TABLE OF CONTENTS 4.0 DESCRIPTION OF THE PHYSICAL ENVIRONMENT............................................ 4­1 4.1 Geology ................................................................................................. 4­1 4.1.1 Methodology ........................................................................................ 4­1 4.1.2 Regional Geological Formations........................................................... 4­2 4.1.3 Local Geological Units ......................................................................... 4­7 4.1.3.1 Atlantic Coast .......................................................................... 4­7 4.1.3.2 Gatun Locks.............................................................................. 4­8 4.1.3.3 Gatun Lake ............................................................................... 4­9 4.1.3.4 Culebra Cut ......................................................................... ...4­10 4.1.3.5 Pacific Locks ...........................................................................4­11 4.1.3.6 Pacific Coast............................................................................4­12 4.1.4 Paleontological Resources ...................................................................4­13 4.1.5 Geotechnical Characterization .............................................................4­17 4.1.6 Tectonics.............................................................................................4­21 4.2 Geomorphology ..............................................................................................4­22 4.2.1 Local Geomorphology.........................................................................4­24 4.2.2.1 Atlantic Coast ..........................................................................4­24 4.2.2.2 Gatun Locks.............................................................................4­25 4.2.2.3 Gatun Lake ..............................................................................4­25 4.2.2.4 Culebra Cut..............................................................................4­25 4.2.2.5 Pacific Locks ...........................................................................4­26 4.2.2.6 Pacific Coast............................................................................4­26 4.3 Soil Characterization.......................................................................................4­26 4.3.1 Objectives and Methodology ...............................................................4­26 4.3.2 Identification and Description of Soils.................................................4­28 4.3.2.1 Ultisol Soils .............................................................................4­28 4.3.2.2 Alluvial Soils ...........................................................................4­29 4.3.2.3 Sedimentary Origin Soils .........................................................4­30 4.3.2.4 Anthropic Soils ........................................................................4­31 Category III Environmental Impact Study URS Holdings, Inc. Panama Canal Expansion Project – i July 2007 Third Set of Locks 4.3.3 Description of Soil Usage ....................................................................4­32 4.3.3.1 Atlantic Coast ..........................................................................4­32 4.3.3.2 Gatun Locks.............................................................................4­33 4.3.3.3 Gatun Lake ..............................................................................4­34 4.3.3.4 Culebra Cut..............................................................................4­35 4.3.3.5 Pacific Locks ...........................................................................4­36 4.3.3.6 Pacific Coast............................................................................4­37 4.3.4 Delimitation of Property ...................................................................4­38 4.3.5 Usage and Capability ..........................................................................4­39 4.3.5.1 Classification of Soils ..............................................................4­39 4.3.5.2 Atlantic Coast ..........................................................................4­43 4.3.5.3 Gatun Locks.............................................................................4­44 4.3.5.4 Gatun Lake ..............................................................................4­45 4.3.5.5 Culebra Cut..............................................................................4­46 4.3.5.6 Pacific Locks ...........................................................................4­47 4.3.5.7 Pacific Coast............................................................................4­49 4.4 Topography and Bathymetry...........................................................................4­50 4.4.1 Methodology .......................................................................................4­50 4.4.2 Topographic and Bathymetric Characteristics of the Specific Study Area ……………….....................................................................................4­50 4.4.2.1 Atlantic Coast ..........................................................................4­51 4.4.2.2 Gatun Locks.............................................................................4­52 4.4.2.3 Gatun Lake ..............................................................................4­53 4.4.2.4 Culebra Cut..............................................................................4­53 4.4.2.5 Pacific Locks ...........................................................................4­54 4.4.2.6 Pacific Coast............................................................................4­55 4.5 Climate ................................................................................................4­56 4.5.1 Methodology .......................................................................................4­56 4.5.2 Characterization of Climate .................................................................4­58 4.5.2.1 Types of Climate......................................................................4­58 4.5.2.2 Precipitation............................................................................4­59 Category III Environmental Impact Study URS Holdings, Inc. Panama Canal Expansion Project – ii July 2007 Third Set of Locks 4.5.2.3 Temperature.............................................................................4­62 4.5.2.4 Relative Humidity....................................................................4­66 4.5.2.5 Wind Velocity..........................................................................4­70 4.5.2.6 Solar Radiation ........................................................................4­76 4.5.2.7 Potential Evapotranspiration ....................................................4­80 4.6 Hydrology ................................................................................................4­81 4.6.1 General Aspects...................................................................................4­82 4.6.2 Quality Superficial Waters ...................................................................4­83 4.6.2.1 Atlantic Coast ..........................................................................4­83 4.6.2.2 Gatun Locks.............................................................................4­87 4.6.2.3 Gatun Lake ..............................................................................4­88 4.6.2.4 Culebra Cut..............................................................................4­99 4.6.2.5 Pacific Locks .........................................................................4­101 4.6.2.6 Pacific Coast..........................................................................4­104 4.6.3 Volumes (Maximum, Minimum, and Annual Average) .....................4­107 4.6.4 Currents, Tides, and Waves ..............................................................4­108 4.6.4.1 Atlantic Coast ........................................................................4­108 4.6.4.2 Pacific Coast..........................................................................4­109 4.6.5 Underground Waters .........................................................................4­110 4.6.5.1 Characterization of Aquiferous Layers ...................................4­110 4.7 Air Quality……………………………………………………………………4­111 4.7.1 Monitoring Sites and Evaluation Methodology..................................4­112 4.7.1.1 Air Quality Monitoring Activities ..........................................4­112 4.7.1.2 Estimates of Current Emissions .............................................4­115 4.7.2 Results Obtained for Specific Study Area .........................................4­115 4.7.2.1 Atlantic Coast ........................................................................4­118 4.7.2.2 Gatun Locks...........................................................................4­118 4.7.2.3 Gatun Lake ............................................................................4­118 4.7.2.4 Culebra Cut............................................................................4­119 4.7.2.5 Pacific Locks .........................................................................4­119 4.7.2.6 Pacific Coast..........................................................................4­120 Category III Environmental Impact Study URS Holdings, Inc. Panama Canal Expansion Project – iii July 2007 Third Set of Locks 4.8 Noise ..............................................................................................4­120