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Chapter 14 Water Management (Drainage) Title 210 – National Engineering Handbook Part 650 Engineering Field Handbook National Engineering Handbook Chapter 14 Water Management (Drainage) (210-650-H, 2nd Ed., Feb 2021) Title 210 – National Engineering Handbook Issued February 2021 In accordance with Federal civil rights law and U.S. Department of Agriculture (USDA) civil rights regulations and policies, the USDA, its Agencies, offices, and employees, and institutions participating in or administering USDA programs are prohibited from discriminating based on race, color, national origin, religion, sex, gender identity (including gender expression), sexual orientation, disability, age, marital status, family/parental status, income derived from a public assistance program, political beliefs, or reprisal or retaliation for prior civil rights activity, in any program or activity conducted or funded by USDA (not all bases apply to all programs). 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Submit your completed form or letter to USDA by: (1) mail: U.S. Department of Agriculture, Office of the Assistant Secretary for Civil Rights, 1400 Independence Avenue, SW, Washington, D.C. 20250-9410; (2) fax: (202) 690-7442; or (3) email: [email protected]. USDA is an equal opportunity provider, employer, and lender. (210-650-H, 2nd Ed., Feb 2021) 650-14.i Title 210 – National Engineering Handbook Chapter 14 Water Management (Drainage) Table of Contents 650.1400 Introduction .............................................................................................................. 14.1 650.1401 Types of Drainage Systems ...................................................................................... 14.8 650.1402 Investigations and Planning ...................................................................................... 14.9 650.1403 Surface Drainage .................................................................................................... 14.17 650.1404 Investigation and Planning of Surface Drainage Systems ....................................... 14.19 650.1405 Design of Open Drains ........................................................................................... 14.25 650.1406 Construction ........................................................................................................... 14.42 650.1407 Maintenance ........................................................................................................... 14.44 650.1408 Subsurface Drainage ............................................................................................... 14.47 650.1409 Applications of Subsurface Drainage...................................................................... 14.51 650.1410 Investigations and Planning .................................................................................... 14.55 650.1411 Field Drainage System Design ................................................................................ 14.58 650.1412 Drain Envelopes ..................................................................................................... 14.78 650.1413 Materials ................................................................................................................. 14.86 650.1414 Appurtenances ........................................................................................................ 14.90 650.1415 Drain Installation .................................................................................................... 14.94 650.1416 Maintenance ......................................................................................................... 14.101 650.1417 Interception Drainage Design ............................................................................... 14.103 650.1418 Water Table Management ..................................................................................... 14.110 650.1419 Controlled Drainage ............................................................................................. 14.112 650.1420 Subirrigation ......................................................................................................... 14.114 650.1421 Drainage Pumping ................................................................................................ 14.120 650.1422 Definitions of Terms ............................................................................................. 14.125 650.1423 References ............................................................................................................ 14.143 650.1424 Acknowledgement ................................................................................................ 14.146 Appendix 14A Ditch Design Tables ...................................................................................... 14A.1 Appendix 14B Tables for Computing Culvert Discharge ...................................................... 14B.1 Appendix 14C Salinity Monitoring Equipment ..................................................................... 14C.1 Appendix 14D Auger-hole Procedure for Hydraulic Conductivity ........................................ 14D.1 Appendix 14E Transient Flow Method.................................................................................. 14E.1 Appendix 14F Drainage Around Home Sites ......................................................................... 14F.1 (210-650-H, 2nd Ed., Feb 2021) 650-14.ii Title 210 – National Engineering Handbook Table of Figures Figure 14-1: Cropland in Need of Drainage Maintenance ....................................................... 14.1 Figure 14-2: Field Drainage System in Need of Maintenance ................................................. 14.2 Figure 14-3: Extent of Subsurface Drainage for a Field as Shown by Infrared Photo and Interpretive Sketch ............................................................................................................ 14.12 Figure 14-4: Drainage Curves ............................................................................................... 14.18 Figure 14-5: Area Application of Drainage Curves ............................................................... 14.18 Figure 14-6: Random Drains ................................................................................................. 14.21 Figure 14-7: Parallel Surface Drains ...................................................................................... 1421 Figure 14-8: Reconstructing Cross Slope Drain System ........................................................ 14.22 Figure 14-9: Surface Drainage Bedding ................................................................................ 14.23 Figure 14-10: Earthmoving Scraper with Laser Grade Control ............................................. 14.24 Figure 14-11: Landplane ....................................................................................................... 14.25 Figure 14-12: Example Computation of Design Flows ......................................................... 14.27 Figure 14-13: Establishing Hydraulic Gradeline ................................................................... 14.28 Figure 14-14: Steepest Side Slopes Recommended for Ordinary Conditions for Mains or Laterals ............................................................................................................................. 14.30 Figure 14-15: Ditch Side Slopes Recommended for Maintenance ........................................ 14.31 Figure 14-16: Permissible Bare Earth Velocities ................................................................... 14.31 Figure 14-17: Value of Manning's n for Drainage Ditch Design ........................................... 14.32 Figure 14-18: Recommended Minimum Berm Widths.......................................................... 14.33 Figure 14-19: Surface Water Inlets ........................................................................................ 14.35 Figure 14-20: Watergate ........................................................................................................ 14.36 Figure 14-21: Watershed Sketch ............................................................................................ 14.38 Figure 14-22: Profile Ditch with Hydraulic Gradient ............................................................ 14.39 Figure 14-23: Open Drain Design Worksheet ....................................................................... 14.40 Figure 14-24: Design Profile ................................................................................................. 14.41 Figure 14-25: Main Drain with Spoil Banks Spread .............................................................. 14.43 Figure 14-26: Seeding Newly Constructed Drain .................................................................
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