Severe water shortages are gripping western Japan, with some reservoirs projected to reach near 0% capacity by early September [1].
The crisis threatens both residential stability and local commerce in a region already struggling with record heat. If rainfall does not return immediately, the depletion of primary water sources could paralyze essential services and food production in Kochi and Kagawa prefectures.
In Kochi Prefecture, the Sōmeira Dam recorded a storage rate of 15.7% at 7 a.m. on Monday [1]. The reservoir is declining by approximately two percentage points per day [1]. Authorities said that storage may be entirely exhausted by the start of next month if weather patterns do not shift [1].
The shortage follows a period of extreme drought and high temperatures. Total rainfall in August reached only 65.5 mm [1], which is roughly 10% of the five-year average for the month [1]. Other regional data suggests rainfall has fluctuated between 10% and 30% of normal levels [2]. The Meteorological Agency had previously issued a long-term advisory regarding high temperatures and low rainfall on July 14 [2].
Kagawa Prefecture has responded by implementing a fourth withdrawal restriction, cutting the water supply by 60% [1]. This is the most severe restriction the prefecture has faced in 18 years [1]. The measures, which began on Aug. 28, have created significant anxiety for local business owners [1].
Small businesses in Takamatsu are particularly vulnerable to the cuts. For example, a typical local udon shop requires between 300 and 400 liters of water per day to maintain operations [1]. Without a steady supply, these staples of the local economy face potential closures or reduced service.
Local officials continue to monitor the Sōmeira Dam, often referred to as the lifeblood of Shikoku, as the region awaits any sign of significant precipitation [1].
“Reservoir storage may be entirely exhausted by the start of next month.”
This crisis highlights the increasing vulnerability of Japan's regional water infrastructure to extreme weather volatility. The reliance on a single primary source, such as the Sōmeira Dam, creates a systemic risk where a single season of failed rainfall can trigger drastic economic restrictions. The 18-year gap between similar restrictions in Kagawa suggests that current urban and industrial water demands may be outstripping the resilience of existing reservoir systems under new climate patterns.
