Hickman, AristaÌý1Ìý;ÌýDiNatale, KellyÌý2Ìý;ÌýMcpherson, BrianÌý3Ìý;ÌýBliss, MattÌý4

1ÌýDiNatale Water Consultants
2ÌýDiNatale Water Consultants
3ÌýDiNatale Water Consultants
4ÌýDiNatale Water Consultants

DiNatale Water Consultants has developed a comprehensive operations and planning model for the East Cherry Creek Valley Water and Sanitation District (ECCV), United Water and Sanitation District (United), and the Arapahoe County Water and Wastewater Authority (ACWWA). These three entities are managing a new water supply project that covers over 100 miles of the South Platte River in Colorado for an annual delivery of over 10,000 acre-feet of water. This water supply project includes sources of water from transferred senior agricultural surface water rights from over 20 irrigation companies and junior direct flow, storage, and recharge rights. The objective of the supply project is to offset alluvial well pumping depletions and delayed historical return flow obligations from changed water rights with reservoir releases and exchanges and lagged accretions from groundwater recharge. Exchanges in designated accounting reaches of the South Platte River are used to make diversions and depletion replacements in upper reaches by providing a replacement supply downstream. The model has undergone numerous alterations to test several combinations of infrastructure and to determine which arrangement of reservoirs, pipelines, wells, and recharge ponds is best suited to meet each entity?s needs while fulfilling the South Platte?s evolving administration guidelines and policies. Now that the infrastructure to be used has been established the model is being rebuilt to better utilize RiverWare objects, accounts, and methods that represent physical features of the river basin. Due to the complex nature of the operating policy, the ruleset was also re-written to reduce solving iterations and incorporate lessons learned over the past few years.