Case Studies Using Uplan SWIM Layers: Sacramento Valley


Base Case Scenario

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This map shows the 2050 population projections from Department of Finance. Using existing general plan zoning, Uplan assigns growth levels within the existing zoning using Attractors and Discouragers. Attractors used in this scenario are economic; for example, highways and major roads attract more businesses and residential growth than non-roaded areas. This can be seen clearly in the rectangular yellow patterns in the "rural" areas between Yuba City in the upper left and Roseville in the lower right, where future growth is predicted to reach medium densities. Between the major roads, densities are projected at low and very low.

White space shows up for different reasons on the map. On the left third of the map, the Sacramento River winds down from the upper left corner as white space; the Feather River flows as white space through Yuba City-Marysville down to join the Sacramento; the Yuba River system white space flows just above the "Sutter" label. This will be given color in future maps. The large white space to the right of Yuba City is Beale Air Force Base. The white space around the Yuba City label, and above the pink growth area of Roseville and further north at Lincoln, are existing urban area which does not show up in this scenario because it is not future growth but existing condition — this likewise will be shown as existing urban area on future maps.

Limiting Factors for Disaster Risk: Flood and Fire

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Two Discouragers are added to the base case in this scenario — flood and fire. The assumption is that at some point insurance will not be available for those wishing to build in either high risk flood or fire areas, using the FEMA floodplains and the FRAP high fire hazard layers as masks (producing no growth).

The flood plain no-growth zone is dramatically defined. For example:

  • The Yuba river flood plain shows up clearly above the "Sutter" label
  • The Feather River becomes more defined in its north-south flow through Yuba City
  • The Bear River flood plain is shown north and west of the "Placer" label
  • Western Placer County creeks show as flood plains

The fire hazard area is generally not visible on this map, as it is at higher elevations above 1000 feet. Auburn is at the 1000 feet elevation level. Thus none of the area which uses fire risk as a Uplan Discourager is on this map.

As a result, all of the discouraged growth from high elevation fire risk, and the discouraged growth from flood plains (showed as white space on this map) is forced into remaining areas where growth is possible. Compare the Base Case Scenario with this Flood and Fire scenario — the areas on the right one third of the map in western Placer and Nevada counties are shown with higher densities than on the Base Case. Western Placer County west of Roseville and Lincoln are shown at higher densities, interspaced with the western Placer creek flood plains shown as white space. Densities become higher between the Feather and Sacramento Rivers, and west of Yuba city. Essentially, flood and fire areas' growth is forced into remaining flood and fire risk-free areas.

Limiting Factors for Resources: Groundwater

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Groundwater is used as a limiting factor in this scenario, as an addition to the flood and risk Discouragers in the previous scenario. Groundwater is plentiful in areas that overly the DWR-defined Sacramento Aquifer, which includes all the Valley to an elevation of up to a couple of hundred feet in elevation. Above that elevation level, groundwater is found in fractured rock. Some geographic formations are devoid of groundwater. Other areas have spotty groundwater availability. Still other areas have a limited capacity which is unknown until it is exceeded by extraction. (A number of foothill areas are experiencing groundwater in fractured rock capacity failure with growing populations/wells. Data does not exist to demonstrate with certainty a direct relationship, but it is increasingly a repeated pattern.)

Areas in Western Placer where surface water is available, as well as areas around Yuba City, gain in density as a result of this groundwater Discourager. Compared to the 2050 scenario, areas with the Discourager of groundwater limitations will see their population diminish and thus other areas of groundwater availability will see increasing density.

Population Explosion

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The Population Explosion scenario takes the Department of Finance 2050 year projections and adds 20%. There may be a number of reasons to do this — DOF projections have been higher and lower in other areas in the past so it may be just a prudent projection scenario; the Sacramento Valley may be a "sleeper" region and have a very high desirability for quality of life, but may have been overlooked to date in the marketplace; earthquakes or sea level rise or fire storms may cause a migration of residents from risk areas to areas of lesser risk. The Sacramento Valley has a desirable climate relative to many other areas; its inherent risk of flooding can be avoided; and, water is not a limiting factor of growth in the area overlying the aquifer. A Discourager was applied in floodplains, but not in fire risk areas or fractured rock groundwater basins.

With the increase of population by 20%, the general plan zoning within Sacramento, El Dorado, Placer and Amador counties had to be altered to accommodate the growth pressure; all the other scenarios used existing general plan zoning to accommodate the 2050 projections. Altering the general plan to accommodate growth was thought to be reasonable, as that has been the trend of the past 100-year history of county and city zoning practice.

Maximum Pressure

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This scenario is a combination of the population explosion (DOFf+ 20%) with the addition of the Discouragers from fire, flood and groundwater. The scenario shows the Sacramento Metropolitan area essentially extending into a Sacramento Megalopolis with a continuous band of urban growth densities of medium or higher all the way through Roseville to Yuba City and beyond (to Redding in the large map).