No flow requirements A management strategy in the COEQWAL scenario library
This strategy removes existing minimum flow requirements on rivers and streams throughout the Central Valley, the Trinity River, and rim watersheds where they are defined in CalSim3. Delta outflow requirements are not removed: D1641 and biological opinion requirements remain in place, as in the Current Operations scenario.
This brief describes a scenario in which minimum flow requirements are removed throughout the Central Valley and CalSim3 model domain, one of 28 management strategies in the COEQWAL scenario library. Each strategy is simulated once under each of five hydroclimates; the references note at the end of this brief lists the model runs.
§2 What this strategy changes
The strategy sets existing minimum flow requirements to zero on rivers and streams throughout the Central Valley, the Trinity River, and rim watersheds where such requirements are defined in the model. Delta outflow requirements are not removed — the requirements of D1641 and the biological opinions remain in place as they are set under current operations. This scenario is intended as an exploratory reference scenario to better understand the effects of existing flow requirements in the system.
The scenario was created by switching flow-requirement options off where switches exist in the model code and manually setting requirements to zero elsewhere. The COEQWAL modeling team could not locate a reliable, comprehensive, and independent listing of the minimum-flow variables in CalSim3 before setting up the run, so some requirements may have been missed, although every attempt was made to find minimum flow requirements in the CalSim3 model code.
The strategy was envisioned as an exploratory reference point against which high-flow-requirement configurations — the functional-flows strategies — and the standard flow requirements can be compared.
§3 The configuration in detail
The table compares the eight operational fields that define this strategy against current operations — the strategy that represents existing operational rules, recent (2020) land use, and TUCPs. Rows that match current operations are shown in light gray; rows that differ are highlighted.
| Aspect | Current operations | This strategy |
|---|---|---|
| TUCP actions | Active | Active |
| SGMA actions | None | None |
| Land use | 2020 LandIQ | 2020 LandIQ |
| Delta regulations | Standard | Standard |
| BiOps | 2019 / 2020 ITP | 2019 / 2020 ITP |
| Infrastructure | Standard | Standard |
| Flows | Standard | Existing minimum flow requirements on Central Valley tributaries and the Trinity River set to zero; Delta outflow requirements maintained as under current operations; functional flows not active |
| Allocation / priorities | Standard | Standard |
§4 Lineage and source
This configuration was created by the COEQWAL team by copying the broader functional-flows study and deactivating all flow requirements — the functional flows along with the pre-existing minimums. It is built on the COEQWAL Current Operations scenario using DWR’s adjusted historical hydrology with the 2020 LandIQ land-use dataset. The CalSim model files for this strategy are referenced by the run IDs in the references note at the end of this brief.
§6 What this doesn't say
This brief describes a scenario representation in CalSim, not a real-world policy proposal or implementation plan. The strategy as modeled may not capture all details necessary to support direct translation to actual operations. The brief does not predict, evaluate, or recommend any outcome — it describes what the scenario changes about CalSim's representation of the system. For what the model produces under this strategy, see the result briefs referenced in §7.
§7 See results for this strategy
To see modeled outcomes under this strategy across all nine key outcomes at the reference hydroclimate, see the Rivers, salmon and the Delta ecosystem theme brief.
To see outcomes at a specific location of interest, see the relevant LOI briefs — particularly those for locations on the Sacramento and San Joaquin rivers and their tributaries.
References — model runs
Each strategy is simulated once under each of five hydroclimates. The table lists the model run behind this strategy and the current-operations run it is compared against, for each hydroclimate, so any reader can trace this page to specific CalSim runs.
| Hydroclimate | This strategy | Current operations |
|---|---|---|
| Historical hydroclimate (adjusted) | s0030 | s0020 |
| Moderate climate stress (EC-Earth3-Veg) | s0143 | s0134 |
| Moderate-high climate stress (cc50) | s0071 | s0047 |
| High climate stress (cc95) | s0091 | s0056 |
| Extreme climate stress (TaiESM1) | s0117 | s0108 |