, & Young, 2015). Daily stream temperature typically peaked later in GC than in BB, suggesting that higher non-advective fluxes (as defined in Section 3.2.2) are needed in BB to compensate for the negative contribution of advective fluxes and maintain an overall positive energy budget.…”

“…Stream temperature showed high variability both in space and time, typical of low thermal capacity headwater streams during the summer season (Dick, Tetzlaff, & Soulsby, 2015). Despite differences in magnitude, stream temperature variability between reaches and sections within the same reach was highly correlated (r > 0.7).…”