Water quality in the New River from Calexico to the Salton Sea, Imperial County, California

Abstract

Introduction 1 Background 1 Purpose and scope 5 Field and laboratory procedures 6 Reconnaissance 6 Data collection 6 Results 7 Comparisons 9 Water-quality investigations 11 Pesticides and trace elements 11 Dissolved oxygen 11 Temperature effects 12 Sag curves (profiles) 12 Diel variations 17 EPA criteria 19 Organic material 20 Oxidation of organics 20 Reaction rates 21 Time-of-travel investigations 22 Longitudinal stream profiles 22 Diel measurements 24 Loads 25 Biota as indicators 26 Benthic invertebrates 27 Phytoplankton 33 Bacteria 35 Potential hazard 35 Observed counts 38 Summary and conclusions 38 Selected references 42 FIGURES 1-2. Maps showing: 1. Location of study area 2 2. Location of sampling sites 3 3-4. Photographs showing: 3. Debris buildup on upstream side of box culvert at Interstate 8 road crossing 4 4. New River valley at Keystone Road crossing 5 5. Graph showing dissolved-oxygen concentration, percent saturation, pH, and specific conductance in the New River at Calexico, May 12, 1977 8 6. Photograph showing New River at Calexico gaging station 9 7-8. Graphs showing dissolved-oxygen concentration at selected sites on the New River: