county in the United States is assigned to at least one node. (In certain 

 cases more than one node was assigned if it was clear that the county's drainage 

 went into more than one waterbody in the network.) The nodal points and water 

 bodies are linked together in the network model in a logical downstream fashion. 



Policy Coocrols 

 for Inventories 



Poinc Sourca 

 Discharge 



Invencory 



Loads and Flow 

 from Upstream 



<te 



i i i 



Node a 



Son poinc Source 

 Discharge 

 Inventory 



counties i, 1 



Qe 



i i v 



azq 



measures 

 ae 3 



Node 3 



aaasures 

 •e3 



Loads and 



Flow to 

 Downstream 



Node Y 



AEQ 



measures 



ac y 



Figure 1. — RFF Water Quality Network Model: Schematic Structure for One Stream 

 *AEQ = Ambient Environmental Quality 



The network model contains estimates for each river nodal point for the 

 following hydrodynamic parameters: 



Streamflow 



Altitude 



Width 



Cross section area 



Velocity 



Surface water temperature 



These estimates are drawn from published and unpublished data maintained by the 

 USGS. 



41 



