Passage Algorithms - CRiSP.1.5 User Manual

II.3.3 - Passage Algorithms

CRiSP.1 calculates arrival of all fish on all days to each river segment ¹ before calculating passage of fish to the next downstream segment. With this set of arrival information, it is possible to assign rules for fish transportation based on a percentage of the total run that will arrive at a dam. Thus, CRiSP.1 moves fish downstream a segment at a time, adding smolts coming from tributaries or hatcheries on a daily basis. The number of fish leaving a river segment on any given day depends on

the number arriving on the same and previous days
water flow rate (kcfs - 1,000 cubic feet per second)
mortality factors related to predation and gas bubble disease.

Dam operations control important variables of CRiSP.1; three major variables being daily total flows, spills and fish transportation.

Dam passage survival depends on the pathway fish take through a dam. At all dams, fish arriving at the forebay can pass over the spillway, or through the powerhouse. The fraction of fish entering the spillway depends on:

percentage of total flow spilled
spill efficiency at the dam
timing of the spill period.

Fish entering the powerhouse can pass through the turbines or be guided by traveling screens. The propensity of a population to be guided is represented by a fish guidance efficiency (fge) which can be set constant or varied over a season for each project and population. Mortality depends on the pathway chosen, accruing for spillway passage, collection, and turbine passage. Dam activities are calculated on a two hour basis and summed over a day to provide a daily fish input to the next reservoir.

Bypassed fish at specified dams may be transported in barges or trucks to any point in the river downstream of the collection site. Bypassed fish not transported are released into the tailrace. CRiSP.1 removes transported fish at a dam, computes a mortality, and releases fish at the transportation site at a later time as determined by a transportation velocity. Whether collected fish are transported depends on rules developed to simulate actual transportation decisions. Factors include:

numbers of fish collected
a fraction of the total run of a species passing a project
arrival of a given Julian Day
transport onset set by number of fish or Julian day
transport termination set by number of fish passing within a specified number of days or by Julian day.
separator operation determined by flow and fraction of run passing a project

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¹ A segment is a section of river between confluences, dams, or headwaters.

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