'Identifying stability, topological significance, and redundancies in water resource networks using parallel coordinate plotting'
Leah Meeks (firstname.lastname@example.org), Utah State University; David Rosenberg (email@example.com), Utah State University
The size and complexity of water resources networks typically require a large number of computationally intensive simulations to test effects of changes in network structure or management. Current tools can only visualize the effects of a few changes. Here, we introduce a new method and tool that uses parallel coordinate plotting to simultaneously visualize large water resources networks plus identify and rank nodes that are (1) stable (their connectivity does not depends on the existence of particular nodes), (2) topologically significant (when removed or added to the network, they cause other nodes to be unstable), and (3) redundant (a node pair that has similar connections). The tool works by calculating node centrality, creating a parallel coordinate plot, calculating pairwise differences between the elements comprising each plot trace, and calculating each node’s stability, topological significance, and redundancy. We apply the tool to the 56-node lower Bear River water system that stretches from southern Idaho to the Great Salt Lake, Utah. Nodes that are connected to only one other node are the least stable, including Great Salt Lake, Malad River, and Evaporation from Hyrum Reservoir. The three most topologically significant nodes are Cutler and the two junctions connecting the South Cache Valley and the Weber branches to the rest of the network. There are five highly redundant node pairs with over 96% of the same connections including the Cache Valley Irrigation and Cache Valley New Municipal and Industrial service areas. These results suggest that the redundant Cache Valley Irrigation service area is a promising source to transfer water from agriculture to urban use. The New Box Elder County Irrigation and South Cache Irrigation service areas have very low topological significance ranks and suggest that these irrigation areas may also be promising sources of water transfers. Results also identify candidate locations to (i) remove dams (reservoirs with low topological significance or high redundancy), (ii) implement conservation measures, develop new alternative supplies, or monitor flows (unstable nodes), and (iii) protect environmental and ecological services (nodes with high topological significance). Future work should incorporate flow direction and magnitude. The tool scales to very large networks and identifies the most promising nodes to subsequently focus computationally-intensive simulation and sensitivity analysis efforts.