Thanks Micha What a mistake with Manning's coefficient! I took off a zero! For infil: the soil is sandy. The 24.1 mm/h is taken from the soil map with published regional data. There are two reference sites in the area of soil delineation: 48% sand and 22% clay: 7.7 mm/h; 52% sand, 14% clay: 24.1 mm/h. If I can, I will go and measure on the ground. But for now, maybe 15 might be good. The result, however, still doesn't convince me. If I try the simulation on "invaso6", with the same parameters as "invaso2", it ends after 10 minutes with a result of 30 cm.
Il giorno mer, 02/08/2023 alle 00.45 +0300, Micha Silver ha scritto: > Hello Enrico: > > Anna knows this subject better than I do, but I noticed a few > problems with your command, so here are some comments that might help > to get a better result. > > First, your man_value is way too high. You probably want something > like 0.03 > Second, you are using the '-t' flag but no `output_step`, If you add > output_step of a few minutes, then you should get multiple output > rasters at each time step. > Third, you have 40 mm/hr rain_rate and 24.1 mm/hr infiltration rate. > Is that correct? That means that 60% of the rain is infiltrating > throughout the 30 minute storm. This might happen in very dry and > sandy soil. Is that your situation? > > Here's what I tried (changing the above 3 parameters): > > r.external ./reservoir_farm_granello/dem_invaso2.tif output=dem_2 > g.region -ap rast=dem_2 > r.slope.aspect elevation=dem_2 dx=dx_2 dy=dy_2 > r.sim.water -t elevation=dem_2 dx=dx_2 dy=dy_2 rain_value=40 > infil_value=15 man_value=0.0368 depth=water_depth_invaso2_40x30mm > discharge=discharge_invaso2_40x30mm niterations=30 output_step=5 > random_seed=42 nprocs=8 --overwrite > > This resulted in 5 depth (and 5 discharge) rasters. For example: > > r.univar water_depth_invaso2_40x30mm.05 > 100% > total null and non-null cells: 1197120 > total null cells: 667811 > > Of the non-null cells: > ---------------------- > n: 529309 > minimum: 4.25896e-05 > maximum: 0.313524 > range: 0.313481 > mean: 0.00323487 > mean of absolute values: 0.00323487 > standard deviation: 0.0125372 > variance: 0.000157182 > variation coefficient: 387.565 % > sum: 1712.24596255017 > micha@RMS:bonuschenricus$ r.univar water_depth_invaso2_40x30mm.25 > 100% > total null and non-null cells: 1197120 > total null cells: 667811 > > Of the non-null cells: > ---------------------- > n: 529309 > minimum: 4.25896e-05 > maximum: 0.406802 > range: 0.406759 > mean: 0.00358821 > mean of absolute values: 0.00358821 > standard deviation: 0.0176433 > variance: 0.000311286 > variation coefficient: 491.702 % > sum: 1899.27293131027 > > r.univar discharge_invaso2_40x30mm.05 > 100% > total null and non-null cells: 1197120 > total null cells: 667811 > > Of the non-null cells: > ---------------------- > n: 529309 > minimum: 0 > maximum: 0.595495 > range: 0.595495 > mean: 0.000783053 > mean of absolute values: 0.000783053 > standard deviation: 0.0121067 > variance: 0.000146571 > variation coefficient: 1546.08 % > sum: 414.477138618156 > micha@RMS:bonuschenricus$ r.univar discharge_invaso2_40x30mm.30 > 100% > total null and non-null cells: 1197120 > total null cells: 667811 > > Of the non-null cells: > ---------------------- > n: 529309 > minimum: 0 > maximum: 0.595495 > range: 0.595495 > mean: 0.000857986 > mean of absolute values: 0.000857986 > standard deviation: 0.0125651 > variance: 0.000157882 > variation coefficient: 1464.49 % > sum: 454.13982509354 > > > Attached is the final depth map (after 30 minutes). You might try a > longer run time (higher niternations) > One other note: Your region resolution is 0.2 meters (from the > original DEM) so each pixel is 0.04 sq meters. The sum of values of > all non-null cells in the final depth map is about 1900 (from the > r.univar result). So the total discharge should be about 76 m³. Does > that sound reasonable? > > HTH > Micha > > On 01/08/2023 21:35, bonushenricus wrote: > > > > > Thank you Anna. > > I will try to attach the two geotiffs in a compressed folder, with > > the simplest example of a single ditch, for both reservoirs. > > EPSG:32632. > > The ditch is not exactly the same for the two reservoirs, they > > change a little bit in the final part of the mouth of the > > reservoir, but it is very similar. > > Sorry I didn't use a sample vector of points, I did it later with > > temporal. > > > > > r.slope.aspect elevation=dem_invaso2 dx=dx_invaso2 dy=dy_invaso2 > > > > > r.sim.water -t elevation=dem_invaso2 dx=dx_invaso2 dy=dy_invaso2 > > > rain_value=40 infil_value=24.1 man_value=0.368 > > > depth=water_depth_invaso2_40x30mm > > > discharge=discharge_invaso2_40x30mm niterations=30 --overwrite > > > > > r.slope.aspect elevation=dem_invaso6 dx=dx_invaso6 dy=dy_invaso6 > > > > > r.sim.water -t elevation=dem_invaso6 dx=dx_invaso6 dy=dy_invaso6 > > > rain_value=40 infil_value=24.1 man_value=0.368 > > > depth=water_depth_invaso6_40x30mm > > > discharge=discharge_invaso6_40x30mm niterations=30 --overwrite > > Thank you very much > > I am sure there is some mistake on my part! > > > > -- > > -- > > 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 13.17 -0400, Anna Petrášová ha > > scritto: > > > > > > > > > > > On Tue, Aug 1, 2023 at 10:23 AM bonushenricus > > > <bonushenricu...@gmail.com> wrote: > > > > > > > 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. > > > > > > > > > > > > > Unfortunately I haven't had time to look at the reported issue. > > > Perhaps you could share your data and provide exact commands and > > > pictures, explaining very clearly what's wrong. > > > > > > > > > > -- > > > > -- > > > > 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? > > > > > > > > > > > > > > > > > -- > > > > > > _______________________________________________ > > grass-user mailing list > > grass-user@lists.osgeo.org > > https://lists.osgeo.org/mailman/listinfo/grass-user
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