Hey Raven team!
I'm having some difficulty in understanding how to setup HRUs that can vary through time in the .rvh file. In other words, can Raven handle a time series of watershed area? This is relevant for mined watersheds where pit development over time can increase or decrease the contributing area to a gauge.
Many thanks!
Justin (Golder)
Time-variable HRUs, Time series of watershed area?
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justinltd
- Posts: 2
- Joined: Mon Jun 24, 2019 11:44 am
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jrcraig
- Posts: 57
- Joined: Tue Jul 05, 2016 1:08 pm
Re: Time-variable HRUs, Time series of watershed area?
Hi Justin,
A time series of area is not possible. Instead, Raven supports landscape change through discrete jumps. For instance, you could have 5 adjacent areas representing the gradation of contributing area. The :LandUseChange command can be used (see the manual) to incrementally convert the land use type to (e.g.) INACTIVE, one HRU at a time. An additional process would have to be used to suppress runoff from this landscape. For instance, in the :HydrologicProcesses block in the .rvi file,
In this case, I assume SOIL[5] is a dummy soil store used only to receive this water, but you could just as readily send it to (e.g.) ATMOSPHERE to get rid of its contribution to the basin discharge. This would move all of the precipitation and snowmelt to this dummy store such that none is available to drain from the landscape. Note, however, you could still have existing water in the HRU drain out through baseflow, etc., unless you suppress that as well.
A time series of area is not possible. Instead, Raven supports landscape change through discrete jumps. For instance, you could have 5 adjacent areas representing the gradation of contributing area. The :LandUseChange command can be used (see the manual) to incrementally convert the land use type to (e.g.) INACTIVE, one HRU at a time. An additional process would have to be used to suppress runoff from this landscape. For instance, in the :HydrologicProcesses block in the .rvi file,
Code: Select all
:Precipitation PRECIP_RAVEN ATMOS_PRECIP MULTIPLE
# snow process here
:Flush RAVEN_DEFAULT PONDED_WATER SOIL[5]
:-->Conditional LAND_USE IS INACTIVE
In this case, I assume SOIL[5] is a dummy soil store used only to receive this water, but you could just as readily send it to (e.g.) ATMOSPHERE to get rid of its contribution to the basin discharge. This would move all of the precipitation and snowmelt to this dummy store such that none is available to drain from the landscape. Note, however, you could still have existing water in the HRU drain out through baseflow, etc., unless you suppress that as well.
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justinltd
- Posts: 2
- Joined: Mon Jun 24, 2019 11:44 am
Re: Time-variable HRUs, Time series of watershed area?
Hey James! Many thanks for the reply. The inactive HRU and dummy soil store are interesting tactics for sure - good to know. Our best bet at this point may be running multiple versions of the model with different watershed area "snapshots" through time.