Population Change

The Darby Watershed lies mostly outside of Columbus, Ohio, and within the fastest growing region in Ohio. Between 1990 and 2000 Central Ohio grew by 15 percent as compared to 9 and 3 percent for regions around Cincinnati and Cleveland. Over the next 30 years, Central Ohio is expected to grow by 36 percent to over 2.15 million people (MORPC, 2004). Land consumption rates have increased considerably and are expected to continue for the next 30 years as household size decreases and lot size and population increase. For example the City of Columbus’ population grew by 68 percent between 1950 and 2000, yet its land area increased by 390 percent. Currently, there is 0.42 acres of land for every person but that number is expected to increase to 0.69 acres by 2030 if current development trends continue. Sprawling subdivisions and increased land consumption is expensive to serve and maintain.

Many of these new residents will seek housing in suburban communities outside of Franklin County in Union, Madison , or Pickaway Counties. Statistics show that vehicle miles of travel increased by 31 percent between 1990 and 2000 whereas the population only increased by 15 percent. In the next 30 years the population is expected to increase by 36 percent, car trips by 44 percent, miles driven by 47 percent, and the hours driven by 66 percent. In western Licking County , just east of Columbus , the development pressures from the Columbus metropolitan area are placing a strain on their roads and emergency services. The city of Pataskala alone grew by 42 percent since 2000. The western portions of Licking County are expecting another 7,500 new homes in 2005. Most of statistics above were from a report completed by The Mid Ohio Regional Planning Commission and AIC Planning in August of 2004 for the seven county region of Central Ohio which included Madison, Union, and Pickaway Counties .

In addition to a more regional approach to population growth and land use change, Dr. Steven Gordon with the City and Regional Planning Department at the Ohio State University completed an analysis of stream health in the Darby Watershed based on population change in 2001. This report estimated the future population growth between 2000 and 2020 as seen in Figure 22.

Figure 22: Percent Future Population Growth
Years	Percent Growth
2000 - 2010	42.51%
2010 - 2020	48.67%
2000 - 2020	111.87%

Source: Gordon, Steve, et. al., 2001. Development and Change in Big Darby Watershed (pdf). Department of City and Regional Planning, OSU. pg. 47.

The areas that were predicted to experience the greatest population growth increases (80% and above) according to this study are the Franklin County portions of the watershed and Allen Township in Union County .

At the time of this report, the current water quality status of the western side of Big Darby in Union and Madison County were both performing at the highest level of water quality, but through projections of growth the quality of the stream is expected to decrease dramatically similarly to what has occurred in the Hellbranch watershed (See Figure 23). Gordon finds a strong correlation between the increase in impervious surface (and population) and lower water quality scores (See Figure 18). Gordon suggests that smart growth techniques can reduce the effects, but not eliminate them (Gordon et. al., 2001. Creating a Screening Tool for Identification of the Ecological Risks of Human Activity on Watershed Quality (pdf). City and Regional Planning, OSU. pg. 36-39)

Figure 23: Unregulated Growth Scenario for Portions of Big Darby Creek Watershed

Source: Gordon et. al., 2001. Creating a Screening Tool for Identification of the Ecological Risks of Human Activity on Watershed Quality (pdf). City and Regional Planning, OSU. pg. 38

Since the Gordon studies of population change in the Darby Watershed, additional data has been released from the U.S. Census Bureau that has allowed for a more detailed analysis of population change in the watershed. Map 12 and Figure 24 illustrate population change between 1990 and 2000 based on census blocks applied to the following municipalities. The numbers below indicate population values for only the Darby Watershed portions of the municipalities listed.

Figure 24: Population Change for Municipalities
		% Change				% Change
Municipality	1990	2000		Municipality	1990	2000
Union County	8,222	10,918	33.8	Logan County	749	1,014	35.3
Allen Twp	887	1,430	61.3	Monroe Twp	14	13	-6.6
Darby Twp	1,180	1,481	25.6	Perry Twp	41	47	14.4
Jerome Twp	1,355	1,800	32.9	Zane Twp	694	953	37.4
Liberty Twp	75	123	64.3
Mill Creek Twp	38	55	44.4
Paris Twp	468	272	-42	Madison County	12,882	13,286	3.13
Union Twp	1,007	939	-6.8	Canaan Twp	2,304	2,486	7.9
City of Marysville	46	999	2,070	Darby Twp	875	839	-4.2
Milford Center Village	651	626	-3.8	Deer Creek Twp	135	81	-40
Unionville Center	238	309	29.8	Fairfield Twp	584	534	-8.6
Plain City	976	895	-8.3	Jefferson Twp	2,419	2,362	-2.4
				Monroe Twp	1,467	1,825	24.4
Franklin County	17,846	30,396	70.3	Pike Twp	506	531	4.9
Brown Twp	1,808	1,949	7.8	Somerford Twp	87	70	-19
Norwich Twp	1,201	943	-21.5	W. Jefferson Village	4505	4558	1.2
Pleasant Twp	5,813	6,048	4.0	Plain City Village	1302	1937	48.8
Prairie Twp	3,145	2,747	-12.7
City of Hilliard	436	1,371	214.7