The dynamic water system on land is programmed as a blueprint.**BP_Watersystem** contains both the logic and the assets of the water system. The backbone of the **BP_Watersystem** is a spline with points. The points represent a change in the water system, for example: input discharge, different structure (pipe, channel, weir..), different dimension. So each point (=Node) is connected with the database **WaterSystemData**. So in between 2 points (=branch) of the backbone spline, everything is the same, based on the information of the downstream point.. Spline and point represent the bedlevel of the structure.

Index 0 spline is downstream

Al the programming is done in the so called construction script. This is a cool feature of Unreal Engine. Al programmed calculations can be done in the editor. It is for example not necessary to run the game, to see what waterlevels will occur. They are already calculated in the editor.

Formulas used for calculation water levels

Some general Notes:

- The basis of the watersystem is a spline. Between 2 nodes the structure is the same. The location of the spline is the bedlevel.
- A
**BP_Watersystem**is one line with no branches and has a fixed direction of flow. - A dendritic system is possible, because the 3D world may contain different
**BP_Watersystems**which are connected at points. When calculation a dendritic system the sequence of making calculations is important. - Strategy for calculating the water-system.We assume a stationary flow. So new calculations are only made when changes are made to the water-system. In the future calculations will be made per time-step and change in storage will also be taken into account.

Link to page with formulas used - To get access to the information, or to change information menu are used.

Link to page Navigation - Internal Unreal uses centimeters, the BP_watersystem uses m
- Backbone of BP_Watersystems is the WaterDataStruct which stores all data (also calculated data) for each branch.

## Connect side branches

- Information on side branch is stored in [ConnectionLeft] and/or [ConnectionRight]
- In FD_GameMode: FD_WaterSystemsref and FD_WatersystemName. Note This does not work in constructionscript ? So it should be a separate function in the constructionscript.
- New function Find_Side_Branches
- Changed variable InputDischarge to a 2dvector. x = de input branch, y is the input from sidebranches

## Design Manhole

- Is not a separate branch, but is generated when 2 culvert pipes branches connect.
- The check is made for the first pipe. Is the second branch also a pipe.

So for the first pipe it is the “next point index” - Switch to add manhole is :

When diameter pipes is different, manhole is added automatically

When diameter pipes is the same, the following switch is used.

Slope X = 0 add manhole, Slope X = 1 no manhole - Manhole is always a rectangle, with max 4 pipes connected. So 2 other BP_watersytems could be connected to the manhole.
- Alle dimensions in m
- When function manhole is activated the following information is defined:

– bedlevel, based on 4 connections

– D1, D2 (left), D3, D4(right)

– Width manhole based on D1 and D4. Width = Max D1 / D3 + 0,6 m

– Length manhole based on D2 en D4. Length = Max D2 / D4 + 0,6 m

– Length manhole / 2 = reduction length (m)

– Surfacelevel is de highest surfacelevelworld of the 4 connections - Manhole is activated before the pipe is drawn. This because the reduction length
- In de first version, side connections is not taken into account.
- Information from the array is also necessary for the Reduction Length for ending and starting pipe.

## Design weir

- Exists of 3 parts, left – middle (=crest) – left
- Width_Diameter_m.x = width weir.
- Width_Diameter_m.y = width sides