Soil partitioning and surface store controls on spring runoff from a boreal forest peatland basin in north-central
The mid- to high-boreal forest in Canada occupies the discontinuous permafrost zone, and is often underlain by glaciolacustrine sediments mantled by a highly porous organic mat. The result is a poorly drained landscape dominated by wetlands. Frost-table dynamics and surface storage conditions help t...
| Main Authors: | , |
|---|---|
| Other Authors: | |
| Format: | Text |
| Language: | English |
| Published: |
2001
|
| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.586.4348 http://people.trentu.ca/rmetcalfe/PDFs/Metcalfe and Buttle 2001.pdf |
| Summary: | The mid- to high-boreal forest in Canada occupies the discontinuous permafrost zone, and is often underlain by glaciolacustrine sediments mantled by a highly porous organic mat. The result is a poorly drained landscape dominated by wetlands. Frost-table dynamics and surface storage conditions help to control runoff contributions from various landscape elements, hydrological linkages between these elements, and basin streamflow during spring snowmelt. Runoff components and pathways in a forested peatland basin were assessed during two spring snowmelts with contrasting input and basin conditions. Runoff from relatively intense melt (up to 16 mm day1) on slopes with limited soil thawing combined with large pre-melt storage in surface depressions to produce high flows composed primarily of meltwater (78 % of the 0Ð29 m3 s1 peak discharge) routed over wetland surfaces and through permeable upper peat layers. Melt intensity was less in the subsequent year (maximum of 10 mm day1) and active layer development was relatively greater (0Ð2 m deeper at the end of spring melt), resulting in less slope runoff. Coupling of reduced slope contributions with lower storage levels in basin wetlands led to relatively subdued streamflows dominated by older water (73 % of the 0Ð09 m3 s1 peak discharge) routed through less-permeable deeper peat layers and mineral soil. Interannual differences in runoff conditions provide important insight for the development of distributed hydrological models for boreal forest basins and into potential influences on biogeochemical cycling in this landscape under a warming climate. Copyright 2001 John Wiley & Sons, Ltd. KEY WORDS boreal forest; spring melt; depression storage; hydrograph separation; permafrost; ground thawing; wetlands |
|---|