Executive summary

Tehran and multiple large Iranian cities are facing a compound water emergency driven by multi-year drought, chronic over-extraction of groundwater, and structural mismanagement. In early November 2025, Iran’s president publicly warned that Tehran could face water rationing and even evacuation if rains fail—with dam storage at multi-decade lows (e.g., Latyan reportedly near 9% capacity). Similar stress signals are now visible in Mashhad, Isfahan, Shiraz, Yazd, and Karaj. Land subsidence from groundwater mining is reducing aquifer storage irreversibly and damaging lifeline infrastructure, raising the risk that “temporary” shortages tip into long-duration disruption. 

This white paper diagnoses the crisis, frames realistic water-failure scenarios (from rolling rationing to partial metropolitan evacuation), and lays out a practical evacuation and population redistribution concept that can be executed in phases if thresholds are breached. It closes with an immediate stabilization checklist and decision triggers for Iranian authorities and potential international partners.

1) Problem diagnosis: why this drought is different

1.1 Hydrologic shock and storage collapse (2024–2025)

Tehran’s multipurpose reservoirs have fallen to their lowest levels in ~60 years, prompting official warnings of rationing and potential evacuations if late-autumn precipitation fails. Latyan Dam has been cited near ~9% of capacity.  Other major cities are also approaching “Day Zero” conditions: reports indicate Mashhad’s supplying reservoirs are below 3%. 

1.2 Groundwater depletion and irreversible subsidence

Independent satellite analyses show extreme, widespread land subsidence across Iran from over-pumping—comparable to (or worse than) Mexico City or California’s Central Valley—reducing aquifer capacity and breaking canals, pipes, and roads. Recent peer-reviewed work documents hotspots sinking up to ~340 mm/year (≈1 ft/yr), with ~56,000 km² affected nationally and tight correlation with irrigated agriculture.  Around Tehran and central provinces, groundwater tables that were 20–30 m deep now require drilling to ~120 m, often still yielding little—evidence of severe storage bankruptcy.  The proliferation of hundreds of thousands of illegal wells compounds depletion and undermines allocation controls. 

1.3 Governance and structural exposure

Decades of water-intensive agriculture and industry sited in arid basins, plus aging irrigation, have locked in demand that can’t be met in dry years. Multiple analyses and official statements acknowledge these structural drivers.  The administration has floated relocating the national capital away from water-stressed, subsiding Tehran—an extraordinary indicator of perceived long-term unsustainability. 

Bottom line: Even if winter rains arrive, the loss of buffer capacity (empty reservoirs, compacted aquifers) makes Tehran and peer cities more brittle to subsequent dry spells. The system’s margin for error has narrowed dangerously. 

2) Risk picture and plausible near-term scenarios

S1 — Managed Rationing (weeks–months).

Nightly/rotational shutoffs, pressure reductions; potable supply reserved for hospitals and critical facilities; increased tanker distribution; hydroelectric shortfalls and rolling blackouts.

S2 — Localized Network Failure (days–weeks).

Burst mains and ground movement from subsidence; contamination risks; emergency desalinated or imported water limited to priority nodes; rising public-health incidents (GI disease, heat stress).

S3 — Partial Metropolitan Evacuation (weeks–months).

Triggered if storage <5–8% with no forecast relief, or if network failures cascade. President’s public acknowledgement of evacuation as a contingency underscores plausibility. 

S4 — Strategic Capital Relocation (years).

Medium-term decision to shift core government functions to a coastal or less-stressed corridor (e.g., Persian Gulf littoral) synchronized with industrial relocation and desalination buildout. 

3) What evacuation would mean—in real terms

3.1 Scale and tempo

Tehran city proper (~9+ million) would not move all at once; realistic planning assumes phased, priority-based partial evacuation in S3, moving hundreds of thousands to a few million over several waves (e.g., 6–12 weeks) while essential workers remain to keep minimal systems running. Triggers would be tied to storage thresholds, forecast precipitation, and network integrity. 

3.2 Priority populations

Tier 1: hospitals and dialysis patients; elderly; infants; critical workers’ dependents. Tier 2: neighborhoods lacking redundant supply routes or sitting on active subsidence zones. Tier 3: broader residential districts as logistics expand.

3.3 Receiving areas

Stressed inland basins (Isfahan, Yazd, Mashhad) have limited spare water; coastal provinces (Hormozgan, Bushehr, Khuzestan’s coast) offer better access to port logistics and desalination prospects, but require rapid shelter, sanitation, and power build-out. The government’s capital-relocation signaling toward the Gulf aligns with this geographic logic. 

3.4 Lifeline considerations

Water: trucking and rail tankers for short bridges; fast-track modular desalination and mobile purification at receiving sites. Power: drought also cuts hydro and thermal cooling water; plan for diesel and gas-turbine peakers and priority fuel corridors.  Health: heat and waterborne disease surge under rationing; deploy field clinics, vaccination and ORS campaigns, and safe water containers at household scale. Food & fuel: designate fuel and grain priority lanes; pre-position in receiving hubs.

4) A phased evacuation and redistribution concept

Phase 0 — Now (stabilize & prepare, 2–3 weeks)

Unified drought incident command linking water, power, health, transport, and public order. Publish transparent storage dashboards (dam % full, daily inflow/outflow, groundwater drawdowns). Rationing with equity: pressure zoning; exemptions for hospitals; surge repair crews for leaks. Contract rail/water-tanker capacity, map evacuation corridors, identify staging sites in coastal provinces. 

Phase 1 — Targeted drawdown (storage ≤10% and falling)

Relocate Tier-1 households (medical-vulnerable) by rail/coach to pre-equipped coastal camps (WASH, power, clinics). Stand up mobile desal (containerized RO) at ports; begin sea-lift of potable water if needed. Institute non-essential industrial shutdowns in Tehran basin; shift water to domestic use.

Phase 2 — Partial evacuation (storage ≤5–8% with no rain forecast)

Issue neighborhood-level movement orders (Tier-2/3) on a rolling schedule; free public transport; fuel price controls to dampen panic. Activate receiving-site schools as shelters, erect modular housing, cash assistance via digital vouchers. Maintain skeleton utilities in Tehran to prevent infrastructure collapse and looting; protect cultural assets.

Phase 3 — Consolidation and service re-balancing

Rebase non-water-intensive government functions and selected ministries to coastal corridor; keep essential security/utility staff in Tehran. Launch coastal industrial relocation tied to desalinated process water and brine management. 

Phase 4 — Recovery or transition

If hydrology improves: reverse-flow return of evacuees by waves, contingent on storage and repaired mains. If aridity persists: shift to longer-term resettlement and accelerate permanent capital-function relocation.

5) Logistics: how to move people and water

Transport

Rail: Prioritize passenger rolling stock on existing mainlines; schedule evacuation “green windows”; reserve freight paths for water, food, fuel. Road: Convoyed coaches with fuel and maintenance support; way-stations every 150–200 km with rest, water, and clinics. Air: Limited capacity; reserve for medical evacuees.

Water bridging

Rail tankers (50–70 m³ each) and road tankers (20–35 m³) to supply staging sites; temporary bladders (100–500 m³) at depots. Containerized RO desal units (0.5–5 MLD each) at coastal ports; scale fast with parallel trains; secure power via mobile turbines. Point-of-use: distribute household chlorination kits, 10–20 L jerrycans, gravity filters for redundancy.

Public health

Sentinel surveillance for diarrheal disease; heat-action plans; ORS and zinc pre-positioned; vector control in camps. Maintain cold chains for insulin, vaccines using generator-backed reefers.

6) Governance, finance, and legal instruments

Emergency water decree enabling rationing, well closures, and rapid procurement; legal indemnity for emergency works. Transparent, daily communication to reduce rumors and unrest; publish objective thresholds (Section 7). Finance: redirect subsidies from water-intensive industry to emergency WASH and desal; seek multilateral support focused on humanitarian water security (equipment and chemicals rather than cash, to avoid sanctions frictions). Law & order: protect pipelines, pumps, and distribution nodes; anti-price-gouging enforcement on tankers and bottled water.

7) Decision thresholds (objective “go / no-go” triggers)

Storage trigger: aggregate potable reservoir ≤8% with 10-day forecast < median and rising demand → move to Phase 2 partial evacuation.  Network integrity: >10% of zones experiencing >24 h outages for 3 consecutive days despite rationing → Phase 2. Health trigger: diarrheal presentations >2× baseline across ≥4 districts → accelerate Phase 2 and surge WASH. Subsidence trigger: new deformation >20 mm/month along major trunk mains → proactive isolation and neighborhood relocation. 

8) How other Iranian cities fit into the picture

Mashhad: acute storage stress (<3% reported), high in-migration; prioritize imported water and limit inbound movements during Tehran evacuation to avoid compounding crisis.  Isfahan / Yazd / Shiraz / Karaj: documented subsidence and aquifer stress; treat as no-spare-capacity receivers—use primarily as transit hubs, not final destinations, unless paired with discrete new desal capacity.  Coastal corridor (Hormozgan/Bushehr): best choice for temporary settlement and medium-term relocation due to port logistics and desal feasibility; aligns with capital-relocation signals. 

9) Immediate stabilization checklist (actions within 14 days)

Leak-loss campaign in Tehran (pressure districting + night crews) to claw back 5–10% system water. Publish storage dashboard and a two-week rationing calendar by zone.  Shut illegal wells near urban perimeters; reassign police to protect critical pumps and reservoirs.  Contract containerized RO and rail/road tankers; pre-position at Bandar Abbas and Bushehr. Stand up coastal receiving sites (WASH-compliant) with clinic capacity for 50–100k each. Announce objective evacuation triggers (Section 7) to reduce panic and hoarding.

10) Strategic outlook (12–48 months)

Demand reset: retire the most water-intensive crops in arid basins; accelerate drip irrigation where viable. Industrial siting reform: migrate heavy/wet industry to coastal zones tied to desalinated process water.  Urban transition: if the capital relocation proceeds, sequence ministries and housing with desal + power build-out to avoid “dry” administrative cities.  Aquifer recovery: enforce well closures; managed aquifer recharge where geology allows (limited expectation given compaction). 

References (key sources)

President’s rationing/evacuation warnings; Latyan Dam ~9%: Associated Press; E&E/PoliticoPro.  Mashhad reservoirs <3%: Guardian/AFP.  Subsidence & aquifer loss: 2025 AGU study; 2024 remote-sensing analysis (PMC).  Illegal wells / extraction estimates: BBC Monitoring.  Capital relocation statement: The Guardian (Oct 2, 2025).  Background syntheses on climate and water scarcity: Fanack Water Iran overview. 

One-page brief for decision-makers (tl;dr)

Severity: Tehran’s water security margin is razor-thin due to record-low reservoirs and irreversibly compacted aquifers; evacuation is a credible contingency, not a rhetorical device.  Action now: stand up incident command, leak-loss cuts, transparent dashboards, containerized desal at ports, and defined go/no-go triggers.  If triggers hit: execute phased partial evacuation toward coastal receiving sites, preserving skeleton services in Tehran; protect health and order. Medium term: couple capital-function relocation and industrial migration with desal-based water supply; reform agriculture and well governance to escape repeated crises.