# Delay Node

## General Description

The **delay node** is a node that delays flow for a given number of timesteps or days. This node will be used when the water propagation time cannot be ignored, compared to the selected time scale. [API Reference](https://pywr.github.io/pywr-docs/master/api/generated/pywr.nodes.DelayNode.html).

## Primary Attributes

<table><thead><tr><th width="180.33333333333331">Name</th><th width="316">Description</th><th>Required</th></tr></thead><tbody><tr><td>allocation penalty</td><td>The cost per unit flow via the node</td><td>Optional</td></tr><tr><td>timesteps</td><td>Number of timesteps to delay the flow</td><td>Optional</td></tr><tr><td>days</td><td>Number of days to delay the flow. Specifying a number of days (instead of a number of timesteps) is only valid if the number of days is exactly divisible by the model timestep delta</td><td>Optional</td></tr><tr><td>initial_flow</td><td>Flow provided by node for initial timesteps prior to any delayed flow being available. This is constant across all delayed timesteps and any model scenarios. Default is 0.0</td><td>Optional</td></tr></tbody></table>

## Examples

coming soon...


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://water-strategy.gitbook.io/waterstrategy/modeling-basics/node-types/water-transport/delay-node.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.