Saturday, November 11, 2023

Section 3.10.2 "SCS Curve Number Method" from the SWMM User's Manual, enhanced with emojis and additional information

 Here's a summarized table for Section 3.10.2 "SCS Curve Number Method" from the SWMM User's Manual, enhanced with emojis and additional information:

CategoryDetailsEmojis and Notes
📜 OverviewThe SCS Curve Number Method approximates runoff using soil type, land use, and hydrologic condition.🌱🌍 A key method in hydrology for estimating direct runoff from rainfall.
🌳 Land Use CategoriesIncludes agricultural, forest, and urban areas, each with different runoff potential.🏙️🌲 Different land uses significantly impact how water moves and is absorbed in an area.
🔍 Soil GroupsFour groups (A, B, C, D) based on infiltration rates, with A being the most permeable and D the least.💧📊 Soil properties greatly influence runoff; permeable soils like sandy soil absorb more water, reducing runoff.
💧 Hydrologic ConditionsDefined as good, fair, or poor, reflecting the efficiency of runoff generation.🌿🚰 The condition of the vegetative cover on the soil plays a critical role in runoff. Good condition means less runoff.
📈 Curve Numbers (CN)Numeric values assigned based on land use, soil group, and hydrologic condition to estimate runoff.🔢 CNs range from 30 to 100, with higher numbers indicating greater runoff potential.
📉 Runoff EquationRunoff is calculated using the CN, rainfall amount, and a specific formula.🌧️🧮 The equation considers the balance between rainfall and the amount that can be absorbed by the soil.
🔄 Adjustments for ConditionsAdjusting CNs for urban areas, agricultural practices, or dry conditions.🏗️🚜 Modifications to the base CN reflect changes in land use or weather patterns.
📚 Example CN ValuesProvides CN values for various scenarios like urban areas, different crops, and forest conditions.🏡🌾 These examples help in applying the method to real-world situations for accurate runoff estimations.

This table encapsulates the key aspects of the SCS Curve Number Method as described in the SWMM User's Manual, providing a clear and concise overview of this important hydrological tool. 🌊📚🌦️

🌊 Table 3-6: Sensitivity of Runoff Volume and Peak Flow to Surface Runoff Parameters 🌧️ from the SWMM5 Hydrology Manual

 

🌊 Table 3-6: Sensitivity of Runoff Volume and Peak Flow to Surface Runoff Parameters 🌧️

ParameterTypical Effect on HydrographEffect of Increase on Runoff VolumeEffect of Increase on Runoff PeakComments
🌳 AreaSignificant📈 Increase📈 IncreaseLess effect for a highly porous catchment
🏙️ ImperviousnessSignificant📈 Increase📈 IncreaseLess effect when pervious areas have low infiltration capacity
📏 WidthAffects shape🔽 Decrease📈 IncreaseIncreasing width tends to produce higher and earlier hydrograph peaks, especially for storms of varying intensity. Affects volume only when reduced width on pervious areas allows more time for infiltration
⛰️ SlopeAffects shape🔽 Decrease📈 IncreaseSimilar to width but less sensitive, as flow is proportional to square root of slope
🌾 RoughnessAffects shape📈 Increase🔽 DecreaseInverse effect as compared to width
💧 Depression StorageModerate🔽 Decrease🔽 DecreaseSignificant only for low-depth storms. Losses like evaporation, depression storage, and infiltration become less important as storm depth increases

🔍 Additional Notes:

  • In flooding scenarios, the land surface behaves increasingly like an impervious surface, hence urbanization has less impact on high-return period events than on common events.
  • Ground saturation consideration may invoke groundwater routines to allow water table rise to the surface.
  • For small storms, depression storage becomes crucial, although it is difficult to estimate and depends on initial conditions.

SWMM3 Acknowledgements Section

 Based on the "Acknowledgements" section you provided from the "SWMM3.docx" document, here is a structured summary listing the contributors and their respective contributions:

Contributor(s)Contribution
Richard Field, Harry Torno, Chi-Yuan Fan, Doug Ammon, Tom Barnwell (EPA colleagues)Continuous improvement of EPA SWMM since 1969-70; Management of SWMM Users Group
Dr. Russell G. Mein (Monash University)Reviewed, programmed, and tested Green-Ampt infiltration routines; Sabbatical at the University of Florida
George F. Smith (Office of Hydrology, National Weather Service)Earliest implementation of continuous simulation in Runoff and Storage/Treatment Blocks
Proctor and Redfern, Ltd. and James F. MacLaren, Ltd.Basic formulation of the snowmelt routines under contract with Ontario Ministry of the Environment and Canadian Environmental Protection Service
Douglas C. Ammon (EPA)Runoff Block surface quality changes based on master's research at the University of Florida
Dennis Lai (Clinton-Bogert Associates)Revision of Transport Block scour/deposition routines
W. Alan Peltz (General Electric)Many lasting improvements in SWMM programming
Corps of Engineers, Hydrologic Engineering CenterSuggested card ID system, user-defined default values, and ratios
Dr. William James (McMaster University)Programming basis aided by exposure to FASTSWMM programs
Murray McPherson, Eugene Driscoll, Dr. Dominic DiToro, John Mancini, Dr. Paul Wisner, Charles HowardEnhanced emphasis on proper use and objectives of SWMM modeling
Reinhard Sprenger (Templeton Engineering), Christian Eicher (Gore and Storrie, Ltd.), Robert Johnson (Lehigh University), Tom Jewell (Union College), Tom Meinholz, Richard Race (formerly of Envirex, Inc.)Various improvements and enhancements to SWMM
Dr. Larry Roesner, Dr. Robert Shubinski (CDM)Development and enhancement of Extended Transport Block; Extran contributions
J. Jay Santos, Efi Foufoula, Michael Kennedy, Kelly Nead, Christina Neff (University of Florida)Programming and testing
Linda Trawick, Jeanette Heeb, Kim Karr, College of Engineering Word Processing Center (University of Florida)Typing assistance
Terri Schubert, Micky Hartnett, Anelia CrawfordDrafting of figures
Northeast Regional Data Center (University of Florida)Computations

This table summarizes the collaborative effort and diverse contributions to the development and evolution of the EPA SWMM, highlighting the role of each contributor in enhancing different aspects of the model.

InfoSWMM: A 2030 AI-Assisted Study Guide

  InfoSWMM: A 2030 AI-Assisted Study Guide delete   InfoSWMM: A 2030 AI-Assisted Study Guide A comprehensive study guide for someone in 2030...