Pottawattamie County Population Projections:

Transcription

1 University of Nebraska at Omaha Publications Archives, Center for Public Affairs Research Pottawattamie County Population Projections: John P. Zipay University of Nebraska at Omaha Follow this and additional works at: Part of the Demography, Population, and Ecology Commons, and the Public Affairs Commons Recommended Citation Zipay, John P., "Pottawattamie County Population Projections: " (1974). Publications Archives, This Report is brought to you for free and open access by the Center for Public Affairs Research at It has been accepted for inclusion in Publications Archives, by an authorized administrator of For more information, please contact

2 POTTAWATTAMIE COUNTY POPULATION PROJECTIONS John P. Zipay Center for Applied Urban Research College of Public Affairs and Community Service University of Nebraska at Omaha May 1974 Prepared for the Omaha-Council Bluffs Metropolitan Area Planning Agency

3 FOREWORD The population estimates and projections to the year 2020 for Pottawattamie County are based upon specific assumptions regarding fertility, mortality, and migration patterns. These projections cannot be interpreted as statements of what necessarily will happen to population, they simply show what will happen if the assumptions upon which the projections are made prove to be correct. It is the res pons i bi 1 i ty of the user of this report to evaluate the reasonableness of the assumptions underlying the projections and to modify such projections if given different sets of assumptions. Ralph H. Todd, Director Center for Applied Urban Research University of Nebraska at Omaha

4 POTTAWATTAMIE COUNTY POPULATION PROJECTIONS: Introduction In late 1972, the Nebraska State Office of Planning and Programming entered into contract with the University of Nebraska at Lincoln's Bureau of Business Research and the University of Nebraska at Omaha's Center for Applied Urban Research to produce a prototype system for state and local population projections. In September 1973, an initial report was produced entitled Nebraska Population Projections. 1 In this report, Nebraska population was projected by 93 counties, 26 planning regions, and 539 places in varying degrees of detail. 2 The data in this product are consistent with the boundaries of the State of Nebraska and do not include adjacent metropolitan counties. Iowa's Pottawattamie County, however, is an integral part of both the Omaha Standard Metropolitan Statistical Area (SMSA) and the Omaha-Council Bluffs Metropolitan Area Planning Agency (MAPA) planning region. To obtain 1 vernon Renshaw, John Zipay, and Duane Hackmann. Nebraska Population Projections: State, County, Regi on, and Town: Lincoln: Bureau of Business Research and Center for Applied Urban Research, September The data published in the Nebraska Population Projections represent only a small portion of the total data generated. For example, medium series county data are by six age categories for seven projection years. Unpublished data available on request from the Nebraska State Office of Planning and Programming, however, contain 16 age groups for all ten projection years. Moreover, while the same detailed data are available for the high and low series, they are published in further abridged form. The tables in this report will be in the same general format as in the Nebraska Population Projections and those available in unpublished form from the State Office.

5 a complete and consistent metropolitan area base, it was necessary to project this county's population within the guidelines established by the State of Nebraska. Because of its involvement with the metropolitan portion of the Nebraska projections, the Center for Applied Urban Research was asked to provide Pottawattamie County data. Population Trends _ib_ Pottawattamie County Of the three counties in the Omaha SMSA, Pottawattamie County has been growing slower than its Nebraska counterparts for the past several decades. Part of this has been indirectly the result of western and southern growth of the Omaha "physical city" at the expense of the Iowa portion, but more directly by the agricultural population losses of rural Pottawattamie County. Although the population grew from 69,682 to 83,102 between 1950 and 1960, the decade of the '60s witnessed an increase to only 86,991. While this increase numbers approximately 4,000 persons, one should note that this same decade experienced a net natural increase (an excess of births to deaths) of over 10,000 persons. From these data one must conclude that there was a net out-migration of 6,000 persons during the decade. Because of the propensity of younger, better educated and more affluent persons to move, the hardest-hit sector of the population is that segment which generates growth, i.e. persons of child-producing age. At a time when the nation has a greater proportion of its population as females of childbearing age than in recent years (a result of the post-world War II "baby boom" one generation removed), Pottawattamie County is at its lowest point. This, coupled with the already low fertility and existing migration rates, implies a slowing of Pottawattamie County's growth in the future. Much of the background for the projections presented in this report may be found in a recent publication entitled The Council Bluffs Area: Past, 2

6 Present and Future. 3 Although this 26-page report does not provide data beyond 1970, there is much discussion of the implications for the future which are supported by the projection data presented herein. Nebraska Projection Methodology The work effort for the State of Nebraska initially involved projection of the state population to the year 2020 by means of the cohort-survival technique based on three different assumptions. These projections resulted in high, medium and low totals based on the following fertility and migration conditions: HIGH PROJECTION * Series 'D' births (completed fertility rate of 2.5 children per woman by the year 2020) * Net in-migration of one percent per five-year period MEDIUM PROJECTION * Series 'E' births (completed fertility rate of 2.1 children per woman by the year 2020) * No net migration LOW PROJECTION * Series 'F' births (completed fertility rate of 1.8 children per woman by the year 2020) * Net out-migration beginning at one percent per period in and declining by 0.1 percentage points per period to the year 2020 This research yielded three complete age and sex structures of the Nebraska population which were used as control totals to which all county 3 Arthur H. Johnson and John L. Tait. The Council Bluffs Area: Past, Present and Future: Population Trends with SocTal and Economic Character:.- istics. Ames: Iowa State University, Cooperative Extension Service, Report No. CRD 93, September

7 data were "fitted". This allocation to the county level involved a ratio "age-phasing" technique strongly related to the present age structure of the individual county population. The town populations were calculated from the resulting county population based on historical population patterns and future economic and locational conditions. Pottawattamie County Methodology Projections of Pottawattamie County population were undertaken with the primary purpose of being as compatible to the Nebraska projection experience as possible. While some of the assumptions and techniques remain the same, there are differences in methodology. First, the development of a state control total and the downward allocation by a ratio technique is not applicable to Pottawattamie County. And secondly, the migration patterns of Pottawattamie County are far from the assumptions made for the State of Nebraska. Instead, the following assumptions built into the cohort-survival technique were used to project Pottawattamie County population. HIGH PROJECTION * Series 'D' births (completed fertility rate of 2.5 children per woman by 2020) * age-specific migration rates through 1985 (slight in-migration) * No net migration from 1985 to 2020 MEDIUM PROJECTION * Series 'E' births (completed fertility rate of 2.1 children per woman by 2020) * age-specific migration rates through 1985 (slight out-migration) * No net migration from 1985 to

8 LOW PROJECTION Features of the Projections * Series 'F' births (completed fertility rate of 1.8 children per woman by 2020) * age-specific migration rates through 1985 (moderate out-migration) * No net migration from 1985 to 2020 The five sections to follow present data on Pottawattamie County and the towns in a format similar to the Nebraska report. Age and sex data for the County and the City of Council Bluffs are also presented in their entirely. In addition, population estimates are given for all county incorporated places as of January 1, The projection data presented in this report are meant to provide a guideline, in realistic terms, to expectations of growth in Pottawattamie County. 4 These expectations hold true only within the parameters of the assumptions presented. Some may argue that the renovation of downtown Council Bluffs, the increasing highway transport linkages, and the anticipated economic merits of the Riverfront Development Program assure a healthy population future for the county. Still others point to the lowest fertility on record, an older and emigrating population, community stigma, and an undesirable housing situation as discouraging growth. It appears that Pottawattamie County growth, however great, will be ordered a long the fo 11 owing priorities: 4 Forecasts of a very rapidly growing population in the county appear inconsistent with past and present trends. Even the Series 'D' fertility expectations commonly used by planners seem far out-of-place today. See especially: H.C. Chang. Population Projections~ Age and Sex for State and Counties of Iowa: Ames: Iowa State University, Agriculture and Home Economics Experiment Station and the Cooperative Extension Service, June In the four most conservative projection series presented (numbers 4, 5, 8 and 9), the 1990 Pottawattamie forecasts range between 125,000 and 132,000 persons. 5

9 a) Proximity to the metropolitan base population and its attendant services and employment opportunities will remain a major stimulant to growth. Only Carter Lake and Council Bluffs have the potential to capitalize on these conditions. b) Despite the fact that the metropolitan area expansion is slowing down in Sarpy County and western Douglas County, it appears that the Nebraska side will still hold a priority for future settlement. c) Future Pottawattamie growth may be inhibited by a lack of a "metropolitan approach" to county and municipal governance. d) Accessibility will be greatly increased through interstate highway linkages in the '70s, but it appears unlikely that major population growth will result. Some suburban and rural growth may be created in the bluffs terrain of the Crescent Council Bluffs axis, but this will likely be limited in scale and low density housing. e) Growth in the small towns of Pottawattamie County will be influenced by their size in the hierarchy of places and their relationship to the Omaha-Council Bluffs core. Many of the small towns in the rural portions of the county do not offer a political, economic and public utilities structure necessary for attracting population. 6

10 SECTION A 1974 POPULATION ESTIMATES Of all political jurisdictions in Pottawattamie County, only Council Bluffs (through its planning department) has the capacity to provide current population estimates. At the time of this writing, Carter Lake is organizing for a 1974 population enumeration conducted by a team of residents. All other places lack the population updating mechanism. In addition to field research in each town, local community resource persons (i.e. bank manager, postmaster, city clerk) were contacted and asked to respond to questions regarding the town at present and their expectations for the future. An average of three persons were interviewed per community. 7

11 1970 CENSUS ANO JANUARY 1, 1974 POPULATION ESTIMATES COUNTY AND TOWN POTTAWATTAMIE COUNTY STATE 19 COUNTY COUNTY POPULATION 86,991 88,035 AVOCA 1,535 h603 CARSON CARTER LAKE 3,268 3,387 COUNCIL BLUFFS 60, ,750 CRESCENT ,_1 _a;qrof"'!r~, l lmtt"'..._,~, MACEDONIA MCCLELLAND MINDEN NEOLA OAKLANO 1,603 1,647 SHELBY t PART J 6 31 TREYNOR UNDERWOOD WALNUT TOTAL CF TOWNS 71,671 74,548 TOT AL OF NON-TOWNS 15,320 13,487 8

12 SECTION B TOWN PROJECTIONS Town populations were projected on the proportion of the expected town population to the county total. As with the Nebraska projections, the relationship of land availability and annexation to rate of growth was an important factor in assessing future town populations. 9

13 l910 CENSUS AND HIGH, MEDIUM, AND LC\'i lol,n PROJECTIONS COUNTY ANO TOWN SERIES ~ POTTAWATTAMIE COUNTY STATE 19 COUNTY COUf\TY POPULATION H 902' M L 850H, AVOCA H , L CARSON H M L CARTER LAKE H M t, L 3391l COUNCIL BLUFFS H M L CRESCENT H M l O,. 1 V~L ,,.... OJ. I 36C... ~ ~ "'T I U HANCOCK H M L MACEDONIA H M 330 3H: l MCCLELLAND tt r, M l't L M[NDEN H I~ ft l L NEOLA H M L OAKLAND H M L

14 CENSUS AND HIGH, MEDIUM, AND LCW TOWN PRCJECTIONS COUNTY AND TOWN SERIES l 'i POTTAWATTAMIE COUNTY ---~ ~----~-I CONTINUED)--~----~-----~~--- SHELBY (PART) H M l TREYNOR H M l soc UNDERWOOD H ~on M V L WALNUT H M l TOTAL OF TOWNS H M '} l 7485<; TOlAL OF NCN-lOWNS H M l 't

15 SECTION C ABRIDGED COUNTY PROJECTIONS This section presents age and sex data for selected years by series for Pottawattamie County. With the exception of the under 18 category, these data are simplified from the complete age structure projections presented in Section D. 12

16 2020 HIGH ' ' ' 2 LOI, {) ~~36 P.7"\hQ l970 CENSUS M,O CCUNTY PROJECTICNS!ABRIDGED) =---- POTTAWATTAMIE COUNTY MED I lm SERIES STATE 19 COUNTY ~ ~ YEAR TOTAL 1970 FE~ALE MALE !Jt ~,2032 TOTAL i FEMALE MALE TOTAL <; FEMALE MALE TOTAL FEl'ALE MALE ' TOTAL FEMALE 419 l ' MALE TOTAL FEMALE lf MALE TOTAL 819 a fejl.(jlle ti,n"'r o~;., L~.:JLU f... ~ti ALE :Jo-to ( TOTAL "-, ~.,.., FEMALE MALE TOTAL HIGH AND LOW SERIES ~-- VEAR SERIES TOTAL 1975 HIGH LOW HIGH LOW HIGH LOW l990 HIGH LOW HIGH ' LOW HIGH lo!i ' LOW

17 SECTION D COUNTY PROJECTIONS This section presents high, medium and low projections for all ages by five-year periods to the year The standard cohort-survival technique was used with the following inputs: a) fertility assumptions and survival rates: Current Population Reports Series P-25, No Projections of the Population of the United States, by Age and Sex: 1972 to December 1972 b) annual county birth and death data: Iowa Department of Vital Statistics data since 1950 c) base population data: U.S. Census of Population reports for 1950, 1960 and 1970 d) age-specific migration methodology: Current Population Reports Series P-23, No. 15. National Census Survival Rates, by Color and Sex, for 1950 to July 12, e) migration data: Current Population Reports Series P-25, No Estimates of Components of Population Change by Color, for States, April 2, 1962 and Current Population Reports Series P-~No Components of Population Change l?.,y_ County, 1960 to June 28,

18 1910 CENSUS ANO COUNTY PROJECTIONS ICOHPLETEJ YEAR TOTAL POTTAWATTAMIE COUNTY HIGH SERIES STATE 19 COUNTY FEMALE 374 l MALE TOT~L FEM~LE MALE TOTAL FEMALE MALE ' TOTAL ~ FEM~LE MALE C l TOTAL } ' FEMALE MALE TOTAL U FEMAlE !i ; HALE % TOTAL FEMALE n MALE ,(J TOTAL FEMALE MALE TOTAL ' FEMALE MALE TOTAL ) B i FEMALE '96 5't MALE TOTAL FEMALE '!ALE 6H TOHL C

19 1970 CENSUS ANO COUNTY PRCJECTIONS I COMPLETE I YEAR TOTAL POTTAWATTAMIE COUNTY MEDIUM SERIES STATE 19 COUNTY FEMALE MALE TOTAL FEMALE MALE ' TOTAL n ,s FEMALE S % MALE TOTAL l985 FEMALE MALE TOTAL E FEMALE,, MALE l TOTAL FEMALE MALE TOTAL E55l FEMALE MALE 't ' TOTAL FEMALE MALE "/ TOTAL FEMALE MALE TOTAL ' Sl FEMALE MALE TOTAL FEMALE MALE ff'6 H TOTAL

20 1970 CENSUS AND c OUNTY PRCJECTIONS I COMPLETE I YEAR ' TOTAL POTTAWATTAMIE COUNTY LOW SERIES STATE 19 COUNTY FEMALE MALE TOTAL Sl ~ FEMALE 2H C MALE B TOTAL 5M FEMALE <t MALE TOTAL FEMALE <J MALE 3233 ZS TOTAL lt FEMALE MALE TOT Al FEMALE ! S MALE U TOTAL ! B" FEMALE n MALE TOT~L 't FEMALE MALE TOTAL , FEMiLE ;~ MALE l SSS TOTAL ; _ gz FEMALE COO S MALE TOTAL FEMALE MALE TOTAL

21 SECTION E CITY PROJECTIONS This section presents data for the City of Council Bluffs in a comparable format to Section D. In the projections it is assumed that the City will maintain the same age structure as the County beginning in The 1975 and 1980 data reflect the slight differences. in age structure between the City and County. 18

22 1970 CENSUS AND CITY PROJECTIONS ICOMPLETEl YEAR ~ TOTAL CITY OF COUNCIL BLUFFS HIGH SERIES STATE 19 COUNTY 155 PLACE FEMALE l7ll 17 llt lcfo MALE L TOTAL C FE~ALE MALE M TOTAL !i 33L FEMALE ?4 1n MALE TOUL t l FE~iLE l 7L ': MALE l TOTAL FEMALE 3730 n L a129 MALE ll l TOUL ~) FEMALE L 15't MALE L TOTAL E FEMALE MALE L TOTAL g7t., FEMALE ' MALE TOTAL l FEMAU: MALE E70 l TOTAL FEMALE MALE ZH L TOTAL '< ! 2020 FEMALE MALE TOTAL ;,

23 1970 CENSUS ANO CITY PROJECTIONS I COMPLETE J YEAR o-.r , ~ TOTAL CITY OF COUNCIL BLUFFS MEDIUM SERIES STATE 19 COUNTY 155 PLACE FEMALE 'i l MAlE TOHl ll C FEMALE ca, MALE 2't TOTAL FEMALE MALE TOTAl ~ < FEMALE MAtE ! TOTAL C FEMALE 2' lt MALE l't ',95 TOTAL 6lC f 24 H tl FEMALE MALE TOTAL 5H6 60H C FEMALE MALE g !0 TOTAL FEMALE S , MALE TOTAL H FE~ALE ) MALE ll TOTAL % FEMALE MALE ,,l lc TOTAL 't ' FEMALE MALE za,~s TOTAL lt

24 1970 CENSUS ANO CITY PROJECTIONS ICOMPLETEl YEAR ' TOTAL CITY OF COUNCIL BLUFFS LOW SER!ES STATE 19 COUNTY 155 Pl.ACE FEMALE MALE SH TOTAL FEMALE ' MALE TOTAL FEMALE MALE f TOTAL 4It FEMALE % MALE TOTAL FEMALE MALE TOTAL FEMALE MALE [651 lolal FEMALE C MALE TOTAL 419 l U FEMALE MALE TOTAL 'i FEMALE % !: ,;962 MALE l.O TOTAL ' l FEMALE " MALE ll TOTAL l ' ' FEMALE , MALE TOTAL