Sorry I was too impetuous. I have to think about it more calmly. In fact, I am too ignorant on the subject. If it were the water blade, it wouldn't make sense for it to grow faster in case of the smaller reservoir. But I would expect, in my logic, that the water depth would again grow in the smaller reservoir. I will do more tests, try to understand. Or maybe the model is not adapted to the presence of small ponds. Consider that these are 30 and 70 m³ ponds, very small indeed. -- -- Perito agrario Enrico Gabrielli progetto F.A.R.M. www.farm-agroecologia.it Tessera n. 633 Collegio Periti agrari prov. Di Modena Biblioteca agricoltura: https://www.zotero.org/groups/aplomb/ https://www.inaturalist.org/observations/bonushenricus
Il giorno mar, 01/08/2023 alle 16.23 +0200, bonushenricus ha scritto: > Thank you, Anna. > r.sim.water finishes the simulation not at the end of the rainfall > event, in my case at 30 minutes, but at an earlier time. In my case, > in the smaller reservoir at 16 minutes, in the case of the more > extensive reservoir at 24 minutes. But the water keeps coming even > after that. I imagined that the calculation ends when it reaches the > steady state of the water blade. > But it's not so. Then I don't understand why it ends at 16 or 24 > minutes. Doesn't the water continue to arrive after that? Shouldn't > it increase? > I cannot understand it. In the reservoirs, the discharge is very low, > as I expect. But if the discharge does not increase and the > precipitation continues, I expect the water depth to rise again. > And it is not understandable that two reservoirs, one twice the > volume of the other, contain the same depth of 30 cm at the end of > the rainfall. > To understand how this works, I would apply waterproofing to the > reservoirs. The ksat, or infil_value, is the only variable that can > explain this: the larger reservoir loses more water. > If both reservoirs were waterproof, I would have removed this > variable. Unfortunately r.sim.water infil=raster where I have marked > value 0 in the reservoirs does not work. There is perhaps a bug that > I have reported. So I haven't had a chance to test this. > I don't know how to do it; I can't trust the 30 cm as a value to > calculate the water volume in the two reservoirs. I will have to use > another model. > I will try to use a distributed model. Since I have the data in > GRASS, I will try using the old geomhydas, hoping the modules will > work in GRASS8, and then use the Mhydas models in OpenFluid. I have > no other chance unless someone can help me find a solution. > -- > -- > Perito agrario Enrico Gabrielli > progetto F.A.R.M. www.farm-agroecologia.it > Tessera n. 633 Collegio Periti agrari prov. Di Modena > Biblioteca agricoltura: https://www.zotero.org/groups/aplomb/ > https://www.inaturalist.org/observations/bonushenricus > > Il giorno mar, 01/08/2023 alle 09.23 -0400, Anna Petrášová ha > scritto: > > > > > > On Mon, Jul 31, 2023 at 11:42 PM bonushenricus > > <bonushenricu...@gmail.com> wrote: > > > Hi Anna > > > I too immediately thought it was enough to compute it for the > > > final step of the simulation, > > > but I noticed that the same slope, same ditches, same rainfall, > > > for two reservoirs at the same location, same length along a > > > contour, but different width and depth, at the final step of the > > > simulation the water depth was always 30 cm, I went to read the > > > article > > > Mitasova, Helena, Chris Thaxton, Jaroslav Hofierka, Richard > > > McLaughlin, Amber Moore, e Lubos Mitas. «Path Sampling Method for > > > Modeling Overland Water Flow, Sediment Transport, and Short Term > > > Terrain Evolution in Open Source GIS». In Developments in Water > > > Science, 55:1479–90. Elsevier, 2004. > > > https://doi.org/10.1016/S0167-5648(04)80159-X > > > where I read the Saint-Venant equation. I am an agricultural > > > technician and geographer unfortunately ignorant of hydrological > > > calculations and serious mathematics, and I understood, looking > > > at the equation, that the water depth is the depth of overland > > > flow = rainfall exces - water flow. > > > So the final 30 cm should not be understood as accumulated water, > > > but as the blade of water that was added at that precise moment. > > > Isn't my interpretation right? > > > > > > > > > No, it should be actual water depth. I didn't understand the > > discrepancy you are describing? > > > > > > --
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