SWMM5 Inlet Spread Code

 📌 Purpose of the Code:

This function determines how much the flow 🌊 spreads across a street's cross-section using equations from HEC-22 based on Izzard's form of the Manning equation.

📂 Inputs:

• Q: 🚰 Represents the flow rate in the conduit (measured in cfs, or cubic feet per second).

📂 Output:

• Returns 📤 the width of the flow spread across the street (measured in feet).

🔍 Detailed Breakdown:

1️⃣ Initial Setup:

• The function starts by setting f to Qfactor, which seems to be a constant derived from the Manning equation 📖 and the geometry of the conduit.

2️⃣ No Depressed Curb:

• If the value of a (seems to represent the depressed curb) is zero, the function calculates the spread of flow Ts1 using a formula from HEC-22 📝.

3️⃣ Depressed Curb Exists:

• If there's a depressed curb (i.e., a is non-zero):

  a. The function first checks if the spread is within the curb width W. It does this using another formula.

  b. If the spread Tw is less than or equal to W, then Ts1 is set to Tw.

  c. If the spread extends beyond the curb width, it goes into a loop ⭕ (for a maximum of 10 iterations) to refine the spread's estimate using another set of HEC-22 equations. The loop keeps refining the estimate until the difference between two successive estimates is very small (less than 0.01).

4️⃣ Final Result:

• The function returns 📤 the final estimated spread, but ensures it doesn't exceed Tcrown (probably the maximum spread possible).

📝 Summary: This function calculates how much water 🌊 flows across a street given the flow rate in a conduit. It uses specific formulas from HEC-22 and considers street geometry, especially the presence of a depressed curb. By determining the flow spread, it helps in understanding how water distributes across the street during events like rainfall 🌧️ or flooding 🌊.

Hope this emoji-laden explanation helps you grasp the essence of the code better! 🌟🥳📚