BEIJING, May 16 (Xinhua) -- Eight new energy law enforcement boats have been put into use in the Miyun Reservoir, Beijing's largest reservoir, the publicity department of Miyun District said Thursday.

Previously, the fuel-powered law enforcement boats in the reservoir had the environmental hazard of fuel oil leakage and pollutants emission.

The new energy boats use liquefied gas-powered engines, which can reduce the emission of carbon monoxide and harmful particles by 70 percent and 95 percent, respectively.

The fuel-powered boats could only patrol for around one hour at a time, while the new energy boats can patrol for an entire day.

The new energy boats are also equipped with positioning systems, which can ensure the safety of the patrollers in foggy weather. The infrared thermal imaging system has night vision within a range of 3 km.

The boats also have drones and supervision systems which can take pictures of illegal activities such as illegal fishing.

Miyun Reservoir in northern Beijing has a capacity of about 4.4 billion cubic meters and a surface area of up to 188 square km.

The district launched law enforcement patrol in the reservoir in 2018. Currently, the reservoir holds 2.57 billion cubic meters of water, the highest amount in 15 years.