Utilization of a GIS for an Environmentally Sensitive Land Use Plan, Zoning and
Subdivision Ordinance
Utilization of a GIS for an Environmentally Sensitive Land Use Plan, Zoning and
Subdivision Ordinance
ABSTRACT: The town of Rockville is located adjacent to the south-west corner
of the City of St. Cloud in Stearns County Minnesota. The Town has an existing
zoning ordinance enacted in 1970. Growth of single family residential dwellings
has been steady between 1970 and 1990. The period between 1990 and 1994 saw
growth exceed the 1980 - 1990 period. Fall of 1995 the Town approached St.
Cloud State University to assist in the development of a new structure and approach
to planning. (the BUZZ word for this is Sustainable Development) The resultant
planning process included an environmentally sensitive start with the geography of
exiting land use, soil productive, hydro-geologic atlas and other environmentally
imperative objective criteria, i.e., digital ortho quarter quads (DOQQ's) as well as
digital elevation models (DEM's) are used. The result will be a set of ordinances
that will guide the Town into the next century, all based upon model development
utilizing data analyzed with ArcView GIS.
INTRODUCTION
The Town of Rockville is an unincorporated township of 1,512 people adjacent to
the City of St. Cloud, in Stearns County Minnesota. The Town is approximately 75
miles north and west of the Twin Cities of Minneapolis and St. Paul. Located in
the north center of the Town is the City of Rockville through which runs State
Highway 23, the City of Pleasant Lake is found in the north west corner of the
Town. The Town has two large lakes in the central and south central portion. The
Town of Rockville zoning ordinance was adopted in 1970 and has served the Town
well over the years. Growth has been steady in the Town and little reason existed to
revisit the ordinance until recently, i.e., the past several years. Fall of 1995 the
Town began to question the magnitude of growth since 1990. The Planning
Commission and the Supervisors began to discuss an update of the existing
ordinance.
Initial meetings discussed options open to the Town and a decision was made to
establish a moratorium on new plats and subdivisions until such time as a new Land
Use Plan, Zoning Ordinance and Subdivision Regulation could be developed. The
moratorium was adopted, following a public hearing in June of 1996.
At the public hearing a draft of the process to adopt these new ordinances was
presented. Monthly progress reports at Planning Commission meetings and active
participation by Commission members led to a work plan that included the
development of extensive natural resource inventories in the Town. The following
coverages (maps) and images were produced or obtained in a Geographic
Information System (GIS) format so that they may be displayed for analysis in an
interactive manner by the Commission.
COVERAGE METADATA (a GIS term meaning data about the
coverage)
Roads TIGER (Topographic Indexed Geographic Encoded and
Referenced, a US Census base map), ability to determine
type of road as well as addresses along a road. Updated
with the MnDOT (Minnesota Department of
Transportation) Base Map.
Section
Lines TIGER
Lakes TIGER, includes lake names
Streams TIGER, includes names of streams as well as county
ditches
Soils Stearns County, includes soil classifications, a data base
tied to soil polygons, as well as point data for inclusions
and line and polygon data showing streams and ditches as
well as short steep slopes. The line and water polygons
within the soils coverage are more accurate than the
TIGER stream coverage, it does not however, have stream
and lake names.
National US Fish and Wildlife Service, includes, wetlands
Wetland classification.
Inventory
DOQQ USGS, Digital Orthophotography Quarter Quadrangle
(DOQQ, 1990/92), photographs with one meter
resolution, used for land use determination.
Land Use The Spatial Analysis Research Center at St. Cloud State
University (SARC at SCSU), interpretation of land use
from DOQQ. Classifications are those utilized by Soil
and Water Conservation Districts (SWCD) and Natural
Resources Conservation Service (NRCS), data where
field checked when necessary:
Forested -- a polygon in which the dominant land use
consists of trees. To be considered forested, the polygon
must contain a scattering of trees whose crowns cover at
least 10 percent of the land area.
Cultivated -- a polygon in which the dominant use is
land that has been recently tilled or harvested
mechanically.
Water -- a polygon in which the dominant land use is
open and permanent water.
Marsh (Wetland) -- A polygon in which the dominant
land use consists of non forested, shallow, permanently
wet, vegetated areas.
Urban Residential -- a polygon containing five or more
residential dwellings and commercial buildings.
Extractive -- a polygon in which the dominance land use
consists of the extraction of minerals, including ancillary
facilities. Examples are mines, tailing piles, and gravel
and quarry pits.
Pasture and Open -- a polygon on non forested land not
used for any identifiable purpose. Examples are grazing
land or abandoned farmland.
Urban Non-residential or Mixed Residential
Development -- a polygon containing at least one
commercial, industrial, or institutional facility (including
golf courses and cemeteries) and possible containing
residential development.
Transportation -- a polygon in which the dominant land
use consists of facilities for the conveyance of people or
materials.
Geologic Minnesota Geologic Survey and Minnesota Department Atlas of Natural Resources.
Cadastre Stearns County, Land ownership parcels
DRG Digital Raster Graphics (DRG), scanned 7.5 minute
United States Geologic Survey (USGS) topographic
sheets that has been projected to match the other
coverages. Consists of 12 colors plus black and white.
Farmsteads Stearns County, includes information on farmstead
ownership, animals utilized on the farmstead and feedlot
status. Additional farmsteads have been added consisting
of any cluster of buildings not currently be used for
farming, but may in the future. The latter do not include
the same data as that obtained from Stearns County.
These coverages provide data necessary to implement zoning based upon the natural
landscape, the environment, for decision making.
ISSUES
1. Agriculture preservation is best summarized by non farm operators as
an open space issue. Open space can be best preserved if the land has
a use that produces income from the investment in land. Absent that
income, the drive for housing development may be unavoidable.
2. Existing non-farm development around Grand Lake and from the City
of Rockville south toward Grand Lake may be unstoppable.
3. New feedlot regulations (County based and currently under
development) may directly impact towns like Rockville that have much
non farm development pressure.
4. Growth of non-farm housing has dramatically increased. This increase
has been recent, i.e., last five years.
OPPORTUNITIES
1. Existing sites identified by others should be further investigated by the
Town for protection in their zoning ordinance. These include but need
not be limited to: Century Farms; Historic and Archaeologic Sites and
Natural and Biologic Survey items.
2. Existing growth trends should be explored and modified according to
newly develop town priorities.
3. The Minnesota Department of Transportation's desire to expand
Highway 23 from two to four lanes should be addressed by the Town.
Recommendations for alignment should follow the town's agricultural
preservation/open space priorities.
4. The desire by the City of Pleasant Lake to provide municipal services
should be supported and incorporated into the Town's new ordinance
structure.
KEY DIRECTIVES AND GUIDING PRINCIPLES
Agriculture and open space are to be preserved.
A home and any kind of service building shall constitute a farmstead. This
further includes non active farm buildings and/or buildings capable of being
converted to agricultural use.
Cluster development shall be the basis for the subdivision ordinance.
A substantial buffer shall be maintained between clustered development and
adjacent agricultural land and open space.
The buffer shall be maintained in perpetuity. How this is maintained shall
become a part of the subdivision ordinance.
The existing ten acre minimum lot size for residential development shall be
continued, albeit within the cluster development subdivision ordinance.
Existing 10 acre lots of record can be further developed with additional
houses under the new ordinance, albeit clustered as a PUD.
PLANNING FRAMEWORK
GROWTH CHARACTERISTICS
The St Cloud Metropolitan Statistical Area (SMSA) is one of the fastest growing
areas in the State of Minnesota. This growth has two centers, the City of St. Cloud
and those areas of Stearns and Sherburne counties along US Highway 10 and
Interstate Highway 94, two major corridors between St. Cloud and the Twin Cities
of Minneapolis and St. Paul and their adjacent suburbs. The Town of Rockville is
necessarily affected by this growth.
A series of thematic maps showing both growth in population as well as percentage
change in population were prepared for the period 1960 to 1994, the most recent
year that population projections are available. Two charts were prepared from these
data, "Population of Rockville Township 1960 - 1994" and "Population Percentage
Change 1960 - 1994". These figures were provided by the State Demographers
Office, Minnesota State Planning Agency and ultimately the US Census. The
summary maps reveal that Rockville is surrounded on the east, north and west by
towns with larger population percentage change between 1960 and 1990.
Furthermore, the two charts show the same population percentage change that
occurred between 1980 and 1990 also occurred between 1990 and 1994, a growth
rate in the four years of the 1990's that equaled the total growth rate of the previous
ten years.
Records from Stearns County Environmental Services Office as well as the Town
of Rockville were checked to further document the growth of the Town. While
differing in specific numbers, they show a similar pattern of increasing growth over
the past sixteen years. The Town records include instances where a seasonal
structure became a permanent structure, mainly around the large lakes found in the
Town. According to these records, the annual average between 1979-1989 was 12
residential building permits. The average increased to 32 for the period 1990-1995,
a more than 200 percent increase. This latter increase stimulated the Town to
revisit their policies dealing with planning, subdivision and general growth.
ANALYSIS AND MODELING
This is a work in progress, the town has, at the time of this writing asked for a bi-directional approach: one based purely on growth management with a numerical, no
more than, approach to residential development; and, one based upon a PUD
environmental imperative model. The latter has the option of being both growth
management and PUD (Planned Unit Development) environmentally imperative.
GROWTH MANAGEMENT MODEL
The Town wishes to grow at a rate no greater than that of the surrounding County.
Specific population projections are not calculated for towns and cities, they are
calculated only for counties. Note that according to the 1994 population estimate,
Stearns county has exceeded the year 2000 population projection. This affirms the
growth pressures external to the Town of Rockville.
Between the 1990 Census of Population and the 1994 estimate Stearns County grew
by 6,380 persons, a 5.4% increase over four years. At the same time the Town of
Rockville grew by 132 persons, a 9.6% increase over the same four years. The
Town grew at a rate that exceeded the growth of the County.
Stearns County annual growth 1994 - 1990 = 1,595 (6,380 / 4 = 1,595 persons per
year)
Town of Rockville annual growth 1994 - 1990 = 132 (132 / 4 = 33 persons per
year)
The extrapolated Stearns County Population by year adding the annual growth
between 1990 and 1994, 1,595 people. (1994 + 1,595 = 1995)
1995 125.177 + 1.595 = 126,766
and so on for each year:
1996 128,361
1997 129,956
1998 131,551
1999 133,146
2000 134,741
2001 136,346
2002 137,931
(Note: this is much larger than the projected 2015 County population of 130,870.)
In 1990 the most accurate current complete census year, the Town of Rockville
represented 1.16% of the population of Stearns County. Since the desire of the
Town is to not grow faster than the growth of the County, 1.16% of 137,931 should
be the year 2002 goal for the town in total population, a total of 1,599 persons by
the year 2000. The 1994 Town estimate is 1,512, we do not know the 1997 Town
population, growth has occurred in 1995 and 1996 prior to the moratorium on new
plats, if we ignore that growth, a conservative estimate indicates that an additional
87 persons over the next five years would be sufficient to match the projected
County population growth. One can convert this into households by dividing 87 by
3.2 persons per household to get a total of 27 homes over five years or 5 + homes
per year. This does not differentiate between farm homes or single family non-farm
homes. A pure growth management ordinance allowing for no more than 5 houses
per year could be justified. Compare this to the 32 building permits issued annually
for the period 1990 - 1994!
PUD MODEL
NET RESIDENTIAL DEVELOPABLE LAND
=
Soil Utility + Slope Utility + Land Use Utility
4 best soils no short no current agriculture land;
out of steep slopes wetlands; flood plains; granite 7 classes out crops
soils capable lake and
of supporting stream set backs.
on-site disposal
systems rated open space and woodlands
The model shown above may be used to determine buildability utilizing a PUD GIS
raster model. The model is implemented when a developer proposes a parcel to the
Planning Commission. Interactively with the developer, the land in question is
processed through the model to determine the number of homes that may ultimately
be constructed as well as recommended placement. Since this is an interactive PUD
process, much give and take between the Planning Commission, Town Board,
public and developer is expected. All parties are expected to review the model, the
various phases of the model as well as options for further analysis. This is intended
to be an iterative process between the parties.
CONCLUSION
This is a work in progress. It is dependent on both availability of software,
ArcView GIS, as well as hardware. It is further dependent on local elected officials
who have the vision to accept a fundamental change in the way in which they both
perceive their environment and react to those perceptions in the abstract. The use of
interactive GIS modeling can replace the flickering light show of slick planning
consultant scenarios only when the decision makers have faith in the ability of the
models to replicate known conditions. The planning industry has finally reached
the stage where abstract models can begin to present various future scenarios in a
realistic manner.
Prof. Robert O. Bixby, Ph.D., AICP
Director, Spatial Analysis Research Center
St. Cloud State University
720 South Fourth Avenue, SH 317
St. Cloud, Minnesota, 56301-4498
Telephone: (320) 255-3160
Fax: (320) 654-5198
bixby@stcloud.msus.edu