WATER–ENERGY SECURITY SITUATION REPORT | Antioquia Hydroelectric Corridor, Colombia

Moderate El Niño Scenario Assessment Using the JANUS Framework
Date: June 2026
Area of Interest: Antioquia Department, Colombia
Scenario: Moderate El Niño Intensification
Methodology: JANUS Water–Energy Security Framework
Prepared by: Emma Lozano (Capybara Center for Risk Analysis)

Executive Summary

A JANUS water–energy security assessment was conducted for the Antioquia Hydroelectric Corridor under a Moderate El Niño scenario. The analysis integrates forecast precipitation anomalies, satellite-derived soil moisture conditions, hydroelectric infrastructure exposure, and population vulnerability indicators into a unified risk framework.

Results indicate the emergence of a coherent drought signal across central Antioquia and the Magdalena Medio region. Hydrologic deficits and soil moisture depletion overlap with watersheds containing multiple hydroelectric facilities, suggesting increased vulnerability of water-dependent energy systems should El Niño conditions strengthen during the second half of 2026.

Although modeled exposure percentages remain relatively low, the concentration of drought indicators around critical infrastructure warrants continued monitoring. The convergence of meteorological, environmental, and infrastructure-related stressors identifies the Antioquia hydroelectric corridor as a priority region for water-energy security surveillance.

Key Findings 

Finding	Assessment
Hydrologic Deficit	Widespread precipitation deficits across central Antioquia
Soil Moisture Deficit	Extensive drying signal consistent with meteorological drought
Hydropower Exposure	Multiple hydroelectric facilities occur within stressed watersheds
Infrastructure Exposure	Roads, transmission corridors, and protected areas intersect modeled stress areas
Strategic Concern	Potential reduction of watershed recharge and reservoir inflows under sustained El Niño conditions
Overall Outlook	Moderate water–energy security concern requiring enhanced monitoring

Situation Overview 

Climate outlooks issued during 2026 indicate increasing probability of El Niño development across the equatorial Pacific. Historically, El Niño events have reduced precipitation throughout large portions of the Colombian Andes, frequently producing drought conditions, declining reservoir storage, reduced streamflow, and increased pressure on hydroelectric generation systems.

Antioquia represents one of Colombia's most strategically important hydroelectric regions. Watersheds within the department support multiple generation facilities that contribute substantially to the national electricity supply. Consequently, prolonged precipitation deficits can create cascading impacts across both water-resource and energy-security systems.

This assessment evaluates how a Moderate El Niño scenario may influence hydrologic conditions and infrastructure exposure within the Antioquia hydroelectric corridor.

Forecast Assessment 

Current climate indicators suggest increasing potential for below-normal precipitation conditions across portions of the northern Andes during the second half of 2026.

Within JANUS, the Moderate El Niño scenario increases drought intensity through:

• Enhanced precipitation deficits
• Increased soil moisture stress
• Elevated reservoir vulnerability
• Greater hydroelectric exposure sensitivity

Model outputs indicate a consistent drought signal across multiple independent indicators.

Forecast Confidence

Component	Confidence
Hydrologic Deficit	High
Soil Moisture Deficit	High
Infrastructure Exposure	Moderate
Population Exposure	Moderate
El Niño Evolution	Moderate

Overall confidence is strengthened by the agreement between precipitation anomalies and independently observed soil moisture conditions.

Forecast Discussion and Outlooks (FDOs)

FDO 01 — Central Andes Hydroelectric Corridor: Emerging Water-Energy Stress Signal

Figure 1. Hydrologic deficit under a Moderate El Niño scenario. Warmer colors indicate increasing precipitation deficits relative to baseline conditions. Purple points represent hydroelectric facilities while cyan polygons represent influence zones.

Component	Assessment
Source/Trace	JANUS posterior hazard signal derived from basin-scale precipitation anomalies (GFS forecast relative to CHIRPS climatological baseline), SMAP surface soil-moisture deficits, reservoir persistence stress indicators, hydroelectric influence-zone exposure, and transmission-network vulnerability weighting. The strongest continuous signal extends across the Antioquia–Caldas–Santander corridor, coinciding with Colombia's principal hydroelectric generation belt and associated transmission infrastructure.
Physical Interpretation	The modeled stress pattern is consistent with the early development of El Niño associated hydrologic deficits. Negative precipitation anomalies reduce catchment recharge, while declining soil moisture indicates reduced infiltration and diminished subsurface storage. Together these processes lower effective runoff generation and reservoir inflows. The signal is not merely meteorological; it reflects a coupled watershed response that directly influences hydroelectric resource availability.
Infraestructure Implication	Hydropower systems in the central Andes depend on sustained inflows from mountain catchments rather than short-duration rainfall events. Persistent precipitation deficits across upstream basins increase the probability of reservoir drawdown, reduced generation flexibility, and heightened dependence on thermal generation assets during periods of peak electricity demand. Transmission corridors traversing the affected region may experience increasing operational sensitivity if generation dispatch becomes concentrated among fewer available hydroelectric assets.
Decision Relevance	XM, UPME, IDEAM, and regional hydroelectric operators should treat the corridor as an emerging monitoring priority for the second half of the year. Reservoir inflow trends, storage trajectories, and basin-scale soil moisture conditions should be evaluated jointly rather than independently, as the JANUS signal suggests that hydrologic stress is propagating through multiple components of the water-energy system simultaneously.
Limits	The model represents exposure and hydrologic stress potential rather than actual generation losses. Reservoir operating rules, inter-basin transfers, emergency dispatch procedures, and future rainfall recovery are not explicitly modeled. Results therefore indicate elevated vulnerability, not deterministic power shortfalls.

Hydrologic deficit analysis reveals extensive precipitation shortfalls across central Antioquia and adjacent portions of the Magdalena Medio corridor. 

The strongest deficits occur near major population centers and within watersheds supporting hydroelectric infrastructure, which depends directly upon sustained recharge and reservoir inflows. The spatial continuity of the anomaly suggests a regional drought signal rather than isolated localized deficits.

These conditions are consistent with historical El Niño impacts in Colombia, where reduced precipitation can limit watershed recharge and diminish reservoir inflows over time.

The analysis does not indicate immediate operational disruption. However, continued precipitation deficits could increase vulnerability to reduced inflows, particularly if El Niño conditions persist into subsequent seasonal cycles.

The spatial overlap between drought indicators and hydroelectric assets identifies the Antioquia corridor as a strategic monitoring priority.

FDO 02 — Soil Moisture Deficit Indicates Catchment Drying Beyond Immediate Forecast Horizons

Figure 2. Soil moisture deficit derived from NASA SMAP observations and adjusted under a Moderate El Niño scenario.

Component	Assessment
Source/Trace	SMAP-derived surface soil moisture anomalies integrated into the JANUS hazard framework and amplified under the Moderate El Niño scenario.
Physical Interpretation	Soil moisture deficits are spatially broader than precipitation anomalies, indicating hydrologic memory within the watershed system. Even where rainfall recovers temporarily, depleted soil-water storage reduces runoff efficiency and delays catchment recovery. The observed pattern therefore suggests accumulated drying rather than a short-term meteorological fluctuation.
Infrastructure Implication	Catchments exhibiting persistent moisture deficits are more likely to produce reduced inflows during subsequent dry periods. This condition increases the likelihood that reservoir levels decline faster than expected from rainfall observations alone.
Decision Relevance	Monitoring programs should prioritize soil moisture indicators alongside precipitation forecasts because reservoir stress may emerge weeks after the onset of basin drying.
Limits	Surface soil moisture does not directly represent groundwater conditions or deep root-zone storage.

 

Soil moisture conditions provide independent confirmation of developing drought stress.

The observed drying pattern closely mirrors the hydrologic deficit distribution, indicating that precipitation anomalies are already influencing environmental moisture availability across the study area.

The overlap between hydrologic deficits and soil moisture depletion increases confidence in the overall assessment. Areas exhibiting both indicators are more likely to experience persistent water stress should below-normal rainfall continue.

From a water-energy perspective, declining soil moisture may reduce watershed efficiency and delay future recharge even if rainfall returns to near-normal levels.

FDO 03 — Exposure Metrics Remain Low Despite Large Hazard Footprint

Component	Assessment
Source/Trace	Posterior-weighted exposure calculations for population, urban areas, cropland, roads, protected areas, and built-up footprint.
Physical Interpretation	Although hydrologic stress is geographically widespread, the highest modeled stress zones remain concentrated within mountainous catchments and reservoir-supporting watersheds. These areas contain relatively limited population and urban infrastructure compared with major metropolitan centers.
Infrastructure Implication	The primary concern is not direct humanitarian exposure but indirect disruption through water-resource and electricity-system dependencies. Small changes in hydrologic conditions within critical watersheds may have disproportionately large downstream impacts on power generation.
Decision relevance	Risk communication should emphasize systemic infrastructure vulnerability rather than population exposure percentages alone.
Limits	Exposure estimates represent expected overlap with the modeled stress field and should not be interpreted as direct impact forecasts. The model is still being calibrated to reflect a more realistic impact.

Exposure calculations indicate measurable impacts across multiple categories:

• Population: ~24,377 people
• Urban footprint: 0.15 ha
• Roads: 4.06 km
• Transmission corridors: 1.01 km
• Protected areas: 4.09 ha

These values represent probabilistic exposure estimates rather than direct impact forecasts.

Relatively low percentages are expected within JANUS because the framework identifies concentrated hotspots of elevated risk rather than assuming uniform impacts across the study area.

Consequently, even modest exposure percentages may be operationally significant when they intersect critical infrastructure.

Assessment

The Moderate El Niño scenario identifies a coherent water-energy security signal across the Antioquia hydroelectric corridor.

Hydrologic deficits, soil moisture depletion, and hydroelectric infrastructure exposure converge spatially across central Antioquia, indicating increased vulnerability should drought conditions intensify during the remainder of 2026.

The agreement between independent indicators strengthens confidence in the assessment and supports enhanced monitoring of hydroelectric watersheds throughout the region.

While the analysis does not predict immediate infrastructure disruption, it identifies conditions that may increase operational sensitivity if below-normal precipitation persists.

Recommended Actions

Immediate (0–30 Days)

• Increase monitoring of precipitation deficits, soil moisture, and reservoir storage across the Antioquia hydroelectric corridor.
• Conduct targeted field verification in watersheds identified as JANUS drought hotspots.
• Share findings with hydroelectric operators, IDEAM, and departmental risk-management authorities.

Near-Term (1–3 Months)

• Evaluate watershed recharge trends and reservoir inflow conditions.
• Strengthen coordination between hydroelectric operators and local governments in affected catchments.
• Prioritize monitoring of facilities located within persistent hydrologic stress zones.

Seasonal (3–6 Months)

• Update JANUS assessments as ENSO forecasts evolve.
• Support watershed resilience initiatives in strategic recharge areas.
• Develop contingency plans for prolonged drought conditions and reduced hydroelectric inflows.

Technical Notes

Framework: JANUS Water–Energy Security Model

AOI: Antioquia Hydroelectric Corridor

Scenario: Moderate El Niño

Forecast Source: NOAA GFS

Baseline Precipitation: CHIRPS

Soil Moisture: NASA SMAP SPL4SMGP

Spatial Resolution: 750 m

Forecast Window: 72 hours

Hazard Components:

• Hydrologic Deficit
• Soil Moisture Deficit
• Reservoir Stress
• Hydroelectric Exposure
• Transmission Exposure

Disclaimer: This report presents modeled risk indicators and probabilistic exposure estimates intended to support situational awareness and planning activities. Results should not be interpreted as deterministic forecasts of infrastructure failure or service disruption.