Muskegon River Mega Model




What is a Scenario?

A scenario is defined as an imagined, yet possible, set of future events. Since the future is always uncertain, scenarios use current information and apply certain assumptions about future trends. In this way, scenarios suggest what could happen in the future, not what will actually happen or what should happen.MREMS

There are different ways to create scenarios. In the Mega Model project, scenarios were developed with the use of several programs and models to represent a way of viewing a series of complex and uncertain futures in the Muskegon River Watershed. These models organized data and information to systematically account for a variety of possible futures in the watershed. The results revealed a sequence of credible changes in the watershed over varying future timeframes.

These resulting scenarios were intended to help decision makers in the Muskegon River Watershed understand the different ways the future might unfold for their communities. These scenarios will provide decision makers the opportunity to use a plausible future to guide their decisions rather than relying on past conditions or current events. They allow decision makers to test their present strategies, such as planning and zoning, against plausible future developments. It is hoped that these scenarios will lead decision makers to consider the implications of the scenarios in their communities and prepare their communities for such change.

These scenarios should inspire and engage constructive discussions about Muskegon Futures among all watershed stakeholders. The scenarios listed below are the landscape management scenarios that project changes in the Muskegon River Watershed landscape for 2070.

Business As Usual:

What is it?
The Business As Usual land management scenario is a future landscape that assumes the average rate of urban and forest growth observed from 1978 to 1998 will continue into the future. These expansions occur at the expense of BAU Scenarioagriculture, and so farming in this version of the future also continues to decline across the watershed.

What are the Key Findings in this Scenario?

  1. Increased urbanization and decreasing forest cover will lead to an increasing river flow and pollution transport
  2. Increases in storm flows and baseflows will lead to an increase in flooding and erosion
  3. A 20 to 30% increase in the annual rate of sediment delivery to the main stem dams system and to Muskegon Lake.
  4. Accelerated rates of eutrophication due to the increase of nutrients (carbon, nitrogen, and phosphorus) being delivered to river channels, Muskegon Lake, and Lake Michigan.
  5. Overall ecological condition of fish and aquatic insect communities would decline, which implies a drop in fish and insect diversity; and shifts in species composition towards more pollution tolerant organisms and smaller populations of rare and sensitive organism.

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Reduced Urban Sprawl:

What is it?
With the Reduced Urban Sprawl land management scenario, future landscapes are modeled with the constraint that urban land use in the watershed grows at half the average of the 1978 to 1998 rate. In reality this could be achieved either by halving the population growth rate, or reducing by the sprawl rate by 50%. Alternately, the same effect could be achieved by simultaneously reducing both population growth and sprawl rate that would result in a 50% reduction in urban land use.

What are the Key Findings in this Scenario?

  1. A future landscape will have less urban area, and more forest area. Urbanization and reforestation occur at the expense of farmland, so agricultural land use is substantially reduced compared to other land management scenarios.
  2. Since the future is still substantially dominated by urbanization in the southwestern part of the watershed, river flows and nutrient levels are still predicted to rise.
  3. This land management scenario is a “greener” vision of the future by far; with not only the most forest cover across the watershed, but also with the lowest projected rates of eutrophication in receiving waters. This scenario also has the least impact on fish and other biological communities inhabiting the river system.

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Farmland Preservation:

What is it?
In the Farmland Preservation land management scenarios, conversion of existing farmland to shrubs and then forest is not allowed. Furthermore, urbanization continues at the expense of agricultural lands, either at a reduced rate (FLP1 uses the RUSScenario Summary sprawl rate), or the observed historical rate (FLP2 uses the BAU sprawl rate).

What are the Key Findings in this Scenario?

  1. Results of the farmland preservation simulations depend upon the accompanying urban sprawl assumption.
  2. Increases in flow and erosion are still substantial. Nitrogen loads are quite a bit higher, but phosphorus loadings are lower than in the BAU scenario.
  3. Overall impact on the ecological health of the river lies likewise between the BAU and RUS scenarios.
  4. Ecologically, this is clearly the least preferable vision of the future Muskegon River.



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This project is funded by the Great Lakes Fishery Trust as part of the Muskegon River Watershed Initiative.
Contact John Koches at for website information.



Page last modified December 7, 2011