SPRUCE Enclosure Corral and Sump System: Description, Operation, and Calibration
Stephen D. Sebestyen, Natalie A. Griffiths · OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) · 2016
This document describes the subsurface corral system that has been designed and constructed to measure water flow and allow the collection of water samples from the outflow of each experimental enclosure at the Spruce and Peatland Responses Under Changing Environments (SPRUCE) experimental site within the Marcell Experimental Forest in northern Minnesota, USA. SPRUCE implemented 10 years of whole-ecosystem warming, deep peat heating, and elevated carbon dioxide (CO2) treatments from 2015-2025 to assess the response of northern peatland ecosystems to increases in temperature and exposures to elevated atmospheric CO2 concentrations. This document: 1. Describes belowground corrals, sump systems, and the operation of sump systems, which are used to calculate the volumes of water that naturally drain enclosures and to trigger automatic collection of water samples; 2. Describes the calibration between water level and water volume in the sump system. This relationship is used to calculate near-surface lateral runoff (“outflow” in L/s) from each enclosure by measuring the change in water level over time. The water volume vs. water level relationship must be re-calibrated if water level sensors (or components) are replaced; and 3. Describes the data and data products that are and will be available from outflow measurements.