|
ASSISTANCE IN DEVELOPING A REVISED TMDL FOR THE TRUCKEE RIVER, NEVADA |
Client:
Carollo Engineers, Walnut Creek, CA
AQUA TERRA served as a subcontractor to Carollo Engineers for the watershed model development subtask of the Reno/Sparks/Washoe County Regional Wastewater Facilities Design - Phases I and II. The study objective was to develop a watershed model to calculate nonpoint nutrient loads to the mainstem of the Truckee River for interface with the DSSAM model so that the integrated modeling system can be used to evaluate the likely water quality impacts of alternative loading scenarios and to develop revised TMDLs.
The work effort was accomplished in two phases: For Phase I, AQUA TERRA assisted in development of the Simulation Plan and the model database. The Simulation Plan described the overall approach to the model application, including available data, model segmentation, land uses and calibration approach. AQUA TERRA developed the database in the form of a Watershed Data Management (WDM) file of available model input and watershed characterization data to support the model study; included were historic timeseries data for meteorologic, flow and water quality. Phase II entailed completing the model input development, performing the calibration and load generation, and preparing the Final Report and model deliverables. Hydrology was calibrated based on flow records at various point on the Truckee mainstem. Nonpoint source nutrient loads were calibrated using available data and expected ranges of loading rates. AQUA TERRA generated the total Truckee mainstem loads for each identified stream reach, along with the Pyramid Lake loads. Model simulations resulted in timeseries of both daily and monthly loads of total nitrogen and total phosphorus, with an estimated division between organic and inorganic forms.