---
title: "1D river simulations - CES tab | Technical Reference"
slug: "ces-tab"
description: "Learn about the CES tab when viewing 1D river results. "
tags: ["1D river modelling", "viewing results"]
updated: 2022-08-05T09:41:19Z
published: 2022-08-05T09:41:19Z
canonical: "help.floodmodeller.com/ces-tab"
stale: true
---

> ## Documentation Index
> Fetch the complete documentation index at: https://help.floodmodeller.com/llms.txt
> Use this file to discover all available pages before exploring further.

# 1D river simulations - CES tab

This tab contains the run options and advanced parameters specific to simulations using the Conveyance Estimation System (CES).

![RiverSimulationsimagesCESimage026.jpg](https://cdn.document360.io/5074bc26-a9ef-4bf4-b1de-a5c6ce628aca/Images/Documentation/RiverSimulationsimagesCESimage026.jpg?sv=2026-02-06&spr=https&st=2026-10-28T14%3A17%3A51Z&se=2026-10-28T15%3A17%3A51Z&sr=c&sp=r&sig=dnrpYPICFQ%2B1JyzDy6XOp2uinCQY%2B5dH%2FvXOOz4rz6U%3D)

*Roughness mode* enables you to select from the minimum, recommended or maximum roughness values.

The CES advanced parameters are as follows:

| Parameter | Description | Default |
| --- | --- | --- |
| Number of depth intervals | Number of depth intervals | 25 |
| Lateral eddy viscosity | Lateral eddy viscosity for main channel | 0.24 |
| Minimum depth | Minimum depth used in calculation | 0.0 |
| Number of vertical segments | Number of vertical segments used in integration | 100 |
| Relaxation | Relaxation (alter if conveyance calculation does not converge) | 1 |
| Temperature | Water temperature | 15 |
| Maximum number of iterations | Maximum number of iterations | 15 |
| Convergence tolerance | Convergence tolerance | 0.001 |
| Wall height multiplier | Multiply the height of the section by x to add an extra wall to the sides of the section | 1.5 |