Rain Brief: Recent Rainfall and Water Situation in Iraq

Iraq experienced above-normal winter rainfall in 2025–2026, resulting in the most significant recovery in national water storage levels in recent years. The Arab Climate Outlook Forum projected above-normal rainfall for this winter, a forecast that broadly materialized. The country now has enough water in reserve to cover drinking and household needs for around two years. 

But improved river flows do not change Iraq's underlying geography — or the climate pressures compounding it. Most of the country lies in arid and semi-arid territory, where water scarcity is a structural condition, not a seasonal one. This recovery, significant as it is, covers barely a quarter of what was lost since 2020 and less than one-fifth of the system’s total capacity. Warmer-than-usual temperatures are already reducing the net benefit due to evaporation. In addition, if approved rice farming plans proceed, this year's gains could be rapidly diminished before the next rainy season arrives.  

The lesson is one of continued concern, whilst high rainfall has contributed to positive recovery, it is still not sufficient to reverse Iraq’s longer-term water stress. The priority must therefore remain focused on reform- including diversification of water resources, integrated water resources and services management, improved water efficiency, investment in infrastructure, and cooperation with neighbouring countries over shared rivers and aquifers. 

Summary

POSITIVE DEVELOPMENT: National live water storage has increased from approximately ~3.5 bn m³ to 20 bn m³ —marking the most significant improvement in recent years. Drinking water and perennial orchards are secured for the near term.

STRUCTURAL CHALLENGES REMAIN: Current live storage remains below 20% of total storage capacity of over 100+ bn m³. Iraq has lost ~56 bn m³ since 2020, and this season’s recovery represents only around 26% of that loss. Extreme droughts are now 25 times more likely.

PRIORITY FOCUS: The current window of improved storage should be used to accelerate investment in data-based water governance. Given the potential impact of approved rice cultivation requests on current storage gains, the decision needs to be reviewed as a priority.

What Happened — and Why

Iraq's winter rains were scientifically anticipated. The Arab Climate Outlook Forum assigned a 50% probability of above-normal precipitation — the dominant signal in the region — driven by a weak La Niña and a negative Pacific Decadal Oscillation. The rains delivered exactly this outcome.

Key reservoir recovery:

• Mosul Dam (Tigris): Live storage rose from 280 million m³ at the start of 2026 to almost the dam’s full safe operating capacity of the dam— a 20-fold increase. Hydropower generation has resumed. Inflow from Turkey increased to 2,000 m³/s.
• Tharthar Lake: Receiving sustained inflows via the Tigris-Tharthar Canal (1500 to > 2500 m³/s diverted). Currently reached its live storage level, and if the inflows rate continues, this will reduce stress on pumping from dead storage. It hit its lowest satellite-recorded level in October 2025, below the 1992 baseline.
• Habbaniyah Lake: Had fallen to just 555 million m³ (17% of 3.3 bn m³ capacity) and ceased discharging to the Euphrates as recently as September 2025. It has now resumed operation following inflows from western desert catchments.
• Haditha Dam, on the Euphrates: The dam remains at a low level. Unlike the Tigris basin, the Euphrates has not received sufficient inflow from Turkey. Recovery here is incomplete.
• Southern marshlands: Eastern valley catchments (Iraq–Iran) generated considerable inflow into the marshlands of Dhi Qar, Maysan, and Basra — critical for fishing and pastoral livelihoods of 4+ million people.

Important caveat: ArabCOF-16 also forecast above-normal temperatures (60% probability). Higher evaporation reduces the net gain from rainfall. Storage figures overstate net hydrological benefit. 

What the Rains Did Not Fix

Groundwater remains critically depleted. Scientific studies found aquifer declines of 0.7–5.4 metres per year since 2003, with the worst depletion in southern Iraq. An estimated 144 billion m³ of groundwater was lost in southern Iraq between 2003 and 2009 alone — a structural deficit one season cannot reverse, given the nature of long-term groundwater recharge. While groundwater provides resilience for communities during drought years, the governance limitations along with insufficient data and unregulated extraction are undermining this resource and increasing the risk of long term depletion. 

In Sinjar and Ba'aj districts (Ninewa), groundwater is the only water source. Over 75,000 people in Wardiya, Solagh, Tal Banat, and Tal Qasab face water shortages, with springs and boreholes depleting rapidly. A 40% decline in rainfall over the past five years — compounded by conflict damage to infrastructure — has made communities entirely dependent on groundwater. 15% of residents have already migrated due to water scarcity. This area's groundwater will not have meaningfully recharged from this season's rains, given limited rainfall in the western desert zone.

Agriculture is operating under emergency constraints. Crop restrictions approved in October 2025 remain in force: rice banned; wheat cultivation halved; only 250,000 hectares permitted under surface irrigation. FAO expects wheat production to drop 30–50%, with import requirements rising to 2.4 million tons — structural import dependence for a food security staple.

Flood impact accompanied the rainfall benefits. At least two fatalities in Sulaymaniyah (December 2025); flash flooding across Erbil, Mosul, Tikrit, and Diyala. Bizibez IDP camp (Anbar, 29 March 2026) saw 300 tents inundated, WASH infrastructure damaged, residents temporarily displaced. The Darbandikhan and Hemrin Dams reaching spillway level caused downstream Diyala River flows to carry Al-Rustumiah wastewater treatment plant effluent into the Tigris, forcing drinking water treatment plants to suspend operations in affected areas.

Water quality risk. 186,006 people remain displaced due to climate factors (IOM DTM, September 2025). Flood events regularly contaminate shallow wells — a pattern requiring water supply sanitation and hygiene monitoring this season.

Climate variability. The heavy rains that affected Iraq in April 2026 highlight the growing impact of climate variability on communities and essential services. While rainfall can replenish supplies, its intensity and irregular distribution also bring risks of flooding, salinity intrusion, and service disruption. The Children’s Climate Risk Index (CCRI) results developed by UNICEF in 2025, already pointed to significant vulnerabilities, with governorates such as Al‑Basrah, Missan, and Al‑Muthanna facing heightened exposure, while others like Duhok and Al‑Sulaymaniyah remain less affected.

For children and families, these disparities affect access to safe water and sustainability of essential services. 

Implications

Political Risk: Falling rural incomes, reduced oil revenues, and political instability compound one another. Public frustration over water scarcity could intensify if rainfall declines again in the coming season. MoWR warns that approved summer rice cultivation requests could reverse this season's storage gains by the next water year.

Food Security: No nationwide acute crisis expected — wheat reserves cover ~14.5 months. Risk is localized: smallholder farmers, displaced households outside the Public Distribution System, southern governorates and IKR. Ongoing regional instability may further affect food security by influencing availability and affordability.

Displacement: Marshland and river recovery in southern Iraq may reduce climate-driven displacement from Dhi Qar, Maysan, and Basra near-term. 186,006 climate-displaced people remain at risk from continued flooding. Sinjar/Ba'aj remain in acute groundwater crisis regardless of surface water recovery, preventing durable solutions and sustainable returns.

Long-Term Trajectory: Temperatures projected to rise 1.6–2.4°C by 2041–2060. Precipitation to decline ~5% by mid-century. Tigris-Euphrates flows already 30% below 1980 levels; projected to fall further due to upstream dam construction and lack of legal transboundary arrangements. Extreme droughts of the types experienced in 2023 are now estimated to be 25 times more likely.

Key Message

The rains represent a significant  and forecast-consistent recovery- the most substantial improvement in years. But live storage at 20 billion m³ remains below 20% of Iraq's total capacity. The rains have bought time; they have not restored Iraq's water capital. Approved rice cultivation requests and future below-average rainfall could rapidly erase these gains. The window must be used to accelerate water governance reform, infrastructure investment, and transboundary cooperation — not to signal normalcy.