A modern Manhattan city planner in New Amsterdam

Question

Background

A small group of professional New York city planners leave work one day, ca. 2015, and decide to visit a different bar than usual for happy hour. The bar, which looks like something out of the wild west, is mostly empty. The bartender, a Michael Cain-esque figure, listens intently to of all their stories while polishing some tumblers. Instead of giving them each another brewsky, he smiles and offers to mix them a special drink of his own creation. Skeptically, they each take a shot of the milky drink, pay their tabs, thank the bartender, and step outside into mid-17th century New Amsterdam.

Question

Okay, the details of time travel aside, how could a group of modern city planners, knowing everything they know about how it will look and grow, affect the development of a large city (such as New York) if they were to go back in time to the early days of that city? If they could plan back then, with everything they know, how would such a city then look today?

Assumptions

• Let's say there are 3 city planners that went back. They each have a considerable amount of practical and historical knowledge of the several boroughs of New York.
• As far as they're concerned, the time travel is one-way. There's no going back (forward?)
• No one in New Amsterdam is suspicious of these newcomers, with their hip music and complicated shoes. In fact, in a matter of weeks, they are accepted as up-standing citizens and are admitted into the city's councils.
• They tell no one they are from the future, except their eventual spouses and children, who absolutely believe them; and this to keep the tradition going of shaping the future of their city to a more ideal state.

EDIT:

• Let's put aside any hard-science related to the time travel aspect of this question, and ignore any temporal paradox that may occur. Even if the city planners accidentally kill their 8th generation grandparents or something, they won't be wiped out. Also, their going back in time and changing things won't be the cause of - or prevent them from - going back in time and changing things.

Answer 1

The first issue is that New Amsterdam will be very different geographically from modern day NYC. Modern New York is partially the result of centuries of landfilling and other engineering, many of the districts of NYC would be marshland or otherwise wild or woodlands in the 1600's.

As well, the primary interests of the people of New Amsterdam were trade (particularly beaver pelts) and protection from both the natives and rival European powers. Your city planners had better have a good understanding of fortifications that could protect the city from sea born attack by cannon armed sailing ships, and the ability to repel attacks from landward by either irregular troops or "regulars" equipped with the latest siege technology from Europe.

On a more practical matter, focusing on public health issues like water and waste disposal would be high payoff projects for our intrepid city planers, followed by making the market and the dockyards as functional as possible. The city fathers of New Amsterdam will be most interested in gaining any sort of commercial advantage over the English, French, Spanish and any other potential rivals (this was close to the time Sweden emerged for a short time as a great power, and Peter the Great will be born in a few decades, so the Dutch have lots of competition to worry about).

So the city planners will have to focus on the needs and issues of their "current" clients in the 1600's, and not worry too much about how the putative subway system or Hudson River Parkway "should" be laid out in the 20th century.

They could have a little bit of fun, however. The current grid layout of Manhattan's streets aligns with the sun on May 28 and July 12 ("Manhattanhenge"). With some careful commissions to build larger public structures and encouraging other new buildings to be aligned in a grid around the public buildings they could align the grid so "Manhattanhenge" really does occur during the equinoxes...

Answer 2

A city planner is typically an architect. As such, i assume they would mostly address the problems at hand, like sewage systems and fire protection, and improve matters with their knowledge in may small ways.
Even more so if they have no reason to assume that anything very long term would affect them or their offspring of the next two generations.

There is hardly any sensible reason for trying to set the path for anything that will only take effect a quarter of a millenium away since they know that the average life span of a normal (non-government and such) building is shorter than that. Plus, persuading people into drastic changes might prove extremely difficult, because the city already developed in a way that at least mostly made a lot of sense for the needs of the time.