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Walker River Decision Support Tool Groundwater Model Component
Greg Pohll
EXHIBIT 119 Walker River Decision Support Tool Groundwater Model - - PDF document
EXHIBIT 119 Walker River Decision Support Tool Groundwater Model - - PDF document
EXHIBIT 119 Walker River Decision Support Tool Groundwater Model Component Greg Pohll DST 2.0 Model Components MODSIM River Basin Management system PRMS models of headwater areas (Supply Side) MODFLOW models of Mason & Smith (Demand
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DST 2.0 Model Components
MODFLOW models
- f Mason & Smith
(Demand Side) PRMS models of headwater areas (Supply Side) MODSIM River Basin Management system
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Groundwater/Surface Water – One Resource
5 – 25% of the surface water budget
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Stream/Aquifer Interaction
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Phreatophyte ET
Deep Water Table Shallow Water Table
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Groundwater Model Construction
- Two groundwater
models were built
- Smith Valley
- Mason Valley
- Key inputs
- Recharge
- Well information
- Hydraulic conductivity
- Phreatophyte ET
- Stream and ditch
information
q
2 2 4 6 8 1 Miles SLIDE 8
Groundwater Model Revisions
- Two groundwater
models were built
- Smith Valley
- Mason Valley
- Key inputs
- Recharge
- Well information
- Hydraulic conductivity
- Phreatophyte ET
- Stream and ditch
information
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Groundwater Model Revisions
- NDOW properties included and ponds simulated
using General Head Boundary (GHB package
- Smith Valley model initial conditions adjusted to
yield better agreement with measured water levels
- HRU water balance, which includes calculations of
groundwater pumping rates is handled in MODSIM
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Recharge
Irrigation Excess Ditch & Drain Losses Mountain Block Recharge
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Well Information
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Hydraulic Conductivity
Mason Smith
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Phreatophyte ET
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Stream & Ditch Information
- A complete water
budget is calculated using the SFR package within MODFLOW for the Walker River and agricultural drains
- Losses from irrigation
ditches are handled separately in MODSIM and are treated as a fluid source term in MODFLOW
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Model Accuracy
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Model Accuracy
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Model Accuracy
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Model Accuracy
Mason Valley Relative Error = 1.98% RMSE = 3.7 m
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Model Accuracy
Smith Valley Relative Error = 5% RMSE = 8.8 m
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Stream Gains and Losses
- Warm Colors –
Losing
- Cool Colors –
Gaining
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Conclusions
- Two groundwater
models were constructed for use in the DST
- These models were
calibrated, validated, and peer-reviewed
- The models are
integrated into the DST to provide groundwater flux information at every time step