Mekong Dam Monitor (Update for Dec. 2 - 15, 2024)

 

Update for December 2-15

Notable changes on the Mekong in the last week. Visit the Monitor home for more, including Burmese, 中文, Khmer, ພາສາລາວ, ไทย, and Tiếng Việt translation.

SPOTLIGHT 2024 Wet Season Dam Restrictions in China: Highest Ever Observed China’s 12 dams restricted more water than ever before during the wet season months of June-November 2024. We tracked a total of 23.1 billion cubic meters of restrictions, slightly higher than 2018’s cumulative restriction of 22.9 billion cubic meters. For the first time in seven years, the Nuozhadu Dam (the largest on the Mekong) filled to full capacity. The dams could fill due to relatively wet conditions in China throughout the wet season. These restrictions reduced roughly 18% of natural wet season flow to Chiang Saen, Thailand, which was relatively low in comparison to previous years given comparatively higher amounts of precipitation this year. In 2019, 2020, and 2021, China’s dams restricted 30% of natural flow to Chiang Saen, Thailand, delivering much more severe negative impacts to the Mekong’s natural floodpulse process and communities downstream. From here onward into 2025, China’s dams will release much of these high reservoir volumes into the downstream, artificially raising the level of the river. In previous years when China’s reservoirs were similarly high, releases for hydropower production have TRIPLED monthly flow to Chiang Saen, Thailand and DOUBLED monthly flow to Stung Treng, Cambodia. Artificially high river levels are extremely damaging to fish migration behaviors and the flooded forest areas along the Mekong River on which local communities rely for food and water security.

IMAGE OF THE WEEK 2024 Wet Season Flow Wetter in the Upstream and Drier in the Downstream The Mekong’s downstream reaches usually contribute more wet season flow than parts of China and northern Laos, but this was not the case in 2024. Combined flow from China, the Golden Triangle, and Northern Laos accounted for 40% of flow at Stung Treng in 2024  (compared to a historical average of around 30% prior to 2007 when dams did not impact natural flow) and flow from northeast Thailand and the 3S Basin accounted for 30% of flow (their combined historical pre-dam average is 40%). Flow contributions in northeast Thailand were particularly low at 10% due to severe drought there. Over the last 15 years, northeast Thailand flow contributions have averaged 20% of flow to Stung Treng. Much of the flow originating in the upstream came from the severe weather events that hit the upper basin in August and September.

Where is the water? Dry season releases for hydropower production have begun and small peaks of water from dam releases are pushing through the Mekong. Last week we observed a cumulative release of 601 million cubic meters of water from 13 dams throughout the Mekong, with the most significant release coming from Nuozhadu (PRC, 496 million cubic meters). These releases artificially raise the level of the river and cause harm to local communities and wetlands.

Most Impactful Dams

River Levels River levels throughout the basin are slightly lower than normal.

Chiang Saen Gauge Stung Treng Gauge

Weather & Wetness Much higher than normal temperatures in the upper basin in China brought rain and extreme wetness instead of snow last week. Most of Laos and Vietnam were also much wetter than normal for this time of year. Conditions were also wetter than usual in most of Thailand and Cambodia, although there was a drier than normal area north of the Tonle Sap Lake near Siem Reap that has persisted for many weeks.

Mekong Dam Monitor (Update for Nov. 25, 2024 - Dec. 1, 2025)

 

Update for November 25 - December 1

Notable changes on the Mekong in the last week. Visit the Monitor home for more, including Burmese, 中文, Khmer, ພາສາລາວ, ไทย, and Tiếng Việt translation.

SPOTLIGHT Mekong Floodpulse continues its retreat The Mekong floodpulse continues its retreat as the basin transitions from the wet season into the dry season. The current amount of seasonal flooding (14,900 square kilometers) is above average for this time of year. However, the floodpulse peaked one month later than the historical norm this year, and therefore its retreat is about one month late. The Mekong Delta in Vietnam tends to benefit from a late retreat because freshwater is available for agricultural purposes longer into the dry season.

Where is the water? At the end of the wet season, we typically observe a mix of releases and restrictions from dams throughout the Mekong. Restrictions were observed at seven dams with the largest at Nuozhadu (PRC, 168 million cubic meters) and Lower Sesan 2 (CAM, 136 million cubic meters). Releases were observed at fourteen dams with no large releases observed. This resulted in a small net restriction of 193 million cubic meters.

Most Impactful Dams

River Levels River levels throughout the basin are generally near normal. Eyes on Earth estimates that 28% of flow is missing at Chiang Saen, Thailand, as a result of upstream dam restrictions.

Chiang Saen Gauge Stung Treng Gauge

Weather & Wetness The upper basin continued to be extremely wet, creating higher than normal river flow from the Mekong headwaters in China. The lower basin was unusually warm with near normal wetness across most of the region. Most of Cambodia and Vietnam’s delta had above average wetness.

Mekong Dam Monitor (Update for November 18-24, 2024)

 

Update for November 18-24

Notable changes on the Mekong in the last week. Visit the Monitor home for more, including Burmese, 中文, Khmer, ພາສາລາວ, ไทย, and Tiếng Việt translation.

SPOTLIGHT Spotlight: Nuozhadu, the Mekong’s largest dam, is filling to new heights Last week, China’s Nuozhadu Dam, the largest dam in the Mekong Basin, surpassed all previously observed reservoir levels (since 2016 when the MDM data archive starts). The previous highest observed reservoir level was 809.6 meters on October 29, 2018. Last week, the reservoir reached an estimated 810.6 meters and an estimated active storage of 11.69 billion cubic meters. This is significant for a few reasons. First, drought in China caused Nuozhadu to fill to much-lower than-normal wet season levels from 2021-2023. Second, typically at this time of year Nuozhadu begins to release water for hydropower production – not fill its reservoir. Wetness and precipitation conditions in the upper Mekong at the end of this wet season have been favorable for filling reservoirs, and data collected since 2022 suggests that the late wet season months are getting wetter. If this trend holds, then it’s possible for dam operators to wait to fill reservoirs until the end of the wet season. Typically, dams fill their reservoirs in the early wet season months much to the detriment of the downstream floodpulse which naturally energizes during the wet season months. A strong floodpulse promotes good fisheries and agricultural production. A new pathway for smarter dam operations and improved ecological conditions downstream is beginning to reveal itself, but it is up to the Mekong’s dam operators to be convinced to follow this path.

Where is the water? At the end of the wet season, we typically observe a mix of releases and restrictions from dams throughout the Mekong. Last week was no exception with releases observed at sixteen dams and restrictions observed at seven dams. The largest releases came from Xiaowan (PRC, 722 million cubic meters), Jinghong (PRC, 144 million cubic meters), and Nam Ngum 2 (LAO, 204 million cubic meters). The largest restrictions came from Huangdeng (PRC, 162 million cubic meters), Nuozhadu (PRC, 332 million cubic meters), Nam Ngum 1 (LAO, 108 million cubic meters). This led to a moderate net flow release of 573 million cubic meters of water that will artificially raise the river level above natural flow conditions.

Reservoir Storage Over Time

River Levels River levels throughout the basin are generally near normal. Eyes on Earth estimates that 26% of flow is missing at Chiang Saen, Thailand, as a result of upstream dam restrictions.

Chiang Saen Gauge Stung Treng Gauge

Weather & Wetness The upper basin in China experienced extreme wetness last week. The center of the basin in much of Thailand and Laos has a mix of wet and dry conditions. Most of Cambodia and Vietnam’s delta are experiencing above normal wetness conditions.

Cáo phó KS. Nguyễn Minh Quang

 

 

SOURCE:

https://www.nguoi-viet.com/phan-uu/ong-nguyen-minh-quang-2/

 

Ông Nguyễn Minh Quang tốt nghiệp Kỹ sư Công chánh tại Trường Cao đẳng Công chánh, Trung tâm Quốc gia Kỹ Thuật Phú Thọ, Sài Gòn năm 1972, Tốt nghiệp Kỹ sư Công chánh (1983) và Cao học Thủy lợi (1985) tại Đại học Nebraska, Hoa Kỳ. Ông là cựu Trưởng ty Kế hoạch, Ủy ban Quốc gia Thủy lợi, Bộ Công chánh và Giao thông, Việt Nam Cộng hòa, đến tháng 4 năm 1975, là chuyên viên Thủy học (Hydrlogist) của Sở Quản trị Thủy lợi, Broward County, Florida đến năm 1989. Từ năm 1990 đến 2015, ông là Kỹ sư Giám sát Trưởng (Senior Supervising Engineer) của Stetson Engineers Inc., một công ty cố vấn về thủy lợi và ô nhiễm nguồn nước, thành lập năm 1957 ở Los Angeles. Ông nghỉ hưu từ năm 2016.

Source: https://usvietnam.uoregon.edu/author/minhquang/

.

Kỹ sư Nguyễn Minh Quang là một kỹ sư công chánh chuyên nghiệp (professional engineer) của tiểu bang California và cũng là một chuyên viên thuộc Hội Khoa học và Kỹ thuật Việt Nam. Trước năm 1975, KS Quang là một chuyên viên phục vụ tại Ủy ban Quốc gia Thủy lợi trực thuộc Bộ Công Chánh và Giao thông ở Sài Gòn. Ông phụ trách công tác nghiên cứu và soạn thảo các kế hoạch phát triển thủy lợi ở miền Nam Việt Nam cũng như công tác đo đạc thủy học và tiên đoán lũ lụt ở ÐBSCL.

Source: https://www.rfa.org/vietnamese/features/Water_Resources_Problems_in_MekongDelta_P7_NMQuang-20060419.html)

 

Kỹ sư Nguyễn Minh Quang là Kỹ sư Công chánh Chuyên nghiệp (Professional Civil Engineer) của Tiểu bang California.  Tốt nghiệp Kỹ sư Công chánh tại Trung tâm Quốc gia Kỹ thuật Phú Thọ, Sài Gòn năm 1972; Trưởng ty Kế hoạch của Ủy ban Quốc gia Thủy lợi thuộc Bộ Công chánh và Giao thông đến tháng 4 năm 1975.  Tốt nghiệp Cao học Thủy lợi tại Đại học Nebraska, Hoa Kỳ năm 1985; Chuyên viên Thủy học (Hydrologist) của Sở Quản trị Thủy lợi, Broward County, Florida đến năm 1989.  Từ năm 1990 đến 2015, Kỹ sư Giám sát trưởng (Senior Supervising Engineer) của Stetson Engineers Inc., một công ty cố vấn về thủy lợi và ô nhiễm nguồn nước, thành lập năm 1957 ở Los Angeles).

Source:

https://nhatbaovanhoa.com/a3791/vi-sao-thieu-nuoc-o-dong-bang-song-cuu-long-vi-cambodia-