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The Idagon River System Flight Simulator. Diagrams and Text from: http://www.wsu.edu/~forda/AAIda.html. Introduction to the Idagon.
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The Idagon River System Flight Simulator Diagrams and Text from: http://www.wsu.edu/~forda/AAIda.html
Introduction to the Idagon The Idagon is an invented River. The name comes from a combination of the States of Idaho and Oregon in the Northwest region of the United States. The Idagon was invented to allow you to experiment with different policies on reservoir operation, land development, land fallowing, and the efficiency of irrigation. These policies are of interest to water resource agencies across the West. The Idagon is simpler than the real river systems in the West, but it is still a challenging system. It is comprised of flows from several tributaries plus the flows in the main stem. The surface flows interact with ground water flows through the Idagon Aquifer. Surface flows are shaped by the operational rules governing the four reservoirs; ground water flows are shaped by hydrological rules. The various "rules" for the way the river works are translated into mathematical equations. The combination of mathematical equations forms a model of The Idagon. (The model is larger than any of the models in Modeling the Environment, and it uses short names that you are not likely to understand. This makes the model different from all of the other models in the book. You'll learn from experimenting with the model, not from studying its stock-and-flow structure.). You will experiment with changes in the model to learn if it is possible to improve the simulated performance. Performance will be measured by the river's contribution to the economy and its contribution to wild life. You will choose the relative importance of serving different goals. Your challenge is to learn the combination of policies to allow for the best use of river system. When you are happy with your policies, discuss your approach with the approach favored by your classmates. You may find that you differ on the relative importance of serving economic or wild life goals, but you might discover that you agree on the best policies for managing the river.
Management Goals 1. Increase the Idagon Economic Product The Idagon Economic Product (IEP) is the principal economic indicator. It counts net income from crop production and electric power production. In most simulations, the IEP will be around $1,000 million per year. It is nearly a "Billion Dollar" system. The goal is to boost the IEP to $1,050 million per year. 2. Maintain Land Use Patterns: Historically, one million acres of land has been irrigated by diversions in Area 1 and by pumping in Area 2. This activity has given rise to the development of support industries as well as to towns and villages. These activities are valued in their own right (i.e., separate from the contribution of crop production to the IEP.) Consequently, an additional goal has been established--to maintain at least 95% of the land in both areas under irrigation. 3. High Flow in the Big Fish During April The 3rd goal is to achieve a rate of flow of 68 MAF/year during April in the section of The Idagon after the Big Fish. This flow is considered important to aid the salmon smolts in their spring migration (see chapter 13 in the book).
Management Goals 4. Adequate Flow Below Canyon Lake The section of The Idagon immediately below Canyon Lake is considered important for water quality, for wildlife and for recreation. The 4th goal calls for at least 4 MAF/year of flow in this section during all months of the year. 5. Maintain High Flow at Big Springs The discharge at Big Springs was around 6 MAF/year one hundred years ago. But the flow is now around 10 MAF/year, and this high flow is important for water quality, for wildlife and for industries that have developed below Big Springs. The 5th goal is to maintain this flow at 9 MAF/year or greater. 6. Adequate Flow Below American Lake The final goal concerns the section of The Idagon immediately below American Lake. It is considered important for water quality, for wildlife and for recreation to maintain at least 3 MAF/year in this section during all months of the year.
Environmental Goals • Environmental Area Below American Lake • One of the six goals concerns the section of The Idagon immediately below American Lake. It is considered important for water quality, for wildlife and for recreation to maintain at least 3 MAF/year of flow in this section during all months of the year. • Environmental Area Below Canyon Lake • One of the goals concerns the section of The Idagon immediately below Canyon Lake. It is considered important for water quality, for wildlife and for recreation to maintain at least 4 MAF/year of flow in this section during all months of the year. • Environmental Area After the Big Fish • One of the goals is to achieve a rate of flow of 68 MAF/year through the section of The Idagon after the Big Fish during April. This flow is considered important to aid the salmon smolts in their spring migration. This flow is highlighted within a box in the report entitled "Idagon Map with Flows."
Management Goals: Setting Priorities • The six goals have been established for the Idagon. All parties agree that each goal has some merit. But there is considerable disagreement about the relative merit of each goal. For the Idagon exercise, you are free to define your own priorities by the "weights" you attach to each of the six goals. Each goal deserves a minimum weight of 1. The sum of the 6 weights must be ten. An illustrative set of weights are listed below. (These are the default values in the flight simulator.) • The minimum weight of 1 has been assigned to the 4th, 5th and 6th goals. This means that each of these goals is considered equally worthy. • A weight of 2 has been assigned to the 2nd and 3rd goals. These goals are considered equally worthy and are twice as important as the previous goals. • The highest weight is assigned to the 1st goal, to increase the IEP by 5%. The weight of 3 suggests that achieving this goal is 50% more important than meeting the 2nd and 3rd goals and it is three times as important as meeting the 4th, 5th and 6th goals. • If you don't agree with these priorities, feel free to use your own weights. But don't forget to check that the weights add up to 10. This will allow you to compare scores with others who are experimenting with the model.
The Scorekeeper To check whether you are meeting the goals during any month of a simulation, click the "keeping score" button. You'll see that the "score keeper" awards you 1 point per month for each goal that is satisfied. The model uses your own weights to calculate a weighted score. Since the weights must add up to 10, the maximum score is 10 points per month or 120 points per year. There is one exception to this score keeping scheme--the exception is needed to deal with the timing of the salmon migration. The salmon smolts goal can only be measured in April, the month when the smolts need a high flow in The Idagon after its confluence with the Big Fish. If you meet the April flow target, the Score Keeper will assign all 12 points for this particular goal in the month of April. You may view how your points are accumulating over time. The graph will show this month's score along with the accumulated score for the entire simulation. "Spikes" will appear in this graph if you happen to meet the flow target for April for the salmon smolts.
American Lake • When experimenting with the model, you may open the graph "In_and_Out_Flow_1_American_Lake” to see if the simulated flows are similar to the illustration shown below. • INFLOW:American Lake receives the combined inflow of the Main Fork and the North Fork of the Idagon. The in-flow averages 10 MAF/year. The month by month variations in the inflow are illustrated in the chart. The peak inflow appears in April during the spring runoff. The inflow declines to under 5 MAF/yr in the summer months and returns to the average value by November. • OUTFLOW:The outflow must meet the minimum flow requirement specified from the controls of the flight simulator. The chart assumes that the minimum flow is set at 3 MAF/year. The outflow matches this target during the Winter and Spring months. The outflow is much higher during the summer irrigation season. • The irrigation season begins in May and extends over a 4 month period which includes half of May, all of June, July and August and half of September. The out flow is over 23 MAF/year during this season. This outflow is calculated to serve as much of the irrigated lands in Area 1 as possible with the flows that are available in the current year. AMERICAN LAKE DIMENSIONS The reservoir storage capacity is 18 MAF or 1.8 years of average annual flow. The lake's surface area is 90,000 acres when the lake is full. The height of water at the dam is 300 feet when the lake is full. The net evaporation rate in this region is 2 feet/year, so the evaporation losses from American Lake amount to around 180,000 AF/yr or roughly 0.2 MAF/year. Thus, evaporation losses should be under 2% of the annual flow. The hydro-electric power production from the American Lake dam depends on the flow through the turbines and the height of water at the dam. Most of the power is produced during the summer months when high outflows are needed for irrigation.
Main Fork River • The Main Fork is an open river. There are no dams to slow or control the flow, and there are no diversions for agriculture. The Main Fork delivers 6 million acre-feet (MAF) in a year. The flow varies from month to month as shown on the graph. The flow in the winter months is similar to the average flow of 6 MAF/yr. • The flow increases during the Spring, and the April flow reaches 12 MAF/year. After the Spring runoff, the flow declines to low values for the summer months. The flow returns to the average value in November. The flow from the Main Fork combines with the North Fork flow before the river enters American Lake in the northeast part of the region.
North Fork River • The North Fork is an open river. There are no dams to slow or control the flow, and there are no diversions for agriculture. The North Fork delivers 4 million acre-feet (MAF) in a year. The chart shows the variation in North Fork flow from one month to another. • The winter months tend to show average flows while the flows during the Spring runoff are much higher. Flows decline to a low in August and gradually return to average values by November. The North Fork joins the Main Fork in the northeast corner of the region where the combined flow enters American Lake.
INFLOW Lake Idagon receives the flow of the Idagon after the river's flow has been increased by the ground water discharge at Big Springs. This flow averages around 13 MAF/year. The month by month variations in the inflow are illustrated in the chart. The inflow is rather constant over the 12 months in a year because the ground water discharge at Big Springs is relatively constant from one month to another. The slight decline in the May and June inflow arises from the upstream diversions to irrigators in Area 1. The slight increase in September and October arises from runoff from Area 1. OUTFLOW The reservoir is used to store water for summer irrigation. The chart shows that 30 MAF/year is released during the irrigation season. Since the irrigation season is one-third of the year, the total release during this season is 10 MAF. This is the amount typically needed to irrigate the one million acres in Area 3. During the other 8 months of the year, the outflow is subject to a minimum flow requirement. In this example, the minimum flow is set to zero. The chart shows that there would be no releases in the fall months as the reservoir is refilled to prepare for the following year. There are some releases in Jan, Feb and March, however. These releases indicate that there is more than enough water flowing through Lake Idagon to meet the irrigation needs in Area 3. Since there is usually ample water for Area 3, the model will always operate Lake Idagon to deliver the full amount needed in Area 3. Lake Idagon LAKE IDAGON DIMENSIONS The reservoir storage capacity is 16 MAF which amounts to about 1.3 years of average annual flow. The lake's surface area is 80,000 acres when the lake is full. The height of water at the dam is 300 feet when the lake is full. The net evaporation rate in this region is 2 feet/year, so the evaporation losses amount to 160,000 AF/yr or somewhat more than 1% of the annual flow. The hydro-electric power production from the Lake Idagon dam depends on the flow through the turbines and the height of water at the dam. Most of the power is generated in the summer irrigation season. When experimenting with the model, you may open the graph "In_and_Out_Flow_2_Lake_Idagon” to see if the simulated flows are similar to the illustration shown above. And to see if the policy of serving 100% of the irrigators in Area 3 is feasible, you might open the graph "Fullness_of_Eastern_Reservoirs” and check if the reservoir is refilled each year.
Irrigators in the Eastthat Divert Water from the Idagon One million acres of irrigated land is located in Area 1. The land is irrigated by diverting flows from The Idagon. The irrigators grow a combination of alfalfa, wheat and potatoes. The sale of these crops brings gross revenues of over 500 $/yr per acre. The irrigators pay variable costs of just under 400 $/yr per acre, so the return per acre is somewhat over 100 $/year. (These results may be checked by opening the "Crop Income Report" if you are using an advanced version of the model.) The diversion requirement depends on the efficiency of the delivery canals and the efficiency of irrigation in the fields. A typical requirement is 10 feet/year per acre, so the one million acres would require diversions of 10 MAF/year. Around 70% of the diverted water enters the aquifer through percolation, both as percolation from the delivery canals and percolation from the fields. About 20% of the diverted water is lost through evaporation and transpiration (E&T losses). The remaining 10% returns to the Idagon via surface runoff. These flows may be checked by opening the "Water Use in Area 1" report. The efficiency of irrigation in Area 1 may be controlled in advanced versions of the model. The model assumes that the American Lake reservoir will be operated to meet as much of the irrigation needs as possible. But it may not be possible to meet 100% of the needs depending on the amount of land, the efficiency of irrigation and the minimum flow requirements at American Lake. The existing land in Area 1 is broken down into land with senior water rights and land with junior water rights. The land with junior water rights is first to be interrupted when it is not possible to irrigate all the land. If you elect to expand the amount of land in Area 1, the new land will be irrigated with the same efficiencies as the existing land. And the new irrigators will face the same market conditions as the existing irrigators. But the water rights associated with the new land are junior to the rights of all the existing irrigators.
Lost River • The Lost River flow averages 6 MAF/year over the 12 months in the year. The flow peaks in April and May due to spring runoff. • The Lost River seems to disappear after it flows out of the eastern mountains. What disappears is the surface flow. The water is not lost, however, because the lost river flow contributes to the ground water stored in the aquifer.
Groundwater Dynamics • Recharge: • The flow from the Lost River contributes around 6 MAF/year to the aquifer. The contribution peaks in the Spring months. • Groundwater Pumping: • Irrigators in Area 2 rely on ground water pumping to irrigate one million acres. The pumping typically removes around 4 MAF/year from the aquifer. The water is removed during irrigation season. • Percolation from Area 2: • About half of the water used for irrigation in Area 2 returns to the aquifer as percolation flows. • Percolation from Area 1: • A large fraction of the water diverted from the Idagon to Area 1 ends up as percolation flow to the aquifer. The percolation flow comes from seepage in the canals as well as percolation from the fields themselves. • Discharge at Big Springs: • The aquifer discharges its contents at Big Springs. The annual flow at Big Springs is around 10 MAF/year. The flow is quite constant from month to month. The Big Springs flow may change over many decades if there are changes in the volume of ground water stored in the aquifer. (If the volume should increase, for example, there will be a larger gradient between the ater table near the irrigation fields and the discharge point. With a larger gradient, we expect a larger discharge.) The flow from Big Springs leads directly into Lake Idagon. Maintaining a high flow in this section is one of the goals for the system.
The huge Idagon Aquifer has a single discharge point at Big Springs. Historians tell us that Big Springs flow was around 6 MAF/year in the decades prior to irrigated agriculture. But the discharge has increased over several decades with the development of irrigated agriculture in Area 1. (Percolation water from the fields and the delivery canals contribute to the ground water storage). Big Springs flow is now around 10 MAF/year. The Big Springs flow changes very little from one month to another because the ground water conditions do not change significantly during a year. Big Springs flow may change over several years (or several decades), however, depending on the long term changes in flows into an out of the aquifer. The large flow at Big Springs is considered important for the region. (The flow is important for both water quality and for "fish farms" that have developed below the discharge point.) One of the six goals for the Idagon is to maintain the flow at Big Springs at 9 MAF/year or higher. To monitor the discharge flow at Big Springs when running the model, you may open the graphs: "Flow_at_Big_Springs" or "Ground_Water_Flows” during the course of a simulation. And if you are using an advanced version of the cockpit, you may monitor how the discharge at Big Springs would be influenced by land development in Area 2 where irrigation water is pumped from the aquifer. To see the "impact," you would add new land to Area 2 (under the "Land Development Program" decisions) and use the "Ground_Water_Impact" graph to learn how long we must wait for the full impact of the additional pumping to show up as a reduction in Big Springs flow. Big Springs
Irrigators in the Eastthat Pump Water from the Aquifer • One million acres of irrigated land is located in Area 2. The land is irrigated by pumping ground water. The irrigators grow a combination of alfalfa, wheat and potatoes. The sale of these crops brings gross revenues of over 500 $/yr per acre. The irrigators pay variable costs of just under 400 $/yr per acre, so the return per acre is somewhat over 100 $/year. (These results may be checked by opening the "Crop Income Report" if you are using an advanced version of the model.) • The pumping requirement depends on the efficiency of irrigation in Area 2. A typical requirement is 4 feet/year per acre, so the one million acres would require the irrigators to pump 4 MAF/year. About half of this water returns to the aquifer through percolation. These flows may be checked by opening the "Water Use in Area 2" report. The efficiency of irrigation in Area 2 may be controlled in advanced versions of the model. The advanced version also allows you to expand or contract the land in Area 2. • The model assumes that 100% of the pumping needs are satisfied. If you are using an advanced version of the model, you may limit the irrigation in Area 2 in two ways. • First, you may simply reduce the fraction of needs satisfied below 1.0. A reduction in this fraction would correspond to a restriction on ground water pumping. • The second way to reduce ground water pumping is through a land fallowing program. If you are using an advanced version, you may reduce the land under irrigation by setting the land fallowing price in Area 2 to exceed the return per acre shown in the "Crop Income Report."
INFLOW Canyon Lake receives the flow of the Idagon after the flow has been increased by runoff from Area 3 and by the White River and the Devil's River. The inflow averages around 13 MAF/year. The month by month variations in the inflow are illustrated in the chart. The chart shows a peak in spring due to peak runoff in the White River and the Devil's River. Then the inflow drops dramatically with the start of the irrigation season in Area 3. Runoff from Area 3 is responsible for the large inflow shown in September. OUTFLOW Canyon Lake is operated for power production and to meet two separate flow targets. The first flow target is set from the cockpit for the months of April and May. This target is set at 40 MAF/year in the illustration below. High flows during April and May are needed to meet flow goals in the reach of the Idagon after the confluence with the Big Fish River. The high flows are required to improve conditions for the salmon smolts spring migration. Improving the April/May flows for the Salmon is one of six goals for the Idagon. Another of the six goals is to maintain sufficiently high flows below Canyon Lake to support water quality and wildlife for the other 10 months of the year. In the chart above, the minimum flow target for the remaining 10 months is set at 4 MAF/year. Canyon Lake will be operated to meet the two minimum flow targets specified in the flight simulator. To check that this operation is feasible, you should open the graph "Fullness_of_Western_Reservoirs” to learn if the Canyon Lake can be refilled each year. You might also open the graph “In_and_Out_Flow_3_Canyon_Lake” to see if the simulated flows are similar to the illustration shown below. Canyon Lake CANYON LAKE DIMENSIONS The reservoir storage capacity is 16 MAF which amounts to about 1.2 years of average annual flow. The lake's surface area is 40,000 acres when the lake is full. The height of water at the dam is 600 feet when the lake is full. The net evaporation rate in this region is 2 feet/year, so the evaporation losses amount to 80,000 AF/yr or somewhat less than 1% of the annual flow. The hydro-electric power production from the Canyon Lake dam depends on the flow through the turbines and the height of water at the dam. Much of the power is generated in April and May when the reservoir is used to support the salmon smolts spring migration.
Irrigators in the Westthat Divert Water from the Idagon One million acres of irrigated land is located in Area 3. The land is irrigated by diverting flows from The Idagon. The irrigators grow a combination of alfalfa, wheat and potatoes. The sale of these crops brings gross revenues of over 500 $/yr per acre. The irrigators pay variable costs of just under 400 $/yr per acre, so the return per acre is somewhat over 100 $/year. (These results may be checked by opening the "Crop Income Report" if you are using an advanced version of the model.) The diversion requirement depends on the efficiency of the delivery canals and the efficiency of irrigation in the fields. A typical requirement is 10 feet/year per acre, so the one million acres would require diversions of 10 MAF/year. There is no aquifer under Area 3, so there are no percolation flows in this area. Around 20% of the diverted water is lost through evaporation and transpiration (E&T losses). The remaining 80% returns to the Idagon via surface runoff. These flows may be checked by opening the "Water Use in Area 3" report. The efficiency of irrigation in Area 3 may be controlled in advanced versions of the model. The Lake Idagon reservoir will be operated to meet 100% of the needs in Area 3. This simple policy is based on the observation that there is usually more than enough water to serve the needs of Area 3. But to check whether this policy is feasible in your experiments with the model , you should open the graph "Fullness_of_Eastern_Reservoirs" to learn if there is enough water to refill Lake Idagon each year.
The White River is an open river. There are no dams to slow or control the flow, and there are no diversions for agriculture. The White River delivers 1 million acre-feet (MAF) in a year. The winter months tend to show average flows while the flows during the Spring runoff are much higher. Flows decline to a low in August and gradually return to average values by November. The Devil's River is an open river which joins the Idagon before the river enters Canyon Lake. There are no dams to slow or control the flow, and there are no diversions for agriculture. The Devil's River delivers 1 million acre-feet (MAF) in a year. The winter months tend to show average flows while the flows during the Spring runoff are much higher. Flows decline to a low in August and gradually return to average values by November. White River and Devil’s River
INFLOW President's Lake receives the flow of the Idagon after the flow has been increased by the Canadian River. The inflow averages around 33 MAF/year. The month by month variations in the inflow are illustrated in the chart below. The chart shows a peak inflow in the spring. The spring peak is caused by the high releases from Canyon Lake in April/May and by the high spring flows in the Canadian River. OUTFLOW President's Lake is operated for power production and to meet two separate flow targets. The first flow target is set from the flight simulator for the months of April and May. This target is set at 100 MAF/year in the illustration below. The second flow target applies to the other ten months of the year. This second minimum flow target is set at 10 MAF/year in the illustration below. President's Lake will be operated to meet the two minimum flow targets specified from the cockpit. To check that this operation is feasible, you should open the graph "Fullness_of_Western_Reservoirs” to learn if the President's Lake can be refilled each year. You might also open the graph "In_and_Out_Flow_4_President's_Lake” to see if the simulated flows are similar to the illustration shown above. President’s Lake PRESIDENT'S LAKE DIMENSIONS The reservoir storage capacity is 16 MAF which is similar to the capacity of other reservoirs in the region. But the inflow is around 33 MAF/year. So the reservoir storage amounts to less than 0.5 years of average annual flow. The relatively low storage is responsible for the close match of inflow and outflow shown in the chart above. (Reservoirs that operate in this fashion are sometimes called "run-of-the-river" reservoirs.) The height of water at the President's Lake dam is 600 feet when the lake is full. There are no evaporation losses from this reservoir since it is located in an area with more rainfall. The hydro-electric power production depends on the flow through the turbines and the height of water at the dam. Much of the power is generated in April and May because of the high flows shown in the spring.
Canadian River • The Canadian River delivers 16 MAF/year. The flow peaks in April due to spring runoff. The low flows appear in the summer. This is a huge river, so you would imagine that it might be "put to use" for power production, flood control or irrigation. • Since our focus is on The Idagon, you will probably ignore such activities on the Canadian since they take place upstream from the confluence of the Canadian and The Idagon.
The Big Fish River is an open river. There are no dams to slow or control the flow, and there are no diversions for agriculture. The Big Fish delivers 4 million acre-feet (MAF) in a year. The winter months tend to show average flows while the flows during the Spring runoff are much higher. Flows decline to a low in August and return to average values by November. The Big Fish River is famous for the salmon that return to their spawning grounds each year. The spawners deposit their eggs in the fall, and the fry emerge in the following spring. These young fish then compete with one another for food and space. Those that succeed survive and grow. After a year, they are ready to make the dangerous migration to the ocean. The juvenile migrant is called a "smolt." This smolt migration begins in April and continues into May. The smolts migrate down the Big Fish and into the Idagon. It has been determined that high flows in the Idagon immediately after its confluence with the Big Fish are extremely important to aid the smolts in their journey to the ocean. (Higher flow means faster flow; and faster water flow is thought to speed the smolts down the river.) A speedy trip down the river is crucial if the smolts are to reach the ocean in time to avoid high mortality from the physiological changes to prepare for saline conditions For these reasons, a high April flow in this key reach of The Idagon is one of the goals for managing the river. Big Fish River
Management Goals 1. Increase the Idagon Economic Product The Idagon Economic Product (IEP) is the principal economic indicator. It counts net income from crop production and electric power production. In most simulations, the IEP will be around $1,000 million per year. It is nearly a "Billion Dollar" system. The goal is to boost the IEP to $1,050 million per year. 2. Maintain Land Use Patterns: Historically, one million acres of land has been irrigated by diversions in Area 1 and by pumping in Area 2. This activity has given rise to the development of support industries as well as to towns and villages. These activities are valued in their own right (i.e., separate from the contribution of crop production to the IEP.) Consequently, an additional goal has been established--to maintain at least 95% of the land in both areas under irrigation. 3. High Flow in the Big Fish During April The 3rd goal is to achieve a rate of flow of 68 MAF/year during April in the section of The Idagon after the Big Fish. This flow is considered important to aid the salmon smolts in their spring migration (see chapter 13 in the book).
Management Goals 4. Adequate Flow Below Canyon Lake The section of The Idagon immediately below Canyon Lake is considered important for water quality, for wildlife and for recreation. The 4th goal calls for at least 4 MAF/year of flow in this section during all months of the year. 5. Maintain High Flow at Big Springs The discharge at Big Springs was around 6 MAF/year one hundred years ago. But the flow is now around 10 MAF/year, and this high flow is important for water quality, for wildlife and for industries that have developed below Big Springs. The 5th goal is to maintain this flow at 9 MAF/year or greater. 6. Adequate Flow Below American Lake The final goal concerns the section of The Idagon immediately below American Lake. It is considered important for water quality, for wildlife and for recreation to maintain at least 3 MAF/year in this section during all months of the year.
Environmental Goals • Environmental Area Below American Lake • One of the six goals concerns the section of The Idagon immediately below American Lake. It is considered important for water quality, for wildlife and for recreation to maintain at least 3 MAF/year of flow in this section during all months of the year. • Environmental Area Below Canyon Lake • One of the goals concerns the section of The Idagon immediately below Canyon Lake. It is considered important for water quality, for wildlife and for recreation to maintain at least 4 MAF/year of flow in this section during all months of the year. • Environmental Area After the Big Fish • One of the goals is to achieve a rate of flow of 68 MAF/year through the section of The Idagon after the Big Fish during April. This flow is considered important to aid the salmon smolts in their spring migration. This flow is highlighted within a box in the report entitled "Idagon Map with Flows."
Management Goals: Setting Priorities • The six goals have been established for the Idagon. All parties agree that each goal has some merit. But there is considerable disagreement about the relative merit of each goal. For the Idagon exercise, you are free to define your own priorities by the "weights" you attach to each of the six goals. Each goal deserves a minimum weight of 1. The sum of the 6 weights must be ten. An illustrative set of weights are listed below. (These are the default values in the flight simulator.) • The minimum weight of 1 has been assigned to the 4th, 5th and 6th goals. This means that each of these goals is considered equally worthy. • A weight of 2 has been assigned to the 2nd and 3rd goals. These goals are considered equally worthy and are twice as important as the previous goals. • The highest weight is assigned to the 1st goal, to increase the IEP by 5%. The weight of 3 suggests that achieving this goal is 50% more important than meeting the 2nd and 3rd goals and it is three times as important as meeting the 4th, 5th and 6th goals. • If you don't agree with these priorities, feel free to use your own weights. But don't forget to check that the weights add up to 10. This will allow you to compare scores with others who are experimenting with the model.
The Scorekeeper To check whether you are meeting the goals during any month of a simulation, click the "keeping score" button. You'll see that the "score keeper" awards you 1 point per month for each goal that is satisfied. The model uses your own weights to calculate a weighted score. Since the weights must add up to 10, the maximum score is 10 points per month or 120 points per year. There is one exception to this score keeping scheme--the exception is needed to deal with the timing of the salmon migration. The salmon smolts goal can only be measured in April, the month when the smolts need a high flow in The Idagon after its confluence with the Big Fish. If you meet the April flow target, the Score Keeper will assign all 12 points for this particular goal in the month of April. You may view how your points are accumulating over time. The graph will show this month's score along with the accumulated score for the entire simulation. "Spikes" will appear in this graph if you happen to meet the flow target for April for the salmon smolts.
