Rational Method Runoff Basics

适用场景

Use this guide for early drainage conversations when you must show assumptions for intensity, area, and coefficient transparently.

要使用的工具

Browser-based preliminary check for Rational Method Runoff Calculator — fast estimates, not code or stamped design output.

打开 Rational Method Runoff Calculator →

步骤

  1. 1Define catchment boundary and contributing impervious vs pervious fractions.
  2. 2Pick a design storm intensity and duration appropriate to local guidance.
  3. 3Choose a runoff coefficient consistent with cover type and slope.
  4. 4Compute peak flow and sanity-check magnitude with experience and alternate methods.
  5. 5Move to hydrograph routing when storage and timing effects dominate.

示例

  • Parking lot inlet sizing discussion.
  • Roof drain peak for a small building.

应避免

  • Using rational method for very large basins without checking validity limits.
  • Mixing intensities from different return periods without labeling.
  • Ignoring downstream constraints while only sizing a pipe segment.

相关工具

博客

工程 中的更多内容

所有任务指南 或前往 工程 专区.

常见问题

Is this code-compliant?

It is a teaching-oriented screening tool; local codes may require approved hydrology methods.

Snowmelt?

Not included; extend model when winter hydrology matters.

所有任务指南 · 工程 工具 · 博客