# Site02 | Future river scenarios

Open [Future River Scenarios](Site02_Water_and_Ecology_Explorer.html#future), or choose **Future** from the original [research atlas](Site02_Water_and_Ecology_Explorer.html). The unified page is entirely English, works offline and preserves the existing graphic style. The former separate future-page address redirects to the future section. Extract the complete package to retain access to source reports and downloads.

## Short-term: a seven-day what-if

This is a **synthetic event**, not a seven-day weather, flow or flood forecast. No live forecast or current gauge level is ingested. The calendar is an editable scenario label and does not provide evidence of future conditions.

Set the assumed peak reference-surface offset from 0 to 8 m, the time to peak (24, 48 or 72 hours), and the return to the initial offset (96, 120 or 168 hours). Initial and final offsets are 0 m; neither represents a measured normal-water or low-flow level. Playback steps through 169 hourly states from hour 0 to hour 168. The default event peaks at +6 m at hour 48 and returns to 0 m at hour 120.

For elapsed hour `h`, peak `P`, time to peak `R` and recovery time `E`:

```
h <= R:     offset = P * h / R
R < h < E:  offset = P * (E - h) / (E - R)
h >= E:     offset = 0
```

Each offset selects the nearest existing 0.5 m terrain-sensitivity map; positive half-step ties round upward. The animation does not calculate a new hydraulic solution at each hour. Its hourly curve is an imposed hypothesis, not a runoff response derived from rainfall. The mapped area is read from the corresponding existing scenario table, not interpolated between map areas.

The assumed continuous offset and the rounded mapped offset are both disclosed. The current-scenario CSV includes the calendar label, elapsed hour, continuous offset, mapped offset, land area and all event assumptions. The linked GIF uses the **default** event, sampled every six hours; it does not update when controls change. Viewport playback pauses when its section leaves view, when the document is hidden, or when Escape is pressed. It does not start automatically. Reduced-motion preferences choose slower short-term playback.

The 1 m DEM uses an unverified vertical datum; the reference surface is constructed from the mapped river. These offsets are not Queens Bridge gauge heights, AHD elevations, measured stage rises or assigned AEP events. The same offset has the same footprint on rising and falling limbs. No drainage lag, residual ponding, velocity, sediment movement, bank migration or damage is calculated. Calendar labels use equal 24-hour days; daylight-saving changes are not simulated.

For actual observations and issued forecasts, consult [BOM river observations](https://www.bom.gov.au/nsw/flood/rain_river.shtml) and [BOM seven-day streamflow forecasts](https://www.bom.gov.au/water/7daystreamflow/). A forecast for an upstream station is not a forecast of Site02 inundation and is not automatically transferable through Googong Dam.

## Long-term: regional climate horizons

The page displays published NARCliM2.0 regional means and model ranges for South East and Tablelands. Baseline: 1990–2009. The 2050 label means the average of 2040–2059; 2090 means 2080–2099. The two emissions cases are SSP1-2.6 and SSP3-7.0. There is no year-by-year interpolation or extrapolation to 2100.

Values are transcribed from Tables 2 and 5, PDF pages 8 and 17, of the NSW Department of Climate Change, Energy, the Environment and Water's *South East and Tablelands Climate Change Snapshot* (August 2024). The original PDF is supplied in `Documents/NARCliM2_South_East_Tablelands_2024.pdf`; numerical values are in [the climate CSV](Tables/future_regional_climate.csv). Whiskers are the reported model ensemble range, not statistical confidence intervals.

Regional mean rainfall is not river discharge or design extreme rainfall. Neither the climate chart nor its animation generates a future Site02 water level, channel shape or species map. The river geometry is held fixed. The ecological questions are research prompts, not quantified forecasts of species loss or migration.

## Long-term: official, undated flood sensitivity

The independent map control compares +10% and +30% design-rainfall sensitivity cases in the official 2020 floodplain study. Section 2.10 uses 0.5% and 0.2% AEP event models as proxies for a 1% AEP event with those respective rainfall increases. It reports Queens Bridge peak-level increases of 1.6 m and 3.4 m. This is the study's **legacy sensitivity method**, not a new calculation or a dated climate projection.

The map colours show **afflux**, meaning additional peak level relative to the reference event, not total flood depth. Purple indicates additional land inundated deeper than 0.1 m according to the source legend. The two official maps retain the same source scales, legends and geographic content; no interpolated flood boundaries have been created.

| Stress | Wider-context figure | Local-corridor figure |
|---|---|---|
| +10% design-rainfall intensity | Figure 2.10, sheet 1; PDF page 19 | Figure 2.10, sheet 2; PDF page 20 |
| +30% design-rainfall intensity | Figure 2.11, sheet 1; PDF page 21 | Figure 2.11, sheet 2; PDF page 22 |

The two map states play at 3.5-second viewing intervals. They are **not assigned to 2050 or 2090**. Changing the climate horizon leaves the stress-test map unchanged. Source figures cover the corridor around Site02; they are not registered to the supplied redline, and no exact site-area calculation is made from them. A new engineering assessment would require current rainfall guidance, calibrated hydrology/hydraulics, verified terrain and vertical datum, channel and structure data, and dam-operation assumptions. See [ARR Version 4.2 climate-change guidance](https://www.arr-software.org/arr-web/).

### Source discrepancy

The page follows the **10%** label in Section 2.10 and Figures 2.10–2.11. The report's executive summary instead refers to **13%** for the same +1.6 m increase. This internal discrepancy is retained as a source limitation; it is not reconciled by recalibrating or relabelling the maps.

## Deliverables

- [Seven-day default GIF](Maps/Future/Seven_Day_Default_Scenario.gif).
- [Official flood sensitivity GIF](Maps/Future/Future_Flood_Sensitivity.gif).
- [Climate comparison PNG](Maps/Future/Regional_Climate_Comparison.png) and [editable SVG](Maps/Future/Regional_Climate_Comparison.svg).
- [Default hourly scenario CSV](Tables/future_7day_default_scenario.csv).
- [Regional climate data CSV](Tables/future_regional_climate.csv).
- Four original map-page renders in `Maps/Future/`, with original source PDFs in `Documents/`.

## Sources, rights and verification

NSW DCCEEW (2024), [NARCliM2.0 South East and Tablelands snapshot](https://www.climatechange.environment.nsw.gov.au/sites/default/files/2024-08/NARCliM2-Snapshot-SouthEastTablelands.pdf). Climate data are attributed to the department and the NARCliM project; retain the supplied source and its notices. No licence for the entire compiled package is inferred from one source.

© Queanbeyan-Palerang Regional Council 2020, study prepared by Lyall & Associates. The supplied flood-study volumes state CC BY 4.0 unless otherwise indicated, with exceptions for third-party materials. Renders retain source notices. The GIF adds explanatory headings around the original figures without altering geography. See [source catalogue](Sources_and_Licenses.md).

Numerical event assumptions, frame selection, area lookup, climate transcription, page references, links, embedded images and JavaScript syntax are verified. Original source and GIS data remain unchanged. Exported maps and climate figures are inspected. Browser rendering and click testing are not completed because the local-file browser route was previously rejected by security policy; no alternate route was used. See `Metadata/future_scenarios_qa.json`.