Creation of a scenario centralized / decentralized question

What do you need?

• Prepare you GIS data using the previous flowchart

• Install pysewer, wetlandoptimizer and DataPlotly (see Installation page, sections external dependencies et third-party QGIS plugins)

• Gather the following informations for preliminary sizing of the sewer network:

  • average daily production of wastewater per person (m³)

  • possible minimum and maximum sewer depths (for pipes) in your context

  • usual diameters for pipes

• Gather the following informations for the pre-design of wastewater treatment trains:

  • usual concentrations for domestic wastewater in your context (TSS, COD,BOD₅, TKN, TN, NO₃-N, TP, e.coli)

  • outfow concentration targets imposed by local regulations (TSS, COD and BOD₅)

This flowchart aims to provide guidance for creating scenarios on your study area.

It is interactive: you can zoom in and click on certain blocks to be redirected to the corresponding sections in the documentation.

        flowchart TB
        A1[I check that: <br/> - all my layers are in the same CRS <br/> <a href="https://elan-gis.org/en/installation.html#dependances"> - external dependencies are installed</a>]
        A2[Do I have a layer with all possible discharge points?]
        B1[Do I want to consider only some of them for this scenario?]
        B2[<a href="https://elan-gis.org/en/petite_anse.html#select-steu">I select the one.s I want to consider</a>]
        A3[<a href="https://elan-gis.org/en/scenario_prb1.html#start-reseau">I launch the *Sewer network* module</a>]
        C1[I specify my wwtp layer and I tick *Selected features only*]
        C2[I specify my wwtp layer]
        C3[I do not specify any wwtp layer]
        A4[- I fill my DEM, building and road layers.<br/> - I change the default values of the parameters I know. <br/> - I select the range of possible gravity-driven diameters. <br/> - I specify a name and save location. <br/> - I run the module. ]
        A5[<a href="https://elan-gis.org/en/scenario_prb1.html#sorties-reseau">I get 7 layers</a>]
        A6[<a href="https://elan-gis.org/en/petite_anse.html#groupe">I gather them in a group</a>]
        A7[Do I want to explore the proposed pre-sizing?]
        D[<a href="https://elan-gis.org/en/petite_anse.html#select-styles">I change the pipes layer style.</a> <br/> <a href="https://elan-gis.org/en/petite_anse.html#view-attributs">I look at the attributes.</a> <br/> <a href="https://elan-gis.org/en/scenario_prb1.html#visualisation-profils">I use the *Longitudinal sewer profile* module.</a>]
        A8[Am I satisfied with the proposed pre-sizing?]
        A1 --> A2
        A2 -- yes --> B1
        B1 -- yes --> B2 --> A3
        B1 -- no --> A3
        A2 -- no --> A3
        A3 --> C1 --> A4
        A3 --> C2 --> A4
        A3 --> C3 --> A4
        A4 --> A5 --> A6 --> A7
        A7 -- yes --> D --> A8
        A7 -- no --> A8
        E["I edit my road and building layers or even my discharge points layer (addition/deletion) to adjust pre-sizing"]
        A9[<a href="https://elan-gis.org/en/petite_anse.html#specify-c">I edit my wwtp layer to state my inflow concentrations and my outflow target concentrations for each discharge point.</a> <br/> For the pollutants with no constraint, I leave the field to NULL.]
        A10[Are there surface constraints at my possible discharge points?]
        F1[<a href="https://elan-gis.org/en/petite_anse.html#define-surface">I create a polygon layer where I define the available areas</a>]
        F2[I check that my discharge points are included in the contoured areas]
        A11[<a href="https://elan-gis.org/en/scenario_prb1.html#start-procedes">I launch the *Processes* module</a>]
        G1[I specify the layer with the available areas]
        G2[I leave the *available area* input empty]
        A12["I choose between *Temperate* ou *Tropical* climate (Tmin >= 18°C all year around)"]
        A13[I fill my *WWTP* layer. <br/> I check that the parameters were correctly detected. <br/> I run the module.]
        A14[<a href="https://elan-gis.org/en/scenario_prb1.html#sortie-procedes">I get 1 treatment trains layer with several options</a>]
        A15[<a href="https://elan-gis.org/en/scenario_prb1.html#plots">I compare the several options using the graphical representations proposed in Elan</a>]
        A16[<a href="https://elan-gis.org/en/scenario_prb1.html#selection">For each discharge point, I pre-select one option among the possible ones</a>]
        A17[Is there several relevant options or option combinaisons?]
        A8 -- yes --> A9 --> A10
        A8 -- not entirely --> E --> A3
        A10 -- yes --> F1 --> F2 --> A11
        A10 -- no --> A11
        A11 --> G1 --> A12
        A11 --> G2 --> A12
        A12 --> A13 --> A14 --> A15 --> A16 --> A17
        H1[I create multiple scenarios for this sewer network configuration]
        H2[I create only one scenario for this sewer network configuration]
        A18[<a href="https://elan-gis.org/en/scenario_prb1.html#creer-scenario">I launch the *Create a scenario* module</a>]
        A19["I specify the sewer network and the associated treatment trains (the ones chosen must be pre-selected). <br/> I run the module."]
        A20[I get 1 gpkg with all my scenario components that will then allow comparison to other scenarios]
        A17 -- yes --> H1 -- for each case under consideration --> A18
        A17 -- no --> H2 --> A18
        A18 --> A19 --> A20