Williams household, Darwin: specialist findings
Release B for the Darwin home: what a twelve-month measurement year found, the specialists' implications, and the data as CSV. Synthetic case data, handed over in week 7.
Synthetic case data. This is a generated measurement year, produced by the course's model to be consistent with the Darwin home. It is not a measurement and no instrument recorded it. It stands in for the year the story says passed between week 7 and Assignment 2, and it is identical for every student who took this home, whatever their Assignment 1said.
Memo
- Dr Mara Quinlan — water systems and hydraulics
- Tomasz Ferreira — soils and horticulture
- Aisha Rahman — monitoring, data quality and records
The specialists report conditions and what follows from them. They do not choose the system. That is your recommendation to make inAssignment 2.
What the year found
| Rain at the site | 1,747 mm | long-term mean 1,733 mm |
|---|---|---|
| Roof inflow to storage | 171.5 kL | 124 m² connected at a runoff coefficient of 0.8 |
| Overflow | 35.3 kL | 6 months with storage empty at month end |
| Indoor use | 219 kL | 150 L per person per day |
| Water imported | 91 kL | mains supply |
| Garden water applied | 10.9 kL | estimated unmet demand 83.5 kL |
| Pump energy | 200 kWh | electricity at $0.33 per kWh |
| Harvest weighed | 132 kg | food waste 7.3 kg/week, 380 kg/year, 61 % plant-based |
| Peak simultaneous flow | 23.5 L/min | 70th percentile event 17.7 L/min; static lift 5.1 m |
| Frost nights | 0 | air temperature below 0 °C |
The measured year, month by month
An extract. The full table, with every fixture group, the bore, overflow and the quality flags, is in SYNTHETIC-monthly.csv below.
| Month | Rain (mm) | ETo (mm) | Roof in (kL) | Tank end (kL) | Indoor use (kL) | Imported (kL) | Garden applied (kL) |
|---|---|---|---|---|---|---|---|
| Apr 2027 | 90.2 | 141 | 8.8 | 7.7 | 17.8 | 0 | 9.7 |
| May 2027 | 5.4 | 126 | 0.3 | 0 | 18 | 10 | 0 |
| Jun 2027 | 2.6 | 115 | 0.1 | 0 | 17.3 | 17.2 | 0 |
| Jul 2027 | 1.9 | 116 | 0 | 0 | 17.9 | 17.9 | 0 |
| Aug 2027 | 8.4 | 125 | 0.6 | 0 | 18.2 | 17.6 | 0 |
| Sep 2027 | 21.8 | 151 | 2 | 0 | 18 | 16 | 0 |
| Oct 2027 | 74.2 | 148 | 7.2 | 0 | 19.5 | 12.3 | 0 |
| Nov 2027 | 202.3 | 157 | 19.9 | 0.8 | 19.1 | 0 | 0 |
| Dec 2027 | 197.8 | 153 | 19.5 | 1.7 | 18.6 | 0 | 0 |
| Jan 2028 | 448.1 | 125 | 44.4 | 26 | 19 | 0 | 0 |
| Feb 2028 | 536.6 | 122 | 53.2 | 28 | 17 | 0 | 0 |
| Mar 2028 | 157.6 | 130 | 15.5 | 23.7 | 18.6 | 0 | 1.2 |
Growing zones
| Zone | Area (m²) | Texture | pH | Organic C (%) | Rooting (cm) | Sun, summer / winter (h) | Class | Note |
|---|---|---|---|---|---|---|---|---|
| G1 North garden | 98 | sandy loam | 5.9 | 1.5 | 70 | 11 / 10 | A | waterlogs briefly after the heaviest storms |
| G2 Main garden | 192 | sandy clay loam | 6 | 2 | 80 | 11.5 / 10.5 | A | best garden soil on the block |
| G3 West orchard | 144 | sandy loam, laterite gravel | 5.7 | 1.2 | 40 | 6 / 5 | C | dense mango shade |
| G4 Nursery area | 72 | sandy loam | 5.8 | 1.1 | 60 | 9 / 8 | B | partly under shadecloth |
Water quality
| Month | Source | Turbidity (NTU) | E. coli (MPN/100 mL) | Hardness (mg/L CaCO₃) | pH | Note |
|---|---|---|---|---|---|---|
| 2027-06 | tank T1 | 0.8 | 0 | 14 | 6.6 | mid dry season |
| 2027-11 | tank T2 | 1.1 | 2 | 12 | 6.5 | |
| 2028-01 | tank T1 | 12 | 34 | 9 | 6.3 | wet season, leaf litter in the inlet screen |
| 2028-02 | tank T2 | 9.5 | 20 | 10 | 6.4 |
Hydraulics
Tank outlet at RL 100.3 m; highest fixture is the shower rose (elevated floor) at RL 105.4 m, giving a static lift of 5.1 m. Currently served: whole house and garden, through the existing pressure pump.
The floor is 3.1 m above ground. The micro-spray zone and the house share the pump, and pressure at the shower drops noticeably when the zone runs.
| Fixture | Flow (L/min) |
|---|---|
| shower | 9 |
| ensuite shower | 8.8 |
| basin | 5 |
| kitchen tap | 7.3 |
| toilet cistern refill | 7.1 |
| washing machine fill | 12 |
| micro-spray zone | 18 |
What it costs the household now
- Electricity at $0.33 per kWh.
- No reticulated supply and no water bill; all water is carted, drawn from the bore or caught on site.
- Carted water at $22 per kL delivered.
- Tank inlet screens cleared monthly in the wet, 30 minutes each.
- Septic pumped out in November, $650, which the household had deferred.
What the specialists conclude
- The tanks overflowed 35 kL in January and February while the household carted water in every month from May to October: a storage timing problem, not a rainfall shortage.
- The west roof plane's gutter falls correctly to two downpipe positions; it can be connected without regrading.
- Overflow currently scours the ground beside the piers. A test pit south-east of the shed drained a filled 300 mm hole in 55 minutes, so a dispersal point there is plausible.
- The micro-spray zone and the house share one pump, and the shower pressure drop when both run is the household's most frequent complaint.
What they could not settle
- Whether a neighbour could check the system during the July absence, which would change what can be left running.
- How long the existing poly tanks will last; both show sun-bleaching on the north side.
Gaps in the record
- 2028-02, tank_end_kl: Logger in tank 1 flooded in February; tank 2's record used for both, which assumes they sit at the same level
A gap is marked as a gap. Interpolated values are flagged in thequality_flag column of the monthly CSV, and anything you conclude from those months should carry the same flag.
Download the findings
Every file's first line says what it is. The data dictionary gives each column its unit, meaning and kind — synthetic measured year, derived,calendar or sourced. Keep those apart in your own workbook.
| File | What is in it | Size | Basis |
|---|---|---|---|
| SYNTHETIC-monthly.csv | The measured year, month by month: rain, temperature, roof inflow, tank level, indoor use by fixture group, imports, garden application, pump energy, frost | 12 rows | synthetic case data |
| SYNTHETIC-zones.csv | Soil and shade by growing zone: texture, pH, EC, organic carbon, nutrients, rooting depth, summer and winter sun, relative productivity | 4 rows | synthetic case data |
| SYNTHETIC-water-quality.csv | Water-quality samples: turbidity, E. coli, hardness, TDS, pH, iron, with the sampling note | 4 rows | synthetic case data |
| SYNTHETIC-flow-events.csv | The ten largest simultaneous-draw events: fixtures involved, peak flow and duration | 10 rows | synthetic case data |
| SYNTHETIC-food-waste-audit.csv | Four one-week kitchen and garden waste audits, split into plant, meat and dairy, and garden | 4 rows | synthetic case data |
| BOM-long-term-014015.csv | Long-term climate statistics for Bureau of Meteorology station 014015, all years of record | 12 rows | sourced |