1 / 15

COHYST2010 Groundwater Model: Phase II Summary

COHYST2010 Groundwater Model: Phase II Summary. April 15 th -16 th Lincoln, NE Nebraska Department of Natural Resources. COHYST 2010 - Groundwater Model Phase III. COHYST 2010 - Phase II Groundwater Model Phase III. High resolution “tracking and accounting”

chione
Download Presentation

COHYST2010 Groundwater Model: Phase II Summary

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. COHYST2010 Groundwater Model:Phase II Summary April 15th-16th Lincoln, NE Nebraska Department of Natural Resources

  2. COHYST 2010 - Groundwater ModelPhase III

  3. COHYST 2010 - Phase II Groundwater ModelPhase III • High resolution “tracking and accounting” • Refinements to put more confidence of parcel-scale, monthly estimates of impacts to river • Impact of local heterogeneity, detail • Boundary conditions, properties would need to be resolved further for site-specific assessments • CROPSIM process that tracks historic variation as measured

  4. COHYST 2010 - Phase II Groundwater ModelSuccesses&Limitations • Temporal discretization • Type curve stresses distribute extreme events • {Seasons, months, days, years} characterized by anomalous (not following average pattern) pumping, recharge preclude a match in the model • Linkage between slow (gw) and fast (sw, weather) systems • Impossible to fully translate impacts of temporal variability scale without a fully coupled multi-physics model • Not comprehensively understood

  5. COHYST 2010 - Phase II Groundwater ModelSuccesses&Limitations • Temporal & Spatial discretization • Time & space scales related • Point stress propagates quickly, effect local • Regional model suited to longer term, broad stresses • At 2640 ft x 2640 ft, not able to match local impacts from point stress • Can approximate regional-level (township, county, NRD) changes

  6. -Multi-year variability magnitude affected by Sy (aquifer property) -Shape of variability driven by net recharge (CROPSIM)

  7. Sy affects seasonal variability some, but with regional impact

  8. -Drawdown, recovery a local phenomenon (~feet) -1/2 mile grid cells CAN’T match this -Measured water levels reflect myriad factor, not all modeled

  9. -Can approximate local response using “equivalent well block” adjustments -Model contains multi-scale information, possible to project behavior at finer scale as a check

  10. COHYST 2010 - Phase II Groundwater ModelSuccesses&Limitations • History Mismatch - Odessa to Grand Island • Reach known to lose part of year • Target shows losses, although noisy • Simulated baseflow gain/loss • Match gains • Don’t simulate losses • Reasons? • Simulated stages approximately correct, heads high • Initial (head) condition high • Non-stream discharges too low (pumping, GW/surface ET)

  11. COHYST 2010 - Phase II Groundwater ModelSuccesses & Limitations • History Mismatch – Initial Condition • Groundwater system moves slowly • Impacts of decades of GW development being propagated at 1985 • But NOT in dynamic equilibrium • Impossible to fully characterize initial state of system for October 1984 • Where synthetic initial state and boundary conditions/stresses don’t align model takes time to equilibrate

  12. Original Distributed Hydraulic Conductivity

  13. COHYST 2010: Groundwater Model: Key Changes since 2010 • Procedural: • “Warm-up” period – either: • separate synthetic stress periods, or • Beginning years of 1985-2005 model • Calibration tools, metrics • Trend differences • Qualitative, quantitative comparisons • Baseflow targets

  14. COHYST 2010: Groundwater Model: Final Run (22a_17_21) • Adjustments to CROPSIM pumping, recharge, runoff (run 22a – addressed by Marc) • Simulated diversions, returns from STELLA run 17 • Minor QA/QC modifications to boundary condition assignments • Updated K, Sy zonation and preferred values from Roger Miller, Lee Wilson

More Related