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Mapping the Northern California Megaregion
• by Gabriel Metcalf and Egon Terplan
This article appears in the November 2007 SPUR Newsletter.
Click here for The Northern California megaregion article
MAP: The driving region: two hour car travel from central cities of Northern California
MAP: The driving region: Four hour car travel from central cities of Northern California
MAP: The sprawling region: Exurban and rural land threatened by development
MAP: The sprawling region: Projected increase in population densities on private land, 2000-2050
MAP: The government-defined region: Multi-county Councils of Government in Northern California
MAP: The government-defined region: Census-defined metropolitan regions
MAP: The bioregion: Rivers and waterways that drain into the San Francisco Bay
MAP: SPUR's proposed core and sphere of influence map of the Northern California megaregion
CHART: The Northern California megaregion
CHART: Quick facts at a glance
Travel time provides one of
the most common-sense ways
to define the region we live
in. This is how we experience
our options for where we work
and play in our daily lives.
So we begin by looking at
the areas accessible within a
two-hour and four-hour driving
distance, from each of the four
central cities of the region:
San Francisco, San Jose,
Sacramento and Oakland.1 (We
can only hope that in the not
too distant future, high speed,
inter-county transit extends
the places that are accessible
beyond what can be reached
by car during the same time
periods.)
Two hours of driving from
these cities reveals a region
that extends east to Lake Tahoe
on Highways 80 and 50, north
to Red Bluff on I-5 and Ukiah
on Highway 101, and south to
Merced on Highway 99, King
City on Highway 101, and Big
Sur on Highway 1.
Two hours from the core
cities yields an end-to-end
driving time of nearly six hours
(without traffic) from the
northeastern end of Lake Tahoe
to Big Sur. Interestingly, none
of the four key central cities
can reach Fresno within two
hours, thus suggesting, in part,
that Fresno is not core to the
Northern California megaregion.
When we extend this out
to four hours from each of the
central cities, we still maintain
a region that can be traversed in one day. From Yreka in
the north 550 miles south to
Santa Maria south of San Luis
Obispo, we have a region that
is less than 9 hours driving
time.
The travel-time maps reveal
several main conclusions that
are relevant to the definition of
the megaregion:
> The two-hour driving
distance reveals a 31 county
area.2
> Central and southern San
Joaquin County are equally
accessible to the Bay Area
or Sacramento. At either two
or four hours, the distances
traveled from the central cities
to the San Joaquin Valley are
quite similar. This suggests
that businesses and residents
in many of these fast-growing
communities have nearly
equal access to the main
central cities. For example,
Merced is equidistant from
Sacramento and the East Bay
(specifically Oakland). Fresno
is nearly the same distance
from Sacramento and San
Francisco.
> Accessibility to the
"Redwood Empire" north of
Sonoma County is limited. Only
southern Mendocino County
can be reached within two
hours from Oakland and San
Francisco, and a limited part of
Lake County from Sacramento.
Even at four hours, much of the
coastal north is inaccessible.
> The greatest distances
traveled out of the central
One key constant in California
has been tremendous
population growth. Future
projections show the growth
moving from the coast and
accelerating in all of the Central
Valley counties, many of the
foothills counties, and east
of Los Angeles in the "Inland
Empire" and north of San Diego.
The state's Department of
Finance has detailed population
growth for each county in
California to 2050. Using these
projections, we identified where
the growth will go - both on
an aggregate county level as
well as how that growth will
be distributed onto private land
shown as an increase in density
(based on county land area
divided by projected population
growth).
Using population-growth
projections, we can identify
where the megaregion will
grow if today's assumptions
are correct.
The population growth
reveals several key conclusions:
> California has two distinct
megaregions in the north
and south. They are merging
together in the San Joaquin
Valley.
> The potential for continued
sprawl and loss of open space
may be greater in Northern
California than Southern
California because of the greater presence of privately
owned land in the north that
can be converted into sprawl
development. For the most
part, Southern California is
surrounded by federally owned
land. While the inner Bay Area
has a protected greenbelt and
much of the Sierra Nevada
in Northern California are
permanent open space, most
of the land in the Central Valley
and to the north and south
along Highway 101 is in private
hands and thus in danger of
sprawl development.
> The threat of exurban
growth is not only along
Interstate Highway 80 and
Highway 99. The foothills, the
rural areas of Lake County and
the area inland of Monterey Bay
are all threatened by significant
exurban growth. Unlike the
Central Valley growth, there is
no real prospect of serving these
areas with high-speed rail, so
the transportation challenges
here require special attention.
The population-growth
maps reaffirm the need for the
megaregional thinking to begin
planning for and managing the
growth that is occurring in the
San Joaquin Valley. It is no
longer the problem of another
region, but a problem generated
by both our lack of growth and
lack of proper planning within
the core of the megaregion. We have mapped Censusdefined
regions such as
"Metropolitan Statistical Areas"
and the larger "Core Based
Statistical Areas," which are
the Census Department's
version of a megaregion. Those
maps reveal four contiguous
census "megaregions" - the
Bay Area, Sacramento, Reno
and Fresno. When we look
at the contiguous MSAs we
include the three fast-growing
Central Valley counties of San
Joaquin (Stockton), Stanislaus
(Modesto) and Merced
(Merced), each as its own
distinct MSA. To the north,
only Butte County (Chico) is
contiguous. To the south, every
county is a contiguous MSA,
in part because the counties to
the south are all quite large.
The metropolitan planning
organizations and councils
of governments help clarify
which counties are appropriate
in the Northern California
megaregion. We mapped
the cross-county councils of
government. The three COGs - Bay Area, Monterey Bay
and Sacramento - extend
from Monterey County to Lake
Tahoe (other counties have
councils of government but
they are not cross-county).
These two sets of maps
allow for the following
conclusions:
> The core of the
megaregion combines the
Bay Area commute shed with
greater Sacramento.
> Monterey and San Benito
counties are in the core of
the megaregion. They are
both in a cross-county COG,
while San Benito is part of
the greater Bay Area census
area. They are also captured
in the Association of Bay
Area Governments' 17-county
commute shed (which also
includes the Central Valley
counties of San Joaquin,
Stanislaus, and Merced).
> The "north coastal range"
counties of Mendocino, Lake,
Glenn and Colusa are not in
the core of the megaregion as
they are neither in MSAs nor
the neighboring COGs.
> Greater Fresno (Madera,
Fresno, Inyo and Kings
counties) is outside the core
of the megaregion.
> Extending the core of the
megaregion to Tahoe and the
Nevada border (and perhaps
beyond) is logical as the
Sacramento CSA includes a
county in Nevada.
The waters that flow from the
Sierra Nevada into the Great
Central Valley all pass through
the San Francisco Bay to the
ocean. These waters begin as
snowpack (and glaciers) in the
high Sierra and make their way
into the Sacramento or San
Joaquin rivers, into the Delta,
and then the Bay. Mapping this
area with the addition of the
adjacent coastal portions of
the state, as an approximation
of our "bioregion," yields a
map that captures all the
major cities and most of the
counties in Northern California.
Interestingly, the upper
boundary of the watershed
share the county boundaries
with Mono and Inyo counties in
the high desert beyond.
We draw these conclusions
from the watershed maps:
> The Sierra Nevada as the
historic hinterland of the Bay
Area is a part of the Northern
California megaregion because
it captures the critical natural
resource flow of water.
> The Great Central Valley
is intrinsically linked to the Bay
Area through the natural flows
of the rivers.
For the Northern California
Megaregion, water is
important. The river system
helped define the routes of
commerce, which structured
the early economic geography,
so it is no coincidence that the
water system and the historic
contado (or hinterland) of San
Francisco overlap.
We present a composite map
of the proposed boundaries
of the Northern California
megaregion.
Each of the prior maps
shows a slightly different
region. In part, this reaffirms
the concept that the
megaregional boundaries
depend on what one is trying
to use it for. When we look at
population growth, we see a
booming Central Valley that
continues to expand south
past Fresno toward Bakersfield
and to the northern boundary
of the Central Valley. But we
suspect that both ends of the
Central Valley are in fact not
very tied to the core of the
region. We argue that the
Northern California megaregion
has both a core and a sphere
of influence. The core includes
the historic centers and the
most accessible areas of
growth, particularly for firm
and family relocations (which
tend to be within a localized
area). The core includes all
the counties in the Bay Area
and Sacramento councils of
government, plus the three
fast-growing Central Valley
counties (San Joaquin,
Stanislaus and Merced). This
is a 21-county area.
Surrounding that core are
a number of closely related
counties that are the sphere
of influence. To the north we
include Mendocino and Lake
counties. We also include
the relatively unpopulated Glenn and Colusa counties
(with I-5 running through
them) and Butte County
(with Chico). To the east we
include Sierra County (the one
county projected to decline
in population by 2050)
and Nevada County (which
includes Truckee) and then the
foothills and Sierra counties
of Alpine, Amador, Calaveras,
Tuolumne and Mariposa. We
are also proposing to include
five counties in Nevada - Washoe, Storey and Lyon
that make up the Reno CSA,
Douglas which is in the
Sacramento CSA, and Carson
City county which is right
beyond Lake Tahoe. To the
south we combine the Fresno
CSA (Fresno and Madera) with
the two closely connected
agricultural counties of Kings
(Hanford) and Tulare (Visalia),
which retain close linkages
with Fresno. This Northern
California Megaregion on the
map takes up the large center
of the state.
We arrived at this
provisional definition of the
megaregion by layering all
the maps presented here
and looking at the available
data on connections between
places. The overlap we have
found between the bioregion,
driving distance and the areas
of growth is something that appears unique among the
10 megaregions in the United
States. We have a "thick" set
of relationships that define
Northern California.
Our composite map of the
Northern California megaregion
excludes the far north and
south ends of the Valley:
> Bakersfield, Kern County.
Although a part of the
watershed and connected via
contiguous MSAs, Bakersfield
cannot be reached within four
hours of any of the key central
cities. It also has the greatest
gaps in potential exurban
growth between it and the
rest of the San Joaquin Valley
cities. In this way we will
exclude Kern County from even
the extended version of the
megaregion.
> Redding, Shasta County.
Although Redding is within four
hours of all the main central
cities in Northern California,
though not by much, it is a
part of its own MSA that does
not connect to any other one
in Northern California. Growth
in Redding is being driven
more by trends in retirement
and tourism than from the
economic growth in greater
Sacramento. As such,
Redding and Shasta County
are outside the boundaries of
the megaregion.
(Endnotes)
- Robert Lang argued that
a megalopolis should
be no more than a day's
drive from one end to
the other. Our driving
distance maps show
that even the four-hour
distance from each of
the four central nodes
creates an extent that
could be traversed end to
end in nine hours.
- This is similar to the NYNJ-
CT region, which has
about a 2-hour radius of
driving time from NYC.
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