The London agents Stirling Ackroyd recently identified enough sites for half a million houses in the London area alone, with no intrusion on green belt.
And yet the green belt around the city does not permit Oxford to expand, driving house prices higher than anywhere in the country, proportional to income.
If your city is on a river or in a green area, you can say it's, it is on the river or it sits on the river, or it is in the green belt, or it sits in the green belt.