VANCOUVER -- They call it the domino effect. When a popular park reaches capacity and the public ends up crowding city parks instead.

Take Bunzten Lake. BC Hydro runs the popular beach and hiking trail, and has been controlling how many people can use it by limiting the number of cars in the parking lot.

Rather than go home, those who didn't make the cut head to much smaller parks in Port Moody and Coquitlam.

"When one park shuts down, closes down or limits capacity, that has a domino effect all the way down," said Port Moody Mayor Rob Vagramov.

The impact is felt right away. Traffic worsens and streets fill with parked cars. It also makes it harder for people to keep a safe distance.

"If too many people get diverted into local parks, then we have a bigger risk than we would if we could spread them out more," said Coquitlam's Mayor Richard Stewart.

"If we can't allow some of our big open spaces to take their share of the load if you will, then we're going to end up with more people in crowded places," argued Stewart.

Both mayors are calling on all levels of government to work together.

That may not be easy. Hydro runs Buntzen Lake, the province oversees its parks, Metro Vancouver has its own, and so do the cities.

"As you can see, it's kind of a nightmare to get all of these entities to work together," said Vagramov.

COVID-19 has created a huge demand for outdoor living, and BC Hydro told CTV News it's seeing four times as many visitors trying to use the beach at Buntzen.

"We are doing our best to accommodate as many visitors at our beach as we can safely support while following the guidelines from the provincial health officer," wrote Hydro spokesperson Mora Scott.

A team watches the shore and when a safe distance can't be met, it closes the gate.

"When more hikers and trail walkers show up than beach goers, we're able to let more people in," Scott added. "As a result, we typically have to reduce parking at Buntzen by about 10 to 20 per cent"

Even so, both mayors argue more leniency is needed in the big parks.

"We know that more people means more risk, but at this point we really happen to spread this demand around, because we can't cope with it on our own," warned Vagramov.