Délimitation des bassins versants des égouts pluviaux urbains

Question

<\/HEAD>J'essaie de délimiter les bassins versants qui contribuent à un réseau d'égouts pluviaux urbains (des centaines d'entrées collectent le ruissellement de surface et le transportent à travers une infrastructure souterraine). Les outils ArcHydro / GeoHMS sont excellents pour délimiter les réseaux de drainage de surface, mais je suis perdu quant à la meilleure façon de procéder. Je vais essayer de délimiter les bassins sans remplir les dépressions (beaucoup des entrées d'égouts pluviaux se trouvent dans des points bas locaux) et avec la définition du cours d'eau réglée assez petite, puis passer par une combinaison visuelle des sous-bassins, mais cela sera plus laborieux que souhaité.<\/P> <\/P> Merci, Andy <\/BODY><\/HTML>

andrewjack1 · Answer

Hi Andy

I just went through this process and didn't really find a great automated approach. Even the Hydro tools didn't seen to give me exactly what I needed. I ended up doing a combination of arc hydro and manual editing to delineate tributary area to each inlet. I essentially started at the larger watershed scale (huc 12) and then worked my way back from every outfall. 2nd Nature llc. outlines, nicely, a methodology for doing this.  They have a tutorial on their site under MAP MS4 TO MEET PHASE II PERMIT REQUIREMENTS- http://www.2ndnaturellc.com/client-access/central-coast-stormwater-ms4-support/ .

DarrenWiens2 · Answer

The way I'm thinking about this, you can make two watershed layers: one over ground, one underground. The pour points over ground would be your drains. The pour points underground are up to you (sewer junctions or something). Then Extract Values to Points​, to transfer underground watershed number to the drains. If the values are the same, then merge those corresponding over ground watersheds together.

edit: this assumes you have some sort of underground sewer data. Do you?

DanPatterson_Retired · Answer

the only application I have seen similar to this, is the individual had to create "trenches" in the DEM so that water could "flow" from one side of the road to the other.  It was for a thesis and looked pretty good but it required manual editing to connect one side of the road to the other.