TY - SER TI - Journal of the Irrigation and Drainage Division. Vol. 115 No. 1 (1989) PY - 0000///[date of publication not identified] CY - New York : American Society of Civil Engineers. N1 - It contains of Papers, Technical Notes and Errata for 1989 in Vol. 115 No. 1; SPECIAL SECTION: SELENIUM. HOW BAD IS IT? EDITOR'S NOTE / William R. Johnston. Agricultural Drainage Water-How Should It Be Regulated in California? / Stephen K. Hall, William R. Johnston, and William J. Miller. Irrigation-Induced Contamination: How Real a Problem? / Jonathan P. Deason. Selenium in Agricultural Drainage: Essential Nutrient or Toxic Threat? / Stephen B. Moore. Regulation of Agricultural Drainage to San Joaquin River / Gerald E. Johns and Dale A. Watkins. Selenium in Arid and Semiarid Soils / R. G. Burau. Economics of Selenium Removal from Drainage Water / Rodney C. Squires, G. Raymond Groves, and William R. Johnston. TECHNICAL PAPERS : Evalution of Irrigation Planning Decisions / Derrel L. Martin, James R. Gilley, and Raymond J. Supalla. Analytical Model of Level Basin Irrigation / Gerd H. Schmitz and Gunther J. Seus. Control of Irrigation Canal Networks / A. J. Clemmens and J. A. Replogle. Characteristics and Spatial Variability of Droughts in Idaho / Dennis R. Horn. Flow Measurement with Trapezoidal Free Overfall / Robert J. Keller and Soon S. Fong. TECHNICAL NOTES : Generalization of SCS Curve Number Method / Miklos Bosznay. Hydraulics of Catenary Irrigation Trail Tubes / Shu-Tung Chu. ERRATA. REVIEWERS OF THE JOURNAL OF IRRIGATION AND DRAINAGE ENGINEERING ER -