outskirts vs. suburbs vs. exurbs

[jimrtex]

Personally, I never really use the term "exurb."  If a city/town/village/whatever is anchored around a "major city," then it is that city's suburb.  Inner, outer, whatever; it's a suburb.  I appreciate the clarity that suburb vs. exurb provides some people, however.  Additionally, there is probably a cutoff for me where at a certain point I feel silly calling somewhere a suburb due to the cultural connotations the word has.  For example, West Des Moines is absolutely a suburb of Des Moines, but I feel kind of goofy calling Morton a "suburb" of Peoria, because it has more of a small town feel (even though, objectively, Morton really IS a "suburb" of Peoria).

Do you consider Indianola a Des Moines suburb?

It seems to be a law of Newtonian physics that Des Moines may not sprawl to the south.

wow, it's almost like sprawl is simply following the Interstate's routes around the area or something.

You will find little clusters of population near the exit/entrance ramps. Suburbs have particularly grown on the west and northwest along the I-35/I-80 overlap that form a loop around the city, while I-235 is the route through the city. The I-35/I-80 belt permits development of offices and shopping centers, which can in turn facilitate commuting from along the interstate.

You can commute 50 miles in an hour along an interstate (as long as you overlook those few days when facing a blizzard). You don't need many services - gas stations, and maybe a grocery store. Schools will add classrooms. If you need a dentist, or lawyer, or a car dealer, you can drive in to West Des Moines. You don't need employment.

Winterset and Indanola might be considered exurban. There distance from the interstates makes them a little harder to commute from, but there may be affordable houses and some jobs, and there is the attraction of living in a small town. One spouse might commute to Des Moines, or perhaps start to do so after they lose a job in the cities.

[jimrtex]

Winterset and Indanola might be considered exurban. There distance from the interstates makes them a little harder to commute from, but there may be affordable houses and some jobs, and there is the attraction of living in a small town. One spouse might commute to Des Moines, or perhaps start to do so after they lose a job in the cities.

It's odd though that development has not gone south along I-35 south of I-80.  And the NE corner of Madison County has never been developed much, even though it is quite near to Des Moines. The county line seems to be some sort of barrier. It reminds me of the county line between LA and San Bernadino counties, where in LA is the city of Pomona that has been around a long time, and is densely built, and Chino next door which was dairy farms until quite recently. The streets just stopped at the county line.

But I see a bridge is being built across the Raccoon River that might jump start things.

By railroad, Winterset and Indianola were fairly isolated.

1902 Railroad Map

The railroads west are tied to the Mississippi River crossings (Burlington and Rock Island) and Burlington is south of Madison and Warren. If you look closely, there were (proposed) interurban railroads from Des Moines to both Winterset and Indianola (they are in black only). Had they been built, there might have developed a commuter culture. and perhaps suburbanization to the south of Des Moines.

The Rock Island dips down to the east of Des Moines, so the I-35/I-80 loop around the city replaces the direct route through the city. I-80 west of the city follows the railroad, so there are smaller towns that can provide a bit of infrastructure for residential development (water and sewer plants mostly and schools), since the developer would build the lines and roads.

I-35 was developed in virgin territory, US-65 goes south to Indianola, and it appears that US-65 was just to create a north-south route down the middle of the first tier of states west of the Mississippi. I-35 was intended to connect established cities (Duluth-Twin Cities-Des Moines-Kansas City-Wichita-OKC-DFW-Waco-Austin-San Antonio-Laredo) where there had never been a transportation corridor.

The Des Moines and Raccoon rivers appear to have guided development towards the west. While the Capitol is to the east of the river, the downtown area is to the west, and there is enough flooding to push residential areas away from the river.

Des Moines Wikipedia, scroll down to density map

Business jobs exceed government jobs (this is why Minneapolis is bigger than St.Paul), and eastern Des Moines is chopped up by rail yards (similar to (north)eastern Minneapolis. Jobs with the railroad and associated industry will be lower paying than in the insurance business. The Des Moines River prevents expansion northward, pushing it more to the northwest. The Raccoon River blocks direct southward expansion, leaving a small area southeast of downtown and south of the Raccoon. The airport makes the area less desirable as a residential area.

Because of the angle of the Raccoon River, West Des Moines can expand slightly southward, and is more SSW (or maybe WbyS) of Des Moines. It appears that the I-35/I-80 north and west bypass facilitated westward expansion of West Des Moines and Urbandale, rather than triggering the expansion. You can build offices and commercial areas along an interstate, and provide jobs with commuting from the east and west. I-235 has facilitated commuting downtown.

There is a south and east loop, and an effort to have it redesignated as an interstate highway (it is claimed that if it shows as an interstate on GPS, it will make Des Moines look like a real metropolitan area, and also enhance sales of freeway frontage (apparently I-435 frontage is more sexy than IA-5 frontage). The loop south of the airport, should provide easier access to West Des Moines from I-35.

Des Moines has annexed south to the Warren County line. Microsoft is planning a major data center in West Des Moines south of the Raccoon River. The data center will be Microsoft's largest, and third in WDM. It is south of the Raccoon River on the Madison-Warren line, and just west of I-35. WDM is proposing to build an extension of the southern bypass west of I-35 (Veterans Parkway) which would connect to your bridge which is part of the Grand Prairie Parkway.

In 1950, Des Moines had 177K persons, and WDM was the only visible suburb with about 6K. Other towns, if they existed had 500-2K or so. Des Moines now has 215K, with most of the growth happening between 1950-60 and 2010-2016.

But during the post-WWII the suburbs to the west have exploded: West Des Moines 65K, Urbandale 43K, Johnston 21K, Waukee 20; Clive 18K, and Grimes 12K. Incidentally, the city limits are reminiscent of the suburbs in Johnson County, Kansas where the cities have expanded westward and southward to avoid being cut off from growth opportunity. It appears that West Des Moines has expanded southward to avoid Des Moines getting to the south of it.

Ankeny to the north, now has 59K. It has access direct access via I-35. It is physically separate from Des Moines. I don't know whether this is due to coal mines in the area with the possibility of tunnel collapses, or some other causes.

Altoona to the northeast 18K and Norwalk to the south 11K have suburban growth patterns, but this is much more recent than the western suburbs, so they are 40 to 50 years behind. Norwalk is an exception to no growth to the south.

Overall, Warren County has had strong growth. It surpassed its 1900 peak by 1960 and has continued to grow (about 20% since 2000). Indianola has about tripled since 1950. It has direct access to Des Moines via US 65 and 69, and its high school plays in the largest division (48 largest high schools in Iowa). I would consider this an exurb. Not directly adjacent to Des Moines, but commutable, and growth based on that.

Madison County might surpass its 1900 peak by 2030. Winterset is about twice as far as Indianola from Des Moines, and is considerable distance from the interstate.

[jimrtex]

I remember my grandmother saying she took the railroad from Winterset to Indianola to get to Simpson College. That would have been from 1903 to 1907. She bemoaned that the RR was gone (she hated automobiles, and never learned to drive).  It must have been that green line that shows up on the map.

I guess that new Microsoft plant and the new roads and bridge will change a lot in the NE corner of Madison County in time.

Interesting Jimrtex. Thanks. It still puzzles me though that development did not flow south along I-35. It has been there for a long time now.

Some interesting tidbits, I had come across:

George Washington Carver attended Simpson College, about a decade before your grandmother. He later went to what is now Iowa State.

Indianola is named for Indianola, Texas which was an early port, that was wiped out by two hurricanes. All that is left is a spreading oak. The founders of the Iowa town had read a newspaper account of the camels being unloaded there. This was an experiment by the US Army during the time Jefferson Davis was Secretary of War. I went to the McDonald Observatory for the solar eclipse. Fort Davis is on the plain below the Davis Mountains where the observatory is located. A video of the history of the fort included an account of the Camel Corps. As one might expect, the narrator of the video was Kareem Abdul-Jabbar. When the fort was reactivated after the Civil War, the enlisted soldiers were mostly Buffalo Soldiers, hence Abdul-Jabbar's selection as narrator. He had a kind of interesting outfit, which was evocative of a military uniform, but not military.

There is a consolidated school district on the Warren-Madison line that is officially named the Interstate 35 District, serving Truro, New Virginia, and St.Charles. If nothing else I-35 facilitates busing of students to a central location so there could be a comprehensive high school.

[jimrtex]

Finding Exurbia: America’s Fast-Growing Communities at the Metropolitan Fringe (PDF)

This is a report by the Brookings Institute to systematically classify exurbs of larger cities following the 2000 Census. They characterize census tracts as exurban if they are outside the Urbanize Area of a large metropolis, have high commuting to the Urbanized Area of a large MSA (> 500K), have a relatively low housing density, and high growth, compared to the rest of the MSA.

This conforms generally to my understanding of an exurban area as being outside the more densely populated suburban area, but with commuting to either the central city, or outlying factories or office parks. The USDA computes tract to tract commuting flows and provides a classification that could permit defining metropolitan areas at a tract level.

The Brookings definition requires that the commuting flow to the central urbanized area be greater than 20%.

The Brookings definition requires that the housing density for the tract be in the least dense tracts that hold 1/3 of the population. For 2000, this resulted in a threshold of 2.6 acres per housing unit. Since the target for a tract is 2000 housing units, this would be a tract of over 8 square miles. Exurbanites are likely seeking lower housing costs and/or a more rural lifestyle. A few acres is affordable, and you can put a mobile home on it, or maybe buy a farm house. Someone can buy a small farm and raise some livestock and perhaps have large garden, and lease the rest for crops or perhaps hay. They can commute to the city for income. They may prefer smaller schools for their children.

The Brookings definition may exclude some small towns that have become exurbs. If someone wants to have municipal water and sewer treatment, and an existing house, and perhaps a minimum level of commercial activity (grocery store, cafe, drug store) they can live in the town and commute to work. If they need to buy a car, furniture, clothing, entertainment, they can drive to the city. Because of the target size for census tracts, a small town might have been placed in one or two tracts, with the surrounding rural territory in another.

The third criteria is that the tract has to have a growth rate greater than the MSA as a whole. This appears to be an attempt to characterize exurbs as a trend, rather than merely a demographic type. There are also special rules, that require the exurban tract to have a growth rate of 10% (between 1990-2000) to exclude cases where the MSA as a whole was low growth (or even no growth or negative growth). In addition, tracts with a growth rate of three times the national growth rate are included even if the MSA is growing faster. For 1990-2000, 3X the national growth rate was 39.6%, for 2010-2020 it is closer to 20%. In addition exurban areas are among the slowest growing areas for this decade. That doesn't mean that they no longer exist, just that they are not expanding (as much).

The report then characterizes counties associated with each MSA.

Exurban counties have 20% or more of their population in tracts classified as exurban. Note exurban counties might or might not be parts of an MSA because inclusion in an MSA is based on commuting from the county as a whole, and not just certain parts.

The remainder of the counties of an MSA are characterized by (1) the  share of the county population in central cities greater than 50%, and (2) 95% or more of the population in Urbanized Areas.

A county that satisfies both criteria is classified as Urban.

A county that satisfies one of the criteria is classified as Inner Suburban, and county that classifies neither is Outer Suburban.

Counties such as Los Angeles, CA (Los Angeles, Long Beach); Allegheny, PA (Pittsburgh); and Hamilton, OH (Cincinnati) fail the first test and thus are classified as inner suburban. Counties such as Pima, AZ (Tucson); Guilford, NC (Greensboro); and Travis, TX (Austin) fail the second test and thus are also classified as inner suburban.