COEQWAL summary brief · key outcome

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Community surface water: modeled outcome levels across 28 management strategies and five hydroclimates

A summary brief reporting modeled outcome levels for one key outcome under every management strategy in the library, read across the five hydroclimates. Each difference from the baseline is split into the hydroclimate effect and the management effect. Run identifiers for every scenario are listed in the references note.

Summary. This brief reports modeled community surface water outcome levels under each of the 28 management strategies and the five hydroclimates in the COEQWAL library. Figure 1 places every result beside the baseline, current operations under the historical hydroclimate, and splits each difference into the hydroclimate effect and the management effect. The table beneath the figure gives the same values as numbers, and the companion data file holds all of them. Cells outlined in the table are those where the two effects run opposite ways; the largest such offset is No flow requirements under extreme climate stress, where the hydroclimate effect is +0.8 and the management effect is −0.7.

What this is

This brief reports modeled community surface water outcome levels, one of the nine key outcomes the COEQWAL outcome-level framework defines. It covers all 28 strategies across all five modeled hydroclimates in the COEQWAL library. Every key outcome has a brief of this form, built around that key outcome’s results. The strategy summary briefs show one strategy across all nine key outcomes. This brief turns that around: one key outcome across all 28 strategies. A scenario is one strategy under one hydroclimate; the five hydroclimates are a sample of stress levels, not a forecast, and the hydroclimates reference brief describes how they were built.

How to read the figure

Each mark in Figure 1 is a community surface water outcome level under one strategy and one hydroclimate. The baseline value for this key outcome is 1.7, the same reference in every column. Each difference from the baseline is drawn as two arrows. The warm arrow is the hydroclimate effect: how much current operations under that hydroclimate differ from the baseline. The blue arrow is the management effect: how much the strategy differs from current operations under the same hydroclimate. The two add to the difference from the baseline; a flat tick is a change smaller than 0.1.

Values sit on a continuous axis from 1 to 4.99 with Level 1 (Optimal) at the top, and the shaded bands are the four levels. A positive effect moves a value toward Level 4 (Critical); a negative effect moves it toward Level 1 (Optimal). This key outcome’s value is the unweighted mean of its 74 locations, so a mark can sit close to the baseline even when the locations behind it differ in both directions; the table ‘Locations behind the means’ shows how many differ, and in which direction. How the split works is explained in Separating the effects of strategy and hydroclimate in COEQWAL results; the scale, thresholds, and rounding rules are in How to read the values below.

All 28 strategies, all five hydroclimates

Panel 1 of 4 — strategies 1 to 7 of 28

Community surface water: the hydroclimate and management effects to the difference from the baseline, 28 management strategies × five hydroclimates, panel 1 of 4 Panel 1 of 4. The figure is drawn as four stacked panels that share one level axis. The strategies are split across four panels only to fit the page; read them as one figure. This panel holds seven of the 28 management strategies. 28 management strategies are drawn across the figure, each holding five narrow lanes, one per hydroclimate in the order historical, moderate, moderate-high, high and extreme climate stress. The vertical axis is the continuous level value from 1 to 4.99, Level 1 at the top, level bands as shaded zones. The dashed line spanning a key outcome is the baseline: current operations under the historical hydroclimate, the same value under every hydroclimate. In each lane a warm arrow runs from the baseline to current operations under that hydroclimate, so its length is the hydroclimate effect, and a blue arrow continues to that strategy under the same hydroclimate, so its length is the management effect. The solid line in each lane is the scenario. A short dotted line where the warm arrow ends and the blue arrow begins marks current operations under that hydroclimate. A short flat tick instead of an arrow means a change smaller than 0.1 on the level scale. Every value is in the table that follows. per lane: warm arrow = hydroclimate effect, blue arrow = management effect dashed line = the baseline, solid line = this scenario, dotted line = current operations under that hydroclimate Level 1 Optimal Level 2 Acceptable Level 3 At-risk Level 4 Critical H M MH Hi E Current operations H M MH Hi E Current operations with historical land use H M MH Hi E Current operations with reintroduction H M MH Hi E Current operations without TUCPs H M MH Hi E Current USBR operations H M MH Hi E Current USBR operations without TUCPs H M MH Hi E Delta Conveyance Project

Panel 2 of 4 — strategies 8 to 14 of 28

Community surface water: the hydroclimate and management effects to the difference from the baseline, 28 management strategies × five hydroclimates, panel 2 of 4 Panel 2 of 4. The figure is drawn as four stacked panels that share one level axis. The strategies are split across four panels only to fit the page; read them as one figure. This panel holds seven of the 28 management strategies. 28 management strategies are drawn across the figure, each holding five narrow lanes, one per hydroclimate in the order historical, moderate, moderate-high, high and extreme climate stress. The vertical axis is the continuous level value from 1 to 4.99, Level 1 at the top, level bands as shaded zones. The dashed line spanning a key outcome is the baseline: current operations under the historical hydroclimate, the same value under every hydroclimate. In each lane a warm arrow runs from the baseline to current operations under that hydroclimate, so its length is the hydroclimate effect, and a blue arrow continues to that strategy under the same hydroclimate, so its length is the management effect. The solid line in each lane is the scenario. A short dotted line where the warm arrow ends and the blue arrow begins marks current operations under that hydroclimate. A short flat tick instead of an arrow means a change smaller than 0.1 on the level scale. Every value is in the table that follows. per lane: warm arrow = hydroclimate effect, blue arrow = management effect dashed line = the baseline, solid line = this scenario, dotted line = current operations under that hydroclimate Level 1 Optimal Level 2 Acceptable Level 3 At-risk Level 4 Critical H M MH Hi E Functional environmental flows H M MH Hi E Functional environmental flows with reduced crop acreage H M MH Hi E Functional environmental flows with reduced crop acreage and reintroduction H M MH Hi E Functional environmental flows with reintroduction H M MH Hi E Groundwater pumping limits in the Central Valley H M MH Hi E Groundwater pumping limits in the San Joaquin Valley H M MH Hi E Groundwater pumping limits via reduced crop acreage in the Central Valley

Panel 3 of 4 — strategies 15 to 21 of 28

Community surface water: the hydroclimate and management effects to the difference from the baseline, 28 management strategies × five hydroclimates, panel 3 of 4 Panel 3 of 4. The figure is drawn as four stacked panels that share one level axis. The strategies are split across four panels only to fit the page; read them as one figure. This panel holds seven of the 28 management strategies. 28 management strategies are drawn across the figure, each holding five narrow lanes, one per hydroclimate in the order historical, moderate, moderate-high, high and extreme climate stress. The vertical axis is the continuous level value from 1 to 4.99, Level 1 at the top, level bands as shaded zones. The dashed line spanning a key outcome is the baseline: current operations under the historical hydroclimate, the same value under every hydroclimate. In each lane a warm arrow runs from the baseline to current operations under that hydroclimate, so its length is the hydroclimate effect, and a blue arrow continues to that strategy under the same hydroclimate, so its length is the management effect. The solid line in each lane is the scenario. A short dotted line where the warm arrow ends and the blue arrow begins marks current operations under that hydroclimate. A short flat tick instead of an arrow means a change smaller than 0.1 on the level scale. Every value is in the table that follows. per lane: warm arrow = hydroclimate effect, blue arrow = management effect dashed line = the baseline, solid line = this scenario, dotted line = current operations under that hydroclimate Level 1 Optimal Level 2 Acceptable Level 3 At-risk Level 4 Critical H M MH Hi E Groundwater pumping limits via reduced crop acreage in the San Joaquin Valley H M MH Hi E Increase Delta outflows (55% unimpaired flow target) H M MH Hi E Increase Delta outflows (65% unimpaired flow target) H M MH Hi E Increase Shasta carry-over storage H M MH Hi E Maintain Delta outflows (45% unimpaired flow target) H M MH Hi E No flow requirements H M MH Hi E Prioritizing full demands of community water systems

Panel 4 of 4 — strategies 22 to 28 of 28

Community surface water: the hydroclimate and management effects to the difference from the baseline, 28 management strategies × five hydroclimates, panel 4 of 4 Panel 4 of 4. The figure is drawn as four stacked panels that share one level axis. The strategies are split across four panels only to fit the page; read them as one figure. This panel holds seven of the 28 management strategies. 28 management strategies are drawn across the figure, each holding five narrow lanes, one per hydroclimate in the order historical, moderate, moderate-high, high and extreme climate stress. The vertical axis is the continuous level value from 1 to 4.99, Level 1 at the top, level bands as shaded zones. The dashed line spanning a key outcome is the baseline: current operations under the historical hydroclimate, the same value under every hydroclimate. In each lane a warm arrow runs from the baseline to current operations under that hydroclimate, so its length is the hydroclimate effect, and a blue arrow continues to that strategy under the same hydroclimate, so its length is the management effect. The solid line in each lane is the scenario. A short dotted line where the warm arrow ends and the blue arrow begins marks current operations under that hydroclimate. A short flat tick instead of an arrow means a change smaller than 0.1 on the level scale. Every value is in the table that follows. per lane: warm arrow = hydroclimate effect, blue arrow = management effect dashed line = the baseline, solid line = this scenario, dotted line = current operations under that hydroclimate Level 1 Optimal Level 2 Acceptable Level 3 At-risk Level 4 Critical H M MH Hi E Prioritizing human health water deliveries to community water systems H M MH Hi E Reduce Delta outflows (35% unimpaired flow target) H M MH Hi E Relax Delta salinity standards H M MH Hi E Winter-run refuge flows H M MH Hi E Winter-run refuge flows with reduced crop acreage H M MH Hi E Winter-run refuge flows with reduced crop acreage and reintroduction H M MH Hi E Winter-run refuge flows with reintroduction

The 28 strategies are shown in four stacked panels that share one level axis. The strategies are split across four panels only to fit the page; read them as one figure.

Figure 1. Modeled level values for community surface water and the two effects that produce their difference from the baseline, 28 management strategies × five hydroclimates. Lanes within each strategy run left to right: Historical (H), Moderate (M), Moderate-high (MH), High (Hi), Extreme (E) climate stress. Vertical axis: continuous level value, Level 1 at top, level bands as shaded zones. Dashed level: the baseline. Solid line: this scenario. A short dotted line where the warm arrow ends and the blue arrow begins marks current operations under that hydroclimate. A short flat tick in place of an arrow is a change smaller than 0.1 on the level scale. Every value is in the table that follows, and the scale is set out in how to read the values.

The same 140 results as numbers

Each cell reads top to bottom: the hydroclimate effect, the management effect, and the resulting value with its band. The two effects add to the difference between the scenario and the baseline. Outlined cells are those where the two run opposite ways. Readers who want to cite a specific column can link to it directly, and the same numbers appear in the companion data file.

Strategy The baseline Historical Moderate Moderate-high High Extreme Management effect across the five
Current operations Hydroclimate effectManagement effectValue (level) L11.7 0.00.0L11.7 +0.20.0L11.9 +0.20.0L11.9 +0.50.0L22.2 +0.80.0L22.5 no change at the 0.1 threshold
0.0
Current operations with historical land use Hydroclimate effectManagement effectValue (level) L11.7 0.00.0L11.7 +0.20.0L11.9 +0.20.0L22.0 +0.50.0L22.2 +0.80.0L22.5 no change at the 0.1 threshold
0.0
Current operations with reintroduction Hydroclimate effectManagement effectValue (level) L11.7 0.00.0L11.7 +0.20.0L11.9 +0.20.0L11.9 +0.50.0L22.2 +0.80.0L22.5 no change at the 0.1 threshold
0.0
Current operations without TUCPs Hydroclimate effectManagement effectValue (level) L11.7 0.00.0L11.7 +0.2+0.1L22.0 +0.20.0L22.0 +0.50.0L22.3 +0.80.0L22.5 one direction
0.0 to +0.1
Current USBR operations Hydroclimate effectManagement effectValue (level) L11.7 0.00.0L11.8 +0.20.0L22.0 +0.20.0L11.9 +0.50.0L22.2 +0.8+0.1L22.6 one direction
0.0 to +0.1
Current USBR operations without TUCPs Hydroclimate effectManagement effectValue (level) L11.7 0.00.0L11.8 +0.2+0.2L22.1 +0.20.0L22.0 +0.5+0.2L22.4 +0.8+0.1L22.6 one direction
0.0 to +0.2
Delta Conveyance Project Hydroclimate effectManagement effectValue (level) L11.7 0.0+0.2L11.9 +0.2+0.4L22.3 +0.2+0.3L22.2 +0.5+0.2L22.4 +0.8+0.2L22.7 one direction
+0.2 to +0.4
Functional environmental flows Hydroclimate effectManagement effectValue (level) L11.7 0.00.0L11.8 +0.20.0L22.0 +0.20.0L22.0 +0.50.0L22.2 +0.8−0.2L22.3 one direction
−0.2 to 0.0
Functional environmental flows with reduced crop acreage Hydroclimate effectManagement effectValue (level) L11.7 0.00.0L11.8 +0.20.0L11.9 +0.20.0L22.0 +0.5−0.1L22.1 +0.8−0.2L22.3 one direction
−0.2 to 0.0
Functional environmental flows with reduced crop acreage and reintroduction Hydroclimate effectManagement effectValue (level) L11.7 0.00.0L11.8 +0.20.0L11.9 +0.20.0L22.0 +0.5−0.1L22.1 +0.8−0.2L22.3 one direction
−0.2 to 0.0
Functional environmental flows with reintroduction Hydroclimate effectManagement effectValue (level) L11.7 0.00.0L11.8 +0.20.0L22.0 +0.20.0L22.0 +0.50.0L22.2 +0.8−0.2L22.3 one direction
−0.2 to 0.0
Groundwater pumping limits in the Central Valley Hydroclimate effectManagement effectValue (level) L11.7 0.00.0L11.7 +0.2−0.1L11.8 +0.2−0.1L11.8 +0.5−0.3L11.9 +0.8−0.3L22.2 one direction
−0.3 to 0.0
Groundwater pumping limits in the San Joaquin Valley Hydroclimate effectManagement effectValue (level) L11.7 0.00.0L11.7 +0.2−0.2L11.7 +0.2−0.2L11.7 +0.5−0.3L11.9 +0.8−0.3L22.2 one direction
−0.3 to 0.0
Groundwater pumping limits via reduced crop acreage in the Central Valley Hydroclimate effectManagement effectValue (level) L11.7 0.0−0.1L11.6 +0.20.0L11.8 +0.2−0.2L11.7 +0.5−0.3L11.9 +0.80.0L22.5 one direction
−0.3 to 0.0
Groundwater pumping limits via reduced crop acreage in the San Joaquin Valley Hydroclimate effectManagement effectValue (level) L11.7 0.00.0L11.7 +0.20.0L11.9 +0.20.0L11.9 +0.5−0.1L22.1 +0.80.0L22.5 one direction
−0.1 to 0.0
Increase Delta outflows (55% unimpaired flow target) Hydroclimate effectManagement effectValue (level) L11.7 0.0+0.2L11.9 +0.2+0.1L22.0 +0.20.0L22.0 +0.50.0L22.2 +0.8+0.2L22.7 one direction
0.0 to +0.2
Increase Delta outflows (65% unimpaired flow target) Hydroclimate effectManagement effectValue (level) L11.7 0.0+0.2L11.9 +0.2+0.2L22.1 +0.20.0L22.0 +0.50.0L22.2 +0.8+0.2L22.7 one direction
0.0 to +0.2
Increase Shasta carry-over storage Hydroclimate effectManagement effectValue (level) L11.7 0.0+0.1L11.8 +0.20.0L11.9 +0.20.0L11.9 +0.50.0L22.2 +0.80.0L22.5 one direction
0.0 to +0.1
Maintain Delta outflows (45% unimpaired flow target) Hydroclimate effectManagement effectValue (level) L11.7 0.0+0.2L11.9 +0.20.0L22.0 +0.20.0L22.0 +0.5−0.1L22.1 +0.8+0.1L22.6 crosses zero
−0.1 to +0.2
No flow requirements Hydroclimate effectManagement effectValue (level) L11.7 0.0−0.1L11.6 +0.2−0.2L11.7 +0.2−0.2L11.7 +0.5−0.5L11.7 +0.8−0.7L11.8 one direction
−0.7 to −0.1
Prioritizing full demands of community water systems Hydroclimate effectManagement effectValue (level) L11.7 0.00.0L11.6 +0.20.0L11.8 +0.2−0.1L11.8 +0.5−0.2L22.0 +0.80.0L22.4 one direction
−0.2 to 0.0
Prioritizing human health water deliveries to community water systems Hydroclimate effectManagement effectValue (level) L11.7 0.0−0.2L11.5 +0.2−0.2L11.7 +0.2−0.2L11.7 +0.5−0.3L11.9 +0.80.0L22.4 one direction
−0.3 to 0.0
Reduce Delta outflows (35% unimpaired flow target) Hydroclimate effectManagement effectValue (level) L11.7 0.0+0.2L11.9 +0.20.0L22.0 +0.20.0L11.9 +0.50.0L22.1 +0.80.0L22.6 one direction
0.0 to +0.2
Relax Delta salinity standards Hydroclimate effectManagement effectValue (level) L11.7 0.00.0L11.7 +0.20.0L11.9 +0.2−0.1L11.8 +0.5−0.1L22.1 +0.80.0L22.5 one direction
−0.1 to 0.0
Winter-run refuge flows Hydroclimate effectManagement effectValue (level) L11.7 0.00.0L11.7 +0.2−0.1L11.8 +0.2−0.2L11.7 +0.5−0.3L11.9 +0.8−0.3L22.2 one direction
−0.3 to 0.0
Winter-run refuge flows with reduced crop acreage Hydroclimate effectManagement effectValue (level) L11.7 0.0−0.1L11.6 +0.2−0.3L11.6 +0.20.0L11.9 +0.5−0.5L11.7 +0.8−0.4L22.1 one direction
−0.5 to 0.0
Winter-run refuge flows with reduced crop acreage and reintroduction Hydroclimate effectManagement effectValue (level) L11.7 0.0−0.1L11.6 +0.2−0.3L11.6 +0.20.0L11.9 +0.5−0.5L11.7 +0.8−0.4L22.1 one direction
−0.5 to 0.0
Winter-run refuge flows with reintroduction Hydroclimate effectManagement effectValue (level) L11.7 0.00.0L11.7 +0.2−0.1L11.8 +0.2−0.2L11.7 +0.5−0.3L11.9 +0.8−0.3L22.2 one direction
−0.3 to 0.0

Locations behind the means

A key outcome’s value is the mean of its locations, so one mean can stand for locations that moved in different directions. The table counts, for each strategy and hydroclimate, how many of this key outcome’s 74 locations differ from current operations by at least 0.1 on the level scale, and in which direction. To see the data for individual locations, view the Locations of Interest summary briefs.

Strategy Historical Moderate Moderate-high High Extreme
Current operations Toward Level 1No differenceToward Level 4 0740 0740 0740 0740 0740
Current operations with historical land use Toward Level 1No differenceToward Level 4 6671 3638 85511 14519 6635
Current operations with reintroduction Toward Level 1No differenceToward Level 4 0740 0740 0740 0740 0740
Current operations without TUCPs Toward Level 1No differenceToward Level 4 2684 15518 26111 25616 2666
Current USBR operations Toward Level 1No differenceToward Level 4 7607 105212 164810 234011 74324
Current USBR operations without TUCPs Toward Level 1No differenceToward Level 4 8579 94520 134714 133625 64325
Delta Conveyance Project Toward Level 1No differenceToward Level 4 65215 63928 14527 103627 74224
Functional environmental flows Toward Level 1No differenceToward Level 4 14537 174512 174116 243416 273215
Functional environmental flows with reduced crop acreage Toward Level 1No differenceToward Level 4 16508 214013 184115 263117 263216
Functional environmental flows with reduced crop acreage and reintroduction Toward Level 1No differenceToward Level 4 16508 214013 184115 263117 263216
Functional environmental flows with reintroduction Toward Level 1No differenceToward Level 4 14537 174512 174116 243416 273215
Groundwater pumping limits in the Central Valley Toward Level 1No differenceToward Level 4 10613 16562 15563 29432 33392
Groundwater pumping limits in the San Joaquin Valley Toward Level 1No differenceToward Level 4 9650 16571 19541 31421 35372
Groundwater pumping limits via reduced crop acreage in the Central Valley Toward Level 1No differenceToward Level 4 19550 14546 24491 31394 11594
Groundwater pumping limits via reduced crop acreage in the San Joaquin Valley Toward Level 1No differenceToward Level 4 7670 4673 10622 22475 10604
Increase Delta outflows (55% unimpaired flow target) Toward Level 1No differenceToward Level 4 54821 133922 134021 163424 83432
Increase Delta outflows (65% unimpaired flow target) Toward Level 1No differenceToward Level 4 54821 124022 124022 203519 53435
Increase Shasta carry-over storage Toward Level 1No differenceToward Level 4 3638 12539 12557 184610 164612
Maintain Delta outflows (45% unimpaired flow target) Toward Level 1No differenceToward Level 4 55019 133922 144020 203816 113429
No flow requirements Toward Level 1No differenceToward Level 4 17561 23474 23474 37325 41303
Prioritizing full demands of community water systems Toward Level 1No differenceToward Level 4 13601 12584 15563 29432 15563
Prioritizing human health water deliveries to community water systems Toward Level 1No differenceToward Level 4 18551 18515 24437 26444 15527
Reduce Delta outflows (35% unimpaired flow target) Toward Level 1No differenceToward Level 4 55316 133922 154217 173819 104024
Relax Delta salinity standards Toward Level 1No differenceToward Level 4 5690 6635 13601 19514 2693
Winter-run refuge flows Toward Level 1No differenceToward Level 4 18533 23447 25454 32384 352910
Winter-run refuge flows with reduced crop acreage Toward Level 1No differenceToward Level 4 20513 28415 234110 37334 362810
Winter-run refuge flows with reduced crop acreage and reintroduction Toward Level 1No differenceToward Level 4 20513 28415 234110 37334 362810
Winter-run refuge flows with reintroduction Toward Level 1No differenceToward Level 4 18533 23447 25454 32384 352910

Per-location detail and the median difference behind each count are in the companion data file at #/rows/*/reach.

What happens in another key outcome? A key-outcome brief reports one key outcome of the water system, every strategy, the same five hydroclimates:

What happens across all nine key outcomes under one strategy? This brief holds the key outcome fixed and varies the strategy. The transpose does the reverse, reporting every key outcome under one strategy, one brief per strategy:

Briefs for all locations of interest are available from the COEQWAL Data page.

How were the five hydroclimates constructed? The hydroclimates reference brief defines them. It reports no results of its own; every brief above is read against the same five.

What this doesn’t say

This brief reports modeled results from the COEQWAL ensemble. It does not predict what will happen, evaluate whether those results are acceptable, or recommend any course of action. The outcome-level framework provides definitional categories; the meaning of those categories for any individual reader, community, or decision is not specified by COEQWAL.

In particular, for this brief: the five hydroclimates are a sample of stress levels, carry no probabilities, and are not a timeline, so no average over them is reported here. Splitting a difference into two effects is arithmetic on modeled values, not a causal claim about the water system, and the two are separable only because each is defined against its own reference. A step or a spread on the level axis is a modeled magnitude, not a benefit or a cost. A key outcome’s value is the unweighted mean of its locations, so locations count equally regardless of the people, acres, or acre-feet each represents, and a location already at either end of the scale cannot move further along it. Locations are modeled nodes, not measured conditions at a place.

A strategy’s highest value does not necessarily fall under extreme climate stress.

References, run identifiers and the build stamp

Model runs (current operations): Historical s0020; Moderate s0134; Moderate-high s0047; High s0056; Extreme s0108. Each row reads its own five runs beside these; they are in the companion data file at #/rows/*/by_hydroclimate/*/run_ids. The baseline is current operations under the historical hydroclimate, s0020.

Build stamp. Snapshot 2026-08-29; builder version 0.1.0; built 2026-09-25T20:58:30Z; snapshot data read 2026-08-29; verification: pass. The verification status is written by the independent check (briefbuilder.verifier), which recomputes every value in the companion data file from the per-location data and reads every arrow on this page, after both files are written. It is not stamped by whatever produced them.

Companion data file: key_outcome_summary_community-water-systems_schema1.json, holding every value in this brief plus the per-location counts, the spread measures, the derivation of every number in the prose and the figure’s declared attribute contract. Per-hydroclimate slices: Historical #/rows/*/by_hydroclimate/BL; Moderate #/rows/*/by_hydroclimate/HC4; Moderate-high #/rows/*/by_hydroclimate/HC1; High #/rows/*/by_hydroclimate/HC2; Extreme #/rows/*/by_hydroclimate/HC3. Built from the locked 2026-08-29 API snapshot (api.coeqwal.org v2.1.1 (locked dataset snapshot)). Decomposition per Decomposition_Math_Quickref (coeqwal-viz): the hydroclimate effect is current operations under that hydroclimate minus current operations under the historical hydroclimate; the management effect is this strategy minus current operations under that same hydroclimate. Axis convention [1, 4.99] per Ordinal_vs_continuous_tiers.md; the visible band is floor(value). A difference of 0.1 on the level scale is required before a difference is reported as movement, before a location is counted as differing from its comparison, and before an effect prints as anything other than 0.0. Color semantics: warm = hydroclimate, blue = management. Strategy identity is its descriptive name; run IDs appear only in this note and the data file.

How to read the values

The level scale runs from 1 to 4.99. Level 1 is the favorable end of the scale: the outcome-level framework names Level 1 Optimal and Level 4 Critical, so a smaller value sits nearer Optimal and a larger value nearer Critical. The API serves this number in a field named weighted_score; that name describes how the number is computed, and does not mean that a larger number is a more favorable result.

Two numbers describe each result. The integer tier_level is the level label. tier_continuous is the position within the band of that label, and always falls inside it: tier_continuous is at least tier_level and less than tier_level plus one. Labels, counts and prose use tier_level; figure positions and statistics use tier_continuous.

Level 1 is Optimal, Level 2 is Acceptable, Level 3 is At-risk, and Level 4 is Critical. These are definitional category names supplied by the outcome-level framework; what a category means for any reader, community, or decision is not specified by COEQWAL.

A key outcome value is the unweighted mean over the locations in that key outcome. Every location counts equally, regardless of the people, acres, or acre-feet it represents.

Any difference between two values under different hydroclimates contains both a hydroclimate effect and a management effect; the two are separable only through the decomposition, because each is defined against its own reference. A strategy is compared with current operations under the same hydroclimate. Comparing one strategy with itself across hydroclimates is a different quantity: the hydroclimate effect plus the change in the management effect. The hydroclimate effect is always measured on current operations, not on the strategy.

One threshold governs every claim and every count here. A difference smaller than 0.1 on the level scale is not reported as movement, and a location is not counted as differing from its comparison. An outcome level is a summary built so that results in nine key outcomes with no shared unit can be compared, and 0.1 on the level scale is the finest reading it carries; a smaller difference is left unstated rather than described.

The five hydroclimates were chosen to span a range of climate stress levels. They are not a sequence, a trend, or a forecast, they carry no probabilities, and no mean is taken over them.

A run ID identifies one modeling run of one strategy under one hydroclimate. It is an internal identifier, used for citation and for tracing a value back to the data platform, not a name for the strategy; the public identity of a strategy is its descriptive name.

Level values are reported to one decimal place throughout this brief — in the prose, in the figure and in the table. The level scale does not carry meaning finer than that. Each effect shown is the difference between the floored values, except that an effect smaller than 0.1 on the level scale, which is the threshold this brief reports movement at, is shown as 0.0, so a row containing one does not add up. Values are floored rather than rounded, so a printed value stays inside the band its own label names; full-precision values are in the machine-readable sidecar this brief is built from.