SPDSS_Task48-2_AlluvialGroundwaterModelingCalibration

• Title: SPDSS Task 48.2 - Development of Calibration Targets and Criteria - Phase 4
• Description: This Technical Memorandum was undertaken under Task 48.2 of Phase 4 of the SPDSS, to develop calibration criteria, including selection of field data ‎(targets)‎ to be used during the model calibration. This TM summarizes the methodology and data that are anticipated to be used in the model calibration process.
• Decision Support - Doc Type: Task Memorandum
• Date: 10/8/2008
• DSS Category: Groundwater
• DSS: South Platte
• Basin: South Platte
• Contract/PO #: C153953
• Grant Type: Non-Reimbursable
• Bill Number: SB01-157, HB02-1152, SB03-110, HB04-1221, SB05-084, HB06-1313, SB07-122
• Prepared By: CDM

model water balance errors, presence of wet and dry cells, comparison of historic
diversions, and locations of groundwater evapotranspiration.
Parameter weighting will be used to address measurement errors >IZ parameters used >IZ
calibration and to allow groundwater level and streaniflow data to be evaluated on a
sinular numeric basis even though they Have different measurement units and
mab zitudes.
Model calibration will be undertaken by varying aquifer hydraulic conductivity,
streambed conductance, recharge, well pumping, lateral boundary inflows and aquifer
specific yield.
Tl1e calibration process is expected to result in a model t11at can be used with confidence
to simulate historic and future groundwater inflows and outflows that are occurring
within the alluvial aquifer of the South Platte River basin.
6.0 Recommendations
The follow>lzg are recommendations from fl1e development of calibration targets and criteria:
• Continue current water level measurement programs, especially at wells that Have data
loggers and Have been surveyed.
• Use the targets and criteria presented in this TM for calibrating the alluvial groundwater
flow model in Phase 5.
P~ SPDSS T~8 2 Final TM 10-08-0t~.doc 19