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3.15 Parameter Tables
User’s Manual » 3 Conceptual Model » 3.15 Parameter Tables
The Parameter Tables window provides a spreadsheet environment for parameter editing. By default, it’s located at the bottom of the main interface. Parameters of each type of hydrologic object is displayed in the same table and sorted by NHYD. These tables are…
8.5.2 Parameter Estimation
Reference Guide » 8 A Review of Design Storm Profiles » 8.5 Chicago Design Storm » 8.5.2 Parameter Estimation
The procedure for determining the constants for the empirical IDF curve was discussed previously in the Intensity Duration Frequency Curves section. The only constant that is required for the Chicago design storm is the ratio of the time before the peak to the storm…
Step 15: Analyze Hydroperiod
Tutorials » Modeling a Wetland: Continuous Simulation, Calibration and Hydroperiod Analysis » Step 15: Analyze Hydroperiod
VO uses the results of one pre-development scenario to calculate the confidence interval for hydroperiod analysis. Therefore, before doing the hydroperiod analysis, we should select one scenario from all the scenarios in the project as the Pre-Development Scenario. To…
1.3 Time to Peak Parameter, TP
Reference Guide » 1 Tips for Modeling Ungauged Rural Catchments » 1.3 Time to Peak Parameter, TP
Unlike the urban catchment hydrographs, rural catchment unit hydrographs do not calculate the time to peak TP as a function of the other variables. The TP parameter must therefore be deter-mined by the modeler. It should be noted that most methods of estimate TP,…
3 Conceptual Model
User’s Manual » 3 Conceptual Model
This chapter introduces the conceptual models implemented in VO.
Step 15: Compare Results by Scenario Comparison
Tutorials » LIDs and Water Quality Single-Event Model » Step 15: Compare Results by Scenario Comparison
Click the Scenario Comparison button in the Simulation toolbar. Select the Design Storm, Scenario and Commands to be compared. The chart will compare the corresponding runoff flow. For example, the figure below compares the runoff at AddHyd – 9, which is the…
3 SWM Pond Modeling
Reference Guide » 3 SWM Pond Modeling
Probably the single biggest use for Visual OTTHYMO is to help create water resources strategies whereby stormwater management ponds are implemented to address issues of water quality control, erosion control, and water quantity (i.e. flooding) control. Visual OTTHYMO…
A.3 Batch Edit
User’s Manual » 12 Appendix A – Tools » A.3 Batch Edit
After selecting multiple commands, users can use Batch Edit to edit the parameters of selected commands in a batch. To use Batch Edit tool, first select commands. Then, right-click on the Schematic or Map View to open context menu and select Batch Edit. Users can…
Step 3: Create StandHyd for Urban Catchment
Tutorials » Creating a VO Model in Schematic View » Step 3: Create StandHyd for Urban Catchment
Navigate to the Tool Box, which is the left-side bar on the screen in the default setting, select StandHyd and drag it to the desired location (somewhere in sub-catchment 1003 in this case) on the canvas and release it. A new StandHyd will be created in the given…
Step 3: Add Water Quality in Model
Tutorials » LIDs and Water Quality Single-Event Model » Step 3: Add Water Quality in Model
This table contains TP and TSS loading rates for different land uses in mg/L. We will be using the default water quality table found in the Resources Library, however users may duplicate this table and edit/add land use types and loading rates. If you choose to…
Step 3: Create NasHyds with Catchment Layer
Tutorials » Creating a VO model with Existing GIS Data » Step 3: Create NasHyds with Catchment Layer
For easy selection of objects on the catchment layers, keep the catchment layer selected and highlighted and hide the other imported layers. Use mouse left click for single selection. Use ctrl + mouse left click for multiple selection. The selected objects will be…
Step 3: Create NasHyd for the rural subcatchment
Tutorials » Modeling a Wetland: Continuous Simulation, Calibration and Hydroperiod Analysis » Step 3: Create NasHyd for the rural subcatchment
Select NasHyd command under the Hydgrographs section in the Tool Box. Drag and drop the NasHyd command from the Tool Box to to the desire location (somewhere in the subcatchment) on the Schematic view. A new NasHyd will be created in the given location. Click…
Step 15: Import the Post-Development Scenarios with Control to the Continuous Project
Tutorials » Analyzing Erosion for New Development » Step 15: Import the Post-Development Scenarios with Control to the Continuous Project
We will go back to the continuous project to evaluate the long-term impact. Save the Single-Event Project Before working on a continuous project, save the single-event project. Click Save Project button in the Home toolbar to save all information (including all…
Step 3: Create a Sub Group for STM Files
Tutorials » Using Resource Library » Step 3: Create a Sub Group for STM Files
In this step, we will create a Sub Group under the Test group and add design storms from STM files. Create a Sub Group by either of the two ways: 1) click the Sub Group button in the toolbar 2) right click the group where we want to include a Sub Group, i.e.…
Step 3: Add Temperature Data to the Resource Library
Tutorials » Working with a Continuous Model » Step 3: Add Temperature Data to the Resource Library
The temperature data can be added to the library in a similar way as the precipitation data. Select the Continuous tab in the Resource Library. Select the group “exercise” and add a new temperature gauge by either of the following two ways: 1) click the…
Step 3: Create a Scenario for Post-development Conditions
Tutorials » Sizing a Pond Using the Route Reservoir Command » Step 3: Create a Scenario for Post-development Conditions
1. Duplicate the scenario of “Existing Conditions” In the Project Manager window, under Drainage Network Scenarios, select the “Existing Conditions” scenario and then duplicate the scenario by either of the following two ways: 1) right click to…
Step 3: Create Scenarios for Post-Development without Control
Tutorials » Analyzing Erosion for New Development » Step 3: Create Scenarios for Post-Development without Control
We will divide the original site of 20 ha into two subscatchments, one NasHyd of 12 ha and one StandHyd of 8 ha. Duplicate the scenario “Existing” by clicking the Duplicate button on the Project Manager. Rename the new scenario as “Post”.…
Step 3: Run Simulations for Post-Development Conditions without LIDs
Tutorials » LIDs and Water Quality Continuous Model » Step 3: Run Simulations for Post-Development Conditions without LIDs
Following the similar procedure to run and view results for the scenario of post-development conditions without LIDs. Find the scenario “Post-Dev. Initial” under the Drainage Network Scenarios group in the Project Manager. Double-click the scenario to open…
2.4 Setting Hydrologic Object Properties
User’s Manual » 2 Quick Start Tutorial » 2.4 Setting Hydrologic Object Properties
Default parameter values are used for newly created hydrologic objects, which may need to be changed to represent the working project. Parameters can be edited with the Properties window or the Parameters Tables window. The Properties window is used to edit the…
3.16 Hydrograph Results / Water Balance Results
User’s Manual » 3 Conceptual Model » 3.16 Hydrograph Results / Water Balance Results
The Hydrograph Results and Water Balance Results window is the same window which appears differently for single-event simulation and continuous simulation. By default, this window is at the bottom of the main interface. It’s used to show the summary results of each…
12 Appendix A – Tools
User’s Manual » 12 Appendix A – Tools
As stated in Chapter 4, hydrologic object parameters can be edited directly in Properties window and Parameter Tables window. In some cases (e.g. model calibration), the parameter values may need to be changed by a certain percentage. Tools have been provided to make…
A.2 Batch Assign
User’s Manual » 12 Appendix A – Tools » A.2 Batch Assign
Parameter values may be available in another source. If these parameters are in the appropriate order, they can be pasted in Parameter Tables window. If not, they can be assigned to hydro-logic objects using the Batch Assign tool. The Batch Assign tool uses an…
3.10 Overview
User’s Manual » 3 Conceptual Model » 3.10 Overview
The interface has been designed to provide plenty of working space for the schematic and map model while maintaining easy access to the hydrologic objects and their associated parameters. The layout consists of various sections as explained in the text below. Most of…
5.7.1 Instantaneous Unit Hydrograph
Reference Guide » 5 Unit Hydrograph Options in Visual OTTHYMO » 5.7 Unit Hydrograph Options for Rural Areas » 5.7.1 Instantaneous Unit Hydrograph
Many ways of deriving synthetic unit hydrographs or IUH have been proposed since the early studies of Snyder in 1938. One frequently used way is by means of a conceptual model made up of a cascade of equal, linear reservoirs, first proposed by Nash in 1957. The IUH for…
Step 4: Create RouteChannel with Stream Layer
Tutorials » Creating a VO model with Existing GIS Data » Step 4: Create RouteChannel with Stream Layer
Turn on the stream layer and turn off other layers on top of the stream layer. Use ctrl + mouse left key to select all the three streams. The selected streams will be highlighted in red. Right click the mouse to open the context menu and select RouteChannel in…
4.1.1 Critical Review of SCS Curve Number Procedure
Reference Guide » 4 Computation of Rainfall Losses » 4.1 Critical Review of SCS Curve Number Procedure » 4.1.1 Critical Review of SCS Curve Number Procedure
The SCS CN procedure is based on the equation (6) It is assumed in the procedure that the initial abstraction = 0.2 S. This results in the equation (7) The curve numbers CN are functionally related to S by (8) CN can be obtained from tables based on land…
3.17 Water Quality Results
User’s Manual » 3 Conceptual Model » 3.17 Water Quality Results
The Water Quality Results window is the same window appearing for single-event simulation and continuous simulation. By default, this window is at the bottom of the main interface. It’s used to show the water quality summary results of each hydrologic object. In…
9.2.1.1 Viewing Summary Data in Table
User’s Manual » 9 Working with Output » 9.2 Single-Event Simulation Outputs » 9.2.1 Summary Data » 9.2.1.1 Viewing Summary Data in Table
To view the summary data in a table, use the Hydrograph Result window at the bottom besides the Parameter Tables window. It shows the summary data of all objects in the model. On the top of the window, there are two options to specify the run and switch to show all…
FAQ
FAQ
Q: Which files should I send for reporting a ticket? A: When reporting an issue, you can send an email to support@smartcitywater.ca by including the following information. Please denote your software version and build numbers. You can find them by clicking the…
3.18 Error List
User’s Manual » 3 Conceptual Model » 3.18 Error List
The Error List window shows the errors and warnings in the model. By default, it’s located at the bottom of the main interface. Certain rules apply to an OTTHYMO model. If these rules are not met, a warning or an error will show in the Error List window. A model…
4.4 Considerations in Using the Rainfall Losses
Reference Guide » 4 Computation of Rainfall Losses » 4.4 Considerations in Using the Rainfall Losses
For flood control purposes and master drainage planning, there are both rural and urban areas in the watershed. In Visual OTTHYMO, the rainfall losses in the rural areas are computed by means of the CN* procedure. The critical storms for rural conditions are…
5 Unit Hydrograph Options in Visual OTTHYMO
Reference Guide » 5 Unit Hydrograph Options in Visual OTTHYMO
In Visual OTTHYMO, the response of a watershed to the effective rainfall is obtained by convolution of a short duration unit hydrograph (UH) derived from the theory of conceptual “instantaneous unit hydrographs” or IUH. The characteristics of these unit…
6.3.9 Defining Layer Symbol
User’s Manual » 6 Working with the Map » 6.3 Using Layers » 6.3.9 Defining Layer Symbol
The appearance of features on the map are defined using symbols. For an empty project, a default symbol is generated for each layer. To change the symbol: Select the Layer Properties menu from layer context menu or click Layer Properties button from GIS toolbar. The…
7.5.2 Adding IDF Group
User’s Manual » 7 Working with Resource Library » 7.5 Adding New Items » 7.5.2 Adding IDF Group
An IDF group is a group of IDF curves of various return periods (2-100 year) for the same location or area. To add an IDF group, first select the parent group and then click the IDF Group button in the Toolbar or choose Add New IDF Group in the context menu, which…
6.6.4.1 Adding Rain Gauges
User’s Manual » 6 Working with the Map » 6.6 Using GIS Tools » 6.6.4 Distributed Rainfall Modeling Technique (DRMT) » 6.6.4.1 Adding Rain Gauges
To have a proper rainfall surface, minimum three rain gauges are required. There are two ways to add rain gauges on the Map: Add rain gauges manually Add rain gauges by importing a shapefile Add Rain Gauge Manually Adding a rain gauge is similar to adding other…
1.2 Modified Curve Number, CN*
Reference Guide » 1 Tips for Modeling Ungauged Rural Catchments » 1.2 Modified Curve Number, CN*
The Modified Curve Number method was first proposed by Paul Wisner & Associates in 1982, and was based on their research and monitoring of rural and urban catchments in Canada. This method has been used successfully in Canada for the past 35 years and has correlated…
3.4.3 WILHYD
User’s Manual » 3 Conceptual Model » 3.4 Flow Generation Hydrologic Objects » 3.4.3 WILHYD
WilHyd is used to simulate hydrographs from rural watersheds with long recession periods. The program uses the Williams and Hann’s unit hydrographs developed in the original HYMO program and the Modified SCS Curve Number Procedure to calculate the rainfall…
5.7.3 William’s Unit Hydrograph
Reference Guide » 5 Unit Hydrograph Options in Visual OTTHYMO » 5.7 Unit Hydrograph Options for Rural Areas » 5.7.3 William’s Unit Hydrograph
WILHYD is the subroutine that uses the unit hydrograph proposed by Williams and Hann (1973). The unit hydrograph is divided into three parts for computation. The first part, from the beginning of rise to the inflection point, , is computed by the 2-parameter gamma…
6.6.3 Calculating Landuse Percentage
User’s Manual » 6 Working with the Map » 6.6 Using GIS Tools » 6.6.3 Calculating Landuse Percentage
In some cases, model parameters are available in GIS layers. The Calculate LandUse Percentage tool reads the parameter values, calculate the area weighted value if necessary and then assign to catchments LandUse. To use this tool: Add the GIS layer that has the…
Step 7: Create Chicago, SCS Type II and AES Design Storm based on IDF Group
Tutorials » Using Resource Library » Step 7: Create Chicago, SCS Type II and AES Design Storm based on IDF Group
Chicago, SCS Type II and AES design storms of each return period could be created based on an IDF Group. The total rainfall volume for each return period is based on the duration. To create these design storms, select the IDF Group created in previous steps, i.e. Test…
6.6.1 Calculating CN
User’s Manual » 6 Working with the Map » 6.6 Using GIS Tools » 6.6.1 Calculating CN
Curve Number (CN) is the most important parameter to determine surface runoff when SCS equation is used. Its value varies for different soil types, land use, and Antecedent Soil Moisture Condition (AMC). The CN for the average antecedent soil condition (CNII) is…
8.3.1 Setting Simulation Engine
User’s Manual » 8 Running a Simulation » 8.3 Continuous Simulation » 8.3.1 Setting Simulation Engine
Continuous simulation has global and command-specific parameters. To change global parameters, click the Engine Options button in Simulation tab. The Simulation Engine window will appear. In the Simulation Engine window, the parameters are grouped to four (4)…
Step 1: Open VO and create a Continuous Otthymo project
Tutorials » Working with a Continuous Model » Step 1: Open VO and create a Continuous Otthymo project
1. Navigate to File -> New Project and select New Continuous Otthymo Project 2. To import Single-event VO Model, use menu File -> Import -> Import VH Scenario (Current project) and browse to the training package. Open…
3.5.4.2 Discharge
User’s Manual » 3 Conceptual Model » 3.5 Flow Routing Hydrologic Objects » 3.5.4 ROUTERESERVOIR » 3.5.4.2 Discharge
Manual Input When users choose Unknown as the shape and Manual Input as discharge type, users need to give the table of Discharge-Storage Curve (Rating Curve). It has pairs of discharge-storage values to describe the Discharge-Storage relationship of the…
3.8.2 STOREHYD
User’s Manual » 3 Conceptual Model » 3.8 Other Hydrological Objects » 3.8.2 STOREHYD
StoreHyd is used to enter ordinates of a hydrograph directly. TABLE 3-10 STOREHYD PARAMETERS Parameter Name Description Default Value AREA The watershed area from which the hydrograph was derived (ha or acre) 30 HYD…
6.6.2 Calculating Area Weighted
User’s Manual » 6 Working with the Map » 6.6 Using GIS Tools » 6.6.2 Calculating Area Weighted
In some cases, model parameters are available in GIS layers. The Calculate Area Weighted tool reads the parameter values, calculate the area weighted value if necessary and then assign to catchments. The imperviousness (TIMP and XIMP) and initial abstraction are two…
1 Tips for Modeling Ungauged Rural Catchments
Reference Guide » 1 Tips for Modeling Ungauged Rural Catchments
This section outlines different methodologies for modeling ungauged rural catchments. While it is preferable to use a calibrated hydrologic model for water resources studies, especially for rural catchments, this is not always possible. Satisfactory results may still…
3.9.8 GREEN ROOF
User’s Manual » 3 Conceptual Model » 3.9 Low Impact Development (LID) » 3.9.8 GREEN ROOF
Green roofs are covered with growing media and vegetation that enable rainfall infiltration and evapotranspiration of stored water. They are particularly cost-effective in dense urban areas where land values are high and on large industrial or office buildings where…
Creating a VO model with Existing GIS Data
Tutorials » Creating a VO model with Existing GIS Data
In this exercise, we will create a VO model in the map view, where a model can be created by manipulating the GIS features. Not only can GIS data be used to create the model structure but it also can be used to calculate parameter values. Please download the…
3.12 Toolbar
User’s Manual » 3 Conceptual Model » 3.12 Toolbar
The following tables list the icons from the Toolbar and their name. There are three (3) tabs in total: Home, GIS and Simulation. A brief description of the contents of these tabs are given in Table 4-3 Table 4-5. For a more detailed description of each Toolbar item,…
3.9.4 PERMEABLE PAVEMENT
User’s Manual » 3 Conceptual Model » 3.9 Low Impact Development (LID) » 3.9.4 PERMEABLE PAVEMENT
Permeable pavement allows stormwater to drain through the surface layer into a stone reservoir. This is where water can be stored and then infiltrated into surrounding soils. Permeable pavement is designed with an overflow and an optional subdrain feature. Key features…
3.4.2 NASHYD
User’s Manual » 3 Conceptual Model » 3.4 Flow Generation Hydrologic Objects » 3.4.2 NASHYD
NasHyd is used to simulate runoff flows with Nash instantaneous unit hydrograph. This hydro-graph is made of cascade of “N” linear reservoirs. The command is mainly used for rural areas but can also be used for very large urban watersheds and to simulate the…
Step 8: Add Design Storms to Model
Tutorials » Using Resource Library » Step 8: Add Design Storms to Model
We will add the design storms created in previous steps to the model. To do that, navigate to Test -> STM group in Library Explorer, right click STM group to open the context menu and choose Add All Design Storms to Project menu. An information window will appear as…
Step 8: Calculate CN
Tutorials » Creating a VO model with Existing GIS Data » Step 8: Calculate CN
Now, the model structure has been created. All parameter values except NasHyd area and RouteChannel length are using default values. GIS layers can help determine some parameter values. In this example, the soil layer and the land use layer will be used to estimate the…
3.4.4 SCSHYD
User’s Manual » 3 Conceptual Model » 3.4 Flow Generation Hydrologic Objects » 3.4.4 SCSHYD
ScsHyd is essentially the same as the NasHyd with the exception that it uses parameters for the SCS Procedure (i.e. initial abstraction is a function of the SCS Curve Number, and the number of linear reservoir “N” is set to 5). This command can be used when the SCS…
3.9.9 FILTER
User’s Manual » 3 Conceptual Model » 3.9 Low Impact Development (LID) » 3.9.9 FILTER
Filter systems is designed to remove the primary pollutants of concern from runoff and allows runoff to be treated close to its source without additional collection. Users could set a targeted treated flow rate with removal efficiencies in VO6. Key features for filter…
I am wondering if VO-SWMM has the capability to estimate catchment areas of each storm? If so, how would I access this feature?
FAQ » I am wondering if VO-SWMM has the capability to estimate catchment areas of each storm? If so, how would I access this feature?
There is a tool in VOSWMM to extract the area of a subcatchment. To do so, you can do the following steps. 1- open VOSWMM and click on the tab “Map” 2- click on “Add Layer” 3- select the layer that you have. You can see that VOSWMM accepts a lot of…
Step 6: Create IDF Group
Tutorials » Using Resource Library » Step 6: Create IDF Group
IDF data includes the rainfall intensity for various return periods. In Resource Library, the rainfall intensities of a certain return period are represented as an IDF Curve. A group of IDF Curves of different return periods is an IDF Group. Each IDF Curve could be…
Step 6: Setup and Run Simulation for Model Calibration
Tutorials » Analyzing Erosion for New Development » Step 6: Setup and Run Simulation for Model Calibration
Click on the Existing scenario tab to show the Schematic view of the existing scenario, because we will use the Existing scenario for model calibration. Click the Run button located at the Simulation tab. In the opened Batch Run window, make sure your setting is…
3.9.2 SOAKAWAY PIT
User’s Manual » 3 Conceptual Model » 3.9 Low Impact Development (LID) » 3.9.2 SOAKAWAY PIT
Soakaway pits are excavations in the ground filled with clean granular stone or other void forming material that receives “clean” runoff designed to infiltrate into the native soil. Soakaway pits are designed with an overflow and an optional subdrain feature. Key…
3.9.7 ENHANCED SWALES
User’s Manual » 3 Conceptual Model » 3.9 Low Impact Development (LID) » 3.9.7 ENHANCED SWALES
Enhanced grass swales are vegetated open channels designed to convey, treat and store stormwater runoff. Enhanced swales will calculate the volume of surface ponding and infiltration throughout the swale. Users have options for designing enhanced dry or wet swales.…
3.6.2 DUHYD
User’s Manual » 3 Conceptual Model » 3.6 Flow Separation Hydrologic Objects » 3.6.2 DUHYD
DuHyd is used to separate the major (street flow) and the minor (pipe flow) hydrographs from a total hydrograph. TABLE 3-8 DUHYD PARAMETERS Parameter Name Description Default Value Major NHYD of major system connection Empty…
1.2 About the User’s Manual
User’s Manual » 1 Introduction » 1.2 About the User’s Manual
The manual is divided into chapters and does not necessarily have to be read from start to finish. Users that are familiar with previous releases of Visual OTTHYMO can probably learn how to navigate around the model on their own and need only refer to the guide for new…
7.5.4.3 New Design Storms Based on IDF Group
User’s Manual » 7 Working with Resource Library » 7.5 Adding New Items » 7.5.4 Adding Design Storm » 7.5.4.3 New Design Storms Based on IDF Group
Chicago, SCS Type II and AES design storms can be created using the IDF data. To create the design storms, Select the IDF Group and choose the corresponding context menu based on the type of design storms to be created. The parameter window will appear as shown in…
1.1 Initial Abstraction Paramters, IA
Reference Guide » 1 Tips for Modeling Ungauged Rural Catchments » 1.1 Initial Abstraction Paramters, IA
This section introduces the calculation and selection of curve number based on initial abstraction parameter.
2.2 Loss Routine
Reference Guide » 2 Tips for Modeling Ungauged Urban Catchments » 2.2 Loss Routine
In both the United States and Canada, either the Horton’s Method (LOSS = 1) or the CN Method (LOSS = 2) are commonly used for urban catchments. The Proportional Loss Method (LOSS = 3) has been successfully used in France for urban catchments. While the selection of…
3.5.3 ROUTEPIPE
User’s Manual » 3 Conceptual Model » 3.5 Flow Routing Hydrologic Objects » 3.5.3 ROUTEPIPE
RoutePipe is used to route hydrographs in circular or rectangular pipes. It uses a simplified form of the RouteChannel input. Only the pipe diameter or width and heights are required and only one Manning’s roughness coefficient is allowed. The hydrologic object…
References
Reference Guide » References
1. Arnell Viktor, “Rainfall Data for the design of Sewer Pipe Systems” Report Series A:8, Department of Hydraulics, Chalmers University of Technology, 1982. 2. Arnell Viktor, “Analysis of Rainfall Data for use in Design of Storm Sewer Systems”…
3.3 Common Parameters
User’s Manual » 3 Conceptual Model » 3.3 Common Parameters
Some parameters are available for all or most of the hydrologic objects. These parameters are given in Table 3-2. TABLE 3-2 COMMON HYDROLOGIC OBJECT PARAMETERS Parameter Name Description Default Value Applicable Hydrologic Object NHYD…
3.8.1 READHYD
User’s Manual » 3 Conceptual Model » 3.8 Other Hydrological Objects » 3.8.1 READHYD
ReadHyd is used to read a previously saved hydrograph from a file. The parameter FILEPN is the file name of the saved hydrograph. For file format, see 10.4.
A.4 Calibrate Commands
User’s Manual » 12 Appendix A – Tools » A.4 Calibrate Commands
For model calibration, a few sensitive parameters may need to be adjusted several times before a good result can be achieved. The adjustment usually comes with a percentage change. To assist on this process, the Calibrate Commands tool can be used. It allows users to…
3.9.5 RAIN GARDEN
User’s Manual » 3 Conceptual Model » 3.9 Low Impact Development (LID) » 3.9.5 RAIN GARDEN
Rain gardens generally function as a stormwater filter and infiltration practice which can be used to temporarily store, treat and infiltrate runoff. The LID is designed with an engineered soil layer to store and treat runoff which then infiltrates into surrounding…
6.4 Using the Map
User’s Manual » 6 Working with the Map » 6.4 Using the Map
The model components and other helper information are displayed on the map. With the geospatial information, the model is easier to understand. Furthermore, it enables to utilize existing GIS layers to create the model structure and determine the parameter values.…
4.3.1 Horton’s Equation
Reference Guide » 4 Computation of Rainfall Losses » 4.3 Infiltration Procedures in STANDHYD » 4.3.1 Horton’s Equation
For pervious areas, there are two options for calculating the infiltration losses. The first option is Horton’s equation where the infiltration capacity rate is an exponential function of time, which decays to a constant rate. It is written as follows: …
1.1.1 Modified Curve Number Method (CN*)
Reference Guide » 1 Tips for Modeling Ungauged Rural Catchments » 1.1 Initial Abstraction Paramters, IA » 1.1.1 Modified Curve Number Method (CN*)
When using the Modified Curve Number Method, the IA parameter should be set to a value in the range of 1.0 mm and 5.0 mm, depending on the circumstances. The IA value must then be used to calculate (see below).
3.9.3 UNDERGROUND STORAGE CHAMBERS
User’s Manual » 3 Conceptual Model » 3.9 Low Impact Development (LID) » 3.9.3 UNDERGROUND STORAGE CHAMBERS
Underground storage chambers are typically designed to store larger volumes of water and are often used for quantity control. Underground storage chambers have large void spaces and typically have open bottoms allowing the system to infiltrate into the surrounding…
5.7.2 Estimation of Time to Peak (Tp) in NASHYD
Reference Guide » 5 Unit Hydrograph Options in Visual OTTHYMO » 5.7 Unit Hydrograph Options for Rural Areas » 5.7.2 Estimation of Time to Peak (Tp) in NASHYD
It is, of course, best to obtain Tp by calibration with measurements. If data is available, the following procedure may be utilized to estimate Tp. DEFINITION OF TIME LAG The first step involves determining the time lag which is defined as the time difference…
3.11 Toolbox
User’s Manual » 3 Conceptual Model » 3.11 Toolbox
The following tables list the hydrologic objects from the Toolbox and their name. Hydrologic objects with bold font can be used in both single-event and continuous simulation. Users of previous versions of Visual OTTHYMO and OTTHYMO will recognize these commands. For a…
7.9 Adding Water Quality Data to Model
User’s Manual » 7 Working with Resource Library » 7.9 Adding Water Quality Data to Model
Water quality calculations have been added in VO 5.2. Total suspended solids (TSS) and total phosphorus (TP) loading and removal rates can be specified and calculated in the model. The user can input loading rates based on existing or proposed land use. To add water…
4.2 Calibration of the Modified SCS CN Procedure
Reference Guide » 4 Computation of Rainfall Losses » 4.2 Calibration of the Modified SCS CN Procedure
The modified SCS CN procedure was tested first on the Seymaz watershed in a joint study by the University of Ottawa and the Ecole Polytechnique Federale de Lausanne who had previously done extensive monitoring. This watershed is composed of 30.2 of rural areas and 8 …
3.9.6 BIORETENTION
User’s Manual » 3 Conceptual Model » 3.9 Low Impact Development (LID) » 3.9.6 BIORETENTION
Bioretention areas filter, detain and infiltrate stormwater runoff. Bioretention areas are known for their water quality, quantity and water balance benefits. The LID is designed with an engineered soil layer to store and treat runoff, a storage layer to detain larger…
Step 4: Assign Land Use for Hydrograph Commands
Tutorials » LIDs and Water Quality Single-Event Model » Step 4: Assign Land Use for Hydrograph Commands
Select the NasHyd command “Farm Field 1” and open the Properties menu. At the bottom of the Properties menu there is a heading for Water Quality. Select the button next the LandUse field and you will see a window with a list of land uses which match those…
9.4.3 Evapotranspiration
Reference Guide » 9 Water Balance Processes in Continuous Simulation » 9.4 Active Soil Zone Water Balance » 9.4.3 Evapotranspiration
A PET reduction factor, PETFACT, is employed to account for lower evaporation during days with rain. The default value is 0.1. The potential evapotranspiration will first be fulfilled by the evaporation from depression storage and then the active soil zone. The…
3.7 Flow Merging or Reading Hydrologic Objects
User’s Manual » 3 Conceptual Model » 3.7 Flow Merging or Reading Hydrologic Objects
AddHyd is used to add any number of hydrographs. There is no parameter associated with AddHyd. A junction is primarily used to read the flow from upstream commands or connections, and no parameters are associated with it. A junction is also a tool for accurately…
9.3.3.3 Plot Calibration
User’s Manual » 9 Working with Output » 9.3 Continuous Simulation Outputs » 9.3.3 Time Series Plot » 9.3.3.3 Plot Calibration
Similar to the single-event simulation, it is important to compare the observed and simulated time-series data for model calibration. For file format, please refer to 10.3 Calibration Files. As there are more than one time-series data available, it is necessary to…
1.7.2 What’s New in Version 6.1
User’s Manual » 1 Introduction » 1.7 What’s New » 1.7.2 What’s New in Version 6.1
For Visual OTTHYMO 6.1 (VO) we have added scenario comparison to single-event and continuous models., upgraded continuous modeling by including GIS tool and hydrograph commands of ScsHyd and NasHyd, improved LID package, expanded the data exporting/importing function…
6.6.4.2 Using DRMT Tool
User’s Manual » 6 Working with the Map » 6.6 Using GIS Tools » 6.6.4 Distributed Rainfall Modeling Technique (DRMT) » 6.6.4.2 Using DRMT Tool
To use the DRMT tool in continuous project, interpolate the rainfall for each catchment: Select subcatchment whose rainfall data to be obtained from DRMT tool. Note that the selected catchments must be assigned to a geometry. If no catchments are selected by users,…
The ADS system has multiple rows of chambers. However, VO asks for only 1 rating curve and outputs only 1 value for outflow. Is the software conceptualizing all the rows into a single row of chambers?
FAQ » The ADS system has multiple rows of chambers. However, VO asks for only 1 rating curve and outputs only 1 value for outflow. Is the software conceptualizing all the rows into a single row of chambers?
What manufacturer you have selected? For StormTech, you just need to know the number of chambers. This means it does not matter whether the chambers have been in rows or not. The number of rows is not a parameter for StormTech. For Triton, you must enter the number…
6.6.5 Obtain Rainfall from Raster
User’s Manual » 6 Working with the Map » 6.6 Using GIS Tools » 6.6.5 Obtain Rainfall from Raster
In case that users have their own raster files and want to obtain time-series rainfall data from those raster files, they can use the Obtain Rainfall from Raster tool. Select subcatchment whose rainfall data to be obtained from raster files. Note that the selected…
3.14.5 CN* Flag
User’s Manual » 3 Conceptual Model » 3.14 Properties » 3.14.5 CN* Flag
When SCS equation is used to calculate the rainfall excess in pervious area, the Curve Number (CN) is the most important parameter. From the early research of OTTHYMO, it has been rec-ommended to use the modified CN, i.e. CN*. VO has provided a tool (Convert to ) to…
9.5 Modeling a Wetland
Reference Guide » 9 Water Balance Processes in Continuous Simulation » 9.5 Modeling a Wetland
The wetland command in VO is designed to mimic a natural wetland, with a wet storage area surrounded by a dry vegetated area. The storage area and dry area are both dynamic in order represent the flooding and drying out seen in many natural wetlands. The way this…
3.5.1 ROUTECHANNEL and COMPOUNDCHANNEL
User’s Manual » 3 Conceptual Model » 3.5 Flow Routing Hydrologic Objects » 3.5.1 ROUTECHANNEL and COMPOUNDCHANNEL
RouteChannel is used to route hydrographs through typical channel cross-sections using the Variable Storage Coefficient (VSC) Method. The open channel cross-sections are described with X and Y co-ordinates. The COMPOUNDCHANNEL command in VO6 has been split to calculate…
3.4.1 STANDHYD
User’s Manual » 3 Conceptual Model » 3.4 Flow Generation Hydrologic Objects » 3.4.1 STANDHYD
StandHyd is used to simulate runoff flows from urban watersheds. Two parallel standard instantaneous unit hydrographs are used to convolute the effective rainfall intensity over the pervious and impervious surfaces. The losses over the pervious surfaces are…
3.9.1 Common Parameters
User’s Manual » 3 Conceptual Model » 3.9 Low Impact Development (LID) » 3.9.1 Common Parameters
LID parameters have been set based on the 2010 Low Impact Development Stormwater Management Planning and Design Guide. Certain parameters are available for most LIDs. These parameters are given in Table 3-11. TABLE 3-11 LIDs COMMON PARAMETERS Parameter Name…
Step 11: Set Parameters for Rain Garden
Tutorials » LIDs and Water Quality Single-Event Model » Step 11: Set Parameters for Rain Garden
Rain Garden in VO does not have an option for entering a underdrain or outflow structure. If these are included in your design, you should use the Bioretention command. The only runoff leaving a Rain Garden is the overflow. 1. Calculate the required total volume The…
How can I calculate the IDF group?
FAQ » How can I calculate the IDF group?
In VO, it is possible to add IDF groups (IDF Group) . However, to calculate IDF manually, you can do the following steps: To calculate IDF, we need recorded precipitation values. Step 1 For each year, select the maximum precipitation with different duration. For…
9.2.3.3 Plot Calibration
User’s Manual » 9 Working with Output » 9.2 Single-Event Simulation Outputs » 9.2.3 Hydrograph Plot » 9.2.3.3 Plot Calibration
It is necessary to compare the observed and simulated hydrograph in model calibration. Plotting the two hydrographs and the corresponding rainfall in the same plot is very helpful to guide the calibration. Identifying the Gauge Objects’ To compare to an…
9.4.4 Groundwater Infiltration
Reference Guide » 9 Water Balance Processes in Continuous Simulation » 9.4 Active Soil Zone Water Balance » 9.4.4 Groundwater Infiltration
The percolation equation used in SWMM (Rossman & Huber, 2016) is used to calculate the groundwater infiltration. where: K = the saturated hydraulic conductivity, ∅ = the soil total porosity, θ = the soil moisture HCO = the percolation coefficient depending on…
8.3.2 Creating and Running Simulations
User’s Manual » 8 Running a Simulation » 8.3 Continuous Simulation » 8.3.2 Creating and Running Simulations
To create a continuous simulation, click the Run button located at the Simulation tab to open the Batch Run window. This layout is similar to the single-event simulation and has more columns which are described below. The first and second columns are the same as…
Step 4: Adjust Schematic Layout
Tutorials » Sizing a Pond Using the Route Reservoir Command » Step 4: Adjust Schematic Layout
Convert hydrograph commands for developed areas to StandHyds. Right click on NasHyd 1003 and select convert to StandHyd. Repeat for NasHyd 1005. You will see the NasHyd commands are changed to NasHyd commands. Delete the link from StandHyd 1003 to RouteChannel…