Equalizing Congressional District Populations

[jimrtex]

This map illustrates the shifts in population (in thousands) necessary to re-equalize congressional district populations.  For Alabama, a total shift of 114.5 thousand, or 2.4% of the state population is needed to achieve balance.

District populations are based on 2009 ACS.

[jimrtex]

Arizona gains a 9th CD, which is located on the junction of AZ-1 AZ-6, and AZ-7 which collectively have the largest population of any trio of districts that meet at a point.  Generally, most all of the excess population for the new district is in AZ-2, AZ-6, and AZ-7.  Despite appearances, AZ-2 is a suburban Phoenix district, connected to Mohave County in the northwest, with a connection through the Grand Canyon to the Hopi Reservation.

Pinal County has roughly doubled in population, and will form the core of the new district with portions of Maricopa County, and some of the smaller counties to the east.  AZ-1 doesn't have the excess population to contribute to the new district, but will receive a major infusion from AZ-1 in the form of Mohave County.

This will make AZ-1 a northern district (Apache, Navajo, Coconino, Yavapai, and Mohave).  It should be possible to AZ-7 and AZ-8 entirely in the southern part of the state out of Maricopa County.  AZ-2, 3, 4, 5, 6, and major portion of 9 will be in Maricopa County.  The rest of AZ-9 will be in Pinal County and counties to the east.

1045.7 thousand will transferred to new districts (15.9), but 732.9 will be those moved into the new AZ-9.  Otherwise about 4.7% of Arizonans will find themselves in new districts.

[minionofmidas]

I understand that this is just a technical exercise, but this ought to make an utterly bizarre Arizona map.

[muon2]

Arizona gains a 9th CD, which is located on the junction of AZ-1 AZ-6, and AZ-7 which collectively have the largest population of any trio of districts that meet at a point.  Generally, most all of the excess population for the new district is in AZ-2, AZ-6, and AZ-7.  Despite appearances, AZ-2 is a suburban Phoenix district, connected to Mohave County in the northwest, with a connection through the Grand Canyon to the Hopi Reservation.

Pinal County has roughly doubled in population, and will form the core of the new district with portions of Maricopa County, and some of the smaller counties to the east.  AZ-1 doesn't have the excess population to contribute to the new district, but will receive a major infusion from AZ-1 in the form of Mohave County.

This will make AZ-1 a northern district (Apache, Navajo, Coconino, Yavapai, and Mohave).  It should be possible to AZ-7 and AZ-8 entirely in the southern part of the state out of Maricopa County.  AZ-2, 3, 4, 5, 6, and major portion of 9 will be in Maricopa County.  The rest of AZ-9 will be in Pinal County and counties to the east.

1045.7 thousand will transferred to new districts (15.9), but 732.9 will be those moved into the new AZ-9.  Otherwise about 4.7% of Arizonans will find themselves in new districts.

Your population flow and descriptions don't seem to match, You have population moving from CDs 2 ,3 and 8 into CD 1, but you describe the new CD 1 as completely in the north. The problem is that moving pop from CD 8 into CD 1 leaves a long finger south on the eastern edge, and makes CD 9 wrap way north. Wouldn't it more sense to show the 35 K from CD 8 going directly to new CD 9 on your map?

BTW The wraparound of CD 9 to the north also constricts the connection between CD 3 and CD 1. I have to keep a finger on the west from Prescott down I 17 to CD 3, while Sedona moves to CD 9.

[minionofmidas]

If that kind of CD7 population is moved to the new CD while it also takes in a piece of CD4, wouldn't that pretty much require CD9 to include a finger into Tucson?

[muon2]

If that kind of CD7 population is moved to the new CD while it also takes in a piece of CD4, wouldn't that pretty much require CD9 to include a finger into Tucson?

Yes it would. There's over 100 K from Tucson in CD 9. Here's what the map would look like from 2009 block group data with equality to 100 persons.

[jimrtex]

Arizona gains a 9th CD, which is located on the junction of AZ-1 AZ-6, and AZ-7 which collectively have the largest population of any trio of districts that meet at a point.  Generally, most all of the excess population for the new district is in AZ-2, AZ-6, and AZ-7.  Despite appearances, AZ-2 is a suburban Phoenix district, connected to Mohave County in the northwest, with a connection through the Grand Canyon to the Hopi Reservation.

Pinal County has roughly doubled in population, and will form the core of the new district with portions of Maricopa County, and some of the smaller counties to the east.  AZ-1 doesn't have the excess population to contribute to the new district, but will receive a major infusion from AZ-1 in the form of Mohave County.

This will make AZ-1 a northern district (Apache, Navajo, Coconino, Yavapai, and Mohave).  It should be possible to AZ-7 and AZ-8 entirely in the southern part of the state out of Maricopa County.  AZ-2, 3, 4, 5, 6, and major portion of 9 will be in Maricopa County.  The rest of AZ-9 will be in Pinal County and counties to the east.

1045.7 thousand will transferred to new districts (15.9), but 732.9 will be those moved into the new AZ-9.  Otherwise about 4.7% of Arizonans will find themselves in new districts.

Your population flow and descriptions don't seem to match, You have population moving from CDs 2 ,3 and 8 into CD 1, but you describe the new CD 1 as completely in the north. The problem is that moving pop from CD 8 into CD 1 leaves a long finger south on the eastern edge, and makes CD 9 wrap way north. Wouldn't it more sense to show the 35 K from CD 8 going directly to new CD 9 on your map?

BTW The wraparound of CD 9 to the north also constricts the connection between CD 3 and CD 1. I have to keep a finger on the west from Prescott down I 17 to CD 3, while Sedona moves to CD 9.

What I did was convert the existing map into a network, with each node representing a district, and each link a bounding pair.  I then located the three districts that joined at a point and added CD 9 with a population of zero.

I then shifted a share (0.2) of the difference between district populations, and did this recursively.  I then culled the smallest link, as long as it would not isolate a node.  After each deletion, the transfers were recalculated.

If a node (or nodes) was isolated so that there was only a single remaining link, the initial transfer was converted to that necessary to get the district(s) to the ideal population.  This can probably be most easily understood with respect to Alabama, where AL-5 in the Tennessee Valley is only connected to AL-4 which crosses the state as well.  We know that the amount to transfer from AL-5 to AL-4 is the amount which will bring AL-5 to the ideal population.

Arizona had a couple of challenges, in that both AZ-1 and AZ-7 border on 6 of the other 7 districts (CD-7 and CD-3 do not border, and CD-1 and CD-4 do not border).  And some districts are not really an areal feature but a collection of points with empty space in between.   This is particularly true of AZ-2 and AZ-7.

When there is a large scale shift, as would be caused by an addition of a new district, or elimination of a district, it could cause a need to rearrange the network as boundaries are cut off.

And it practice, it may not be desirable to make some shifts.  For example, it might not make sense to shift from AL-6 in to both AL-2 and AL-3, but rather to shift from AL-6 to AL-3 and from AL-3 to AL-2.  This would avoid any additional county splits.

So in Arizona, the areas shifted from AZ-4 to AZ-7 and from AZ-8 to AZ-1 would end up in AZ-9.  This would let AZ-9 go to the New Mexico border and south, rather than north.  And you would eliminate the Tucson portion of AZ-9 as well.

[Kevinstat]

So the current AZ-5 went from having approx. 1/8 of Arizona's population in 2000 to being estimated to have 6.6K less than 1/9 of Arizona's population in 2010?  Is it estimated to have lost population since 2000 or have gained some, just not nearly as high a percentage as the state as a whole?  If the latter, is it estimated to have grown more or less than the national average?  If Arizona only narrowly got an 8th seat in 2000 and narrowly missed a 10th in 2010, a district that had grown just a bit more than the nation percentage-wise (and yes I know overseas population is included in the apportionment calculations but not redistricting within a state, but anyway) it could still have to gain some territory.

Then-US House Speaker Thomas Foley's WA-5 may have gained more territory than it lost in 1992 when Washington gained a 9th congressional district.  I remember reading in the Almanac of American Politics 1992 at my college library that it wouldn't have to change much.

[jimrtex]

So the current AZ-5 went from having approx. 1/8 of Arizona's population in 2000 to being estimated to have 6.6K less than 1/9 of Arizona's population in 2010?  Is it estimated to have lost population since 2000 or have gained some, just not nearly as high a percentage as the state as a whole?  If the latter, is it estimated to have grown more or less than the national average?  If Arizona only narrowly got an 8th seat in 2000 and narrowly missed a 10th in 2010, a district that had grown just a bit more than the nation percentage-wise (and yes I know overseas population is included in the apportionment calculations but not redistricting within a state, but anyway) it could still have to gain some territory.

Then-US House Speaker Thomas Foley's WA-5 may have gained more territory than it lost in 1992 when Washington gained a 9th congressional district.  I remember reading in the Almanac of American Politics 1992 at my college library that it wouldn't have to change much.

Just not as fast as Arizona.  The percentages are relative to the national average.  The ranking are national ranking.  So AZ=6 and AZ-2 at the western and southeastern edges of the Phoenix area, are two of the 5 most populous districts in the country.  A7-7 also has a good share of high growth area in Maricopa County, plus healthy growth in the Tucson and Yuma areas.

Arizona   6   974,431   138%   4
Arizona   2   956,842   136%   5
Arizona   7   892,390   127%   14
Arizona   8   768,301   109%   71
Arizona   4   761,146   108%   82
Arizona   1   758,406   108%   87
Arizona   3   757,962   108%   88
Arizona   5   726,300   103%   132

If you add the percentages up, the 8 districts have a population of about 938% of the national average, so Arizona is well on its way to a 10th district.  The average for 9 Arizona districts is 732,864 vs. a national average of 704,384.

[bgwah]

So the current AZ-5 went from having approx. 1/8 of Arizona's population in 2000 to being estimated to have 6.6K less than 1/9 of Arizona's population in 2010?  Is it estimated to have lost population since 2000 or have gained some, just not nearly as high a percentage as the state as a whole?  If the latter, is it estimated to have grown more or less than the national average?  If Arizona only narrowly got an 8th seat in 2000 and narrowly missed a 10th in 2010, a district that had grown just a bit more than the nation percentage-wise (and yes I know overseas population is included in the apportionment calculations but not redistricting within a state, but anyway) it could still have to gain some territory.

Then-US House Speaker Thomas Foley's WA-5 may have gained more territory than it lost in 1992 when Washington gained a 9th congressional district.  I remember reading in the Almanac of American Politics 1992 at my college library that it wouldn't have to change much.

WA-5 barely changed in 1992 (Click here for maps)

[minionofmidas]

If that kind of CD7 population is moved to the new CD while it also takes in a piece of CD4, wouldn't that pretty much require CD9 to include a finger into Tucson?

Yes it would. There's over 100 K from Tucson in CD 9. Here's what the map would look like from 2009 block group data with equality to 100 persons.

Wait... are you using the app's ACS figures or a separate source? Because if the former, you have an error in your CD2-to-CD1 transfers that makes the map ugly. The areas you transferred have 203k inhabitants max - that's assuming you moved all of Wickenburg and Lake Havasu City (hard to tell from the map).

EDIT: Oh, I see. I was fixed on that 224k figure, but it appears that that is either wrong or comes from a different source.

[minionofmidas]

So in Arizona, the areas shifted from AZ-4 to AZ-7 and from AZ-8 to AZ-1 would end up in AZ-9.  This would let AZ-9 go to the New Mexico border and south, rather than north.  And you would eliminate the Tucson portion of AZ-9 as well.

Still not working without either fenceline connections, or transferring some territory into CD7 in exchange. The Maricopa portion of CD7 is too large.

[muon2]

Arizona gains a 9th CD, which is located on the junction of AZ-1 AZ-6, and AZ-7 which collectively have the largest population of any trio of districts that meet at a point.  Generally, most all of the excess population for the new district is in AZ-2, AZ-6, and AZ-7.  Despite appearances, AZ-2 is a suburban Phoenix district, connected to Mohave County in the northwest, with a connection through the Grand Canyon to the Hopi Reservation.

Pinal County has roughly doubled in population, and will form the core of the new district with portions of Maricopa County, and some of the smaller counties to the east.  AZ-1 doesn't have the excess population to contribute to the new district, but will receive a major infusion from AZ-1 in the form of Mohave County.

This will make AZ-1 a northern district (Apache, Navajo, Coconino, Yavapai, and Mohave).  It should be possible to AZ-7 and AZ-8 entirely in the southern part of the state out of Maricopa County.  AZ-2, 3, 4, 5, 6, and major portion of 9 will be in Maricopa County.  The rest of AZ-9 will be in Pinal County and counties to the east.

1045.7 thousand will transferred to new districts (15.9), but 732.9 will be those moved into the new AZ-9.  Otherwise about 4.7% of Arizonans will find themselves in new districts.

Your population flow and descriptions don't seem to match, You have population moving from CDs 2 ,3 and 8 into CD 1, but you describe the new CD 1 as completely in the north. The problem is that moving pop from CD 8 into CD 1 leaves a long finger south on the eastern edge, and makes CD 9 wrap way north. Wouldn't it more sense to show the 35 K from CD 8 going directly to new CD 9 on your map?

BTW The wraparound of CD 9 to the north also constricts the connection between CD 3 and CD 1. I have to keep a finger on the west from Prescott down I 17 to CD 3, while Sedona moves to CD 9.

What I did was convert the existing map into a network, with each node representing a district, and each link a bounding pair.  I then located the three districts that joined at a point and added CD 9 with a population of zero.

I then shifted a share (0.2) of the difference between district populations, and did this recursively.  I then culled the smallest link, as long as it would not isolate a node.  After each deletion, the transfers were recalculated.

If a node (or nodes) was isolated so that there was only a single remaining link, the initial transfer was converted to that necessary to get the district(s) to the ideal population.  This can probably be most easily understood with respect to Alabama, where AL-5 in the Tennessee Valley is only connected to AL-4 which crosses the state as well.  We know that the amount to transfer from AL-5 to AL-4 is the amount which will bring AL-5 to the ideal population.

Arizona had a couple of challenges, in that both AZ-1 and AZ-7 border on 6 of the other 7 districts (CD-7 and CD-3 do not border, and CD-1 and CD-4 do not border).  And some districts are not really an areal feature but a collection of points with empty space in between.   This is particularly true of AZ-2 and AZ-7.

When there is a large scale shift, as would be caused by an addition of a new district, or elimination of a district, it could cause a need to rearrange the network as boundaries are cut off.

And it practice, it may not be desirable to make some shifts.  For example, it might not make sense to shift from AL-6 in to both AL-2 and AL-3, but rather to shift from AL-6 to AL-3 and from AL-3 to AL-2.  This would avoid any additional county splits.

So in Arizona, the areas shifted from AZ-4 to AZ-7 and from AZ-8 to AZ-1 would end up in AZ-9.  This would let AZ-9 go to the New Mexico border and south, rather than north.  And you would eliminate the Tucson portion of AZ-9 as well.

I think a key element in your node calculation is how you set the number of links when a new district is added. One observation is that as links are reduced, the possibility of new links to the new district will exist. Based on your final allocation, AZ-9 could have as many as six links instead of three. AZ 5-9 and AZ 8-9 could appear when the AZ 1-7 link disappeared. AZ 4-9 could appear when the AZ 5-7 link disappeared.

This dynamic addition of links to a new district should allow the new district to gain in size from all neighbors. From an efficiency point of view this has the advantage of minimizing population shifts, since a shift to the new district should never be accompanied by a second shift of people out of the receiving district. In the AZ example, AZ-4 sends population to AZ-7, and AZ-7 sends population to AZ-9, resulting in 21.7 K people being moved twice. Likewise there is a chain of 35.4 K people moving from AZ-8 to AZ-1 then to AZ-9. The more efficient move sends 21.7 K directly from AZ-4 to AZ-9 and 35.4 K directly from AZ-8 to AZ-9.

[muon2]

If that kind of CD7 population is moved to the new CD while it also takes in a piece of CD4, wouldn't that pretty much require CD9 to include a finger into Tucson?

Yes it would. There's over 100 K from Tucson in CD 9. Here's what the map would look like from 2009 block group data with equality to 100 persons.

Wait... are you using the app's ACS figures or a separate source? Because if the former, you have an error in your CD2-to-CD1 transfers that makes the map ugly. The areas you transferred have 203k inhabitants max - that's assuming you moved all of Wickenburg and Lake Havasu City (hard to tell from the map).

EDIT: Oh, I see. I was fixed on that 224k figure, but it appears that that is either wrong or comes from a different source.

I'm not sure how the aggregation of block groups works in the ACS, but there is an inconsistency between the old CD populations used directly by jimrtex with 2009 ACS, and those calculated by adding 2009 ACS block group populations in Dave's App.

[minionofmidas]

Fairly major inconsistencies too - certainly not explained by the (true) fact that several block groups are actually split between CDs.

Oh, also, Muon, I think you have one or more noncontinuous bits of CD8 hidden in Cochise County towns.

'Course, given that we know the Arizona estimates to be fairly bad... why don't we just wait for the Census figures?

[jimrtex]

If that kind of CD7 population is moved to the new CD while it also takes in a piece of CD4, wouldn't that pretty much require CD9 to include a finger into Tucson?

Yes it would. There's over 100 K from Tucson in CD 9. Here's what the map would look like from 2009 block group data with equality to 100 persons.

Wait... are you using the app's ACS figures or a separate source? Because if the former, you have an error in your CD2-to-CD1 transfers that makes the map ugly. The areas you transferred have 203k inhabitants max - that's assuming you moved all of Wickenburg and Lake Havasu City (hard to tell from the map).

EDIT: Oh, I see. I was fixed on that 224k figure, but it appears that that is either wrong or comes from a different source.

I'm using the 2009 ACS which has estimates for large areas (greater than 60,000).

Dave Bradlee is using the 2005-2009 ACS which has estimates for small areas down to block groups.  Because the data was accumulated over a longer period of time, it is probably more representative of the population around 2007.

[jimrtex]

I think a key element in your node calculation is how you set the number of links when a new district is added. One observation is that as links are reduced, the possibility of new links to the new district will exist. Based on your final allocation, AZ-9 could have as many as six links instead of three. AZ 5-9 and AZ 8-9 could appear when the AZ 1-7 link disappeared. AZ 4-9 could appear when the AZ 5-7 link disappeared.

This dynamic addition of links to a new district should allow the new district to gain in size from all neighbors. From an efficiency point of view this has the advantage of minimizing population shifts, since a shift to the new district should never be accompanied by a second shift of people out of the receiving district. In the AZ example, AZ-4 sends population to AZ-7, and AZ-7 sends population to AZ-9, resulting in 21.7 K people being moved twice. Likewise there is a chain of 35.4 K people moving from AZ-8 to AZ-1 then to AZ-9. The more efficient move sends 21.7 K directly from AZ-4 to AZ-9 and 35.4 K directly from AZ-8 to AZ-9.

That requires knowledge of the population distribution. 

This originally started out as a thought exercise for the Texas Senate.  Where the individual senators are most interested in preserving their districts (this is not 100% self-interest, since they probably think of themselves as representative of their community, and that their district has enough common interest that it can be represented by them).

In this thought exercise, the number to transfer would be determined (this might also consider the length of the boundary).  The two senators would independently specify the areas to be shifted.  Areas that they agreed on would be shifted, then each could unilaterally specify 1/2 of the population that he alone had shifted.  At each step, new boundaries could be opened up, or old ones closed off.

[jimrtex]

This is based on merging the two adjacent districts with the least total population, LA-2 and LA-3, and that each would contribute half of the population of the new district.  Notable is that LA-2 would only need to shed 115.6K to reach 1/2 of the ideal population size (755.6K), and that is enough to only boost LA-1 and LA-6 up to the needed level.  This then requires CD-3 to supply the necessary population to LA-4, LA-5, LA-7.  This would lead to a long extension of LA-5 down the Mississippi.

[Kevinstat]

This is based on merging the two adjacent districts with the least total population, LA-2 and LA-3, and that each would contribute half of the population of the new district.  Notable is that LA-2 would only need to shed 115.6K to reach 1/2 of the ideal population size (755.6K), and that is enough to only boost LA-1 and LA-6 up to the needed level.  This then requires CD-3 to supply the necessary population to LA-4, LA-5, LA-7.  This would lead to a long extension of LA-5 down the Mississippi.

Did you use the 2010 census redistricting data for Louisiana?  That's the first one of the states you've done where that data has come out.

[jimrtex]

Did you use the 2010 census redistricting data for Louisiana?  That's the first one of the states you've done where that data has come out.

Yes.

I'm doing an alternative version where LA-6 disappears.

[jimrtex]

This version eliminates LA-6.  It might be fairly feasible were it not for VRA considerations.

[jimrtex]

Pretty simple, assuming no problems with the VRA for MS-2

[minionofmidas]

There's still some minemadge areas in MS-1 and MS-3 near the borders with MS-2, so shouldn't be a problem a-tall.

[jimrtex]

The four new districts were placed in the following manner.  The 33rd district was placed at the common intersection of the three districts with the largest combined population, that is the districts that had the most excess population which could be used to form the new district.  The deficit between their combined population and the population equivalent to 4 districts.  The deficit represents the additional population needed to form 4 equipopulous districts.  The deficit was apportioned among the neighbors of the three districts in proportion to those neighbors population in excess of the ideal population.  This recognizes that additional population must flow into the area of the new district, and also tends to distribute the new districts around the state.

This process was repeated for the 34th, 35th, and 36th population.  After the location of the new districts was determined, they were initialized with zero population, and the flow was calculated in the same it would be in states where no districts were added.

The four new districts (Red stars on map above):

TX-33 is in the Cedar Park, Round Rock, north Austin area at the intersection of TX-10, TX-21, and TX-31.  These three districts have a population equivalent to 3.923 districts, which means that a new district can be formed almost exclusively from their excess population.  As it turns out, excess population from the DFW and Houston area flows into TX-31 and TX-10 so that TX-21 doesn't actually contribute to the new district.

TX-31 shifts northward into the western Fort Worth suburbs, and becomes much less Austin focused.  Similarly TX-10 becomes much more of a Houston district.

TX-34 in the Frisco area at the intersection of TX-3, TX-4, and TX-26.  These 3 districts have a population equivalent to 3.728 districts, which requires about 200,000 more persons from other districts in North Texas.  TX-3 and TX-26 contribute excess suburban growth to the new district.  TX-4 continues to withdraw to the north and east, giving somewhat of the appearance of a small city district: Sherman, Denison, Greenville, Paris, Texarkana, etc., but continues to have a significant suburban presence.

TX-35 in the Baytown area at the intersection of TX-2, TX-14, and TX-22.  These three districts have a population equivalent to 3.526 districts, which requires around 330,000 from other districts.  The placement of the district to the east of Houston is a consequence of the excess population of TX-10 being used to form TX-33, and not available for creation of a new district in the faster growing northern or western suburbs.  In a sense, TX-33 is a re-creation of the old TX-9 in the Beaumont, Galveston, Clear Lake area.  TX-2 becomes more obviously a northern and northeast suburban Houston district, and TX-14 shifts southwestward down the coast.

TX-36 is near China Grove southeast of San Antonio at the intersection of TX-21, TX-23, and TX-28.  The three districts have a population equivalent to 3.407 districts which means that an additional 420,000 is needed from other districts.  This deficit of 420,000 was based on allocating the excess of TX-21 to TX-33.  Since this is not required, about a large share of the needed population can come from TX-21, with addition contributions from elsewhere.

Texas-wide shifts:  Only 7 districts are completely outside the major metropolitan areas, while 2 others have a significant core outside those areas, while still extending into the suburban areas of the major metropolitan areas.  TX-2, TX-4, TX-5, TX-6, TX-8, TX-10, TX-21, TX-23, and TX-31 have a superficial appearance of being rural districts, but their population is concentrated in the suburban areas.

TX-1 in East Texas has an excess population of 25,000 that is shifted to TX-4.  TX-13, TX-19, and TX-11 have a deficit of around 25,000, a tiny deficit of about 400, and a surplus of 12,000 respectively.  TX-13 takes a major infusion from the DFW area, but passes most of it on to TX-31 and the Austin and San Antonio areas.  TX-11 transfers its surplus to TX-21.

TX-16 in El Paso County has an excess of 59,000 which is transferred to TX-23.  TX-15 and TX-27 in south Texas have an excess of 132,000 which they shift to TX-14 as they concentrate more towards the border.

TX-17 extends into the southern DFW suburbs, but would be described as a Waco, Bryan-College Station central Texas district.  Its excess of 62,000 is shifted into TX-31 for transport further south.

TX-28 includes San Antonio suburbs, but has a focus in Laredo and other south Texas areas.  The northern portion will be used in creation of TX-36.

It appears that the Houston area is a little bit short of the excess population needed to create TX-35 (inflow from TX-15 and TX-27 minus outflow from TX-8, but growth in the Harris County portion of TX-10 provided a significant share of the excess that went into creation of TX-33.

The DFW area has an excess of about 150,000 plus a significant portion of the surplus in TX-17.  This is used to top off TX-13, with the bulk being shifted southward to the Austin and San Antonio areas.

A total of 4.105 million persons are shifted in Texas, representing 14.0% of the state, or the equivalent of 5.03 districts.  But this includes the persons moved into the 4 new districts.

If those persons are excluded, then 717 thousand, or 2.9% of the population is shifted.



In the DFW area, most shifts are associated with creating TX-34 in the Frisco area, with direct transfers from TX-3, TX-4, and TX-26, supported by secondary transfers from TX-1 (not shown), TX-5, TX-6, and TX-24.  TX-32 is the least populated district in Texas, and TX-30 has a very small surplus.  Population is transferred from TX-6 to make up this deficit in TX-32.

The DFW area produces a surplus of 149K (210K if the surplus in TX-17 is attributed to the suburban areas (Johnson and Hood counties).  This surplus is directed from TX-12 into TX-13, and then into TX-31.  About 25,000 of the surplus is used to erase the deficit in TX-13, one of four Texas districts that are underpopulated.  This could be made up from Wise County.  The remaining population from Parker County would be moved into TX-31.  If the transfer from TX-17 to TX-31 takes place from the northern end of the district, then TX-31 is shifted northward, with roughly comparable population in the western DFW suburbs, Bell County (Killeen and Temple) and northerly parts of Williamson County.



In the Houston area, TX-35 is formed east of the city.  This unexpected result is a consequence of TX-33 being created in the Austin area, which depletes the excess population in TX-10 in northwest Harris County, which might have been used to form a new district in areas to north and west of the city.  But in effect, TX-10 becomes a Houston area district with the transfer of the Travis County portion into TX-33.

Rather than population flowing into the Baytown area, TX-35 would be created from the east portions of TX-2 (Jefferson) and TX-14 (Galveston and Chambers).  The contribution from TX-22 might also include Galveston County, along with areas of southeast Harris County.  Thus TX-35 would be somewhat like the old TX-9.

TX-2 would become more clearly a northern and northeast suburban district, while TX-22 would become more of a southwestern suburban district.  TX-14 would move back down the coast, but would continue to have a significant Houston area population.  This process would be aided by a transfer of population of 132K from the extreme northern portions of TX-15 and TX-27.

There are additional secondary transfers from TX-7, TX-8, and TX-9 into TX-2 and TX-14 to make up for the population used to create TX-35.  TX-29 is one of 4 districts below the ideal population which is matches with a similar small surplus in TX-18.  TX-8 provides a small outflow into TX-10, which strengthens the new Houston orientation of TX-10.



Two new districts are created in the San Antonio-Austin area, TX-33 in north Austin and its suburbs and TX-36 southeast of San Antonio.

Because of an inflow of about 185K into TX-31 from the DFW area and 65K into TX-10 from the Houston area, no population is transferred from TX-21 into the new TX-33.  If one wanted to avoid a an additional county split, the small transfer of 18K from TX-31 to TX-21 could be from Travis County, with TX-31 then providing a larger portion of TX-33.  With half of a congressional district being contributed to TX-33 by both TX-10 and TX-31, these districts are shifted out of the Austin area, with TX-10 becoming a Houston area district, and TX-31 becoming a central Texas district stretching north to the western DFW suburbs, while the new TX-33 if fully an Austin area district.

TX-36 is created southeast of San Antonio, but would have most of its population in Bexar County.  In effect Bexar county would have 4 districts: TX-20 in the center, TX-23 in the west extending all the way to El Paso; TX-21 in the north extending into the Hill Country and to Austin, and the new TX-36 in south and east extending into counties further east.  I suspect that TX-36 would have the largest share of Bexar County after TX-20.

TX-25 would also contribute to the new district, with counties southeast of Travis County being shifted through TX TX-28 into the new district.  TX-28 would be moved out of the San Antonio area.  TX-16 (El Paso) contributes its surplus of 59K to TX-23 which moves that district slightly to the west.  TX-11 shifts its small surplus to TX-21.  TX-11 also makes up the tiny deficit (400 persons) in TX-19.

[jimrtex]

This map shows the shifts for Texas 31 senate districts.  Since no new districts are created, it gives a better picture of intrastate growth.



The Houston area has a surplus of about 70,000 which is shown as an outflow from SD-3 and SD-18, which is mainly from growth in Fort Bend and Montgomery counties.  The DFW area has a surplus of about 120,000 which is shown as outflow from SD-2 and SD-30 as these districts become increasingly suburban, shedding more rural areas while suburban areas grow (senate districts needed to add 135,000 people to just keep even).

Central Texas has a surplus of about 175,000, which includes the excess from TX-5 and TX-14 from Williamson and Travis counties, plus the population needed to bring TX-16 in El Paso up to equality.

Inflows into rural areas include 80,000 in to SD-1 in northeast Texas, which is the only district in the eastern part of the state not to include a suburban area that provides enough growth to maintain the districts configuration.  Presumably the split of Smith County will be eliminated.

SD-13 and SD-19 in west Texas collectively need about 150,000, but SD-13 has to get its 85,000 from SD-19, which will bring it south to include all of the panhandle (the senate redistricting chairman is from Amarillo, so an Amarillo-Lubbock district is not on the table.  

SD-19 will probably need to take Abilene (Taylor County) though it is more than is needed from SD-24.  SD-24 can then extend north to absorb the excess from SD-30.  This will make Bell County the dominant area in SD-24 which is becoming a central Texas district.

SD-16 in El Paso needs enough about 50,000 more, which will place all of El Paso County in the district, and to reach closer to equality, Hudspeth, Culberson, and Jeff Davis.

SD-24 needs  net of about 25,000 as growth in places like Bell and Burnet counties have helped it keep up with the state.  But will the loss of Abilene, it has to continue moving east.  To avoid taking in part of Williamson or Travis counties, it might take Coryell from SD-22 and the southern part of the Hill Country from SD-19 and SD-25.  While SD-25, SD-26, and SD-19 slide north from San Antonio towards Austin.

SD-21 needs about 60,000 which in the flow map map would come from TX-18 taking counties in the direction of Victoria.

Since SD-19 will be losing the top if its tail in El Paso, it would make sense to remove it completely.  SD-31. SD-24, and SD-28 could nibble southward, and then Maverick, Val Verde, and the remnant of the Trans Pecos moved to SD-21.  Certainly Eagle Pass and Del Rio have more in common with Laredo than they do with San Antonio.   SD-19 then would then become a San Antonio and southern suburbs district.  SD-18 could be brought south to include San Patricio and Bee counties, while counties like Bastrop, Caldwell, and Gonzalez are shifted to SD-25.

SD-20 and SD-27 together have about the right population.  If Nueces were swapped for the eastern part of Hidalgo county, the Hidalgo split could be eliminated.



In the Houston area, SD-7 in has a surplus of 200,000; while SD-6 has a deficit of 170,000 and SD-13 has a deficit of 80,000.  Since the latter two are minority majority districts, the population shift may have to come from SD-15, with traditionally black areas in northwest Houston and Denver Harbor being moved into SD-13, and areas in east Harris county, Baytown, etc. being moved into SD-6.

It is likely that the fishhook of SD-17 will be eliminated.  The remainder of Jefferson and Chambers counties could be moved to SD-4, with SD-15 taking in northeast Harris County to compensate.  SD-11 could take in the remainder of Galveston, and let SD-6 come southward.  SD-22 would then take more of west Houston from SD-7.  Harris barely has enough population for 5 senators, so pushing SD-4 out of the county makes sense, which would leave SD-11 and SD-17 both partially in the county.



In the DFW area, SD-12 has a surplus of 210,000, and SD-8 has a surplus of 130,000; while SD-16 has a deficit of 170,000 amd SD-24 has a deficit 60,000.  SD-2 and SD-30 have small surpluses, but they need to replenish SD-1 in east Texas, and SD-24 and SD-28 further west, so they will need some population from the more central districts.

Presumably SD-16 and SD-23 will move northward.  Dallas County is a bit short of the population needed for 3 senate districts, so having SD-13 and SD-23 in Dallas County, and parts of SD-8 and SD-2 in the county would make more sense.  Collin County is just short of the population needed for its own senate district, so it SD-8 could end up as the entire county.  SD-9 and SD-12 would not be changed much, while SD-30 would take a much larger share of Denton County.  In 2020, Wichita Falls could be shifted west, and then SD-30 will become a suburban district with Denton County as its core.



In central Texas SD-5 and SD-14 have shifts which are shown as westward shifts to help replenish the west Texas districts, but would result in a a split of Williamson and and additional split of Travis.  An alternative is to transfer Coryell from SD-22 to SD-24, and then have SD-14 swing further south into SD-5.

The excess of SD-14 can be moved into SD-25, which could give up Kendall County to SD-24, with other portions going to SD-19, which would transfer Bandera, Real, Edwards, and Sutton to SD-24.

With the realignment of the western tail of SD-19 to SD-21 (see above), SD-5 would become definitively a San Antonio-Austin district, while SD-19 would become a San Antonio and southern suburban counties district.

The current five border districts are short about 150,000 short.  So instead of continuing to move them northward, reducing them to 4 districts which are likely to elect someone from a border community makes more sense.