A redesign of sprawling Crissy Field will be one of the last puzzle pieces in a decades-long process by the National Park Service to turn the Presidio into a park friendly to both wildlife and humans.

The Park Service, Golden Gate National Parks Conservancy and Presidio Trust are taking suggestions from the public on what people would like to see changed in the 100-acre shoreline park on the northeastern edge of the Presidio.

No specific design has been put forward for the reconfiguration, dubbed Crissy Field Next, but project managers say part of the plan would be to create a green gateway for people wandering down from Tunnel Tops, the 14-acre park that will soon be built across the eastern tunnels of Presidio Parkway.

“This project proposes to make improvements to Crissy Field so that all visitors are able to enjoy and connect with the park,” says the Golden Gate National Recreation Area website dedicated to the project. “There may be new features, while the sense of tranquility and history that makes it such a special place will always be preserved.”

Crissy Field was transformed from a decrepit military airstrip into a bayside park in 2001. It now draws nearly 1.2 million people a year who stroll, cycle and walk dogs on a 1.5-mile promenade that skirts coastal scrub habitat, a tidal marsh and beaches in the shadow of the Golden Gate Bridge.

Park officials have been gathering ideas for improving the space at workshops and public scoping sessions. They hope to break ground on the project in 2021, about the same time the Presidio Tunnel Tops are scheduled to open to the public.

For more information: https://www.parksconservancy.org/projects/crissy-field-next

Peter Fimrite is a San Francisco Chronicle staff writer. Email: pfimrite@sfchronicle.com. Twitter: @pfimrite