A MATHEMATICAL-MODEL OF SALMONID SPAWNING HABITAT

A simulation model [Salmonid Spawning Analysis Model (SSAM)] was devel oped as a management tool to evaluate the relative impacts of stream s ediment load and water temperature on salmonid egg survival. The model is useful for estimating acceptable sediment loads to spawning habita t that may result from upland development, such as logging and agricul ture. Software in common use in the USA were adapted for use in gravel bedded rivers and linked to simulate water temperature (the USFWS Ins tream Water Temperature, SNTEMP model) and water and sediment routing (the USAE Scour and Deposition in Rivers and Reservoirs, HEC-6 model, version 3.2). These models drive the redd (spawning nest) model (the U SDA-ARS Sediment Intrusion Dissolved Oxygen SIDO model) which simulate s sediment intrusion and dissolved oxygen concentration in the redd en vironment. The SSAM model predictions of dissolved oxygen and water te mperature compared favorably with field data from artificial redds con taining hatchery chinook salmon eggs.