---
title: "Computing H1 for Cast In-situ Drain"
description: "A [cast in-situ drain](https://mes100.com/docs/precast-drain-vs-cast-in-situ-drain-in-mits/#1-toc-title) is a type of drainage system constructed directly on-site using poured concrete. Unlike [pre-cast drains](https://mes100.com/docs/precast-drain-vs-cast-in-situ-drain-in-mits/#0-toc-title), which are manufactured off-site (*fixed dimension*) and transported to the location, cast in-situ drains are formed and poured at the construction…"
url: "https://mes100.com/docs/computing-h1-for-cast-in-situ-drain/"
updated: "2026-10-12"
category: Exposition / Drain
---

# Computing H1 for Cast In-situ Drain

A [cast in-situ drain](https://mes100.com/docs/precast-drain-vs-cast-in-situ-drain-in-mits/#1-toc-title) is a type of drainage system constructed directly on-site using poured concrete. Unlike [pre-cast drains](https://mes100.com/docs/precast-drain-vs-cast-in-situ-drain-in-mits/#0-toc-title), which are manufactured off-site (*fixed dimension*) and transported to the location, cast in-situ drains are formed and poured at the construction site (*custom dimension*). This method allows for customization to fit specific site conditions and design requirements. Therefore, the height of the cast in-situ drain can be varied depending on its surrounding terrain (ground level).

So, how does MiTS calculate (iterate) the cast in-situ drain height? A simple formula is used;

Cast In-situ Drain (Half-round, Block):

| Total Height (H1+H2) | = |   Ground Level – End Invert Level |
| --- | --- | --- |
| H1 | = |   GL – End IL – H2 |

Sample Project File **[HERE](https://largefilehosting.s3.ap-northeast-1.amazonaws.com/ProjectSharing/Client%20Project%20-%20Saiful/13226%20-%20Cast%20In-situ%20Drain.zip)**

![](https://i0.wp.com/mes100.com/wp-content/uploads/2026/10/google-a53c03e725.png?w=1080&ssl=1)

| Drain (End Node) | GL, m | End IL, m | H2, mm | Calculated H1, mm | Iterated H1, mm |
| --- | --- | --- | --- | --- | --- |
| 1 (2) | 26.113 | 25.883 | 112.5 | 117.5 | 116.928 |
| 2 (3) | 26.151 | 25.807 | 225 | 119 | 118.104 |
| 3 (4) | 26.464 | 25.627 | 112.5 | 724.5 | 724.583 |
| 4 (5) | 26.372 | 25.596 | 225 | 551 | 550.899 |
| 5 (6) | 24.543 | 24.256 | 150 | 137 | 136.703 |
| 6 (7) | 24.057 | 23.701 | 225 | 131 | 131.868 |

In conclusion, the calculation for the cast in-situ drain heights show that the **iterated heights closely match the calculated values**, indicating accurate and consistent design adjustments by software. The custom dimensions (**iteration**) of the drain, which are based on ground level, ensure that the drain fits well. Overall, the design process successfully adapts to the site conditions while maintaining precision in the final dimensions.

### *Related*

 [![](https://i0.wp.com/mes100.com/wp-content/uploads/2024/10/me-small.jpg?resize=100%2C100&ssl=1)](https://mes100.com/author/admin/)[Ngu Soon Hui](https://mes100.com/author/admin/)

I’m the [Benevolent Dictator for Life](https://en.wikipedia.org/wiki/Benevolent_dictator_for_life) for MiTS Software cum Editor of this website. Read more [here](/about-ngu-soon-hui/).

You can also contact me at soonhui@mes100.com