Based on the information in Section 3.10.1 "Runoff Coefficient Method" from the SWMM User's Manual, here's a summarized table

Based on the information in Section 3.10.1 "Runoff Coefficient Method" from the SWMM User's Manual, here's a summarized table:

Parameter	Description	Impact on Runoff (💧)	Implementation in SWMM (🖥️)
Runoff Coefficient Method	Used in preliminary models for generating runoff flows with minimal site-specific data.	-	Simplifies runoff computations.
Runoff Coefficient (C)	Represents the fraction of rainfall that becomes runoff.	Higher values lead to more runoff.	Set subcatchment's percent imperviousness to 100 and its percent of imperviousness with no depression storage to 0.
Rainfall Rate (i)	Rate of rainfall (ft/s).	Higher rates increase runoff.	Use with the runoff coefficient in the formula: Q = CiA.
Subcatchment Area (A)	Area of the subcatchment (ft²).	Larger areas increase runoff.	Define in subcatchment settings.
Infiltration Rate (f)	Rate at which water infiltrates into the ground (ft/s).	Higher rates reduce surface runoff.	Implement as a constant infiltration rate in SWMM.
Depression Storage	Volume that must be filled before runoff occurs.	Influences the delay in runoff initiation.	Assign the same depression storage depth to both pervious and impervious areas.
Manning’s Roughness (n)	Coefficient indicating surface roughness.	Higher values indicate rougher surfaces, reducing runoff speed.	Use 0 for pervious and impervious areas to simulate immediate runoff.

This table captures the key aspects of the Runoff Coefficient Method as outlined in the SWMM User's Manual. The method provides a simplified approach for estimating runoff, particularly useful in initial, screening-level analyses. 🌧️📈🖥️💻🌍🌱🚰📊

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:

Category	Details	Emojis and Notes
📜 Overview	The 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 Categories	Includes 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 Groups	Four 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 Conditions	Defined 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 Equation	Runoff 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 Conditions	Adjusting CNs for urban areas, agricultural practices, or dry conditions.	🏗️🚜 Modifications to the base CN reflect changes in land use or weather patterns.
📚 Example CN Values	Provides 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 🌧️

Parameter	Typical Effect on Hydrograph	Effect of Increase on Runoff Volume	Effect of Increase on Runoff Peak	Comments
🌳 Area	Significant	📈 Increase	📈 Increase	Less effect for a highly porous catchment
🏙️ Imperviousness	Significant	📈 Increase	📈 Increase	Less effect when pervious areas have low infiltration capacity
📏 Width	Affects shape	🔽 Decrease	📈 Increase	Increasing 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
⛰️ Slope	Affects shape	🔽 Decrease	📈 Increase	Similar to width but less sensitive, as flow is proportional to square root of slope
🌾 Roughness	Affects shape	📈 Increase	🔽 Decrease	Inverse effect as compared to width
💧 Depression Storage	Moderate	🔽 Decrease	🔽 Decrease	Significant 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.