Is annexation helping or hurting Peoria?

From the January 26, 1979, issue of Illinois Issues:
In the mid-1960s the city of Peoria proposed to annex Richwoods Township, which consisted of roughly 10 square miles of and, much of it already developed. Opposition was bitter and was fueled by fears of school integration that might result if and when the Peoria school district expanded to encompass the new territory. The vote by township residents on the annexation referendum was close, but the referendum was approved.
 
The annexation nearly doubled the size of Peoria, providing room for future expansion. During the four-year period, 1970-73, when Springfield approved 237 annexations, Peoria approved only four, amounting to only a tenth of a square mile. Most of Peoria’s development occurred within its newly enlarged boundaries. The population of “old” Peoria slipped from 106,000 in 1960 to less than 100,000 in 1970, but the addition of Richwoods added some 25,000 new residents to its population. Present city officials believe that the tax revenues collected from the Richwoods section have been vital to the city in maintaining its services in the older parts of Peoria.
 
The annexation has not been without cost to the city. Because Richwoods, like so many fringe areas around Illinois cities, had been developed according to the relatively lax zoning, construction and planning standards of county government, resulting deficiencies became Peoria’s responsibility to remedy. Fortunately, a preannexation agreement with Peoria County spared the city from having to remedy all the problems at once. As Peoria’s Mayor Richard E. Carver complained recently: “Our city is, even today, spending millions of dollars developing the basic road network which would normally have been constructed as the area developed had there been an adequate degree of planning and control present at that time.”
 
Peoria suffers as well from the presence of an unincorporated urbanized enclave situated well inside its boundaries. But because it is larger than 60 acres, may not be annexed unilaterally by the city even though, in the mayor’s words, it is “receiving indirectly many of our services, yet [is] contributing nothing to the revenues of our city.”
 
The need to control the urbanization of land (especially unincorporated land) within and immediately outside their borders is a common topic of conversation among mayors across the country. Peoria’s Carver, who is an officer of the U.S. Conference of Mayors and a director of the National League of Cities, shares their concerns. “A direct correlation can, in fact, be drawn between the health of American cities,” he wrote recently, “and their ability to move their boundaries in conjunction with urban expansion.”
It’s been over 25 years since that article was written, and around 40 years since Richwoods township was annexed.  Today (as of the 2000 census), Peoria covers 44.4 square miles with a population of 112,936, or 2,543 people per square mile.  Between 1990 and 2000, population dropped 0.5% while land mass grew by 8.6%.  Thus, population density dropped 8.4% (source:  Demographia).  And almost every city council meeting there is a request to annex yet more land.
 
They say hindsight is 20/20, so let’s look back.  Has all this annexation helped or hurt Peoria?  Have the tax revenues in annexed areas helped to maintain services in older parts of Peoria, or have they siphoned services away from older neighborhoods?  Has the drop in population density made the cost of servicing such a large area unsustainable?  Was the population shift from the older parts of town to the north end really inevitable, or was it accelerated by annexation?