Modeling MSA and CSAs

[Erik]

In the context of the 2021 OMB Standards and Census Bureau mapping, a Continuous Urban Area (UA) is defined by physical development on the ground rather than political city limits.

​It is a "built-up" nucleus characterized by high-density housing and commercial structures that are physically linked. For Saunders or Dodge to become "Central," the Omaha UA must physically reach them through these specific criteria:

​1. The Core Density Requirement

​To be considered part of the "initial" UA core, a census block must typically have a housing unit density of at least 425 housing units per square mile.

​The Logic: If you have 425 houses in a square mile, you are no longer in a rural area; you are in a suburban or urban fabric.

​The Link: Any block with this density that touches the existing Omaha UA is added to it. ​2. "Hop" and "Jump" Rules (Connectivity)

​The UA is considered "continuous" even if there are small gaps in housing, provided they are connected by infrastructure:

​Hops: The UA can "hop" over non-residential areas (like a park, a small field, or an industrial zone) if the gap is less than 0.5 miles and there is qualifying high-density development on the other side.

​Jumps: It can "jump" over larger gaps of up to 2.5 miles along a road connection, provided the road has some level of development (commercial strips, gas stations, etc.) linking two high-density residential areas. ​3. The "Impervious Surface" Rule

​Large areas of asphalt and buildings—like an airport (Eppley), a massive shopping mall, or a large industrial plant—count as "urban" even if no one lives there. These act as the "connective tissue" that keeps the UA continuous across county lines.

[Erik]

Looks like those large, low density lake housing projects in west douglas county will be a bit too low density to qualify for UA. But some will qualify.

If such a continuous UA fails to manifest, we will need Yutan to surpass 50,000 people for the county to qualify

If a continuous 425-housing per square mile is reached, then Saunders becoming a core county manifests much quicker once Yutan really accelerates.

[Erik]

Here is a table based on the 425 rule alone

Code: Select all

PROJECT NAME                ACRES     LOTS       UNITS/SQ MI   CORE?
​Still Water Lake (Prop)     123.5      327       1,694         YES
Standard 180th St Sub       640.0      1,500     1,500         YES
Ginger Cove                 140.0      160       731           YES
Valley Shores               350.0      325       594           YES
Mallard Landing             200.0      149       476           YES
​Flatwater Lake              226.0      131       371           NO
Bluewater                   500.0      268       343           NO
West Shores                 640.0      291       291           NO
Harvest Heights (Prop)      110.0      39        226           NO
Hills Farm Lakes (Prop)     500.0      154       197           NO

[Erik]

Here are the rules for acreage developments with businesses:

How Businesses Help "Pass" the Measure

​1. The Pavement Bridge (The 35% Rule)

​In areas where housing density is low, businesses can "save" the urban status.

​Waterloo West: This project plans for significant commercial frontage along Highway 275. Even if the housing count was low, a dense strip of commercial buildings and parking lots creates an "Urban" census block by meeting the 35% impervious surface requirement.

​2. The Mixed-Use Spike

​Iron Bluff: This project is designed as a true "Mixed-Use" hub. Because it has businesses integrated with high-density residential, it hits both requirements: it has the housing units (over 425) and it has the impervious surface (parking garages and retail roofs). This makes it a guaranteed anchor for the Omaha Urban Area.

​3. Why it Fails at the Lakes

​West Shores / Bluewater: These projects are strictly residential. Their "business" component is usually limited to a single marina or a small office. ​The Result: The vast majority of the land is either water (the lake) or grass (the yards). Because they lack the dense rooftops and massive parking lots of a commercial business center, they cannot use the 35% rule to "bypass" the housing requirement.

[Erik]

One thing to keep in mind, is how continuously UA is looked at. Do they include the lakes? Do they only look at the connected density of developed land and leave out these pseudo-nature parts?

[Erik]

​1. The "Water Drain" Effect

​Because the lake is included in the "square mile" calculation but contains zero houses, it acts as a massive "density drain."

​Standard Square Mile (No Lake): 640 acres of land. If you build at 1 house per acre, you have 640 houses. (Passes the 425-unit rule). ​Lake Square Mile: 320 acres of land + 320 acres of water. If you build at the same 1 house per acre on the land, you only have 320 houses. (Fails the 425-unit rule). ​2. The Census Rule on "Inland Water"

​There is one specific exception: The Census Bureau excludes "Large Water Bodies" from land area calculations if they meet certain size thresholds (usually over 40 acres of open water).

​The Catch: Most man-made sand-pit lakes in West Douglas County (like West Shores or Bluewater) are technically classified as "Inland Water." * The Result: When calculating density for the Omaha Urban Area, the Census Bureau often subtracts the lake acreage from the denominator. This actually helps the density number on paper, but only for the specific block containing the water. ​3. The "Impervious Surface" Rule (The Business Side)

​As we discussed earlier, businesses help because of pavement.

​The Comparison: * A lake is considered "Natural/Open Space" (0% impervious). ​A parking lot is considered "Developed" (100% impervious). ​To pass as "Urban" via the 35% Impervious Rule, you need pavement. A created lake makes it almost impossible to hit that 35% mark because the water takes up the space where parking lots or roofs would be.

Code: Select all

PROJECT                 ACRES      UNITS      UNIT/SQMI      IMP%      CORE?
​Iron Bluff (Prop)       160.0      600        2,400          45%       YES
Still Water Lake        123.5      327        1,694          38%       YES
Standard 180th Sub      640.0      1,500      1,500          40%       YES
Ginger Cove             140.0      160        731            20%       YES
Valley Shores           350.0      325        594            18%       YES
Mallard Landing         200.0      149        476            15%       YES
​West Shores (+Apts)     640.0      416        416            12%       NO
Flatwater Lake          226.0      131        371            10%       NO
Bluewater               500.0      268        343            8%        NO
Harvest Heights         110.0      39         226            5%        NO
Hills Farm Lakes        500.0      154        197            3%        NO

[Erik]

Approximate lake size

Code: Select all

PROJECT             LAKE ACRES    CORE? REASON
​West Shores             240+       NO   Density still <425 even w/ deduction
Bluewater               250+       NO   Lots are too spread out (Estate scale)
Hills Farm Lakes        160+       NO   Rural density; deduction not enough
Valley Shores           ~80        YES  Townhome infill + land deduction
Ginger Cove             ~60        YES  Clustered lots pass on net land area
Mallard Landing         ~60        YES  Borderline pass on net acreage
Still Water Lake        ~53        YES  MU Spikes + land deduction = High Density
​Flatwater Lake          ~35*       NO   Under 40-acre rule; full area counted
Harvest Heights         <10*       NO   Pond only; full area counted

[BRoss]

FYI - I changed the CSS for the code blocks so the text isn't so light now. I do still recommend using PRE or NFO blocks instead though. But it's certainly ok if you prefer using code blocks.

[Erik]

FYI - I changed the CSS for the code blocks so the text isn't so light now. I do still recommend using PRE or NFO blocks instead though. But it's certainly ok if you prefer using code blocks.

Ill look back at our previous message and check out the formats.

Which of the two is the best of the best?

Thank you for your help in this

[BRoss]

FYI - I changed the CSS for the code blocks so the text isn't so light now. I do still recommend using PRE or NFO blocks instead though. But it's certainly ok if you prefer using code blocks.

Ill look back at our previous message and check out the formats.

Which of the two is the best of the best?

Thank you for your help in this

Honestly it's just preference. The NFO blocks have panels around them similar to the code blocks and the PRE blocks just change to a mono-spaced font with no other style changes. They both technically use <pre> HTML elements to wrap their contents - NFO just has more styling. I'd probably use NFO personally to have it stand out more and not blend in as much with any statements about what it contains.

This is NFO.
It has a panel around it.

This is PRE.
It's just inline with the post with no background difference.

[Erik]

FYI - I changed the CSS for the code blocks so the text isn't so light now. I do still recommend using PRE or NFO blocks instead though. But it's certainly ok if you prefer using code blocks.

Ill look back at our previous message and check out the formats.

Which of the two is the best of the best?

Thank you for your help in this

Honestly it's just preference. The NFO blocks have panels around them similar to the code blocks and the PRE blocks just change to a mono-spaced font with no other style changes. They both technically use <pre> HTML elements to wrap their contents - NFO just has more styling. I'd probably use NFO personally to have it stand out more and not blend in as much with any statements about what it contains.

This is NFO.
It has a panel around it.

This is PRE.
It's just inline with the post with no background difference.

I worked on a table of regional cities and their growth using NFO. It does look a lot better.

[BRoss]

I worked on a table of regional cities and their growth using NFO. It does look a lot better.

Glad you like it. One big reason I recommended them other than the text color issue I adjusted (honestly that grey color it used didn't make sense even if it is code) is that they don't limit the height of the block and put scrollbars in. So it's easier to see the whole table. Also, if you use the Zeina board style like I have been recently, the CODE blocks do syntax highlighting.

[Gobears27]

Where do you find total employment by county data?

[Erik]

Where do you find total employment by county data?

Its based on the commute data file from the 2016-2020 ACS commuter flow tables. The number of commuters from every county to one county adds up to total the total workers for said county.

There will be a new file later this year for 2021-2025