Travel/POI: Glen Canyon Dam (格蘭峽谷大壩), Arizona

Glen Canyon Dam, rising 710 feet above bedrock within the steep, rust-colored sandstone walls of Glen Canyon, is the second-highest concrete-arch dam in the United States—second only to Hoover Dam, which stands at 726 feet. It is located on the Colorado River in northern Arizona, near the town of Page. The dam was constructed between 1956 and 1966 and forms Lake Powell, one of the largest man-made reservoirs in the U.S., with a capacity of more than 25 million acre-feet.

The operation of Glen Canyon Dam helps ensure an equitable distribution of water between the states of the Upper Colorado River Basin (Colorado, Wyoming, and most of New Mexico and Utah) and the Lower Basin (California, Nevada, and most of Arizona). Hydroelectric power produced by the dam’s eight generators helps meet the electrical needs of the West’s rapidly growing population. This power is distributed to Wyoming, Utah, Colorado, New Mexico, Arizona, Nevada, and Nebraska.

The dam has been controversial since its inception, with environmental activists and others arguing that the reservoir was unnecessary and destroyed the canyon’s pristine ecosystem. The environmentalist David Brower called it "America's most regrettable environmental mistake." Human actions built the reservoir, and now human actions are also causing it to shrink. The debate over remedial solutions continues.

格倫峽谷大壩矗立在格倫峽谷陡峭的鐵鏽色砂岩壁間，高出基岩 710 英尺（約 214 公尺），是美國第二高的混凝土拱壩，僅次於 726 英尺（約 219 公尺）高的胡佛大壩。它位於亞利桑那州北部的科羅拉多河上，靠近佩吉鎮。這座大壩建於 1956 年至 1966 年間，形成了鮑威爾湖－美國最大的人工水庫之一，容量超過 2,500 萬英畝英尺（約 2.5 億公頃）。

格倫峽谷大壩的運作有助於確保科羅拉多河上游流域（科羅拉多州、懷俄明州以及新墨西哥州和猶他州的大部分地區）和下游流域（加州、內華達州和亞利桑那州大部分地區）之間水資源的公平分配。大壩的八台發電機產生的水力發電可以滿足美國西部快速增長的人口的電力需求。這些電力輸送到懷俄明州、猶他州、科羅拉多州、新墨西哥州、亞利桑那州、內華達州和內布拉斯加州。

大壩自建成以來一直備受爭議。環保人士和其他人士認為，水庫毫無必要，它破壞了峽谷原始的生態系統。環保人士大衛·布勞爾 (David Brower) 稱之為「美國最令人遺憾的環境錯誤」。人類的作為建造了水庫，如今又導致水庫萎縮。關於補救方案的爭論仍在繼續。

Photo Date: 2023.09.17

Flashback 回顧

2017.09.18

The water level in 2017 was noticeably higher than in 2023, based on the discoloration of the rock near the edge of the dam.

根據大壩邊緣附近岩石的變色情況，2017 年的水位明顯高於 2023 年。

2019.11.18

2026.08.14

Lake Powell's water level has fallen to a new record low, reaching approximately 3,517 feet as of early September 2026 — lower than 98% of Septembers in the reservoir's 64-year record, and well past the previous all-time low of 3,519.92 feet set in April 2023. This puts the reservoir roughly 27 feet above the 3,490-foot "minimum power pool" threshold, the level below which Glen Canyon Dam's turbines can no longer generate hydroelectric power. While the dam has not yet dropped below that critical line, federal projections earlier this year warned the reservoir could fall below minimum power pool without major intervention, raising serious concerns about reduced hydropower capacity and the broader strain on the Colorado River Basin's water and power systems, which serve roughly 40 million people across the region.

截至 2026 年 9 月初，鮑威爾湖的水位已降至約 3,517 英尺，創下歷史新低。這一水位不僅低於該水庫 64 年記錄中 98% 的 9 月份同期水位，更遠低於 2023 年 4 月創下的 3,519.92 英尺的歷史最低紀錄。目前，水庫水位僅比 3,490 英尺的「最低發電水位」高出約 27 英尺；一旦水位跌破此臨界值，格倫峽谷大壩的渦輪機將無法繼續進行水力發電。雖然目前水位尚未跌破該關鍵紅線，但聯邦機構今年稍早的預測警告稱，若不採取重大干預措施，水庫水位可能跌破最低發電水位。這一前景引發了嚴重擔憂，人們不僅擔心水力發電能力將因此受損，更憂慮科羅拉多河流域的水務與電力系統將面臨更大壓力——該系統為整個地區約四千萬人口提供服務。