Source
https://doi.org/10.1016/j.jenvman.2010.09.009 — original source (opens in a new tab; the file is not redistributed)
Rygaard et al. 2011 — the urban water self-sufficiency ratio (LIT_063)
The foundational water self-sufficiency formula (WSR = Qlr/Qtd)
The peer-reviewed article that formalises the water self-sufficiency ratio — locally-sourced water ÷ total demand — the basis for the NI model’s
water_ssi(D03). Based on 113 cases + 15 in-depth case studies. Boundary-dependence (building vs community vs region) is the key modelling caveat.
Summary
Rygaard, Binning & Albrechtsen review how cities increase water self-sufficiency and formalise a simple, portable measure: the self-sufficiency ratio Qlr/Qtd (water sourced locally ÷ total demand). Across 113 documented cases and 15 in-depth studies, observed ratios span 15–80%, achieved via recycled wastewater, seawater desalination and rainwater harvesting. The paper identifies the drivers (water scarcity, constrained infrastructure, high-quality-water demand, institutional pressure) and the challenges (energy requirements varying >10× between techniques, trace-contaminant risk in reclamation, public resistance). For NI, it grounds the definition of water_ssi and flags its boundary-dependence.
Key claims
- claim: "THE WATER SELF-SUFFICIENCY RATIO (verbatim - the foundational formula). 'To evaluate self-sufficiency we define the self-sufficiency ratio as Qlr/Qtd, where Qlr is the amount of water sourced from within a given area, i.e. recycled wastewater, harvested rainwater or desalinated water from local shores and Qtd is the total water demand in the same area, e.g. a single building or a larger urban area.' The ratio is explicitly boundary-dependent: 'the self-sufficiency ratio depends on the definition of the area or system boundaries' (here taken as geographic boundaries) - so the same system scores differently at building vs community vs regional scale. This is the formal basis for the NI model's water_ssi (locally-sourced ÷ total demand)."
source_location: "Section 2 (methodology), p.7 — self-sufficiency ratio definition"
- claim: "EMPIRICAL RANGE (verbatim). 'The self-sufficiency ratios between 15-80% are observed: from small scale implementations like local rainwater collection providing 25% of the household consumption in Stenlose, Denmark, to citywide water management strategies with desalination and wastewater reclamation plants' (e.g. Singapore, >100,000 m3/day). The abstract reports 'increases in self-sufficiency ratios to as much as 80% with contributions from recycled water, seawater desalination and rainwater collection', and notes some cities have cut import dependency by more than 15% via rainwater collection alone."
source_location: "Abstract; Conclusions (self-sufficiency range)"
- claim: "DRIVERS. 'The main drivers for increased self-sufficiency were identified to be direct and indirect lack of water, constrained infrastructure, high quality water demands and commercial and institutional pressures.'"
source_location: "Abstract; Section on drivers"
- claim: "CHALLENGES. 'The introduction of alternative water resources raises several challenges: Energy requirements vary by more than a factor of ten amongst the alternative techniques, wastewater reclamation allows trace contaminants to reach the drinking water, and changes to the drinking water system can meet tough resistance from the public.'"
source_location: "Abstract; Section on challenges"Neobiome Intelligence relevance
Grounds the model’s water_ssi (D03) as a self-sufficiency ratio — locally-sourced water ÷ total demand — with a named academic pedigree rather than an ad-hoc definition. Two direct modelling implications:
- Boundary-dependence is a real caveat, not a nuance. The ratio changes with the system boundary; the NI choice (the community boundary) must be stated, because a building-scale rainwater score and a community-scale score are not comparable. This is the methodological grounding for the D28 water-cascade’s “locally-sourced” accounting.
- The >10× energy spread across water techniques supports the model’s water↔energy nexus — desalination (a D28 backstop) costs an order of magnitude more energy than rainwater, so the cascade’s self-sufficiency-order ranking (rainwater → bore → mains → desalination) is energetically as well as economically justified.
Feeds d03_water_waste_circular.
Research targets
Documents to retrieve
- None. This resolves RT_018 (the foundational I03/water-SSI formula primary).
Research gaps
- None new. (An NZ-specific community water self-sufficiency benchmark is tracked elsewhere; this is the international methodological anchor.)
Notes
Primary — the peer-reviewed postprint, read verbatim. data_quality: verified. Green-OA copy from DTU Orbit (the corresponding author’s institution); not AI-prepared. ⚠ Corrects the upstream citation-metadata error (journal, DOI, and I03→D03 layer tag) carried by CR_002.
Connections
Links to
Sources (1): CR_002
EDT domains (1): D03: Water, Waste & Circular Systems
Referenced by
Sources (4): CR_002 · CR_053 · LIT_065 · LIT_075
EDT domains (1): D03: Water, Waste & Circular Systems