SurvCADD Hydrology Module

SurvCADD Hydrology Module

Overview The Hydrology Module consists of several routines that work together in sequence. This manual only explains the operation of the commands and not hydrology concepts. For example, you will need to know the storm type and soil type for your area. Some routines are based on the TR-55 programs and the TR-55 manual, Urban Hydrology for Small Watersheds, may be useful. The Hydrology Module also links to TR-20, SEDCAD and HEC-2. The SEDCAD links are with capacity files for pond design and by drawing SEDCAD hydrographs. SEDCAD, by Civil Software Design, has become a standard in the mining industry for the computation of flows and sedimentation. HEC- 2 is a computer program prepared by the Corps of Engineers to compute water surface profiles in stream and river channels. D.T.M. Commands The pull-down menu for the Digital Terrain Model commands of the Hydrology module is shown below. Most of these commands are also in the DTM-Contour module. Only the Slope At Points command is unique to this menu. The other commands are described in the DTM section of the DTM-Contour module manual. These DTM commands are included here because the surface models defined by grid files (.grd) are used by hydrology commands such as watershed modeling. Slope At Points This command labels the slope percent at user picked points or at the grid interval. The slope is computed from the surface model defined by a grid file which is created by the Make 3D Grid File routine. As the crosshairs are moved across the grid, the slope at the current position is displayed in the bottom of the screen menu. In addition to labeling the slope value at the user specified points, an arrow is drawn in the uphill direction. The point of the arrow is drawn at the location of the calculated slope. The number of decimal places used to label the slope value is set by the decimal places in the AutoCad UNITS command. The SurvCADD d0,d1,d2, and d3 keyboard marcos can also be used to set the AutoCad decimal places. Page 7-2 Hydrology Module - DTM Commands

Prompts Enter the slope label layer <SLOPE>: Press Enter. The text output of this command will be drawn in this layer. Enter the slope label text size <4.0>: Press Enter. This is the size for the output text. The default is the horizontal scale multiplied by the text size scaler from Drawing Setup. Slope label format (Ratio/Degree/<Percent>): Press Enter Grid File Selection dialog box Choose the grid file that models the surface. Reading Row 51> Extrapolate grid to full grid size (Yes/<No>)? Yes. If the limits of the surface data doesn't cover the entire grid area, then the values for the grid cells beyond the data limit must be extrapolated in order to compute slopes in that area. This prompt only appears if there are grid cells without values. Calculate slopes at pick points or grid interval (<Pick>/Grid)? Press Enter Enter or pick point (Enter to End): pick a point. As the crosshairs are moved, the slope at the current position is displayed at the bottom of the screen menu. Enter or pick point (Enter to End): Press Enter to exit the routine Hydrology Module - DTM Commands Page 7-3

Pull-Down Menu Location: DTM in the Hydrology module Prerequisite: Use Make 3D Grid File to create a grid file that models the surface. Keyboard Command: ptslope File Names: \lsp\cntr_grd.arx Draw grid file and Slope At Point labels using grid interval on same area as first example. Page 7-4 Hydrology Module - DTM Commands

Universal Soil Loss This command calculates the volume of sediment that can be expected from a watershed by soil erosion due to precipitation. It allows the user to specify multiple watershed areas, each with its own set of geometric and hydrological parameters. The Universal Soil Loss Equation (USLE) is used in calculating the soil loss. For each area, the area, slope and length can be manually entered by the user or it can be calculated by the program directly. For direct calculation of the geometric properties of the area, the user must have a grid file that models the surface. This can be created using the Make 3D Grid File command. In addition, the area must be defined by closed polylines for inclusion perimeter. Exclusion perimeters are optional for excluding areas from calculations. The program starts with the dialog below, where the user can add as many areas as needed to include in the USL calculation. Each area added is shown in the listbox with all its parameters listed. To add a new area, click the "Add" button. To edit the parameters of an existing area, highlight that item and click the "Edit" button. To remove an existing area, highlight it and click "Remove". Hydrology Module - DTM Commands Page 7-5

The "Edit" or "Add" button brings up the dialog box shown here, where the various parameters of the area can be specified or edited. The "Landuse" is just an identifier for the area and has no further significance. Soil Erodability, K (tons/ acre) is a property of the soil, which determines the amount of sediment resulting from a precipitation event in an area. The rainfall factor, R, is a dimensionless factor that accounts for the relationship between erosive forces of falling rain and runoff. The Cover factor, C, is a dimensionless factor that relates the effectiveness of vegetal cover in reducing erosion. The Topographical factor, Ls, is a dimensionless length slope factor that accounts for variations in length and slope in the area. The (Conservation) Practice factor, P, is a dimensionless factor to determine how landuse effects its erodability. If the area of the watershed is known and is entered manually, then the length and slope of the area have to be entered manually as well and the Ls factor will be calculated from these geometric properties. The area can also be calculated directly if the boundary is defined as a closed polyline and the grid file that models the surface is also made. The user clicks the button "Select area" and the program asks the user to select the grid file as well as the closed polyline representing the area. Then, the Ls factor and the slope are calculated by the program and displayed (the "length" is not needed in this case). After filling in all values, click on "Calculate USL" to calculate the soil loss rate per unit area for the area selected. The user can change the parameters corresponding to this are and recalculate, if needed. Click "OK" to return to the main dialog box. The area should now appear in this dialog box if the parameters as specified. After all required areas are input, the sediment volume can be calculated by clicking the "Calculate" button on the main dialog. This brings up the USLE Calculation dialog box as shown here. Specify the Delivery ratio, which determines what portion of the gross erosion is actually Page 7-6 Hydrology Module - DTM Commands

left for deposition at the final destination, accounting for losses during sediment transport. Also, specify the Time period for which deposition has occurred. Specify the Density of the sediment, so as to be able to determine the volume of the deposit from its mass in tons. Also, specify the amount of Rainfall (inches or cm) for which runoff volume has to be calculated. The program then calculates the Runoff volume based on the total area and the amount of rainfall. It also calculates the sediment volume, using the Universal Soil Loss Equation (USLE) and adds it to the sediment volume and reports it as the total pond volume. A report of the form shown below is generated. This report also gives a detailed account of the calculations performed. For further information about the estimation of the various parameters used in this program or about the USLE, please refer to "Applied Hydrology and Sedimentology for Disturbed Areas" (1981), Barfield, B.J., Warner, R.C. and Haan, C.T., Oklahoma Technical Press. Pull-Down Menu Location: DTM in the Hydrology module Prerequisite: Use Make 3D Grid File to create a grid file that models the surface. Keyboard Command: soilloss File Names: \lsp\cntr_grd.arx, \lsp\peakflow.dcl, \lsp\soilloss.lsp Hydrology Module - DTM Commands Page 7-7

Watershed Commands The Watershed pull-down menu is shown below. These commands are arranged in the order that they would be applied. The first command calculates the watershed boundary. Using the watershed area and land use types, the curve number can be calculated which leads to time of concentration and hydrographs. Then the peak flow can be calculated. Page 7-8 Hydrology Module - Watershed Commands

Watershed Above Point This command creates a closed 3D watershed polyline of the area that drains through user specified points and reports the horizontal and slope areas, average slope, and longest flow path values. This watershed is calculated from the surface that is modeled by a grid file or triangulation file. Watershed 2 Report Processing GRiD file: D:/SC12/DATA/SIMO.GRD Lower left grid corner : 186384.62,57529.63 Upper right grid corner: 186885.68,58014.67 X grid resolution: 65, Y grid resolution: 60 X grid cell size: 7.71, Y grid cell size: 8.08 Horizontal Area is 9868.302 sq ft, 0.227 acres Slope Area is 10934.185 sq ft, 0.251 acres Average Slope is 25.548% Longest horizontal dist: 180.84, Longest slope dist: 180.84 Vertical drop: 30.23, Avg slope: 20.39%, Max slope: 57.13% The grid file can be created by the Make 3D Grid File command and the triangulation file can be created with the Write Triangulation File option in Triangulate & Contour in the DTM & Contour module. A triangulation surface model has the advantage of finding sharp break lines that a grid might skip over such as narrow ditches. For regular surfaces such as a surface defined by existing contour polylines, the grid surface model should be used because it is much faster. Also when using a grid surface model it is sometimes better to decrease the grid resolution (have fewer grid cells) because this helps avoid local minimums. The program prompts for points on the left and right side of the downstream flow line. The watershed polyline will include the area of runoff lines that pass between these two points. The left and right sides is relative to facing up the slope. To generate a watershed that excludes a smaller watershed within it, create both watersheds and then use the 2D Polyline with Follow command. Prompts Enter the watershed boundary layer <WATERSHED>: Press Enter Grid File Selection dialog box Choose the grid file that models the surface. Reading Row 51> Extrapolate grid to full grid size (Yes/<No>)? Yes. If the limits of the surface data doesn't cover the entire grid area, then the values for the grid cells beyond the data limit must be extrapolated in order to compute slopes in that area. This prompt only appears if there are grid cells without values. Pick bottom LEFT bank of watershed: pick a point on the left bank. Left is relative to facing uphill. Pick bottom RIGHT bank of watershed: pick a point on the right bank. Right is relative Hydrology Module - Watershed Commands Page 7-9

to facing uphill. Tolerance range at through point <10.0>: Press Enter. This is the distance to offset from the picked point. Pick bottom LEFT bank of watershed: Press Enter to end. Pull-Down Menu Location: Watershed Prerequisite: A.grd file created by Make 3D Grid File Keyboard Command: watershed File Names: \lsp\cntr_grd.arx Multiple Watershed Polylines This command finds all the sub-watersheds on a surface modeled by triangulation (.flt) or grid (.grd) file. The watershed boundaries are drawn as closed polylines with the option to solid fill these areas. The program also generates a report with the watershed average slope and horizontal and slope areas. The surface is modeled by a triangulation file (.flt file) created by Triangulate & Contour. The program draws watersheds for all the sinks. Sinks are where an area flows off the edge of the surface or a local minimum on the surface. The options for this routine are set in the dialog shown below. Rainfall Level is for avoiding local minimums or puddles. If the depth of the puddle is less than the Rainfall Level, then the watershed will enclose this area. Otherwise this local minimum becomes a sink and the area that flows into it becomes a watershed boundary. Pull-Down Menu Location: Watershed Prerequisite: An.flt triangulation file Keyboard Command: waterdeli File Names: \lsp\cntr_grd.arx Watershed Report Processing TIN file: C:\scdev\data\simo2.flt Sink #1 location X: 2476.46, Y: 8903.36, Z: 161.70 Horizontal Area is 73903.893 sq ft, 1.697 acres Slope Area is 76237.321 sq ft, 1.750 acres Average Slope is 19.762% ---------------------------------- Sink #2 location X: 1419.61, Y: 9525.77, Z: 124.02 Horizontal Area is 4000.481 sq ft, 0.092 acres Slope Area is 4006.388 sq ft, 0.092 acres Average Slope is 5.195% ---------------------------------- Sink #3 location X: 2658.64, Y: 9048.32, Z: 79.46 Horizontal Area is 5959.110 sq ft, 0.137 acres Slope Area is 6321.574 sq ft, 0.145 acres Average Slope is 29.898% ---------------------------------- Sink #4 location X: 1717.49, Y: 1548.70, Z: 86.92 Horizontal Area is 953900.644 sq ft, 21.899 acres Slope Area is 980891.891 sq ft, 22.518 acres Average Slope is 20.466% ---------------------------------- Sink #5 location X: 2618.02, Y: 1229.49, Z: 70.26 Horizontal Area is 482639.991 sq ft, 11.080 acres Slope Area is 509441.311 sq ft, 11.695 acres Average Slope is 28.836% Page 7-10 Hydrology Module - Watershed Commands

Surface contours Solid filled watershed areas Hydrology Module - Watershed Commands Page 7-11

Run Off Tracking This command draws 3D polylines starting at user picked points downhill until they reach a local minimum or the end of the grid. In effect it simulates the path of a rain drop. The surface is modeled by a grid file as created by Make 3D Grid File or a triangulation file created by Triangulate & Contour. The program also reports the horizontal and slope distances, average slope, maximum slope, and vertical drop. These values can be used for time of concentration calculations. Prompts Enter the run off path layer <RUNOFF>: Press Enter Grid File Selection dialog box Choose the grid file that models the surface. Reading Row 51> Extrapolate grid to full grid size (Yes/<No>)? Yes. If the limits of the surface data doesn't cover the entire grid area, then the values for the grid cells beyond the data limit must be extrapolated in order to compute slopes in that area. This prompt only appears if there are grid cells without values. Pick origin of rain drop: pick a point at the top of the run off polyline Pick origin of rain drop (Enter to end): Press Enter Pull-Down Menu Location: Watershed Prerequisite: A.grd file created by Make 3D Grid File Keyboard Command: runoff File Names: \lsp\cntr_grd.arx Page 7-12 Hydrology Module - Watershed Commands

3D Polyline Flow Values This command simply reports the horizontal and slope distances, vertical drop, maximum slope, and average slope of 3D polylines. The 3D polylines may be created by the Watershed Above Point or Run Off Tracking commands. The reported values could be applied to the Time of Concentration routine. Prompts Select 3D polyline flow line: pick a 3D polyline Horiz dist: 217.96, Slope dist: 219.08, Vertical drop: 19.22 Average slope: 8.82%, Maximum slope: 17.68% Select 3D polyline flow line or Enter to end: Press Enter Pull-Down Menu Location: Watershed Prerequisite: 3D polyline Keyboard Command: flowvals File Names: \lsp\cntr_grd.arx Rainfall Frequency and Amount This command allows you to view rainfall maps while entering the rainfall amount to be used by other hydrology commands. First choose a storm and duration from the list. Then choose your location from the state list or pick your location on the map. You can enter the rainfall amount in the box in the lower left or pick your location on the map. Reference maps are provided for all fifty states for the different storm intervals. You can also setup user-defined lookup tables for up to five areas. For each area, you can specify a name and rainfall amounts for each storm interval. The first time the you select a user-defined storm interval, the rainfall amount will be blank. Enter in the rainfall amount and the next time that interval is selected, your entered value will be there. The user-defined values are stored in a file called rainmap.ini in the SurvCADD USER directory. Hydrology Module - Watershed Commands Page 7-13

Pull-Down Menu Location: Watershed Prerequisite: none Keyboard Command: rainmap File Names: \lsp\rainmap.lsp & \sup\slides\*.sld Sub-Watersheds By Land Use This command divides land-use polylines into closed polylines within a watershed polyline. The closed land-use polylines inside the watershed can then be used to determine the area of each land-use for the watershed. The Curve Numbers & Runoff command has an option to select closed polylines for determining the weighted average curve number from the polyline areas. Prompts Select closed polyline of watershed: pick the polyline Select land-use closed polylines. Select objects: pick the polylines Pull-Down Menu Location: Watershed Prerequisite: Closed polylines for the watershed and land-use areas. Keyboard Command: landarea File Names: \lsp\mineutil.arx Page 7-14 Hydrology Module - Watershed Commands

Curve Numbers & Runoff This command calculates the either the weighted curve number or C-factor and the runoff. The curve number is used by routines based on the TR-55 program. The C-factor is used by the rational method for Peak Flow calculation. The weighted curve number is a weighted average of the curve numbers for each subarea of the watershed. The weights are based on the areas. The calculated C-factor is also weighted by area. This routine has spaces for both curve numbers and C-factors but you only need to fill in one type. The Description and Soil Type fields are used in the report. To select the subareas from AutoCad, click on the Select Areas from Screen button. Then select all the subarea closed polylines. These polylines can be generated by the Sub-Watershed by Land Use command. After selecting the areas, the program cycles through each area by highlighting the polyline and prompting for the curve number. Either enter the curve number or type T to select a curve number from the table. The areas and curve numbers selected in this procedure overwrite any previous entries. When all the land-use curve numbers and areas are entered, click on the Calc CN button to calculate the weighted curve number. This curve number can then be used in the Time of Concentration and Peak Flow commands. To calculate the runoff given the weighted curve number, enter the rainfall for the storm in question and then click on the Calc Runoff button. The Runoff Volume equals the Runoff Q times the total area. Runoff Curve Number and Runoff Project: Park By: TW Date: 01/30/99 Location: Checked: Date: Present 1. Runoff curve number (Cn) Cover description CN Soil Type Area Open Space 79 A 28.816 Acres Sandy 86 B 31.231 Acres Woods, good 70 A 15.476 Acres CN (weighted): 80 2. Runoff Frequency... : 100 yr Rainfall, P (24-hour).. : 4.80 in Runoff, Q... : 2.72 in Runoff Volume... : 17.14 Acre-Ft Hydrology Module - Watershed Commands Page 7-15

Pull-Down Menu Location: Watershed Prerequisite: None. Keyboard Command: curveno File Names: \lsp\cntr_grd.arx & \lsp\hydro.dcl Table to select CN from. Page 7-16 Hydrology Module - Watershed Commands

Time of Concentration This command calculates the time of concentration (Tc) by either the TR-55 method, Rational method or the SCS method from A Method of Estimating Volume and Rate of Runoff in Small Watersheds. The Tc value is used in the Hydrograph and Peak Flow commands. Time of concentration is the time required for water to flow from the most distant point in the watershed to the measurement point. Rational method dialog The rational method calculates based on the curve factor, length of flow and average slope. These values are set in the dialog shown. The formula is: Tc = (1.8 * (1.1 - cf) * sqrt(length)) / (slope ^ 0.33) The SCS method calculates based on the curve number, length of flow, and average slope. The curve number defaults to the weighted curve number from the Curve Numbers & Runoff routine. When the three inputs are entered, click on Calculate to compute the Tc. Choose Select Flow Line from Screen to use a 3D polyline in the drawing. This sets the length of Dialog for Tc by SCS method flow and average land slope. A 3D polyline that models the flow can be created with the Watershed Above Point or Run Off Tracking commands. While reading in the 3D polyline, the Tc is calculated by adding the Tc's for each segment of the polyline. This yields a different and more accurate Tc than using the average slope with the Calculate button. The TR-55 method divides the type of flow into sheet, shallow concentrated and channel flow. The time of concentration is the sum of the times for the three types. The manning's n for the sheet and channel flow can be chosen from a table by clicking the Select from Table button. Pull-Down Menu Location: Watershed Prerequisite: None. Keyboard Command: flowtc File Names: \lsp\cntr_grd.arx & \lsp\hydro.dcl Hydrology Module - Watershed Commands Page 7-17

Dialog for Tc by TR-55 method Page 7-18 Hydrology Module - Watershed Commands

Time of Concentration (Tc) or Travel Time (Tt) Project: Parking By: TW Date: Location: West Checked: Date: Developed Tc through subarea 1 Sheet flow (Applicable to Tc only) Segment ID: AB 1. Surface description... : Dense Grass 2. Manning s roughness coeff. (n)... : 0.240 3. Flow length, L (total L < 300 ft)... : 100.0 ft 4. Two-yr 24-hr rainfall, P... : 3.60 in 5. Land slope, s... : 0.010ft/ft 6. Tt... : 0.296 hr Shallow concentrated flow Segment ID: BC 7. Surface unpaved 8. Flow length, L... : 1400.0 ft 9. Watercourse slope, s... : 0.010ft/ft 10. Average velocity, V... : 1.60 ft/s 11. Tt... : 0.243 hr Channel flow Segment ID: CD 12. Cross sectional flow area, a... : 27.00 ft^2 13. Wetted perimeter, Pw... : 28.20 ft 14. Hydraulic radius, r... : 0.96 ft 15. Channel slope, s... : 0.005ft/ft 16. Manning s roughness coeff. (n)... : 0.050 17. Velocity, V... : 2.05 ft/s 18. Flow length, L... : 7300.00 ft 19. Tt... : 0.991 hr 20. Watershed or subarea Tc or Tt... : 1.530 hr Tc by TR-55 method report Hydrology Module - Watershed Commands Page 7-19

Peak Flow - Graphical Method This command calculates peak flow using the graphical method from the TR-55 program. The program is run through the dialog shown below. The inputs in the top section default to the values from the Curve Numbers & Runoff and Time of Concentration routines. When all the inputs are entered, click on the Calculate button to obtain the peak flow at the bottom line. The peak flow value can then be used for Detention Pond Sizing or Channel Design. Pull-Down Menu Location: Watershed Prerequisite: None. Keyboard Command: peakflow File Names: \lsp\peakflow.lsp, \lsp\peakflow.dcl, \lsp\cntr_grd.arx Graphical Peak Discharge Project: Parking Date: 11/13/95 Location: West Date: Developed By: TW Checked: 1. Data: Drainage area:...a = 27.1500 Acres Runoff Curve Number:...CN = 70 Time of Concentration:...Tc = 0.75 2. Frequency...yr = 100 3. Rainfall,P(24-hour)...in = 6.00 4. Initial abstraction, Ia... = 0.8571 5. Compute Ia/P... = 0.1429 6. Unit peak discharge, qu...csm/in = 410.22 7. Runoff,Q...in = 2.8052 8. Pond & swap adjustment factor,...fp = 1.00 9. Peak Discharge,qp...cfs = 48.8172 Page 7-20 Hydrology Module - Watershed Commands

Peak Flow - Tabular Hydrograph Method This command calculates peak flow using the tabular hydrograph method from the TR-55 program. The program is run through the dialog shown below. The Curve Numbers & Runoff and Time of Concentration routines can be used to calculate the subarea input values. When all the inputs are entered, click on the Calculate button. The input values can be saved to a file by clicking the Save button. Then the Load button can be used later to recall these entered values. The peak flow report lists the flow for each subarea at different time. The peak flow value is listed at the end of the report. This value can then be used for Detention Pond Sizing or Channel Design. See the TR-55 manual for more details on this routine. One difference between SurvCadd and the TR-55 example is that SurvCadd interpolates the flow for the subarea Ia/P between the two nearest table Ia/P values whereas TR-55 uses the one closest Ia/P table entry. Consider a subarea with an Ia/P value of 0.14 and table entries of 100 cfs at 0.1 Ia/P and 75 cfs at 0.3 Ia/P. TR-55 would use 100 cfs from the nearest 0.1 Ia./P entry. SurvCadd would interpolate between 100 and 75 cfs resulting in 95 cfs. Pull-Down Menu Location: Watershed Prerequisite: None. Keyboard Command: peakflow File Names: \lsp\peakflow.lsp, \lsp\peakflow.dcl, \lsp\cntr_grd.arx Hydrology Module - Watershed Commands Page 7-21

Peak Flow Tabular Hydrograph Method Subarea Drainage Time of Travel Downstream Travel Rainfall Curve Runoff name area concen- time for subarea time number (sq.mi.) tration subarea names summation 1 0.3000 1.50 0.00 3,5,7 2.50 6.00 65 2.35 2 0.2000 1.25 0.00 3,5,7 2.50 6.00 70 2.81 3 0.1000 0.50 0.50 5,7 2.00 6.00 75 3.28 4 0.2500 0.75 0.00 5,7 2.00 6.00 70 2.81 5 0.2000 1.50 1.25 7 0.75 6.00 75 3.28 6 0.4000 1.50 0.00 7 0.75 6.00 70 2.81 7 0.2000 1.25 0.75 0.00 6.00 75 3.28 Time 11.0 11.3 11.6 11.9 12.0 12.1 12.2 12.3 Subarea Discharge (cfs) 1 0 0 1 1 1 1 1 2 2 0 1 1 1 2 2 2 2 3 1 1 2 2 2 2 3 3 4 2 2 3 3 4 4 4 5 5 3 4 5 7 7 8 9 10 6 4 6 7 10 11 11 12 14 7 6 8 11 15 18 24 34 51 Total 17 23 30 40 45 53 65 87 Time 12.4 12.4 12.6 12.7 12.8 13.0 13.2 13.4 Subarea Discharge (cfs) 1 2 2 2 2 3 3 3 4 2 2 2 3 3 3 4 4 5 3 3 3 4 4 5 6 7 11 4 5 6 6 7 7 9 11 16 5 11 13 16 20 26 48 80 115 6 16 19 23 29 39 74 127 186 7 75 104 137 165 184 202 173 139 Total 114 149 189 230 267 345 406 475 Time 13.6 13.8 14.0 14.3 14.6 15.0 15.5 16.0 Subarea Discharge (cfs) 1 5 6 8 17 38 85 134 130 2 6 8 13 27 56 101 122 92 3 20 39 65 96 91 59 29 17 4 28 54 96 161 185 147 82 48 5 143 156 152 126 97 67 44 32 6 234 257 253 213 166 116 78 57 7 107 85 69 52 41 31 25 21 Total 544 606 654 692 674 608 516 397 Page 7-22 Hydrology Module - Watershed Commands

Time 16.5 17.0 17.5 18.0 19.0 20.0 22.0 26.0 Subarea Discharge (cfs) 1 94 64 46 35 25 19 15 10 2 59 39 28 22 16 13 10 7 3 13 11 10 9 7 6 5 3 4 33 27 23 21 17 15 11 8 5 25 21 18 16 13 12 9 3 6 46 39 33 30 25 22 17 6 7 18 16 15 13 12 11 8 1 Total 289 217 173 146 115 99 74 39 Peak Discharge: 692 cfs Hydrology Module - Watershed Commands Page 7-23

Peak Flow - Rational Method (General) This command calculates peak flow using the rational method, Q=CIA. The program is run through the dialog shown below. Depending on your area, there are different methods for determining the Intensity of Rainfall which you will need to know for this routine. The weighted Runoff Coefficient or C-factor can be calculated by the Curve Number & Runoff routine. The peak flow value can then be used for Detention Pond Sizing or Channel Design. Pull-Down Menu Location: Watershed Prerequisite: None. Keyboard Command: peakflw3 File Names: \lsp\peakflw3.lsp, \lsp\hydro.dcl, \lsp\cntr_grd.arx Rational Peak Discharge Project: Parking By: TW Date: 11/13/95 Location: West Checked: Date: Developed 1. Data: Drainage area:...a = 27.1500 Acres Weighted Runoff Coefficient:...C = 0.400 Intensity of Rainfall:...I = 2.10 in/hr 2. Peak Discharge,...cfs = 22.8060 Peak Flow Rational Method Report Page 7-24 Hydrology Module - Watershed Commands

Peak Flow - Rational Method Kentucky This command calculates peak flow using the rational method, Q=CIA, with rainfall intensity coefficients specific to regions of Kentucky. The program is run through the dialog shown below. The weighted Runoff Coefficient or C-factor can be calculated by the Curve Number & Runoff routine. The peak flow value can then be used for Detention Pond Sizing or Channel Design. Pull-Down Menu Location: Watershed Prerequisite: None. Keyboard Command: peakflw2 File Names: \lsp\peakflw2.lsp, \lsp\hydro.dcl, \lsp\cntr_grd.arx Watershed Settings (Save and Load) These commands save and load watershed parameters to a data file with a.hyd file name extension. The watershed values include settings from the commands in the top portion on the Watershed menu such as rainfall, storm type, weighted curve number. These commands allow you to recall these values after reloading the drawing at a later time. Pull-Down Menu Location: Watershed Prerequisite: None. Keyboard Command: saveshed, loadshed File Names: \lsp\loadshed.lsp, \lsp\saveshed.lsp Hydrology Module - Watershed Commands Page 7-25

SEDCAD Draw Flow Polylines This command draws polylines in the SEDCAD layer that represent flow lines. When drawing a network of flow lines, first draw the main branch. Then begin drawing the other flow lines from the top of flow and use the Join option to connect onto the main branch. Draw Flow Polylines is the first command in a series that produce the Junction, Branch, and Structure labels for SEDCAD. Prompts End/Pick point: pick a point Undo/End/Join/Pick point: pick a point Undo/End/Join/Pick point: pick a point Undo/End/Join/Pick point: Press Enter Draw another flow polyline (<Yes>/No)? Press Enter End/Pick point: pick a point Undo/End/Join/Pick point: pick a point Undo/End/Join/Pick point: Join Select flow polyline at place to join: pick the main branch at the junction Draw another flow polyline (<Yes>/No)? No Pull-Down Menu Location: Watershed, SEDCAD Structure Layout> Prerequisite: None. Keyboard Command: sedcad1 File Names: \lsp\poly3d.arx SEDCAD Locate Structures This command is the second step for creating the SEDCAD layout. Locate Structures places triangle symbols on flow polylines that represents structures for SEDCAD. Prompts Symbol size <4.0>: Press Enter Pick location on flow polyline for structure: pick a point on a polyline Pick location on flow polyline for structure: pick a point on a polyline Pull-Down Menu Location: Watershed, SEDCAD Structure Layout> Prerequisite: flow polylines Keyboard Command: sedcad2 File Names: \lsp\hydro1.lsp Page 7-26 Hydrology Module - Watershed Commands

Label Structure Layout This command is the third and final step for creating the SEDCAD layout. Label Structure Layout draws text labels for the junctions, branches, and structures in the network. A junction, branch, and structure report is also generated. Flow polylines Example of labeled SEDCAD structure layout and structure symbols must be drawn before running this routine. This command uses the labeling rules as described in the SEDCAD manual. Prompts Symbol size <4.0>: Press Enter Junction offset tolerance <10.0>: Press Enter. Flow lines that meet the main branch within this distance of each other are considered the same junction. Select flow polylines and structure symbols. Select objects: pick the polylines and symbols J5,B1,S1 J4,B2,S1 J4,B1,S1 Hydrology Module - Watershed Commands Page 7-27

J3,B2,S1 J3,B1,S2,S1 J2,B2,S1 J2,B1,S2,S1 J2,B3,S1 J2,B1 J1,B2,S1 J1,B3,S1 J1,B4,S1 J1,B1 Write report to file (Yes/<No>)? Press Enter Write report to printer (Yes/<No>)? Press Enter Pull-Down Menu Location: Watershed, SEDCAD Structure Layout> Prerequisite: flow polylines and structure symbols Keyboard Command: sedcad3 File Names: \lsp\poly3d.arx SEDCAD Civil Software Design is the author of Sedcad which is sold separately from SurvCADD. Sedcad is a comprehensive hydrology and sedimentology package, useful for all varieties of runoff and sediment control design calculations. Sedcad can be run directly from the SurvCadd hydrology menu. The directory where Sedcad is installed must be defined in the Configure SurvCadd command. Page 7-28 Hydrology Module - Watershed Commands

Draw Flow Polylines (TR-20) This command draws polylines that represent flow lines. When drawing a network of flow lines, first draw the main branch. Then begin drawing the other flow lines from the top of flow and use the Join option to connect onto the main branch. Always draw the flow polylines from the highest to lowest elevation (in the direction of flow). Draw Flow Polylines is the first command in a series that produce the watershed schematic for TR-20 Hydrograph Development. These flow polylines only represent the layout of the watershed and they do not need to be drawn to scale. After each flow polyline is drawn, the program prompts for the drainage area, curve number and time of concentration of the branch associated with that flow polyline. This data is used in the RUNOFF statement in TR-20. The flow polyline label shows the area over the curve number and time of concentration. Main flow polyline with one branch Prompts Text size <4.0>: press Enter. This will be the text size for the flow polyline labels. End/Pick point: pick a point Undo/End/Join/Pick point: pick a point Undo/End/Join/Pick point: pick a point Undo/End/Join/Pick point: Press Enter Drainage Area Dialog Draw another flow polyline (<Yes>/No)? Press Enter End/Pick point: pick a point Undo/End/Join/Pick point: pick a point Undo/End/Join/Pick point: Join Select flow polyline at place to join: pick the main branch at the junction Drainage Area Dialog Draw another flow polyline (<Yes>/ No)? No Pull-Down Menu Location: Watershed Prerequisite: None. Keyboard Command: trflow File Names: \lsp\poly3d.arx Hydrology Module - Watershed Commands Page 7-29

Locate Structures (TR-20) This command places a structure on a flow polyline of the watershed schematic for TR-20 Hydrograph Development. The program prompts for elevation, discharge and storage data for the structure which is equivalent to the TR-20 STRUCT table data. At the bottom left of the dialog, the Water Elevation at T=0 is the water-surface elevation at the structure at the beginning of the storm. A triangle structure symbol that contains the structure data is drawn on the flow polyline. The File button can be used to read the stage-discharge in.stg files and the stagestorage in.cap files. The storage or discharge in the file is added to the table. Stage-storage files can be created with the Bench Pond Design, Valley Pond Design and Calculate Stage-Storage commands. Stage-discharge files can be created with the Drop Spillway, Design Channel and Design Culvert routines. Prompts Symbol size <4.0>: Press Enter Pick location on flow polyline for structure: pick a point on a polyline Structure Data Dialog Pick location on flow polyline for structure: press Enter Pull-Down Menu Location: Watershed Prerequisite: flow polylines Keyboard Command: trstruct File Names: \lsp\hydro1.lsp,\lsp\hydro.dcl & \lsp\poly3d.arx Page 7-30 Hydrology Module - Watershed Commands

Locate Reach This command places a reach on a flow polyline of the watershed schematic for TR-20 Hydrograph Development. The program prompts for the reach length, end area coefficient and exponent M. These variables are explained in the TR-20 manual. A square reach symbol that contains the reach data is drawn on the flow polyline. The reach labels show the length above the end area coefficient and exponent M. Prompts Symbol size <4.0>: Press Enter Pick location on flow polyline for reach: pick a point on a polyline Reach Data Dialog Pick location on flow polyline for reach: press Enter Reach on flow polyline Pull-Down Menu Location: Watershed Prerequisite: flow polylines Keyboard Command: trreach File Names: \lsp\hydro1.lsp, \lsp\hydro.dcl & \lsp\poly3d.arx Edit Layout Element This command allows you to edit the data stored with a part of the watershed schematic. For flow polylines the area, curve number and time of concentration can be changed. For structures the elevation, discharge and storage can be changed. For reaches, the length, end area coefficient and exponent M can be changed. Prompts Select flow line, structure or reach to edit: Pick a flow polyline, structure symbol or reach symbol Pull-Down Menu Location: Watershed Prerequisite: flow polylines Keyboard Command: tredit Hydrology Module - Watershed Commands Page 7-31

Hydrograph Development This command routes runoff through branches, structures and reaches. The dialog first prompts for storm data. Descriptions of these variables are in the TR-20 manual. After the dialog, select the flow lines, structures and reaches that were created by the Draw Flow Polylines, Locate Structure and Locate Reach commands. The program then creates a TR-20 input file called temp.dat in the SurvCadd exec directory and runs TR-20. The output can be sent to a file, printer or screen from the report viewer. Watershed schematic with two flow lines, one structure and two reaches to be used as input for Hydrograph Development Hydrographs are created at each flow line junction, structure and reach. The hydrographs are stored in files with a.h1 extension. These files are named automatically and placed in the SurvCadd data directory. Hydrographs entering a structure start with an 'S' and then the structure number. The structure number is labeled next to the structure symbol. Hydrographs entering a junction start with a 'J' and then the junction number. The junction number is also labeled next to the junction. The next part of the file name is either 'RUN' for runoff, 'OUT' for the hydrograph at the end of Page 7-32 Hydrology Module - Watershed Commands

the structure, 'REA' for the end of a reach, or 'ADD' for the combination of two hydrographs. A more detailed description of the hydrograph is in the third line of the hydrograph file. Prompts Calculate Hydrographs Dialog Select flow polylines, structure and reach symbols. Select objects: pick the objects Pull-Down Menu Location: Watershed Prerequisite: A flow polyline. Structures and reaches are optional. Keyboard Command: runtr20 File Names: \lsp\runtr20.lsp, \lsp\poly3d.arx, \lsp\hydro.dcl & \exec\tr20.exe Single Runoff Hydrograph This command creates a hydrograph for the runoff of one drainage area. The Use TR-20 toggle in the upper left chooses between using TR-20 and using the SCS method from A Method for Estimating Volume and Rate of Runoff in Small Watersheds. The hydrograph is stored in a file with a.h1 extension that can be drawn with the Draw Hydrograph command. Prompts Calculate Hydrograph Dialog Select Hydrograph File Dialog Pull-Down Menu Location: Watershed Prerequisite: None Keyboard Command: calchgrf File Names: \lsp\calchgrf.lsp, \lsp\poly3d.arx, \lsp\hydro.dcl & \exec\tr20.exe Hydrology Module - Watershed Commands Page 7-33

Draw Hydrograph This command draws a hydrograph from a hydrograph file (*.h1) that is created by SEDCAD, the Hydrograph Development, or the Single Runoff Hydrograph command. Multiple hydrographs can be drawn on the same grid by first running Draw Hydrograph with the Draw Grid option on. Then run Draw Hydrograph for each additional hydrograph with the Draw Grid option off and pick the same starting time and same lower left grid corner. Page 7-34 Hydrology Module - Watershed Commands

Prompts Range of Times: <0.0-49.998> Starting time <0.0>: Press Enter Ending time <49.998>: Press Enter Draw Hydrograph settings dialog box Pick starting poind for axis <0.0, 0.0>: pick a point Pull-Down Menu Location: Watershed Prerequisite: a hydrograph file Keyboard Command: hydrogrf File Names: \lsp\hydrogrf.lsp, \lsp\makegrid.lsp, \lsp\hydro.dcl Prepare HEC-2 Input File This command is designed to allow the user to create HEC-2 input files. HEC-2 is a computer program prepared by the Corps of Engineers to compute water surface profiles in non-prismatic stream and river channels. The bulk of the input to the HEC-2 program consists of crosssectional data of the stream and adjacent flood plain. It is in the preparation of this data that SurvCADD can be of real assistance. The Prepare HEC-2 Input File routine converts *.sct files prepared in SurvCADD to HEC-2 input data. The files are given the same name as the *.sct file used to make them and are given the *.h2i file extension. Each line in the HEC-2 text file, begins with a two letter identifier, followed by the corresponding data in a fixed format. Each segment of the stream is represented by a group of lines. The header for the section is the X1 line. On this line is recorded the general information about the section and the channel reach. The X1 line may be preceded by several change channel lines. NC cards as the only representative of the change lines in this routine. This line defines the stream frictional resistance by the Manning s n. The X1 line is followed by a series of GR lines representing the ground at the section. This representation is a list of elevations and distances from a baseline. The baseline is on the left side facing downstream and the distances are positive values, increasing as the section is read from left to right. Sections are identified in HEC-2 by a 6 character identifier on the X1 line. The sct2hec conversion program uses the integer value of the centerline station as the identifier for the section. This allows sections at stations up to 9,999+99. This corresponds to study reaches of 189 miles. For the sake of standardization horizontal distances along the section are taken to the even foot and elevations to the 0.1 foot. Hydrology Module - Watershed Commands Page 7-35

The next piece of information on the X1 line is the number of points on the following GR cards. The limit of 100 points in HEC-2 is checked and an alert box generated if applicable. The next two items of data on the X1 card are the stations of the left and right banks of the stream. In HEC- 2 the points must be points on the GR cards. Therefore these entries are made by selecting points from the list of points. The last data on the X1 line is the lengths of the channel and overbanks within the reach from the prior section to the current section. The distance between the sections is determined by the difference in stations of the sections on the *.sct file. This distance is presented as the default value for the length of both overbanks and the channel. On the first section these three values are 0, which tells HEC-2 to begin a profile. If the original polyline defining the *.xms file was along the thalweg of the channel then the channel length default is correct. The overbank lengths should be edited for curves in the channel. A SurvCADD *.sct file may be made by any one of the seven methods listed on the Sections pulldown of the Section-Profile module. A *.sct file made by any of these procedures can be converted to a *.h2i file. The procedure to create an *.sct file from a surface model begins with establishing a polyline as the centerline by which the sections will be oriented and spaced. This should be along or near the thalweg, or center of flow, of the stream and drawn in an upstream direction. From this polyline a *.mxs file is created. The width and location of sections at regular intervals and at special stations are defined in this step. It is this *.mxs file which SurvCADD uses to define the inundated regions latter in the hydrology modeling. Then the sections are cut and the *.sct file created by the normal means in SurvCADD. SurvCADD allows limiting the number of points in the section. Since HEC-2 has a limit of 100 points in a section, that limit should be Page 7-36 Hydrology Module - Watershed Commands

observed when cutting the sections. When running the convert a *.sct file to a *.h2i file, an input *.sct file is first requested by a file selection dialogue box. Then an offset distance prompted for on the command line. This distance should be larger than the greatest right offset used in making the *.sct files. The horizontal distances, called stations in HEC-2, along the cross-section must all be positive numbers increasing across the section. The HEC-2 section represents the ground as a left to right section looking downstream. For the HEC-2 computations the sections are read from the downstream end working upstream. Thus the need to begin the *.mxs file at the downstream end of the stream reach. (The preceding applies to the predominate case of subcritical flow and is reversed for analysis of supercritical flow.) As each section is read the user is presented with a dialogue box to edit data specific to each section. In the upper left corner of the dialogue box are 3 edit boxes for the channel and overbank reach lengths. The distance between sections is used as the default in all three boxes. The user may edit these values to correspond to channel curvature or other conditions as hydraulically warranted. Below these are five boxes with the Manning s n coefficients for the channel and overbanks separated by the top of bank stations. The n values may be edited just like any edit box. The top of bank stations are assigned values by selecting points from the list of all the points in the section displayed along the right of the dialogue box. The first station selected is assumed to be the left bank and the second the right bank. If the user changes his mind about the bank station, after the first two selections from the list the user can select either right or left bank. These boxes do not update their display until the user has selected another box to edit. The top of bank stations must correspond to points on the following GR cards, which is why user entry of any number is not allowed. The bank stations are used by HEC-2 to apply the Mannings n values assigned by the user. A complete, but minimal, input file is created by this conversion routine. Certain default values were selected and written to the output file to make it a complete file. These are: Begin computations using the slope/area method with 0.01 / slope; Flow = 500 cfs; Only a single profile will be computed; On the T2 card the input *.sct file is recorded; At each section the default top of bank stations are the first and last points. Older versions of HEC-2 for PCs (322k in size) can be run by shelling out of AutoCad. Newer versions (as distributed by Hastead Methods and others) use the Pharlap extender to access extended memory and will now run in an AutoCad shell. The user will normally need to edit the *.h2i file to represent the flows and beginning conditions to model and the type of output desired. Other parameters which may be added to the input file are: Contraction and expansion coefficients for energy loss, Multipliers to Manning s n, Call printer plots, Hydrology Module - Watershed Commands Page 7-37

Channel modifications, Bridges by normal or special methods, Custom output formats, Ice conditions and Encroachments. All of these items can be entered into the file on the appropriate cards using the DOS Edit program, the Display-Edit selection in SurvCADD or a similar editor. The output of the conversion is in the fixed 80 column format expected by the HEC-2 program. If the user is making significant changes or additions to the data it may be advisable to use the FREE format option for hand entered data. The default values for Manning n are 0.020 in the channel and 0.030 for both overbanks. These can be edited for the first section and the edited values will apply to all following sections. Editing the values in latter sections will create a new NC line to be written ahead of that section. The availability of easy input data to the HEC-2 program will change the way engineers use HEC- 2. In the past the location and number of sections was carefully considered to get the best result with the fewest, most representative, sections. Now a common topographic survey of the channel reach can provide easily sections at close intervals. Changes to the stream geometry can be easily modeled in the site plan and converted to HEC-2 data for analysis. This practically eliminates the need for channel improvement CI lines. Pull-Down Menu Location: Watershed Prerequisite: Cross section.sct file. Keyboard Command: sct2hec File Names: \lsp\sct2hec.lsp, \lsp\hydro.dcl HEC-2 Programs The HEC-2 programs include HEC-2, EDIT-2, PLOT-2, and SUMPO. These programs were developed by the Corps of Engineers and their documentation is separate. The programs are distributed with the Hydrology module and are placed in the SurvCADD EXEC directory. The HEC- 2 programs can be placed in another directory and run from SurvCADD by setting the HEC-2 directory in the Configure SurvCadd command. Page 7-38 Hydrology Module - Watershed Commands

Draw Watermark This command draws a closed polyline representing the high watermark as calculated by HEC- 2. The program uses the water depth at each station from the HEC-2 output file, the existing section file and a centerline polyline. Prompts Select Section File Cross-sections of the surface Select HEC-2 Output File This is a user-specified file created in HEC-2 Select centerline polyline: pick the polyline Starting station of centerline <0.0>: Press Enter Pull-Down Menu Location: Watershed Prerequisite: a section file, HEC-2 output file, and a centerline polyline Keyboard Command: drawhec File Names: \lsp\regrade.arx Prepare HEC-RAS Input File This program reads cross-section files and the corresponding MXS files (please see the material on Sections in Chapter 6 of this manual) and creates input files that can be used to run the HEC- RAS program for river analysis. The HEC-RAS program could be considered to be an advanced Windows-based version of the HEC-2 program. This program makes it easier for CADD and GIS systems to import their data directly for river network analysis. It is also very convenient because the output from the program can be exported directly to CADD programs where this data can be used to create water surface models for inundation mapping. Data Format : HEC-RAS input files consist of three data sections : * A header, containing data relevant to all sections of the data in the file. * A description of the stream network, containing reach locations and connectivity. * A description of the model cross-sections, containing cross-section location and geometric data as well as additional HEC-RAS modelling information. The header information is mainly for the purpose of identifying the project and is mostly not used by the program. The only important information needed by the program is the "Units" section and the value must be "ENGLISH" or "METRIC". Hydrology Module - Watershed Commands Page 7-39

The network is modelled as a set of interconnected streams. Each stream is a set of interconnected reaches. Each reach, hence, MUST have a unique Stream ID and Reach ID. The Stream Network section contains a series of Point Numbers and the corresponding coordinates. In addition, this section has information pertaining to each Reach. For each Reach, the following information is provided : * Stream ID and Reach ID. These are 16 character alphanumeric strings. Together these two items uniquely identify a Reach. * Starting (FROM or upstream) point and ending (TO or downstream) point of the Reach. The FROM point and TO point here are given by their Point Numbers, as identified above. * The coordinates on the Centerline of the Reach, starting with the FROM point coordinates and ending with the TO point coordinates. The Cross-Sections portion of the input file contains data describing the geometric properties at each cross section in the network. The following information is provided at each Cross- Section : * Stream and Reach ID, to identify which Reach the Cross- Section is on. * Station, position of the Cross- Section, relative to the Stream. The Station is taken as the distance from the current station to the end of the stream. For this purpose, the stream MUST be drawn Downstream to Upstream. THIS IS THE MOST FUNDAMENTAL REQUIREMENT OF THE PROGRAM. If the Stream is drawn in the other direction, then, it must be reversed using the command Reverse Polyline under Modify>Polyline Utilities * Cut Line : Series of point coordinates, identifying the surface line of the Cross- Section. HEC-RAS identifies Page 7-40 Hydrology Module - Watershed Commands

the cross-sections as going from left to right as seen from upstream to downstream. The user only needs to make sure that the stream network is drawn in the right direction (downstream to upstream); all other conventions are taken care of by the program. Modelling Guidelines : Some additional guidelines in drawing the river network in the CAD so as to model correctly for HEC-RAS : * All the Reaches in the Stream Network must be connected at common End Points; disjointed Stream Networks are not allowed; Reaches must also NOT cross each other. * Streams cannot contain parallel flow lines. If three reaches connect at a node or End Point, at the most TWO of them can have a common Stream ID. (Please note that a Reach is uniquely identified by a Reach ID and a Stream ID). * Cross-Section lines can cross a Reach line only once and cannot cross other X-section lines. Program Execution: Before starting the "Prepare HEC-RAS Input File" command, all the SCTfiles and their corresponding MXS files should have been created for every Reach. Points where two streams meet would form a node in the stream network. Sections of a stream between such nodes should be modelled as a Reach. and drawn as a separate polyline. Now, change to the Section-Profile Menu. The MXS file for each Reach is created using the command Input Edit Section Alignment under the Sections pulldown menu. Based on any of the methods for creating section files (described in chapter 6 of this manual), the Section file for the Reach is created. The user must manage the.mxs file and the.sct file corresponding to each Reach. At this point, a Stream ID and Reach ID may be assigned to every Reach, based on a convenient naming convention, which is entirely up to the user. These IDs would be needed when creating the HEC- RAS input file. The program starts by asking the user for the Header information. The user can input as much information in this dialog box as possible. The "Units" can be "Metric" or "English". Next, the user will be prompted to enter the.mxs and.sct file names, the Stream ID and Reach ID for each Reach that you wish to add to your model. The user can enter data (IDs and file names) for as many Reaches as wished. That is, the user can create input files for each Reach individually and import them individually into HEC-RAS or create a combined input file for all the Reaches in Hydrology Module - Watershed Commands Page 7-41

the Stream Network. This makes it very convenient to add more Reaches to the HEC-RAS model at a later stage or do the analysis for various sections separately. After entering as many Reaches as needed, the user presses "Exit" to stop entering any further Reaches and to continue with the program execution. On pressing "Exit", the user is prompted for the Input HEC-RAS file to be created. HEC-RAS input files have a.geo extension. When the file is chosen at the prompt, the program creates the input file for HEC-RAS. This file can be used to import geometric data into HEC-RAS, as described below. You must have HEC-RAS version 2.0 or higher installed on your computer. HEC-RAS : After starting HEC-RAS, select "Geometric Data" from under the "Edit" pulldown menu. This brings up a Geometric data editor, complete with a CAD screen and various options. From the "File" pulldown menu of the Geometric data editor, choose the "Import Geometric Data -> GIS Format" command. This brings up a file browser and allows you to choose a geometric data file. Choose the.geo file just created. This should load the geometric data into HEC-RAS, which is then converted into a CAD format drawing and shows up in the Geometric Data Editor in the form of a Stream network, with EndPoint, Stream ID and Reach IDs, Cross Sections stationing information, along with directions of in each Reach. At this point, the user can edit several aspects of the data where Survcadd only provides default values. Specifically, the Bank Positions and overbank reach lengths can be adjusted here. In addition, the Mannings coefficient has to be entered for all the cross-sections for all the left, right and center flows. As of HEC-RAS release 2.0, there is no way to input a default value for the Mannings coefficient, but this situation may improve in future releases of HEC-RAS, in which case the Survcadd program will be modified immediately. Other data that needs to be modified is the location of the left and right banks. By default, the left bank is given to be at 0.45 times the cross-section length and the right bank is given to be at 0.55 times the cross-section length. In order to correctly model the channel geometry, the location of the banks must be accurately defined for each cross-section. This can be done by clicking on the "Cross-Sections" icon in the "Geometric Data Editor" or by clicking with the left mouse on the cross-section to be edited. This brings up all the geometric data related to that particular cross-section, which may be edited as required. Page 7-42 Hydrology Module - Watershed Commands

The left and right overbank lengths are defaulted to equal the centerline length ( which may not be equal in the case of a sharp bend in the stream). These values can also be edited in the same cross-section editor as mentioned above. Geometric data can be stored by running "Save Geometric Data" from the "Geometric Data Editor". The file extension assigned for Geometric data files is *.g*, which means that successive geometric data files will be given file extensions in a numeric sequence, beginning with *.g01. Information specific to each analysis can be entered in the "Steady Flow Data Editor", which can be brought up by selecting "Steady Flow Data" from the Edit pulldown menu of the main HEC- RAS window. The data that can be selected here are the number of profiles that need to be run, flow in each reach for each profile simulation and the Hydraulic boundary conditions at each Reach for each Profile simulation. This information is stored in a file with the extension *.f01 and so on for successive files. Once all the geometric data and Steady flow data has been entered, the simulation can be run by selecting "Steady Flow Analysis" from the "Simulate" pulldown menu in the main HEC-RAS window. After selecting the type of flow condition (sub-critical, super-critical or mixed), the user selects the "Compute" button to complete the analysis. If there are errors or serious warnings, the program reports them in a text editor. Otherwise, the program shells out to a DOS screen and completes all the necessary calculations. Several options are available for viewing and editing output from the HEC-RAS program, which are best explained in their manual. Hydrology Module - Watershed Commands Page 7-43

Structure Commands Shown here is the Structure pulldown menu. The Design Bench and Valley Pond commands are described in the DTM-Contour Module section. Page 7-44 Hydrology Module - Structure Commands

Detention Pond Sizing This command calculates the runoff and storage volumes for a detention pond. The program uses the method from the TR-55 program as described in the Urban Hydrology for Small Watersheds manual. The command is run through the dialog box shown here. When the input values are filled in, click on the Calculate button to obtain the output values. The drainage area can be either entered directly or selected from AutoCad by clicking on the Select Area button and then selecting the closed polyline from the screen. The peak inflow will use the value calculated in the Peak Flow- Graphical Method command. Likewise the runoff Q will use the value from the Curve Numbers & Runoff routine. The output of this command, the storage volume value, can be applied to the Design Bench, Valley or Rectangular Pond routines. Prerequisites: None File Name: \lsp\det_pond.lsp Keyboard Command: dpond Pulldown Menu Location: Structure within Hydrology Menu Hydrology Module - Structure Commands Page 7-45

Rectangular Pond Design This program will draw rectangular ponds and calculate storage at any level in the pond corresponding to top of pond, emergency spillway, principal spillway and sediment (cleanout) level. Elevations can be reverse-calculated based on requested storage amounts. All calculations derive from input length-width and slope ratio values. Only one common ratio is used for the interior pond slopes (e.g.. 1:1 or 2:1, etc.). The program will output scaled and fully annotated plan view, section A-A and section B-B drawings, complete with principal and emergency spillways. For simplicity, the principal spillway is considered to be a pipe spillway, and the emergency spillway is considered to be a flat-bottom weir spillway. If the pond in question has only one spillway, then the appropriate spillway elevation is entered in the dialog box, and the other spillway option is left blank. Page 7-46 Hydrology Module - Structure Commands

There are two other output options available. The user can produce a table of storage values as an ASCII file output by selecting Write Report. This will include the Required Freeboard and Peak Storm Event values, which are used for the ASCII file output only. This information, in turn, can be read back into the drawing and plotted beside the pond details using TEXT IMPORT located under the MISC pulldown menu. The last output option is the Pond Capacity File, which creates a.cap file which can be plotted using the file option within the POND STAGE STORAGE CURVE routine located under the POND pulldown menu. The net effect of the Rectangular Pond Design routine is that you can calculate necessary pond storages, plot the pond detail drawings, write out and import the ASCII text summary and plot the pond stage-storage curve, all in about 3 minutes. There are ways to use the routine in shortcut form to draw ponds. Simply by completing 3 dialog entries (base width, base length and total depth) the user can draw the plan view, section A-A and section B-B. This is why the Pond Elevation items are considered optional. The programs can also be used as a pond storage calculator. Any of the Pond Elevation options (excepting peak stage), when completed will lead to recalculated storage values. Storage values can likewise be altered and will lead to recalculated elevations. The act of pressing enter inside a dialog box activates the calculation process. If there is no need to plot the pond detail drawings, the cancel button in the dialog can be selected following calculations. Prompts The program begins by presenting the dialog. One effective way to fill out the dialog boxes is to pick the upper left box and work down and through the options by pressing the tab key after each entry. If all items are filled out as shown, the following prompts will appear: Path/File Name for Report: POND.TXT Path/File Name for Pond: POND Enter Scale Factor for Pond Drawing(s) <1>: Press Enter Draw Plan View: (<y>/n): Press Enter Pick Lower Left Corner: Plot Cleanout and Spillway Lines (<y>/n): Press Enter Pick Location of Principal Spillway: Draw Section A-A Horizontal (y<n>): y Pick Left Location of Section A-A: Pick Right Location of Section A-A: Draw Section B-B Vertical (y/<n>): y Pick One Side of Section B-B: Pick one Side of Section B-B: Pick Upper Left Corner for Section A-A: Plot Cleanout and Spillway Lines (<y>/n): Press Enter Pick Upper Left Corner for Section B-B: Plot Cleanout and Spillway Lines (<y>/n): Press Enter If no Section A-A or Section B-B identifier lines are drawn, no section A-A or Section B-B details will be drawn. Thus if you want Section A-A only, say "y" to Draw Section A-A Horizontal but "n" or Enter to Draw Section B-B Vertical. If you entered only length, width and depth in the original dialog, the resultant prompting would be: Enter Scale Factor for Pond Drawing(s) <1>: Press Enter Hydrology Module - Structure Commands Page 7-47

Page 7-48 Hydrology Module - Structure Commands

Draw Plan View? (<y>/n): Press Enter Pick Lower Left Corner: Draw Section A-A Horizontal (y/<n>): y Pick Left Location of Section A-A: Pick Right Location of Section A-A: Draw Section B-B Vertical (y/<n>): y Pick One Side of Section B-B: Pick Other End of Section B-B: Pick Upper Left Corner of Section A-A: Pick Upper Left Corner of Section B-B: The resultant plots produced by the entries in the above dialog are shown above. Keep in mind that the scale factor, if other than 1, will enlarge or reduce the size of the detail drawings to suit the users needs, yet will annotate dimensions correctly in all cases. The imported text based on the output ASCII file POND.TXT (located in \SC12\WORK by default) would appear as follows: Top of Pond Elevation: 1070.00 feet Peak Stage (25th year-24 hour Storm Event): 1069.45 feet Includes 1.00 feet of Freeboard Emergency Spillway Elevation: 1067.00 Emergency Spillway Bottom Width: 10.00 Principal Spillway Invert Elevation: 1065.50 feet Principal Spillway Diameter: 42.00 in. Principal Spillway Slope: 2.00 % Sediment Pool (Cleanout) Elevation: 1064.00 feet Bottom of Pond Elevation: 1060.00 feet Storage Volume at Emergency Spillway: 0.2990 ac.ft. Storage Volume at Principal Spillway: 0.2150 ac.ft. Storage Volume at Sediment Pool: 0.1430 ac.ft. The routines are fully metric and will substitute meters and cubic meters appropriately for feet and acre-feet. Pipe sizes, however, will default to diameters in inches. Pull-Down Menu Location: Structure menu in Hydrology Module Prerequisite: None Keyboard Command: rpond File Name: \lsp\drawpond.lsp, \lsp\drawpond.dcl Hydrology Module - Structure Commands Page 7-49

Drop Pipe Spillway Design This program calculates the spillway discharge at different water elevations. As the water elevation initially rises above the riser, the flow is controlled by weir flow. At higher water elevations the flow is under orifice control. When the barrel flows full, the flow is controlled by full pipe flow. Given the water elevation and spillway dimensions, the program calculates the type of flow and discharge. 1. Data: Pool elevation:... = 976.00 ft Top of riser elevation:... = 975.20 ft Bottom of riser elevation:.. = 973.00 ft Outlet elevation:... = 968.00 ft Diameter of riser pipe:... = 20.00 in Diameter of culvert pipe:... = 30.00 in Length of culvert:... = 145.00 ft Entrance loss coefficient:.. = 2.1600 Friction coefficient:... = 0.0220 Weir coefficient:... = 3.3000 Orifice coefficient:... = 0.9500 2. Spillway discharge: Weir Flow Discharge... = 12.36 CFS Orifice Flow Discharge... = 14.87 CFS Full Pipe Flow Discharge... = 23.50 CFS Spillway discharge... = 12.36 CFS The Calculate button will read the values in the dialog, calculate the flow and report this flow value at the bottom of the dialog. The Report button will generate a report of the input values and calculated flows. The File routine will create a stage-discharge (.stg) file. The Draw function will draw and label the drop pipe spillway in the drawing at the specified scale. The Graph button creates a stage-discharge graph. Prerequisites: None File Name: \lsp\spillway.lsp Keyboard Command: spillway Pulldown Menu Location: Structure within Hydrology Menu Page 7-50 Hydrology Module - Structure Commands

Pond Weir Spillway Design This program calculates the dimensions of a rectangular weir given the outflow discharge. The default discharge uses the value from the Detention Pond command. The weir width and depth are two free variables. Enter a value for one and Press ENTER. Then the value for the other is calculated. The weir design may optionally be applied to a pond design. First enter a Required Storage Volume which can come from the Detention Pond command. Then click Apply to Actual Pond and choose a Storage Capacity File (.cap). This.cap file can be created by Bench or Valley Pond Design and by the Stage-Storage command. The program then computes the elevation at the required storage volume and the corresponding elevation for the bottom of the weir given the weir depth. When the Draw Spillway Detail option is checked, a drawing of the weir is created as shown below. Prerequisites: None File Name: \lsp\spilweir.lsp Keyboard Command: weir Pulldown Menu Location: Structure within Hydrology Menu Hydrology Module - Structure Commands Page 7-51

Design Spillway This command creates a spillway with 3D polylines in the drawing. The program uses a surface model of the area for the spillway, a spillway centerline and spillway dimensions (width, elevation, etc.). The surface model of the area can be defined by contour polylines, points and 3D polylines or can be created by the Design Bench or Valley Pond commands. The spillway dimensions can be calculated by the Design Channel commands to meet the desired discharge. The amount of cut required to make the spillway is calculated and reported. Prompts Source of surface model (File/<Screen>)? Press Enter. Use the File option to select a.grd file. Pick Lower Left limit of surface area: Pick lower left Pick Upper Right limit of surface area: Pick upper right Be sure to pick these limits well beyond the area of the spillway centerline in order to make room for the outslopes. Make GRiD File Dialog After selecting the limits of the disturbed area the program will generate a 3D grid that represents the surface. Specify the grid resolution desired and select OK. Pick the spillway centerline: Select polyline that crosses the dam Pick a point within the pond: the program needs to know which end of the spillway centerline is within the pond Enter slopes as percent grade or slope ratio (Percent/<Ratio>)? Enter Enter the side slope ratio <1.0>: Press Enter Enter the flow slope ratio <100.0>: Press Enter Range of existing elevations along spillway centerline. Enter spillway elevation <1476.5>: 1475.0. This is the entrance elevation of the spillway Enter the spillway width <10.0>: Press Enter Prerequisites: surface entities that model the pond File Name: \lsp\pond.arx Keyboard Command: spill Spillway Report Pulldown Menu Location: Structure within Hydrology Menu Spillway inlet elevation : 1445.0000 Spillway outlet elevation: 1445.0000 Spillway width: 10.0000 Side slope percent grade: 100.00, slope ratio: 1.00 Flow slope percent grade: 1.00, slope ratio: 100.00 Spillway EarthWork Volumes Total cut: 55.593 C.Y., 1501.00150 C.F. Page 7-52 Hydrology Module - Structure Commands

Spillway added to valley pond Calculate Stage Storage This command calculates stage-storage values for a pond that is already drawn in the drawing. Before running this routine, the surface model for the pond must be created as a grid file with Make 3D Grid File. A closed polyline for the perimeter of the pond is also required. Prompts Choose Grid File Select the.grd file that models the pond surface Pick the top of dam polyline: pick the closed polyline perimeter Choose method to specify storage elevations (<Automatic>/Manual)? Manual Range of pond elevations: 367.07 to 383.63 Enter stage elevation (Enter for none): 370 Enter stage elevation (Enter for none): 374 Enter stage elevation (Enter for none): 378 Enter stage elevation (Enter for none): 382 Enter stage elevation (Enter for none): Press Enter Pond Storage Volumes Water Elev: 370.00, Pond Storage: 10290.113 C.Y., 6.37817 Acre Feet Hydrology Module - Structure Commands Page 7-53

Water Elev: 374.00, Pond Storage: 42518.613 C.Y., 26.35451 Acre Feet Water Elev: 378.00, Pond Storage: 81085.584 C.Y., 50.25966 Acre Feet Water Elev: 382.00, Pond Storage: 123449.853 C.Y., 76.51850 Acre Feet Write stage-storage to SEDCAD file (Yes/<No>)? Press Enter Prerequisites: surface entities that model the pond File Name: \lsp\makegrid.arx Keyboard Command: postpond Pulldown Menu Location: Structure within Hydrology Menu Pond for Calculate Stage Storage Page 7-54 Hydrology Module - Structure Commands

Draw Stage Storage Curve This routine draws a pond stage storage curve with pond elevation on the vertical axis and acrefeet of storage on the horizontal axis. It will plot and label the emergency spillway, principal spillway and cleanout levels and will produce a table of storage data. The program will read and write a ".CAP" file of pond storage, based on areas at each stage or elevation. CAP files (short for Hydrology Module - Structure Commands Page 7-55

"capacity") are made by Bench Pond Design, Valley Pond Design, Rectangular Pond Design and by the Stage Storage Curve program itself. These are the same files produced and read by SEDCAD, a popular hydrology and sedimentology program. In addition to file-based inputs, the user can enter pond dimensions directly by length-width, area at each stage, or volume at each stage. Since volume-based entry does not include area information, no CAP files are stored with this option. However, the curves plot in all cases. Plots are sized to fit on 8-1/2 x 11 sheets at the selected scale for plotting. They are particularly suited for permit applications, so the program will prompt for permit number and page. Prompts Name of Pond <Sediment Control Structure No. 1>: Permit Application Number (e.g. 898-5252): A-17 Permit Item Number (eg. 30.3): 10.1 Page Number <1>: (File Input or known (A)rea, Length/Width (D)imensions or <V>olume: D Stage No. 1 Elevation: 940 Width: 20 Length: 60 <Enter> for more, (R) to Revise, (E) to exit entry: If you made a mistake, you could enter R and then enter a revised Elevation, Width and Length. Otherwise, press Enter to continue. Stage No. 2 Elevation: 945 Width: 30 Length: 70 <Enter> for more, (R) to Revise, (E) to exit entry: Press Enter Stage No. 3 Elevation <950.00>: (the program "defaults to the last interval) Width: 40 Length: 80 <Enter> for more, (R) to Revise, (E) to exit entry: E (to exit!) A table appears, similar to the following: Inc. Vol Acc. Vol Elev Width Length Area Interval Avg. Area Ave Ft. Ave Ft. Stage 940 20.0 60.0 0.028 0.00 0.028 0.000 0.000 0.00 945 30.0 70.0 0.048 5.00 0.038 0.189 0.189 5.00 950 40.0 80.0 0.073 5.00 0.061 0.304 0.494 10.00 Areas are in acres. If the area method of entry were chosen instead, the user would have been prompted for area at each elevation (stage), and the summary table would be blank under the width and length columns. The file input method would also only report area values. Similarly, if entry was by volume (in cubic feet), all width, length and area columns would be blank. Page 7-56 Hydrology Module - Structure Commands

Calculate Storage or Elevation Points (y/<n>): y Known (E)levation or known <s>torage: Storage (eg. 0.2 or %60 for 60% of total): %60 Storage: 0.30 Elevation: 946.759 Calculate Storage or Elevation Points (y/<n>): Press Enter Pressing Enter moves on. The advantage of this option is the ability to find exact spillway and cleanout levels by experimenting with needed storages or desired elevations. For example, sediment cleanout levels are often set at 60% of total storage, which would be in this case 946.76. Elevation of Top of Structure: 950 Elevation of Emergency Spillway: 948.5 Elevation of Principal Spillway (Enter if same): Enter Elevation of Cleanout Level: 946.76 Is Above Data OK (<y>/n): Enter (n leads to re-entry of above 4 items) Range of Elevation: 10.0 Desired Elevation Interval: 2 (for gridding purposes) Total Storage Range in Ac.Ft.: 0.4936 Desired Storage Interval: 0.1 (for gridding purposes) Pick Starting Position: pick a point Enter Scale of Drawing <50.0>: Press Enter Text for Horiz. Scale <ACCUMULATIVE STORAGE (ac-ft)>: Enter The user controls the axis labels. If you want the horizontal axis to read STORAGE, then you would type this in the above. Similar prompts continue: Text for Vert. Scale <ELEVATION MSL>: Press Enter Title of Plot <STAGE STORAGE CURVE>: Press Enter Data Title <STORAGE VOLUME COMPUTATIONS>: Press Enter (C)ertification, (B)usiness Address or <E>xit: C Certification Line 1 <KY certification>: Enter A business address or typed-in certification can be entered here. If the user wanted to save a different default certification, lines 1008, 1009, 1014, 1020 and 1026 could be changed in the actual STAGE-LSP ASCII file program. We normally don't recommend altering source code, but it can easily be accomplished with a text editor. Store Pond Capacity File (y/<n>): y Path/File Name (no extension): POND (goes to the data directory by default). Prerequisites: None File Name: \lsp\stage.lsp Keyboard Command: stage Pulldown Menu Location: Pond within Hydrology Menu and Surface within Mining (CoalCad) Menu. Hydrology Module - Structure Commands Page 7-57

Draw Stage-Discharge Graph This program draws a stage-discharge graph with the stage (water elevation) on the Y-axis and the discharge on the X-axis. The data to graph is read from a stage-discharge (.stg) file which can be created by several routines including Design Channel, Drop Spillway, etc. First you are prompted to select a STG file to draw. Then the program asks for the ending discharge for the graph which defaults to the highest discharge in the file. Next this dialog is displayed to enter the graph scale and intervals. The height of the annotation equals the horizontal scale times the Axis Text Scaler. Prerequisites: Stage-Discharge file (.stg) File Name: \lsp\hydrogrf.lsp, \lsp\hydro.dcl Keyboard Command: stage2 Pulldown Menu Location: Structure within Hydrology Menu Page 7-58 Hydrology Module - Structure Commands

Channel Design - Non-Erodible (Manning's Equation) This will compute channel depth, flow and velocity based on channel parameters such as side slopes, base dimensions and Manning's n value. It handles triangular, trapezoidal, rectangular and irregular channels. Entry of a depth leads to calculation of flow and velocity. Entry of one of the other items (flow or velocity) will lead to calculation of the remaining items. In addition to functioning as a channel calculator, the program will output a typical section or detail of the channel as well as a report of the channel output. The routine also works in metric units. It applies to nonerodible channels, primarily. The user can select to output an ASCII file report of the channel input and output values as well as a standard detail shown below for the above example. Prompts When the routine is selected, the dialog box shown below appears. Select, for example, a trapezoidal channel, equal sides, with side slopes of 3 (for 3:1) and a base dimension of 16. Then at the lower Hydrology Module - Structure Commands Page 7-59

left, plug a value of 4.5 for the depth. This will calculate a flow of 862 cfs and a velocity of 6.5 fps, as shown below. To use the routine as a calculator, enter the known value in the lower left area of the dialog (flow, depth, or velocity), then press enter while still in the entered item. The other two items are then calculated. Note that the routine will default to the last values used during the current SurvCADD work session, and will capture the flow values calculated in Water Runoff under the Watershed Pull-down. When entering the Manning's n value, a table of n values can be brought up and an appropriate Manning's selected. Pull-Down Menu Location: Structure Prerequisite: Use Drawing Setup to activate Metric or English outputs. If English is configured, the formula v=(1.486/n)(r^2/3)(s^1/2) is used, where n is the Manning's value, R is the water cross section divided by the wetted perimeter and s is the slope ratio. If Metric is configured, the formula becomes v=(1.0/ n)(r^2/3)(s^1/2) and outputs are in meters. Keyboard Command: channel1 File Names: \lsp\channel.lsp & \lsp\hydro.dcl Page 7-60 Hydrology Module - Structure Commands

Channel Design - Erodible (Manning's Equation) This command uses the same Manning's equations as non-erodible channel design. In this case, the discharge and velocity are known. The velocity must be less than a maximum to prevent erosion. The program calculates the channel dimensions that meet the requirements. First choose the channel and water type. Then either enter the Manning's n, velocity, and tractive force or select them from a table of channel types by clicking Select from Table. Also fill in the slope and discharge. Finally, choose either Calc Base or Calc Ratios to compute the channel dimensions. The Standard Parameters are used in drawing the channel detail. When OK is selected, the routine ends and the channel is drawn if Draw Channel Detail is checked. When choosing Calc Base or Calc Ratios, there will be a message Error: unable to solve these parameters on the top line if the design parameters never reach erosion conditions for any channel Hydrology Module - Structure Commands Page 7-61

dimension. Consider an extreme error case with a discharge of 1 cfs, a slope of 0.1%, and a velocity of 5.0 fps. There are no dimensions that meet these requirements. So, for this case, the channel dimensions can be set anyway to avoid erosion. Pull-Down Menu Location: Structure Prerequisite: None. Keyboard Command: channel2 File Names: \lsp\chan_erd.lsp & \lsp\hydro.dcl Pipe Culvert Design The pipe culvert routine reports discharge and velocity for any pipe flow depth. Fixed inputs include diameter of pipe, pipe length, slope and Manning's n value. The operative variable is depth of flow. This can be entered in the dialog box at lower left and the solution is obtained by clicking Solve or by pressing enter with the Depth of Flow box clicked. Prompts When entering the fixed inputs under Culvert Design Input Parameters, the best approach is to work from the Manning's n for Pipe up to the Embankment Elevation (bottom-to-top). The main reason for this is that Depth of Flow at the lower left is solved by subtracting Maximum Water Elevation minus Inlet Elevation, which leads to large depths if Maximum Water Elevation is entered first in a top-to-bottom sequence. The Manning's n may be selected from a table of pipe values. When the Manning's n is selected, the type of pipe is shown at the lower right. The Embankment Elevation refers to the top of the road, or the elevation above which the water backed up behind the pipe would overflow. Clearly, one goal in culvert design is to size the pipe such that the peak water flow will not overflow the Embankment Elevation. Another design goal might be to prevent the discharge velocity from exceeding a certain speed (such as 5 fps), to protect against erosion. The user can accomplish these design goals by altering pipe slope, pipe diameter and depth of flow in particular. Type of Pipe Flow Three types of flow are considered: (1) Open Channel, valid for depths up to 94% full, (2) Orifice (inlet) Control and (3) Pipe Control. Open Channel Flow Click Open Channel at right and enter a depth less than full flow and the program will calculate velocity and discharge. If a depth is entered greater than full, the program will report 0 velocity and discharge, indicating open channel flow does not apply. The above dialog box shows calculated discharge and velocity for a depth of flow of 1.2 feet in a 24 inch pipe. Page 7-62 Hydrology Module - Structure Commands

Orifice (Inlet) Control Click on Orifice Control and enter any depth greater than 1/2 of the diameter to calculate velocity and discharge. Orifice control does not consider the values for the Inlet Head Loss Coefficient. Pipe Control Click on Pipe Control and obtain velocity and depths for pipes flowing full or above full. The calculations are affected by the Entrance Loss Coefficient, which can be selected by picking one of the types in the upper right, or directly entered. It will generally be noted that at greater depths at the inlet and lesser pipe slopes, the pipe control will tend to give lower discharge results than the orifice control. The user should accept the value which is the lesser of the two. Thus in the case shown in the above dialog, pipe control governs, using an entrance loss coefficient of 0.78. Hydrology Module - Structure Commands Page 7-63

Other Pipe Conditions Besides standard open channel, orifice control and pipe control, there are other conditions not directly considered in the calculations. For example, when the outlet of the pipe is submerged in a pond, it is considered to have "tailwater". Pipes emptying out on a hillside have no tailwater, and the value should remain 0. If the user enters a tailwater, this will appear on the standard detail if selected. However, the affect of tailwater is not at present factored into the calculations. Also, subtle flow affects in the near full condition are also ignored, as open channel flow passes into orifice and pipe control. Output Options Write Report If this box is clicked, upon exit of the dialog box (after clicking OK), the program will present a report screen and provide the option of printing, drawing the report in AutoCad or storing the report to a file. Write Sedcad File This option produces a file with a.cvt extension that can be used as one of the building blocks for the SedCad program (a third party hydrology and sedimentology stand-alone software package). The file is identical to what is produced within SedCad by its utilities program. The file for the above pipe control example appears as follows: 37 0.78 80.0 1.25 0.024 4.5 0.0 Page 7-64 Hydrology Module - Structure Commands

Draw Pipe Detail When clicked, this will produce a fully annotated standard detail, with user-controlled inlet and outlet stope entries and scaling. The detail is shown below with the results of Write Report. Write Stage/Discharge File This will produce a file of flow for increasing depths at the inlet. It is useful for computing pond depths at increasing flows. The file is used by the Hydrograph Development program within the Watershed pulldown, which tracks flow through a watershed passing through structures, using the SCS TR20 program. The stage/discharge file has a.stg extension. Pull-Down Menu Location: Structure Prerequisite: None. Keyboard Command: culvert File Names: \lsp\culvert.lsp Hydrology Module - Structure Commands Page 7-65

Sewer Pipe Design This command calculates the travel time, flow depth, and velocity for a section of pipe. The Individual option calculates for one pipe section using the dialog shown below. The Read Profile option reads the stations and elevation of a sewer or pipe profile (*.pro) created by the Design Sewer/Pipe Profile command in the Section-Profile module Pull-Down Menu Location: Structure Prerequisite: None. Keyboard Command: swrpipe File Names: \lsp\swrpipe.lsp Profile Report Dialog for the Individual method Sewer Profile Station Invert-IN Invert-OUT Distance Slope Width(in) Depth(in) Time(min) Velocity(fps) 0+40.44 61.80 61.80 285.53 2.50% 10.00 1.51 2.21 2.15 3+25.88 68.94 68.94 274.20 2.40% 10.00 1.53 2.16 2.12 6+00.00 75.52 75.52 200.02 1.50% 10.00 1.71 1.86 1.80 8+00.00 78.52 78.52 Flow rate: 50.0 (GPM) Manning s n for pipe: 0.020 Total travel time: 6.23 (min) Report from the Read Profile option Page 7-66 Hydrology Module - Structure Commands

Lift Station Design This command aids in the design of duplex sanitary or storm sewage lift stations. The program assumes a duplex station, with the second pump used solely fro backup. That is, there are no provisions for multiple pump operation. The system head curve and pump curve are calculated using the least squares method of curve fitting through three points. To calculate the three points input the length of the force main (length of pressurized pipe), an assumed low-level wastewater surface elevation in the wet well, the elevation of the static lift in the force main, the sum of minor loss coefficients in the force main, and three flowrates that adequately cover the desired range of pump operation. The total dynamic head is calculated for each of the three flowrates by adding the static head, friction losses, velocity head, and minor losses that are calculated by the program from the input data. The next step is the calculation of the pump curve. The user should select one or more pumps from a manufacturer's catalog that will produce the desired operating conditions. The input data consists of the pump shutoff head (flow rate equal to zero), a head and flowrate near the desired operating point, and a head and flowrate beyond said operating point of the pump curve. Hydrology Module - Structure Commands Page 7-67

The system head curve and the pump curve are then intersected to produce preliminary operating point results. If the user is not happy with the results, click the Edit Input Values button and change any of the parameters. When the user attains the desired results then proceed with the wet well design by clicking OK. Input for the wet well design includes type of wet well, wet well dimensions, invert elevation of the lowest line entering the wet well, and minimum wastewater depth in the wet well (usually specified by the pump maker). The lead pump's wet well volume is calculated using a formula from Metcalf & Eddy's Wastewater Engineering: Collection and Pumping of Wastewater: V = CT/4 where V equals required volume in gallons, C equals pump capacity (GPM), and T equals minimum time in minutes of one pumping cycle. After wet well design the program assigns a new low level wastewater surface elevation in the wet well, and then recalculates the system head curve and final operating point. At this point the user may change any or all of the input parameters. If no changes are needed then click OK to show the Final Results report. Pull-Down Menu Location: Structure Prerequisite: None. Keyboard Command: LIFTSTA File Names: \lsp\liftstat.lsp & \lsp\liftstat.dcl Page 7-68 Hydrology Module - Structure Commands

Hydrology Module - Structure Commands Page 7-69

Set Sewer File This command sets a sewer network file as the current file. The other sewer network commands will reference this file. Either a new file can be created or an existing sewer file can be modified. The sewer network file stores all the sewer structure data (elevation, flow) and all the network connection data (slopes, pipe sizes). This file has a.sew file extension. Keyboard Command: setswr Pull-down Menu Location: Structure within Hydrology Menu Prerequisite: None File Names: \lsp\pswrfile.lsp Locate Sewer Structure This command adds a manhole to the sewer network. The location of the manhole can be placed either by picking the location, specifying a point number or by station and offset from a centerline. A surface model is required to calculate the default rim elevation and the minimum cover of any pipe connections. The surface model can be a grid file or triangulation file created by the Make 3D Grid File or Triangulate & Contour commands. Once the manhole location is set, the Sewer Structure Data dialog appears for setting the manhole parameters. To change the manhole position, pick the Change Location button which allows you to pick the manhole location. The Structure and System Names identity this manhole. Each manhole in the network must have a unique name. The Symbol Number specifies the symbol to draw for this manhole. The size of the symbol is determined by the Horizontal Scale and Symbol Size in the Drawing Setup command. Invert Elevation IN is the bottom elevation at the manhole inflow. Each upstream connection has a separate invert in elevation. Invert Elevation OUT is the bottom elevation at the outflow. Page 7-70 Hydrology Module - Structure Commands

Rim Elevation is the surface elevation. Depth is the elevation difference from the Rim Elevation to the Invert Elevation IN. Area specifies the drainage area that flows into this manhole. The area units can be either square feet, square miles or acres. The Select Area button allows you to select a closed polyline that the program will calculate the area from. Time to Inlet is the time of concentration in minutes for this drainage area. Intensity is the Inches per Hour rainfall intensity to be used with the rational method. Runoff Coefficient is the rational method number. Given the Time to Inlet, Intensity and Runoff Coefficient the program will calculate the flow into the manhole (Q) using the rational method. Upstream Connections shows a list of the upstream manholes that this manhole is directly Hydrology Module - Structure Commands Page 7-71