The closures -- which affect 400 miles of waterways -- are due to critically low reservoir levels mainly impacting in northern and central England, with some routes in the south also impacted.
The national drought group, which includes the Met Office, regulators, government, water companies and other organisations, convened on Monday as five regions of England remain in official drought, with more likely to declare drought status within weeks.
Some reservoirs that feed canals run by the Canal & River Trust, including sections of the Grand Union, Leeds & Liverpool, Oxford, Peak Forest and Macclesfield, are critically low, the group heard.
Approximately 20% of the Canal & River Trust network is closed because of low water levels, concentrated mainly but not exclusively across northern and central England, with around 400 miles affected.
This compares with 15% in 2022.
This comes as groundwater and reservoir levels across England continue to decline despite the recent rainfall, officials have said, as they warned that drought conditions will likely continue through autumn.
While unsettled, wet and windier weather has arrived with September, England is still facing a scarcity of water.
August's rainfall was just 42 per cent of its long-term average and the summer has been declared the hottest since records began in 1884, following one of the driest springs on record.
More widely, rainfall from January to August this year was 69 per cent of the long-term average for those eight months, according to the Environment Agency.
The water shortfall has been defined as a "nationally significant incident" based on the number of areas affected and widespread damage that is being inflicted on the environment and agriculture.
Drought conditions have hit crop yields, affected the breeding patterns of some animals, harmed wetlands and river ecosystems, increased the wildfire risk and prompted several areas to impose hosepipe bans.
During the meeting on Monday, the national drought group heard that reservoirs fell by 1.4% last week.
They are now 56.1% full on average across England, compared with the average of 82.8% for this time of year.
The lowest reservoirs are the Pennines group, at 29% full, Yorkshire stocks, at 30.3%, and Ardingly in West Sussex, at 34.1%.