Global Surface Water Monitor

The Global Surface Water Monitor is intended to provide an independent, imagery based source for the condition and operation of key water reservoirs worldwide. These reservoirs help ensure both human security and national security to the areas they serve providing vital sources of water for drinking, food and power production, as well as protection from flooding. Monitoring water levels of key reservoirs can help warn of and assess the severity of disasters and foster cooperation across political boundaries by enabling transparent, basin-wide data sharing. To access the data, click on the link below.

Go to the Global Surface Water MonitorSlide1

Conditions as of May 2016


The Guri Dam, Venezuela’s primary source of electric power, was at record low conditions leading to widespread water and power outages amid protests and a government directive to switch to a 2-day work week until the situation improves.

Sao Paulo, Brazil, the largest city in the western hemisphere, continues to experience very difficult water shortages as its primary reservoirs remain near record lows even as they have experienced some recovery recently. Brazil will be hoping for improved conditions over the next few months in the lead-up to the 2016 Summer Olympics.

Reservoir levels in El Salvador were also observed at extremely low levels as the country declared a drought emergency for the first time ever.

Panama was also experiencing low water levels affecting Panama canal traffic.


In Thailand, Vietnam and other parts of Southeast Asia, drought has significantly impacted key reservoirs there. China recently agreed to release more water from its dams on the Mekong to assist as shown in our world surface water monitor data, but may also be partly to blame for the water shortages.

In Kyrgyzstan, low water levels have forced the country to import power from Kazakhstan.

In Russia, water levels at the large Sayano-Shushenskaya reservoir fell to their lowest levels since the 2009 disaster.

Reservoirs in the vicinity of Pyongyang, North Korea also showed very low levels, likely contributing to power and food shortages in the country.


The Kariba Dam, a critical source of power and water for Zimbabwe and Zambia, was near record lows. The power station’s general manager told reporters that dam levels were at 12 percent of capacity, a level last recorded in 1992.

Reservoirs in Ethiopia were also low following recent El Nino conditions. Water levels at Lake Nasser, Egypt’s large dam on the Nile, failed to increase last year for the first time in decades due to the dry conditions upstream. Planned reservoir filling at the Grand Ethiopian Renaissance Dam over the next few years could lead to a similar situation over consecutive years which could limit Egyptian water availability.

Middle East

Reservoirs in many ISIS affected areas of Iraq and Syria were low, particularly the Haditha Dam. Reservoirs in Turkish reservoirs upstream are currently at normal levels.

A Note on the Global Surface Water Monitor

The Global Surface Water Monitor makes use of Google Earth Engine to monitor water level changes through time, bringing historical context to current conditions. Rather than providing specific water levels, the data examines interpreted water extent compared to a derived long term monthly average. Thresholds for classification as normal, above normal, low, very low, or extremely low have been set based on common standard deviation thresholds. Additional data on each dam, to include some of this time series data, can be found by clicking on one of the points on the map interface. Related press reporting and context can also be viewed by clicking on the situation arrows. The techniques and algorithms used are still under development and results may not accurately reflect conditions in all cases. Comments and requests for additional data can be sent to