EMB ERJ 145 ER/LR
Flight Crew Air Transport Pilot (ATP)
Confusion; Communication Breakdown; Situational Awareness; Time Pressure
ATC Issue All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Fuel Issue
Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification
Procedure; Weather
ZHU ARTCC gave us new routing prior to takeoff (at the hold short line of the runway.) We inputted the new data into the FMS and it checked out. During climb; we discussed why ATC wanted us to join an arrival all the way over New Orleans; since we were to the West of Houston. We discussed whether to divert. I made the suggestion that we should just tell ATC that the reroute is not good due to fuel; and see if we can get a route similar to our planned route.  After getting clearance to do a new route; which was originally our planned route; ATC then started vectoring the rest of the air traffic on 'our' route. Interestingly; if we did divert for fuel; and then ended up doing the planned route; we would have to have gone in a hold due to being over-weight. The main threat and error was due to not realizing; until after takeoff; that due to only taking enough fuel for the planned trip; we could not safely do the re-route. The FMS calculated that by flying past IAH to New Orleans; and then back to IAH; we would land with 800 LBS of fuel.I suggest Dispatch plan for the aircraft to carry more fuel; or Houston ARTCC getting more familiar with the new Arrivals and Departures which seem to be still causing traffic flow/confusion for the airspace.
An EMB-145 approach IAH from the West was told to fly an arrival which began near MSY for weather; but because of fuel the crew would have had to divert. ATC did modify the route preventing the divert.