Modeling San Juan-Chama Project Water with the Upper Rio Grande Water Operations Model (URGWOM)

Craig Boroughs (B&H Engineering)

The San Juan-Chama Project was authorized in 1962 as a means to allow New Mexico to use its portion of San Juan water under the Upper Colorado River Basin Compact. Facilities constructed for the Project are included in the physical system modeled with the Upper Rio Grande Water Operations Model (URGWOM). Diversion restrictions are simulated, and the resulting two types of water in the Rio Grande (San Juan-Chama Project water versus native Rio Grande water) are tracked. Separate accounts are established for the different contractors for San Juan-Chama Project water. The rules established to set daily outflows from each dam include consideration for the separate demands for San Juan-Chama Project water versus native Rio Grande water. A resulting predetermined total outflow for each dam is checked against all pertinent flood control criteria and other restrictions, and the final reconciled outflow of San Juan-Chama Project water is used to set supplies as pass-through, to payback debts, or to fill storage accounts based on identified priorities. Exchanges and leases for San Juan-Chama Project water are also tracked. San Juan-Chama Project water is one of the key factors that complicates modeling of operations in the Rio Grande basin.