Evapotranspiration
Covers for
Landfills and
Landfills and
Waste Sites
Victor L. Hauser
CRC Press
Taylor & Francis Group
Boca Raton London New York
Contents
Preface......................................................................................................................xv
Acknowledgments..................................................................................................xvii
The Author..............................................................................................................xix
Chapter 1 Introduction ..........................................................................................1
1.1 Waste Disposal................................................................................................1
1.2 Waste Containment .........................................................................................1
1.3 Covers for Landfill Containment ....................................................................2
1.4 Laws and Regulations.....................................................................................3
1.4.1 Innovative Technology.........................................................................3
1.4.2 The Current Situation ..........................................................................4
1.5 Purpose............................................................................................................4
References..................................................................................................................4
Chapter 2 Landfill Remediation with Covers.......................................................7
2.1 Requirements for Landfill Covers...................................................................7
2.2 Risk-Based/Performance-Based Remediation................................................8
2.3 Factors That Influence Remediation ...............................................................9
2.3.1 Climate.................................................................................................9
2.3.2 Landfill and Waste Characteristics.................................................... 10
2.3.3 Hydrogeology..................................................................................... 10
2.3.4 Gas Production................................................................................... 11
2.3.5 Soils and Plants.................................................................................. 11
2.3.6 Seismic Environment......................................................................... 11
2.3.7 Reuse of Landfill Areas..................................................................... 12
2.4 Cover Selection ............................................................................................. 12
References................................................................................................................ 13
Chapter 3 Conventional and Alternative Covers................................................. 15
3.1 Conventional Landfill Covers ....................................................................... 15
3.1.1 RCRA Subtitle C, Barrier Cover ....................................................... 15
3.1.1.1 The Cover Soil Layer ........................................................... 15
3.1.1.2 The Drainage Layer.............................................................. 16
3.1.1.3 The Barrier Layer................................................................. 16
3.1.1.4 The Gas Collection Layer..................................................... 17
3.1.1.5 The Foundation Layer .......................................................... 17
3.1.2 RCRA Subtitle D, Barrier Cover ....................................................... 17
vi Evapotranspiration Covers for Landfills and Waste Sites
3.2 Alternative Barriers for Covers..................................................................... 18
3.2.1 Capillary Barrier................................................................................ 18
3.2.1.1 Capillary Barriers without Vegetation ................................. 19
3.2.2 Asphalt Barrier................................................................................... 19
3.3 Alternative Covers.........................................................................................20
3.3.1 The MSR Cover .................................................................................20
3.3.2 Vegetative Covers...............................................................................20
3.3.3 Infiltrate–Stabilize–Evapotranspire Cover........................................ 21
3.4 Performance of Barrier Covers..................................................................... 21
3.4.1 Compacted Soil.................................................................................. 21
3.4.2 Compacted Clay.................................................................................23
3.4.3 “US EPA” Barrier Cover with Bare Soil Surface ..............................24
3.4.4 Geomembrane Barriers......................................................................25
3.4.5 Composite Barriers............................................................................25
3.5 Performance of Alternative Covers...............................................................26
3.5.1 Capillary-Barrier Covers ...................................................................26
3.5.1.1 Vegetated Surface.................................................................26
3.5.1.2 Bare Soil Surface..................................................................28
3.5.2 Vegetated Covers ...............................................................................28
3.5.2.1 The MSR Cover....................................................................28
3.5.2.2 Vegetation-Only Landfill Covers.........................................30
3.5.3 Asphalt Replaced by Vegetated Cover...............................................30
3.5.4 ISE Cover........................................................................................... 31
3.5.5 Common Elements of Vegetated Cover Failure................................. 31
3.6 Focus of This Book ....................................................................................... 31
References................................................................................................................ 32
Chapter 4 Evapotranspiration Landfill Covers ................................................... 35
4.1 Definition ...................................................................................................... 35
4.1.1 Minimum Requirements and Function.............................................. 35
4.1.2 Soil Water Storage and Plant Roots...................................................36
4.2 Differences....................................................................................................37
4.3 Concept Background and Proof....................................................................37
4.3.1 Water Balance by Soil Water Measurements.....................................37
4.3.2 Experimental Proof............................................................................38
4.3.2.1 Short-Term Experiments ......................................................39
4.3.2.2 Wet Climate and Modified Soil............................................39
4.3.3 Long-Term Proof................................................................................39
4.3.3.1 Great Plains Water Balance..................................................40
4.3.3.2 Pawnee National Grasslands................................................40
4.3.3.3 Saline Seep Region............................................................... 41
4.3.3.4 Texas High Plains................................................................. 42
4.4 Recovery from Fire ....................................................................................... 45
Contents vii
4.5 Cost Comparison...........................................................................................46
4.6 Advantages and Disadvantages.....................................................................46
4.6.1 Advantages.........................................................................................46
4.6.2 Disadvantages.................................................................................... 47
4.7 Concept Use .................................................................................................. 47
References................................................................................................................48
Chapter 5 Basic Technology ............................................................................... 51
5.1 Soil ................................................................................................................ 51
5.1.1 Soil Physical Properties..................................................................... 51
5.1.1.1 Solids.................................................................................... 52
5.1.1.2 Liquid ................................................................................... 53
5.1.1.3 Air ........................................................................................54
5.1.2 Soil Water...........................................................................................54
5.1.2.1 Soil Water-Holding Capacity................................................ 55
5.1.2.2 Soil Water Pressure .............................................................. 55
5.1.3 Hydraulic Conductivity of Soil.......................................................... 58
5.1.4 Soil Water Movement......................................................................... 59
5.1.4.1 Water Movement to Plant Roots...........................................60
5.1.4.2 Preferential Flow.................................................................. 61
5.1.5 Soil Chemical Properties................................................................... 62
5.1.5.1 Soil pH.................................................................................. 62
5.1.5.2 Soil Nutrients........................................................................63
5.1.5.3 Cation Exchange Capacity ...................................................63
5.1.5.4 Soil Humus...........................................................................65
5.1.5.5 Harmful Soil Constituents....................................................66
5.1.6 Soil Properties and Root Growth.......................................................66
5.1.6.1 Soil Tilth and Other Factors.................................................66
5.1.6.2 Soil Strength and Density..................................................... 67
5.1.6.3 Soil Density .......................................................................... 67
5.1.7 Soil Modification ...............................................................................68
5.1.7.1 Natural Changes of Physical Properties...............................69
5.1.7.2 Chemical and Physical Modification....................................69
5.2 Plants.............................................................................................................70
5.2.1 Plant Selection....................................................................................70
5.2.2 Sod and Bunch Grasses...................................................................... 71
5.2.3 Trees and Shrubs................................................................................72
5.2.4 Selecting Native Plant Species...........................................................73
5.3 Plant Roots.................................................................................................... 74
5.3.1 Root Distribution within the Soil....................................................... 75
5.3.2 Root Growth Rate and Maximum Depth .......................................... 76
5.4 Other Technology.......................................................................................... 78
5.4.1 Soil Temperature................................................................................ 78
5.4.2 Salinity of the Soil Solution............................................................... 78
viii Evapotranspiration Covers for Landfills and Waste Sites
5.4.3 Soil Oxygen........................................................................................ 78
5.4.4 Air-Filled Porosity ............................................................................. 78
5.4.5 Chemical Toxicity..............................................................................79
5.4.6 Allelopathic Toxicants.......................................................................79
References................................................................................................................79
Chapter 6 Climate, Weather, and Water Balance ...............................................83
6.1 Climate and Weather.....................................................................................83
6.1.1 Climate...............................................................................................83
6.1.2 Weather..............................................................................................84
6.1.3 Precipitation Measurement ................................................................85
6.1.3.1 Accuracy of Precipitation Measurements ............................85
6.1.3.2 Standard Rainfall Measurement ..........................................86
6.2 Hydrologic Water Balance ............................................................................86
6.2.1 Actual and Potential Evapotranspiration ...........................................87
6.2.2 Surface Runoff...................................................................................88
6.2.3 Lateral Flow and Change in Soil Water Storage................................88
6.2.4 Deep Percolation................................................................................88
6.3 Measuring Hydrologic Water Balance ..........................................................89
References................................................................................................................90
Chapter 7 Potential Application..........................................................................93
7.1 Limited Percolation.......................................................................................93
7.1.1 Evapotranspiration .............................................................................93
7.1.2 Calculations .......................................................................................94
7.1.3 PET-to-Precipitation Ratio.................................................................95
7.1.4 Water Stress Days per Year................................................................96
7.2 Increased Percolation for Waste Stabilization ..............................................97
7.3 Appropriate Use ............................................................................................97
References................................................................................................................98
Chapter 8 ET Landfill Cover Design Steps.........................................................99
8.1 Site Characterization.....................................................................................99
8.2 Performance Criteria...................................................................................100
8.2.1 Cover Requirements......................................................................... 101
8.2.2 Allowable Leakage through Covers................................................. 102
8.2.3 A Leakage Criterion ........................................................................ 103
8.3 Cover Type .................................................................................................. 103
8.4 Preliminary Design..................................................................................... 104
8.4.1 Design Model................................................................................... 104
8.4.2 Cover Soil Properties....................................................................... 104
8.4.3 Plant Cover....................................................................................... 105
Contents ix
8.4.4 Preliminary Cover Thickness.......................................................... 105
8.4.4.1 Sensitivity Analysis and Calibration .................................. 105
8.4.4.2 Thickness Estimate ............................................................ 106
8.5 Site-Specific Design.................................................................................... 108
8.5.1 Weather............................................................................................ 108
8.5.2 Soils.................................................................................................. 108
8.5.3 Plants................................................................................................ 109
8.5.4 Integration and Interaction............................................................... 110
8.6 Final Design ................................................................................................ 110
8.6.1 Layered Soil Covers......................................................................... 110
References.............................................................................................................. 111
Chapter 9 Models for Design and Evaluation ................................................... 113
9.1 A Model Philosophy.................................................................................... 113
9.2 Requirements for ET Landfill Cover Models.............................................. 113
9.2.1 Water Balance .................................................................................. 114
9.2.2 Actual ET......................................................................................... 114
9.2.3 Models and Calibration.................................................................... 115
9.2.4 Design Model Requirements ........................................................... 115
9.3 Potential Model Accuracy........................................................................... 116
9.4 Modeling Soil Water Movement ................................................................. 117
9.4.1 Richards’ Equation .......................................................................... 117
9.4.2 Water Storage Routing..................................................................... 118
9.5 Previous Model Evaluations........................................................................ 118
9.6 Evaluation of Three Models........................................................................ 119
9.6.1 HELP Model.................................................................................... 119
9.6.2 EPIC Model......................................................................................120
9.6.3 HYDRUS-1D Model........................................................................120
9.6.4 Model Differences ........................................................................... 121
9.7 Model Test Data .......................................................................................... 122
9.7.1 Coshocton Data................................................................................ 122
9.7.2 Bushland Data.................................................................................. 122
9.8 Comparison of Three Models..................................................................... 123
9.8.1 Data Evaluation................................................................................ 123
9.8.2 ET Estimates....................................................................................124
9.8.3 Q Estimates......................................................................................124
9.8.4 PRK Estimates.................................................................................124
9.8.5 Monthly Estimates........................................................................... 127
9.9 Model Choice ..............................................................................................128
9.9.1 HELP Model....................................................................................128
9.9.2 HYDRUS-1D Model........................................................................128
9.9.3 EPIC Model...................................................................................... 129
9.9.4 Model Conclusion ............................................................................ 129
References.............................................................................................................. 129
x Evapotranspiration Covers for Landfills and Waste Sites
Chapter 10 Design Components ......................................................................... 133
10.1 Weather ....................................................................................................... 133
10.1.1 Precipitation.................................................................................. 133
10.1.2 Solar Radiation ............................................................................. 133
10.1.3 Length of Weather Record............................................................ 134
10.1.4 Weather Record Uncertainty ........................................................ 134
10.1.5 Future Weather ............................................................................. 135
10.2 Soil .............................................................................................................. 136
10.2.1 Natural Soils................................................................................. 136
10.2.2 Soil Descriptions........................................................................... 137
10.2.3 Soil Design Data ........................................................................... 137
10.2.3.1 Preliminary Soil Data................................................... 138
10.2.3.2 Final Soil Data.............................................................. 140
10.3 Plant Properties........................................................................................... 140
10.4 Interaction of Plants, Soil, and Climate ...................................................... 140
10.5 Critical Design Event .................................................................................. 141
10.6 Layered ET Cover Soils.............................................................................. 143
10.7 Soil Erosion................................................................................................. 144
10.7.1 Water Erosion ............................................................................... 146
10.7.2 Wind Erosion ................................................................................ 146
10.7.3 Erosion at Arid Sites..................................................................... 146
10.7.4 Soil Erosion Comparisons............................................................ 147
10.7.5 Erosion Control Structures........................................................... 148
10.8 Landfill Settlement...................................................................................... 149
10.9 Landfill Cover Slope ................................................................................... 151
10.10 Safety Factor for Minimum Percolation ..................................................... 151
10.10.1 Soil Thickness Basis..................................................................... 152
10.10.2 Hydrologic Basis........................................................................... 153
References.............................................................................................................. 153
Chapter 11 Construction ..................................................................................... 155
11.1 Soil .............................................................................................................. 155
11.1.1 Soil pH.......................................................................................... 155
11.1.2 Soil Humus Content...................................................................... 155
11.1.3 Harmful Constituents in Soil........................................................ 156
11.1.3.1 Soil Salt......................................................................... 156
11.1.3.2 Sodium.......................................................................... 157
11.1.4 Soil Physical Properties................................................................ 158
11.2 Soil Density and Strength ........................................................................... 158
11.2.1 Causes of Soil Compaction........................................................... 159
11.2.2 Soil Water Content........................................................................ 159
11.2.3 Field Estimate of Plastic Limit ..................................................... 159
11.2.4 Vehicle or Machine Weight .......................................................... 160
11.2.5 Wheels and Tracks........................................................................ 160
Contents xi
11.2.6 Measurement of Soil Density and the Cone Index ....................... 161
11.2.7 Field Operations and Remediation ............................................... 161
11.3 Soil Placement............................................................................................. 162
11.3.1 Machinery and Haul Roads.......................................................... 162
11.3.2 Remediation of Compaction ......................................................... 163
11.3.3 Test Covers.................................................................................... 163
11.4 Interim Soil Erosion Control....................................................................... 163
11.5 Grass Establishment.................................................................................... 165
11.5.1 Species.......................................................................................... 165
11.5.2 Fertilizer ....................................................................................... 165
11.5.3 Seeding Machines......................................................................... 165
11.5.4 Seeding Methods.......................................................................... 166
11.5.4.1 Hydroseeding................................................................ 166
11.5.4.2 Solid Sod Application and Sprigging ........................... 166
11.5.4.3 Broadcast Seeding ........................................................ 166
11.5.4.4 Drill Seeding in Bare Soil ............................................ 167
11.5.4.5 Drill Seeding Mulch Cover........................................... 167
11.6 Drill Seeding in Standing Crop Residue.......................................... 167
11.6.1 Benefits ........................................................................................ 167
11.6.2 Mulch Crop................................................................................... 167
11.7 Irrigation .................................................................................................... 168
11.8 New Grass Establishment Methods........................................................... 168
11.9 Construction Completion ........................................................................... 169
References........................................................................................................... 169
Chapter 12 Maintenance and Monitoring........................................................... 173
12.1 Deep Percolation Monitoring...................................................................... 173
12.2 Cover Integrity ............................................................................................ 174
12.3 Groundwater Monitoring ............................................................................ 174
12.4 Vegetation Management.............................................................................. 174
12.5 Burning ....................................................................................................... 175
12.6 Grazing........................................................................................................ 175
12.7 Weed Control .............................................................................................. 175
12.8 Soil Fertility and Chemistry ....................................................................... 176
12.9 Soil Density Control.................................................................................... 176
References........................................................................................................... 177
Chapter 13 Miscellany and Summary ................................................................ 179
13.1 Design and Prescriptive Rules .................................................................... 179
13.2 Allowable Leakage...................................................................................... 179
13.3 Technical Resources.................................................................................... 180
13.4 Research Needs........................................................................................... 180
13.5 Summary..................................................................................................... 181
Appendices........................................................................................................... 183
Index..................................................................................................................... 191
xii Evapotranspiration Covers for Landfills and Waste Sites
0 تعليقات
شكرا لتعليقك .. سيتم الرد عليكم في اقرب وقت ممكن .
كوكب المنى