CITY OF SPRINGDALE, ARKANSAS CHAPTER 106 DRAINAGE CRITERIA MANUAL Revised December 2017 APPROVED: JANUARY 23, 2018 1 Contents SECTION I - SUBMITTAL PROCEDURES ............................................................... 8 1.1 GENERAL ................................................................................................................................................ 8 1.1.1 PRE-PRELIMINARY GRADING PLAN & SWPPP .............................................................. 8 1.1.2 PRELIMINARY GRADING PLAN & SWPPP ....................................................................... 8 1.1.3 FINAL GRADING PLAN & SWPPP ..................................................................................... 8 1.2 DRAINAGE REPORT ................................................................................................................................ 8 1.2.1 - DRAINAGE REPORT CHECKLIST ............................................................................... 10 1.3 PLANS AND SPECIFICATIONS ................................................................................................................ 13 1.3.1 TITLE SHEET ................................................................................................................... 13 1.3.2 GENERAL LAYOUT SHEET ............................................................................................ 14 1.3.3 OTHER REQUIREMENTS .............................................................................................. 14 1.4 GLOSSARY ............................................................................................................................................ 15 SECTION II - DETERMINATION OF STORM RUNOFF .......................................... 26 2.1 GENERAL .............................................................................................................................................. 26 2.2 CITY OF SPRINGDALE DRAINAGE METHODS ........................................................................................ 26 2.3 RATIONAL METHOD .............................................................................................................................. 27 2.3.1 RUNOFF COEFFICIENT ("C") ......................................................................................... 27 2.3.2 SOIL ................................................................................................................................. 28 2.3.3 SELECTION OF RUNOFF COEFFICIENTS ................................................................... 28 2.3.4 RAINFALL INTENSITY ("I") .............................................................................................. 28 2.3.5 DRAINAGE AREA (A) ....................................................................................................... 28 2.3.6 TIME OF CONCENTRATION (tc) .................................................................................... 28 2.3.7 CHANNEL FLOW ............................................................................................................. 32 2.3.8 APPLICATION OF THE RATIONAL METHOD ................................................................. 32 2.3.9 MAJOR STORM ANALYSIS ............................................................................................ 32 2.4 SOIL CONSERVATION SERVICE METHOD, TABULAR TR-55 ................................................................... 33 2.4.1 GENERAL ........................................................................................................................ 33 2.4.2 METHOD FUNDAMENTALS ........................................................................................... 33 2.4.3 LIMITATIONS ON TABULAR METHOD USE ................................................................... 34 2.4.4 TABULAR METHOD USE ................................................................................................ 34 2.5 HEC-1 COMPUTER MODEL ................................................................................................................... 35 2.5.1 GENERAL ........................................................................................................................ 35 2.5.2 STREAM NETWORK MODEL.......................................................................................... 35 2.5.3 SUBWATERSHED HYDROGRAPH MODEL COMPONENT .......................................... 36 2.5.4 RIVER ROUTING MODEL COMPONENT ...................................................................... 36 2.5.5 RESERVOIR ROUTING MODEL COMPONENT ............................................................ 37 2.5.6 ROUTING AND COMBINING HYDROGRAPHS ............................................................. 37 2 2.5.7 DESIGN STORM PRECIPITATION ................................................................................. 37 2.5.8 INTERCEPTION/INFILTRATION ..................................................................................... 37 2.6 STORMWATER RUNOFF ANALYSIS SOFTWARE ..................................................................................... 38 2.6.1 QUICK TR-55 ................................................................................................................... 38 2.6.2 HEC-1 .............................................................................................................................. 38 SECTION III - FLOW IN STORM DRAINS AND DRAINAGE .................................. 39 3.1 GENERAL .............................................................................................................................................. 39 3.2 STORM SEWER DESIGN REQUIREMENTS ............................................................................................. 39 3.2.1 MINOR AND MAJOR DRAINAGE SYSTEMS ................................................................. 39 3.2.2 DRAINAGE CHANNELS .................................................................................................. 40 3.3 REQUIREMENTS RELATIVE TO IMPROVEMENTS.................................................................................. 41 3.3.1 BRIDGES AND CULVERTS ............................................................................................ 41 3.3.2 CLOSED STORM SEWER .............................................................................................. 42 3.3.3 MINIMUM GRADES ......................................................................................................... 42 3.3.4 VEGETATED CHANNELS (a.k.a., OPEN DITCHES) ...................................................... 42 3.3.5 OPEN PAVED CHANNELS ............................................................................................. 43 3.4 FULL OR PART-FULL FLOW IN STORM DRAINS ..................................................................................... 43 3.4.1 GENERAL ........................................................................................................................ 43 3.4.2 ROUGHNESS COEFFICIENTS ...................................................................................... 44 3.4.3 MINOR HEAD LOSSES AT STRUCTURES .................................................................... 44 3.4.4 MANHOLE LOCATIONS.................................................................................................. 46 3.4.5 PIPE FLOW CHARTS ...................................................................................................... 46 3.5 UTILITIES .............................................................................................................................................. 47 SECTION IV - CULVERT HYDRAULICS ................................................................ 49 4.1 GENERAL .............................................................................................................................................. 49 4.2 INLET CONTROL .................................................................................................................................... 49 4.3 OUTLET CONTROL ................................................................................................................................ 49 4.4 HEADWALLS AND ENDWALLS .............................................................................................................. 50 4.4.1 GENERAL ........................................................................................................................ 50 4.4.2 CONDITIONS AT ENTRANCE ........................................................................................ 50 4.4.2 SELECTION OF HEADWALL OR ENDWALL ................................................................. 50 4.5 CULVERT DISCHARGE VELOCITIES ........................................................................................................ 51 4.5.1 ENERGY DISSIPATERS ................................................................................................. 51 4.6 CULVERT TYPES AND SIZES ................................................................................................................... 53 4.7 FILL HEIGHTS AND BEDDING ................................................................................................................ 54 4.8 TYPES OF CULVERT FLOW .................................................................................................................... 54 4.9 CULVERT DESIGN PROCEDURE ............................................................................................................. 54 4.10 CULVERT ANALYSIS