Evapotranspiration and microclimate at a low-level radioactive-waste disposal site in northwestern Illinois

Abstract

Introduction 1 Background 1 Purpose and scope 2 The Sheffield site 2 Location and history 2 Climate 2 Soils 3 Vegetation 5 Techniques for estimating evapotranspiration 5 Aerodynamic profile 5 Energy budget 8 Water budget 9 Potential evapotranspiration 10 Instrumentation 10 Precipitation 10 Radiation 10 Wind 11 Air temperature and water-vapor pressure 11 Soil-heat flux and temperature 11 Soil-water content and tension 12 Surface runoff 12 Microclimate of the trench covers 12 Precipitation 12 Radiation 12 Wind 19 Air temperature and water-vapor pressure 20 Soil-heat flux and soil temperature 21 Soil-water content 23 Evapotranspiration estimates 25 Energy-budget method 25 Aerodynamic-profile method 26 Water-budget method 27 Potential evapotranspiration 28 Error analysis 28 Summary 29 References cited 36 III IV Contents Contents

WATER BALANCE AT A LOW‐LEVEL RADIOACTIVE‐WASTE DISPOSAL SITE1

“…Readings from all meteorological instruments were taken every 10 seconds and then averaged by a data logger to produce hourly values. Additional information on these instruments and the evapotranspiration calculations is contained in Healy et al (1987).…”

Water movement and water chemistry in the unsaturated zone at a low-level radioactive-waste disposal site near Sheffield, Illinois, 1986-87

“…Annual water budgets for July through June 1982June -83, 1983June -84, 1984June -85, 1985June -86, and 1986 are presented in table 3; budgets for the period 1982-84 were prepared by Mills and Healy (1991). Annual water budgets were compiled for the period July through June to allow comparison with previously reported water-budget data for the site (Healy, deVries, and Sturrock, 1989;Healy, Gray, and others, 1989;Mills and Healy, 1991).…”

“…2 Evapotranspiration values for July 1982 through June 1984 from Healy, deVries, and Sturrock (1989).…”

“…In some cases, data from the earlier reports are included in this report to show changes in previously described trends or reinterpretation of the trends. To avoid substantial replication of data, however, the reader generally is referred to the earlier reports (Foster, Garklavs, and Mackey, 1984a;Healy, deVries, and Sturrock, 1989;Mills and Healy, 1991;and Peters and others, 1992) for discussions of pre-1986 data.…”

“…The comprehensive research project included studies of the hydrogeology (Foster and Erickson, 1980;Foster, Erickson, and Healy, 1984;Foster, Garklavs, and Mackey, 1984a,b;Garklavs and Toler 1985;Garklavs and Healy, 1986), runoff, and landform modification (Gray, 1984(Gray, , 1986Gray and McGovern, 1986) at the site. Subjects of studies of the unsaturated zone, also undertaken as part of that project, include evapotranspiration and microclimate of a trench cover (Healy, deVries, and Sturrock, 1989), water movement through a trench cover (Healy, 1989), gaseous transport of radionuclides (Striegl, 1988), waste-induced effects on water chemistry (Peters and others, 1992), and water movement through the full thickness of the unsaturated zone (Mills and Healy, 1991). Peters and others (1992) concluded that, with the exception of increased concentrations of tritium and dissolved organic carbon, water chemistry near the disposal trenches was not substantially different from natural, off site water chemistry.…”