Truckee River Flow Models Presented to Truckee River

Truckee River Flow Models Presented to Truckee River Nutrient WQS and TMDL Review Stakeholders December 14, 2011 Tami Thompson - MBK Engineers

How Flow Models Work Hydrology / Physical Data Initial Conditions Demands Alternative Scenario Operations FLOW MODEL SIMULATION Modeled Results Input data or other information OUTPUT POST-PROCESSORS Spatially and Temporally Disaggregated and Adjusted Results Data for Water Quality Modeling and Verification

TROM vs. Riverware Timestep Recognized and accepted accretions/depletions TROM / Instream Riverware 19 periods per year Daily Yes Not yet Aggregated accretions/depletions No, but reaches matched to Water Quality Limno. Tech has models process No, further postprocessing required Implementation of Operational decisions Yes for TRA and TROA Mostly for current operations, not for TROA Completed model Yes Not yet Simulation results consistent with TROA EIS and recent hearings Yes Not yet

Description of Truckee River Operations Model (TROM) Ø Monthly mass-balance accounting and simulation model of the Truckee and Carson River watersheds Ø Implements prescribed water management practices such as: l l Truckee River Agreement (TRA) Truckee River Operating Agreement (TROA) Ø Uses fixed demands and water uses for the simulation period

Extents of Truckee River Operations Model

Alternative Scenarios Considered from the TROA EIS Ø Future No Action l Estimated “Buildout” Level of Development (2033) l Truckee River Agreement Operations (TRA) Ø TROA l Estimated Buildout Level of Development l Truckee River Operating Agreement Operations (TROA)

TROM Input Data Ø Data common to all alternatives l Hydrology l Physical Reservoir Data l Forecasting coefficients Ø Data that vary by alternative l 220 operational “switches” l Initial reservoir and account conditions l Demands (consumptive and non-consumptive) l Accretions/depletions (dependent on land use) l Credit water operations l Instream flow and Pyramid Lake inflow targets

Post-Processing for River Flows l l TROM Output • Monthly volume (acre-feet) • Aggregated diversion data • Limited river data locations INSTREAM Post-processor • Translation of monthly volumes into flow for 19 periods annually • Estimates specific diversions • Estimates accretion/depletion by reach • Estimates river flows at additional locations

Flow Data Requirements for Water Quality Modeling Ø Water Quality Inputs l l l Truckee River reservoir releases Diversions Truckee Meadows Water Reclamation Facilities (TMWRF) Flows Ø For Verification of Water Quality Modeling l l l River flows Return flows Accretions and depletions (including creek inflows)

Questions?