Amherst Population Forecasts and Land Usage

Between 1960 and 1980 the town of Amherst, NH underwent tremendous population growth.  The US Census listed the town population at 2061 in the 1960 census and at 8243 in the one taken in 1980.  That is, in twenty years time the town’s population doubled twice.  This was a time when Amherst was transitioning from farms to the bedroom community as we know it today.  Some questions we might want to consider are what might the town’s population look like in the future and where will whatever growth we have take place in town.  The answers to these questions have a lot of impact on town planning needs, and frankly, these sorts of questions interest me in general.

In 1998 the town put together a master plan that, among other things, created a projection of the town’s population out to 2020.  As you can see from the graph below, the blue master plan projection numbers assumed that the growth rate of the last twenty years would continue into the next twenty years.   And maybe even increase a bit.  The forecast being created in 1998, the 2000 number matches well with the 2000 US Census, but overpredicts the 2010 numbers by about 1000.  Given the amount of developable land remaining in town and the zoning laws we have (e.g., 2 acre minimum lot sizes for new developments), the rest of the forecast looks suspiciously high.

Historic Amherst, NH population (red) and 1998 Master Plan projection (blue).

Historic Amherst, NH population (red) and 1998 Master Plan projection (blue).

In 2013 the State of New Hampshire’s Office of Energy and Planning put together municipal population forecasts for New Hampshire towns out to 2040.  Their projections are considerably more cautious than the ones the town created 15 years earlier, and suggest that we will slowly reach a peak population of about 12,000 people in about the next two decades.  In other words, population growth in Amherst is expected to continue, but not at rates even close to what the 1998 predictions suggested.

Historic Amherst, NH population (red) and 2013 state projection (yellow).

Historic Amherst, NH population (red) and 2013 state projection (yellow).

This seems to be reasonable.  Thanks to the fine folks at the Nashua Regional Planning Commission, we can take a look at the land usage in Amherst to get a feel for how much and where land is available in town for future growth.  In the plot below I have colored the various land usages in Amherst to correspond with how they are used.  So there are conservation land, lots currently used for housing, town property (schools, town offices, cemeteries, recreation land, etc.), commercial or industrial land, and wetlands and floodplains.  The uncolored lots are (or should be) available for development, although I can’t comment on how feasible they are.  It is an interesting map, and worth a close up look.  Perhaps 12,000 or so is the most people we can actually have in town.

Amherst, NH parcel map.  Colored lots are either developed, conservation land, town property, commercial/industrial, or floodplain/wetland.  Data courtesy of Nashua Regional Planning Commission.

Amherst, NH parcel map. Colored lots are either developed, conservation land, town property, commercial/industrial, or floodplain/wetland. Data courtesy of Nashua Regional Planning Commission.

The map above should be understood as a guide, as I can’t validate when the NRPC updates their parcel usage data.  But clearly the unused land that is available for potential development is in the minority of land in town, and that will be the limiting factor to the town’s future population.

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Historic Population and Growth of Amherst and Neighboring Towns

The town of Amherst, NH has had much growth in the past few decades.  Some insight into that growth can be found by digging through town records as published in our annual Town Reports (available in the Reference Room in the town library).  Page 80 of the town report for the year 2000 provides data on the town’s annual population, as taken by Selectmen’s census, since 1960 and is shown here.  I find it interesting that we had only 2000 people in town in 1960.  These are very informative data, but are somewhat limited in value because in their short time scale.

Amherst, NH population as recorded in annual town reports.

Amherst, NH population as recorded in annual town reports.

The US Census records the decennial population, something they’ve been doing since 1790, which is plotted below for Amherst from 1910 until the most recent one in 2010.  Take note that the US Census data and the Selectmen’s Census from above do not generally agree in their absolute numbers, though they do follow the same trends during the years they overlap.  These US Census data, while they does not contain the fine level of detail that the Selectmen’s Census does, paint a much broader picture of the history and growth of the town and are useful for that analysis.

US Census data for the town of Amherst, NH.

US Census data for the town of Amherst, NH.

From is information, we can consider how and when our population has changed significantly.  For this, we will examine the percentage of change of the population of town from the previous decennial census (graph appears below).  These values paint a remarkable picture of the town’s growth.  The 1960 and 1970 decades (1970 and 1980 census values) show enormous growth in the town.  Between 1960 and 1970, the town’s population more than doubled (from 2061 to 4605).  And from 1970 to 1980 it almost doubled again (4605 to 8243).  After 1980, the growth rate plummeted and has remained relatively low.

The percentage change in the population of Amherst, NH from its previous decennial US Census.

The percentage change in the population of Amherst, NH from its previous decennial US Census.

To understand if this trend was broad or simply localized to Amherst, we can look at the same historic data for nearby towns.  The US Census populations of Bedford and Hollis are plotted together below with the Amherst data from above.  Note the large similar large population growths at approximately the same times.

US Census data for the towns of Amherst, Bedford, and Hollis, NH.

US Census data for the towns of Amherst, Bedford, and Hollis, NH.

We can also calculate the percent change for Bedford and Hollis and plot those data with our Amherst data from above.  The absolute values vary somewhat, but the data for the three towns all have in common several decades of large growth which peaked around the 1970 time period.

The percentage change in the population of Amherst, Bedford, and Hollis NH from their respective previous decennial US Census.

The percentage change in the population of Amherst, Bedford, and Hollis NH from their respective previous decennial US Census.

From these combined charts, we can conclude that the rapid population growth in the 1960s and 1970s was not localized to just Amherst.  Amherst and its neighboring towns experienced a population boom in the decades following the “baby boom” (1946-1964).