Validating No-Pumping Scenario Approach in CVHM2 (MODFLOW-OWHM) for Stream Depletion Analysis

[Behrooz Etebari]

Hello everyone,

I am working with the Central Valley Hydrologic Model version 2 (CVHM2) within the MODFLOW-OWHM framework. My objective is to estimate the depletion of Interconnected Surface Waters (ISW) basin-wide using a superposition/scenario-deduction approach.

To simulate the "No-Pumping" scenario, I isolated the Farm Process (FMP) well file: ...\model\FMP\static\WELLS_TIME_FRAME.in

I modified the input matrix by setting the maximum capacity (QMAX) to 0 for all records across the simulation timeline while keeping the rest of the historical crop demand and surface water allocation structures completely intact. An excerpt of my modification looks like this:

Plaintext

# Name FARM LAYER ROW COL QMAX Date_Start Date_End FMP190 1 0 2 92 0 403 END FMP681 1 0 7 93 0 1 END FMP770 1 0 8 84 0 1 402

By comparing the net SFR network leakage (FLOW_SEEPAGE from SFR_DB_Budget.txt) between my baseline and this zero-capacity run, I calculated a basin-wide stream capture fraction of 14.97%.

I would highly appreciate it if anyone with MF-OWHM or CVHM expertise could help me verify if zeroing out QMAX in WELLS_TIME_FRAME.in is the standard, physically robust way to enforce a zero-groundwater-capacity constraint in FMP, or if there are unintended feedback loops (e.g., hidden secondary supply adjustments) I should watch out for.

Thank you for your time and insights!