Three pocket parks with views of downtown waterways are in the early design stage.

Napa’s redevelopment agency solicited comments Monday from people with downtown interests for a creekside plaza behind the Napa Valley Opera House, an overlook park at the southwest corner of First and Soscol and another park at the southwest corner of Third and Soscol.

All three public spaces will have views of the Napa River, while vistas behind the Opera House will feature Napa Creek and a planned flood bypass channel.

These areas will be popular with pedestrians once the flood control project finishes trails and promenades in downtown, said Jennifer LaLiberté, the agency’s project coordinator.

While the county and federal government build the flood project, the city will be using downtown redevelopment revenue to enhance adjacent public spaces, LaLiberté said.

The first of the new parks will be in the area behind the Opera House, the Wiseman office building and the Main Street Exchange. Measuring two-thirds of an acre, this space has been used for parking.

Gretchen Stranzl McCann Landscape Architects revealed two development options Monday. Both called for tables and patches of lawn and allowed for outdoor restaurant dining.

Under one scenario, all the trees on the creek would be removed. Under another, two of four redwoods would be retained.

It’s important that the new views created by flood control effort not be obstructed, said Bart Ito of McCann Landscape Architects.

The architects proposed retractable bollards — or posts — that would allow truck deliveries to the Opera House and other businesses, while keeping the plaza vehicle-free most of the time.

After receiving comments from such groups as Friends of the Napa River, the Napa Downtown Association, the Parks and Recreation Commission, adjacent property owners and the flood district, the agency wants to present a plan for City Council approval by summer, LaLiberté said.

Construction could occur in 2008, LaLiberté said. The agency has $250,000 set aside for construction, but this is an out-of-date figure, she said. Costs may have doubled since the estimate was drawn up.

The agency is spending $50,000 to design Creekside Plaza behind the Opera House and $75,000 to design the Third Street Green at Soscol Avenue, which measures nearly four-fifths of an acre.

No construction is likely at Third and Soscol for years, LaLiberté said. The flood project intends to use this property early in the next decade to stage construction of flood walls south of Third Street, she said.

With the flood project falling behind schedule for lack of federal funding, there is no certainty when this flood work will be done, she said.

The third site, at First and Soscol, is now the location of Napa Sanitation District’s Edmunson Pump Station. The district plans to demolish the station in 2008, freeing up the site for city improvements.

Architects sketched a two-level plaza, allowing pedestrians to drop below the traffic for views of the confluence of Napa Creek, the Napa River and the bypass channel.

Because construction of the bypass channel, now called Oxbow Commons, is lagging, some of the $650,000 earmarked for public amenities there could be diverted to the pocket parks, she said.

The redevelopment agency is ending its 43-year life in 2012. December 2012 is the deadline for the agency to contract for work in the downtown area, LaLiberté said.

Agency funds come from property tax growth in downtown since the early 1970s.