6 ms·

This is a great analysis. However, this seems a little off: "Based off of our estimate, for every inch of rainfall at the Oroville dam, 136,790.5 acre-feet wil

by caseyf7 10y ago

This is a great analysis. However, this seems a little off: "Based off of our estimate, for every inch of rainfall at the Oroville dam, 136,790.5 acre-feet will be added to the reservoir." The relationship probably isn't linear. Much less of the first inch of rain makes it to the reservoir vs. the 5th inch of rain. Hopefully, the next iteration will project how many inches of rain it will take this weekend to top the spillway again.

AnimalMuppet 10y ago
> Much less of the first inch of rain makes it to the reservoir vs. the 5th inch of rain. Depends on whether the ground is already saturated.
- pilom 10y ago
  Even if the ground is saturated, plants still will absorb more of the first inch than the 5th.
  - AnimalMuppet 10y ago
    I don't think that's right. If the ground is saturated, the plants won't absorb any of it, because it won't sink into the ground at all, because the ground is saturated. (That is, unless you're talking about plants absorbing water from their leaves directly, before the water hits the ground. I don't know that plants do that when their roots already have plenty of water, but I also don't know that they don't.)
acomjean 10y ago
They have models for run off. In my previous career we used tr55 analysis of watersheds, this included surface types, slopes and areas. You model for various storms once the model is built. We didn't have to deal with mountain snow packs which add another factor. Edit: I think newer programs to model exist now. Some are here https://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/national/water/manage/hydrology/?cid=stelprdb1042480 https://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/nationa... 165 page PDF describes it. https://www.hydrocad.net/pdf/TR-55%20Manual.pdf https://www.hydrocad.net/pdf/TR-55%20Manual.pdf
karlkatzke 10y ago
It is quite a bit off. The Upper Butte Creek Watershed, which is the watershed that drains into Lake Oroville, is 3200 square miles. Much of this watershed is mountainous. The amount of water that will flow into Lake Oroville is heavily dependent on temperature (what forms snow vs. what melts snow), the existing snowpack, the ground saturation state, and precisely where in that 3200 square miles the rain falls.

by caseyf7 10y ago

AnimalMuppet 10y ago

> Much less of the first inch of rain makes it to the reservoir vs. the 5th inch of rain. Depends on whether the ground is already saturated.

pilom 10y ago
Even if the ground is saturated, plants still will absorb more of the first inch than the 5th.
- AnimalMuppet 10y ago
  I don't think that's right. If the ground is saturated, the plants won't absorb any of it, because it won't sink into the ground at all, because the ground is saturated. (That is, unless you're talking about plants absorbing water from their leaves directly, before the water hits the ground. I don't know that plants do that when their roots already have plenty of water, but I also don't know that they don't.)

acomjean 10y ago

They have models for run off. In my previous career we used tr55 analysis of watersheds, this included surface types, slopes and areas. You model for various storms once the model is built. We didn't have to deal with mountain snow packs which add another factor. Edit: I think newer programs to model exist now. Some are here https://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/national/water/manage/hydrology/?cid=stelprdb1042480 https://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/nationa... 165 page PDF describes it. https://www.hydrocad.net/pdf/TR-55%20Manual.pdf https://www.hydrocad.net/pdf/TR-55%20Manual.pdf

karlkatzke 10y ago

It is quite a bit off. The Upper Butte Creek Watershed, which is the watershed that drains into Lake Oroville, is 3200 square miles. Much of this watershed is mountainous. The amount of water that will flow into Lake Oroville is heavily dependent on temperature (what forms snow vs. what melts snow), the existing snowpack, the ground saturation state, and precisely where in that 3200 square miles the rain falls.