Diversion-Runoff Calculator User Manual

DRC output integrates into RiverWare© for larger-scale water budgeting and water rights accounting. RiverWare is a robust, object-oriented modeling platform developed by the University of Colorado Center for Advanced Decision Support for Water and Environmental Systems (CADSWES) that simulates and optimizes river and reservoir operations for planning, management, and decision support. 

Typically, the level of conceptualization applied to RiverWare© does not afford the ability to track changes to individual water users. The DRC can be used to locally compute canal losses, crop depletion, net irrigation requirements, and runoff in order to provide realistic estimates of diversion flows based on various irrigation practices. The diversion flows, along with return flows, are passed into RiverWare© in order to systematically account for drought mitigation actions by individual water users. To do this efficiently, diversion flows at individual canals are lumped together and applied to a specific RiverWare© node. 

RiverWare© must also account for local inflow between stream gages. One component of the local inflow is the irrigation runoff. The DRC computes runoff and generates a "River_LocalInflows.csv" file that aggregates the irrigation runoff returning to the natural streams upstream of a particular gage. The figure below shows an example of the various RiverWare© node groupings as colored points and the return flows associated with specific gages as color-coded flowlines.

Note: The steps outlined below are necessary whenever the Water Rights Distribution Network are updated. 

A point feature layer provides the mapping between individual diversions and their respective RiverWare© nodes. The layer assigned as DiversionsSHP supplies this mapping. The DiversionsSHP is a modified version of the "NetNodes.shp" shapefile supplied by the Utah Division of Water Rights (DWRi). The modified file is a subset of points representing locations of main diversions. Attribute fields "Divert_From", "Divert_To", and "RWNode" are added to the attribute table. Divert_From is the name of the main diversion canal. Divert_From is the name of the river being diverted. RWNode is the specific node from the RiverWare© model onto which the diversion is grouped. These fields are shown below. In the geodatabase, the RWNode can be associated with a coded value domain containing a list of the RiverWare© nodes in order to ensure consistent naming for proper aggregation.

The diversion mapping is included with the model layers provided. This only needs to be modified if the aggregation scheme changes or when a new set of feature layers is generated, for example when the DWRi distribution network is updated. When updates do occurs, the original diversion layer can still be used as long as the main canal list and node mapping hasn't changed.

To do this efficiently, diversion flows at individual canals are lumped together and applied to a specific RiverWare© node. A user supplied shapefile (or geodatabase feature class) provides the mapping between individual diversions and their respective RiverWare© nodes. A subset of the "NetNodes.shp" shapefile produced by DWRi, which represents the main diversions and is used for this mapping.

Return flows are mapped directly in the NetFlowlinesSHP shapefile. A "ReturnFlow" field is added by the UCRAF ArcToolbox during the '01 Populate Geodatabase' step. Only flowlines that are part of the natural stream network are assigned a ReturnFlow property. These properties are generally assigned to the next downstream local inflow node in the RiverWare© model (typically the next downstream gage). In the example provided below, the ReturnFlow is associated with a coded value domain containing a list of the stream gages where local inflows are applied in RiverWare© to ensure consistent naming conventions are used when the DRC reads this file.

When the optional aggregation mode is specified in the input file, an internal flag called "RiverWareAggregation" is set in order to output a file called "ObservedAndDRCDiverisions.xlsx". This file contains columns of aggregated simulation and observed diversion flow, canal losses, return flows, and water rights corresponding to the RiverWare© nodes. The optional DiversionsSHP file described above is required to utilize this option. The NetFlowlinesSHP must also contain the ReturnFlow field in order to run in aggregation mode. The example input file below highlights these optional requirements.