instantiates an object from class of createReach
# S3 method for default
createReach(name="Unttitled",routingMethod="muskingum",inflow=NA,
routingParams=list(k=3,x=0.2,bedWith=NULL,
sideSlope=2,channelSlope=NULL,
manningRoughness=0.025,riverLength=NULL),
delayInflow=1,label,downstream=NA)
a string: the name of reach to be instantiated
a string: the method of channel routing. available types: 'muskingum', and 'muskingumcunge'
a vector (optional): a time series of direct inflow rather than flows comming from upstream (cms)
a list : parameters associated to the routingMethod: 'k' and 'x' for 'muskingum', 'bedWith' (m), 'sideSlope' (m/m), 'channelSlope' (m/m), 'manningRoughness', 'riverLength' (Km) for 'muskingumcunge'
an integer (optional): presenting the time steps to delay direct inflow time series
an integer: a unique number, as label
an integer: the code of downstream object
a list: an object from class of createReach