Autodesk Technologist with Information about Stormwater Management Model (SWMM) for watershed water quality, hydrology and hydraulics modelers (Note this blog is not associated with the EPA). You will find Blog Posts on the Subjects of SWMM5, ICM SWMM, ICM InfoWorks, InfoSWMM and InfoSewer.
Degree day snowmelt is a method of predicting the rate at which snow will melt based on temperature. It is often used by utilities, highway departments, and other organizations to predict the amount of snowmelt runoff that will occur during the spring thaw.
To use degree day snowmelt, you need to know the average daily temperature and the base temperature for snowmelt. The base temperature is the temperature at which snowmelt begins to occur. It is typically between 32 and 35 degrees Fahrenheit, depending on the type of snow and the location.
To calculate the degree days for snowmelt, you will need to subtract the base temperature from the average daily temperature for each day. For example, if the base temperature is 32 degrees Fahrenheit and the average daily temperature is 40 degrees Fahrenheit, the degree days for snowmelt would be 8 (40 - 32 = 8).
Once you have calculated the degree days for each day, you can use a degree day snowmelt model to predict the rate at which the snow will melt. Several different models are available, each with its own set of equations and input parameters. Some models may also require additional data, such as the depth of the snowpack or the type of soil beneath the snow.
It's important to note that degree-day snowmelt models are based on statistical averages and are intended to provide a general estimate of snowmelt runoff. Actual snowmelt rates may vary due to factors such as the type of snow, the amount of sunshine, and other weather phenomena such as rain or wind.
In "Les Misérables," the character of Jean Valjean seeks refuge in the Parisian sewers after escaping from prison. The sewers are a hidden world beneath the city, where the outcasts and the unwanted can find shelter and support. However, the sewers are also a dangerous and treacherous environment, with strong currents and unpredictable flows that can pose a threat to those who are not familiar with their secrets. The importance of having the right hydraulics in the sewer system is highlighted in this context, as it ensures that the sewers can continue to serve as a lifeline for those in need, while also protecting the city from the dangers of flooding and water contamination.
The 1D St Venant flow equation is a vital tool for understanding the hydraulics of the sewer system. It allows engineers to calculate the speed and direction of flow in a sewer based on the geometry of the pipes and manholes, the volume of water entering the system, and other factors. The flow depth or d/D ratio, which is the ratio of the actual flow depth to the full flow depth, is an important consideration when using the St Venant equation, as it can indicate the hidden capacity of the sewer and help engineers to design a system that is efficient and effective.
Additionally, software like InfoWorks ICM can be used to model the complex flows within the sewer system, taking into account factors such as the rules of the system, the physical structure of the pipes and manholes, and how the system will behave over time. This can help engineers to design and maintain a system that is safe, efficient, and equitable, ensuring that the sewers continue to serve as a vital part of the city's infrastructure
Here is a table comparing some of the key features and capabilities of InfoWater Pro and EPANET:
Feature
InfoWater Pro
EPANET
Purpose
Water distribution network analysis and design
Water distribution network analysis and design
Platform
Windows
Windows, Linux, MacOS
Programming language
C++
C
License
Commercial
Open source (GNU GPL)
Input data formats
GIS layers, hydraulic profiles, demand patterns, and other data
Pipe layout, elevation data, and other data
Output data formats
Results and reports in various formats (e.g. maps, charts, tables)
Results and reports in various formats (e.g. maps, charts, tables)
Analysis capabilities
Water quality, energy, fire flow, water hammer, and other analyses
Water quality, energy, fire flow, and other analyses
Network modeling approach
Network model
Network model
Hydraulic solver
EPANET-based solver or Giswater-based solver
EPANET-based solver
Network visualization
3D visualization, GIS integration, and other visualization options
2D visualization and other visualization options
Additional features
Optimization, real-time monitoring, and other advanced features
Customization, scripting, and other advanced features
As this table illustrates, both InfoWater Pro and EPANET offer a range of capabilities for analyzing and designing water distribution networks. Ultimately, the choice between the two tools will depend on the specific needs and goals of the user, as well as factors such as the platform, programming language, license, and additional features that are most relevant to their project.
To improve the process of defining culvert inlet and culvert outlet losses for an InfoWorks network, a new field - Culvert code - has been added to their properties. This code is based on the culvert shape and material, and inlet and edge types, as defined in the Hydraulic Design of Highway Culverts, Third Edition, published by FHWA. When a code is selected, the values for K, M, c, Y, and Inlet headloss coefficient (Ki) fields are automatically populated if the #D flag is set on those fields. Previously, you could only manually enter these values. Note that for a culvert outlet, the Culvert code field is only displayed when its Reverse flow model is set to INLET.
How to Make InfoDrainage show you the INP file and SWMM5 modified report file
change the parameters in bold in the file C:\Users\yourname\AppData\Roaming\Innovyze\InfoDrainage\InfoDrainage.xml to have SWMM5 Output and INP file in the output directory
The NRCS dimensionless unit
hydrograph and the NRCS triangular unit hydrograph are widely utilized in the
United States to develop storm hydrographs for evaluating and designing soil and water resources management practices. These unit hydrographs are based
on a standard set of assumptions and are commonly used to model water flow in various hydrologic systems. However, in some regions of the country,
such as the Delmarva Peninsula, the local topography is relatively flat, and
there is a large amount of surface storage available. As a result, the shape of
the observed storm hydrographs in these areas can differ significantly from
those generated using the NRCS unit hydrographs.
To address this issue, a unit hydrograph
known as the Delmarva unit hydrograph has been developed and used by utilities
in Delaware, Maryland, Virginia, and some parts of New Jersey. This unit
hydrograph is similar to the NRCS dimensionless unit hydrograph, but it has
been modified to better represent the runoff characteristics of the Delmarva
Peninsula. By using the Delmarva unit hydrograph, utilities in these states can more accurately model the flow of water in their systems and better
understand the impacts of various soil and water resources management
practices. Overall, the Delmarva unit hydrograph is an important tool for
helping to improve the management and conservation of water resources in this
region.
The Delmarva unit hydrograph uses the following equation to estimate the peak flow rate.
Qp = 284 * A / Tp
where
Qp = peak flow rate in cfs.
A = area of the watershed, in square miles, draining to the location of the unit hydrograph.
Tp = time to peak of the unit hydrograph in hour
Time to peak, and lag time are calculated according to Equations 97 and 98, respectively. When compared with the NRCS methods, the Delmarva unit hydrograph produces lower peak flow rate but yields the same flow volume.
In addition to physical components, InfoSewer employs four types of informational objects to describe the behavior and operational aspects of a sewer collection system. The informational objects are loads, curves, patterns, and controls.
Loads
Sanitary sewer system flow has two main components: sanitary or dry-weather loads and wet-weather loads. These loads are based on knowledge of the area land use patterns, wastewater generation characteristics, industries, inflow and infiltration characteristics, external flows, etc.
Sanitary or dry-weather flow results from human activity and is defined as the flow that exists in the sewer collection system during rainless periods. This flow is composed of domestic, commercial, industrial, and institutional waste. The sanitary loads are the basic data required for any hydraulic computation.
Wet-weather flow is related to rainfall activity and consists of groundwater infiltration (extraneous flow entering the sewer system because of poor construction, corrosion of the pipe, ground movement or structural failure through joints, porous walls or breaks) and structure inflow (extraneous flow entering the sewer system through manhole covers, basement drains and other sources).
For steady-state modeling, manhole loads can be either unpeaked or peaked as follows:
Unpeakable Flow type - The corresponding load for each manhole is modeled as a direct flow into the sewer system.
where Qbase represents the average base flow (in flow units).
Peakable Base Flow - InfoSewer uses a general form of the Federov’s formula as follows:
where K and ρ are peaking factor parameters.
Default values are K = 2.4 and ρ = 0.89. Values of K and ρ can be modified.
Peakable Coverage Flow - InfoSewer uses the following formula which can describe both the Harman and Babbitt equations:
where P represents the population and a, b, c, d and e are peaking parameters. The default values for these parameters are: a = 5; b = 0; c = 0.2 , d = 0, and e = 1 which represents Babbitt equation (Babbitt and Baumann 1958). For the Harman equation (Babbitt and Baumann 1958): a = 14; b = 4; c = 0.5, d = 1 and e = 1.
For an extended period simulation, no peaking formula is used, instead, the multiplication factors from the diurnal pattern are used to adjust (multiply) all types of loads before they are aggregated. An example peaking-factor pattern is shown below.
Infiltration and inflow affect the operation of a sanitary sewer system and pumping, treatment, and overflow regulators facilities.
Infiltration occurs in gravity pipes while inflow occurs at manholes and wet wells. Infiltration loads refer to the volume of groundwater entering the sewer system from the soil through defective joints, broken or cracked pipes, improper connections, or manhole walls. Accurately determining infiltration is generally difficult as these loads depend on soil type, soil moisture conditions, system size and integrity, water table level, and the number of illegal connections. They are normally computed by subtracting base flow from total metered flow during dry weather or by compiling flow isolation measurements. Infiltration can be defined as proportional to the pipe length; proportional to the pipe length and to the pipe diameter; proportional to the pipe surface area (pipe length multiplied by its perimeter); proportional to the number of defects in the pipe (count-based); or as a pattern load/hydrograph (flow vs. time).
Inflow loads refer to stormwater or other drainage water and wastes (extraneous water) entering the sewer system through manhole covers. Inflow is measured during wet weather conditions and is determined by subtracting base flow and infiltration from data recorded during wet weather conditions. Inflows can be specified as pattern loads/hydrographs (flow vs time) for any manhole.
Patterns
Patterns are used to represent temporal variations within the system. They consist of a collection of multipliers (multiplication factors) that are applied to a base load to allow it to vary over time during an extended period simulation. The time interval used in all patterns is a fixed value set by the user. Although all patterns must utilize the same time interval, each can have a different number of periods. If the duration of a pattern is less than the total duration of the simulation, then the pattern will repeat itself and will wrap around to its first period again.
Two options are available for representing a pattern: stepwise or continuous (linear). A stepwise pattern is one that assumes a constant multiplication factor for each pattern time period. Within each time period a quantity remains at a constant level equal to the product of its nominal value and the pattern's multiplier for that time period. A continuous (linear) pattern is one that linearly interpolates for the multiplication factors between two adjacent time periods.
Different patterns can be applied to individual manholes or groups of manholes to accurately represent actual loading categories (e.g., low density residential, commercial, and industrial).
As an example of how patterns work consider a manhole with an average load of 2.0 CFS. Assume that the pattern time interval has been set to 4 hours and with the following multipliers:
Period
1
2
3
4
5
6
Multiplier
0.5
0.8
1.0
1.2
0.9
0.7
Then during the simulation, the actual load collected for this manhole will be as follows:
Hours
0-4
4-8
8-12
12-16
16-20
20-24
Load
1.0
1.6
2.0
2.4
1.8
1.4
Curves
Curves are objects that contain data pairs representing a relationship between two quantities. Two or more objects can share the same curve. An InfoSewer Pro model can utilize the following types of curves:
Volume curve
Peaking curve
Flow split curve
Design and analysis criteria curves
Replacement and duplication design cost curves
VOLUME CURVE
A volume curve determines how the wet-well volume (Y in cubic feet or cubic meters) varies as a function of the wastewater level (X in feet or meters). It is used when it is necessary to accurately represent a wet-well whose cross-sectional area varies with height (e.g., non-circular wet-wells). The lower and upper wastewater levels supplied for the curve must contain the lower and upper levels between which the wet-well operates. A valid volume curve must have increasing volume with increasing water height.
PEAKING CURVE
The peaking curve represents the variation of peak flows (Y-axis) as a function of base flows (X-axis) and is an alternative approach to compute flow data (loads) for peak conditions. Any peaking curve can be specified to estimate base flow peaks and model peak flow - base flow relationships.
FLOW SPLIT CURVE
A flow split curve determines how the flow split (Y in percentage or flow units depending on the desired split method) varies as a function of the total flow in the manhole (X in flow units). If the splitting method is the Variable Flow Split Percentage method then the Y data are specified in percentage. If the Inflow-Outflow Flow Split method is used then the Y data are specified in flow units. The data points must be defined in an increasing order of flow.
CRITERIA CURVES
Criteria curves are entered as a series of pipe diameters (X in inches or millimeters) along with their acceptable depth-to-diameter (d/D) ratios (Y unitless). The analysis criteria curve is used for determining the d/D ratios of existing pipe capacities while the design criteria curve is used for designing relief or replacement pipes when their capacity as determined by the analysis criteria has been exceeded. The data points specified for the above curves must be defined in an increasing order. For example, existing pipes up to 15 inch in diameter are allowed to flow only half full, up to 21 inch pipe can flow three-quarters full, and all other pipes are allowed to flow at full capacity.
DESIGN COST CURVES
A design cost curve determines how the design unit costs (Y in cost currency per unit of length) varies as a function of the diameter of the pipe to be designed (X in inches or millimeters). The user specifies one curve for each type of improvements, i.e., the construction of a new pipe (replacement method) and the placement of a parallel/relief pipe (duplication method). The data points for the above curves must be defined in an increasing order. Only those pipe diameters defined will be considered as candidate design sizes. Each pipe can also have specific design cost tables for replacement or duplication. The cost currency is user-specified.
DESIGN TABLE
InfoSewer supports modeling of circular and non-circular conduits for all the hydraulic simulations performed by the model (i.e., steady state analysis, design, and dynamic simulations). Unlike circular pipes that can be fully described in terms of a single input parameter (i.e., diameter), geometry of non-circular conduits is a function of multiple variables such as channel depth, channel width, and side slopes. As a result, the carrying capacity and the costs associated with replacing and duplicating non-circular pipes cannot be defined in terms of a single input parameter, thus limiting application of criteria curves and cost curves to circular pipes only.
For non-circular channels, the model provides a design table through which the user may supply inputs related to conduit sizes, flow depth to channel depth ratio for analysis as well as design criteria, replacement cost, and duplication costs for non-circular channels. The model calculates conveyance factor of the channel (a measure of channel’s carrying capacity) and associates this factor with their respective criteria and cost values. As described earlier, InfoSewer uses Manning equation to determine pipe flow in gravity mains. For Manning’s equation, the conveyance factor is given as:
where
Kf = conveyance factor, ft8/3 (m8/3)
R = hydraulic radius, i.e., the flow area divided by the wetted perimeter, ft (m)
A = flow area, ft2 (m2)
Controls
InfoSewer provides comprehensive operational control schemes to accurately simulate the dynamic hydraulic behavior of a sanitary sewer collection system. During an EPS, controls describe the on-off status and relative speed setting of selected pumps as a function of the flow levels or volumes of wet-wells, or to match a targeted pump discharge flow.
Level controls are stated in terms of the height of wastewater above the wet-well bottom elevation. The default “ON Setting” value is the top wastewater level/volume of the wet-well while the default “OFF Setting” is the bottom wastewater level/volume of the wet-well.
An example of level control is given below:
IF (level in wet-well WW1 drops below 2 feet) THEN (turn OFF pump P1)
The default pump speed setting is one (pump speed ratio of 1). The initial pump status is overwritten by the operational controls during an extended period simulation.
