1 / 30

Groundwater Model Update COHYST2010

Groundwater Model Update COHYST2010. December 17-18 th , 2012 HDR Offices – Omaha, NE Nebraska DNR James Gilbert, Mahesh Pun, Ruopu Li, Jesse Bradley, Jim Schneider. Monday 12/17 – Morning Discussion. Groundwater Model Report: Review of work done since 11/2/2012 Workshop

vaughan
Download Presentation

Groundwater Model Update COHYST2010

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. Groundwater Model UpdateCOHYST2010 December 17-18th, 2012 HDR Offices – Omaha, NE Nebraska DNR James Gilbert, Mahesh Pun, Ruopu Li, Jesse Bradley, Jim Schneider

  2. Monday 12/17 – Morning Discussion • Groundwater Model Report: • Review of work done since 11/2/2012 Workshop • Optimization/PEST - Recharge • Scenario structure • Target Review • Status of Model – Results Unique to GW model • Head calibration • Trends • Residuals

  3. GW Model: Progress Since November • Inverse model runs – Recharge • Goal: improve GW model & STELLA head, flux, and flow calibration • Using: 1) CROPSIM-consistent soil zonation (3, then 9 from 17) 2) PEST optimization of GW model using recharge multipliers

  4. GW Model: Progress Since November3-Zone Recharge Optimization (11/16 – 11/30)

  5. GW Model: Progress Since November3-Zone Recharge Optimization (11/30/2012) • 3- Zone Optimization Results: • Increase Sandhills recharge • Decrease recharge everywhere else • Challenge to resolve North-South trend discrepancies

  6. GW Model: Progress Since November9-Zone Recharge Optimization (based on 17 CROPSIM zones)

  7. GW Model: Progress Since November9-Zone Recharge Optimization (12/6/2012) • 9- Zone Optimization Results: • Increase recharge in Sandhills area north of North Platte (zone 3) • Decrease recharge everywhere else (except spurious zone 1 Platte Valley) • Again, challenge to resolve North-South trend discrepancies; “problem” area in SW Custer/NW Dawson counties

  8. GW Model: Progress Since November9-Zone Recharge Optimization (based on 17 CROPSIM zones)

  9. GW Model: Progress Since NovemberRevised9-Zone Recharge Optimization (12/12/12) • Revised 9- Zone Optimization: • Held Kx in Platte River Zone 5 Constant at 61 ft/d • Results: • Decrease recharge everywhere except Zone 4 (Perkins, SW Lincoln counties) • Manual adjustments to recharge multiplier in SW Custer Co did little to affect trend differences • Suspect issue with boundary conditions in region

  10. Recharge Optimization Conclusion • Head residuals and trend differences reduced by model-wide reduction in recharge • Outbasin flux calibration improved through reduction of recharge in Blue Basin area • Mainstem Platte flux calibration mostly insensitive to reduction in RCH • Outcome: • CROPSIM Run019 – reduced recharge

  11. CROPSIM Run019 and Kx Optimized – Outcome12/13/2012 • Head calibration • Areas of improvement (Blue Basin, south central model area) • Remaining issue areas • Outbasin Fluxes

  12. Head Trends Progress– Early Sept 2012

  13. Head Trends Progress– CROPSIM Run019, Dec 2012

  14. Head Trends Progress– CROPSIM Run019 (Kx optimized, zone 5 Kx constant), Dec 2012

  15. Head Trends Progress– CROPSIM Run019, Dec 2012 – Censored Calibration Window (1990-2005)

  16. Head Trends Progress– CROPSIM Run019 (Kx optimized, zone 5 Kx constant), Dec 2012 – Censored Calibration Window (1990-2005)

  17. CROPSIM Run019 and Kx Optimized – Outcome12/13/2012 • Head calibration – remaining issues: • SW Custer, NW Dawson counties • Perkins & Clay county clusters • 50 worst head trend sites – what is good enough? • Outbasin Fluxes: • In ballpark with most using Run019 RCH • Close enough given uncertainty and location outside area of interest?

  18. GW Model: Platte Fluxes, Issues • Platte river flux (baseflow) calibration • Adjustments made to STR package • Targets (focus on Reach 1) • SPR, Roscoe to NP • Proposed revisions • History matching • Cumulative, seasonal, annual • Issues • Critical for model purposes • Acceptable - Explain and justify

  19. GW Model: Baseflow to North Platte • Adjustments • Moved Sutherland return point downstream to be closer to actual geographic location • Resolved runoff, canal return routing mistake on North Platte River • Effect on baseflows minor, but ensures conceptual and geographic consistency

  20. GW Model: Baseflow to North Platte • Baseflow Targets: • Error in Roscoe to North Platte reach • Result of inconsistent filtering between upstream, downstream gage locations – introduced erroneous shift • Resolved by ensuring baseflow gain does not exceed total flow gain • Resolved issue of negative runoff by assigning all losses as baseflow • Previously losses, as with gains, were partitioned into a runoff and baseflow component

  21. GW Model: Baseflow to North Platte • Baseflow Targets: • In process of applying total flow gain check on all reach targets • so far only SPR Roscoe-North Platte seems to have been affected • The moving average smoothing was applied when the goal was a “less flashy” target • Model only simulated baseflow gain or loss from Platte using baseflow-derived stage (very minor stage variability  very minor baseflow fluctuations) • Now model “sees” all the water that actually is in the river- variability in stage and target now appropriate • Solution: Revert back to un-smoothed targets

  22. Reach 1 and Other Hydrographs • PDFs of baseflowhydrographs • Time series – by season • Hydrograph_20121215_Flux.pdf • Hydrograph_20121215_Flux_Irrig.pdf • Hydrograph_20121215_Flux_nonIrrig.pdf • Cumulative – by season • Hydrograph_accu_20121215.pdf • Hydrograph_accu_20121215_Irrig.pdf • Hydrograph_accu_20121215_NonIrrig.pdf

  23. Issues • Critical • Potential boundary condition issue in SW Custer Co • Baseflow and runoff targets – GW model contribution to integrated model • Do sites with large head residuals indicate a local/regional problem? • Convergence issues with Kx-optimized Run19_06_13 • Informational • Stage variability in STR • ET in Platte Valley • Baseflow losses on north side Platte tributaries

More Related