instantiates an object from class of createReach
createReach(name,routingMethod,inflow,routingParams,delayInflow,label,downstream)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