Theory and practice of hydrostatic lysimeters for direct measurement of net seepage in a patterned mire in north Scotland

摘要

A novel design oflysimeter for use in mires (peatlands) with shallow water tables is described.It employs an hydraulic mechanism for the automaticequilibration of soil moisture distribution between the outside and the insideof the lysimeter tank but uses no electronic components orelectrical power; and it can be installed with minimal disturbance in surfaceswith poor load-bearing capacity. The system was deployed on amire in northern Scotland to investigate the distribution of shallow seepageassociated with catenary arrays of different types of surface (microtopes).During the three-year period 15 November 1988 to 19 November 1991, the fractionof rainfall dispersed as seepage was 52% in a pool system;62% in ridge-furrow microtopography; and 59-67% in unpatterned sloping mire. Thedata provide preliminary confirmation of the hypothesis ofK. E. Ivanov that different microtopes within the same mire differ in theirhydrological norms; and suggest that the range ofecohydrological differences at the study site may be similar to those obtainedby Ivanov in western Siberia. Details of lysimeter design, construction,installation and operation are appended together with a discussion of the theoryof the lysimeter. style="line-height: 20px;">Keywords: acrotelm, blanket mire, ecohydrology, evapotranspiration, pool system, valleyside flowe, water balance