LAND COVER CHANGES ON THE LOWER ST. CROIX

BETWEEN 1984 AND 2010Josiah Emerson, Majory Silisyene,

Cynthia RatzlaffFR 3262 Section 1

Stillwater on the St. Croix

Introduction

The Lower St. Croix National Scenic Riverway is the last 52 miles of the St. Croix River.

Is jointly managed by the National Park Service (NPS) and the Department of Natural Resources (DNR) of the states of Minnesota and Wisconsin.

Much of the land on the river is under private ownership, and thus, are managed under scenic easements.

Background information

In 1972 the Lower St. Croix River was added to the National Wild and Scenic River System (NWSRS), and in 1975, the original boundary for the river was published.

Since its inclusion in the NWSR, it has been managed as a recreational and scenic river.

The increase in diverse recreational use and population near in and around the river caused a need for a new look at management planning.

Significance of the study

Development pressure due to high (18%) human population growth rate in Washington County.

Experience show that people feel the need to utilize their lands more profitably; therefore, possibly not abiding to agreements made in the scenic easements.

Consequently, possible removal of vegetation, or practice farming techniques that go against easement agreements.

Evaluate the effectiveness of the Wild & Scenic Rivers Act (WSRA) of 1969.

Need to determine land cover changes that could result in a detrimental impact to the river.

Study objectives

1. To analyze land cover in private lands within 500meters from the St. Croix River.

2. Determine land cover changes within our study area by comparing land cover in 1984 (nine years after a management plan was set) to land cover in 2010.

Hypothesis

HO: Land cover in privately owned lands has not changed over the past twenty-six years of implementation of the WSRA of 1969

HA: Land cover in privately owned lands has changed over the past twenty-six years of implementation of the WSRA of 1969

Methods and procedures

Materials and tools 1984 image (LT50260291984141XXX01) and

2010 image (LT50260292010148PAC01). Acquired from http://glovis.usgs.gov/

Shapefiles - Minnesota County Boundaries, ownership types (as of 2008 ) and St. Croix river. Acquired from http://deli.dnr.state.mn.us/

Softwares - ArcMap 10 and ERDAS Imagine 2011

Google map

Methods and procedures cont’

Identifying Study Area – Using ArcMap 10 Overlaid the Minnesota county boundary

shapefile with the St. Croix River shapefile and then extracted an area found near the river and within Washington County.

We made a buffer of 500meters on the St. Croix River section found in the Washington County.

Using the union tool, we overlaid the 500meters buffer with the land ownership shapefile

We further reduced our study area by clipping areas only found in Afton Township

1984

Clipped images before classification

2010

Methods and procedures cont’

Methods and procedures cont’Land cover change analysis Image preparation – image stacking and projection Extraction of study area - we used a shapefile of

our study area to extract a portion of the image from the two images

Classification – Supervised classification of individual images

- at least 7 sites were included in training sites- Identified classes - forest, agricultural land, grasses land, commercial, developed – rural, and beach area

Change detection (Thematic change) – Used a matrix union (not complete)

- Summary report of matrix tool was used to obtain the amount (in acres) and percentages of land that has changed in each class.

Results and discussion

Observed land cover changes include; From forests to rural development From grassy areas to rural development From forest to impervious (beach area)

Note: These results may be incorrect because of misinterpretation of some features due to inexperience,small study area, and poor resolution of images used.

Land Cover Pie Charts

1984 LAND COVER PERCENTAGE

2010 LAND COVER PERCENTAGE

Chart TitleAgriculture

7%

Developed-ru-ral

22%

Forest21%

Beach3%

Com-mercial

7%

Water40%

Chart TitleAgriculture

12%

Developed - rural10%

Forest29%

Grasses2%

Marina (dock)10%

Water37%

Chart Title

Shortcomings of our study

Some areas may be incorrectly classified due to low resolution images used

Inconclusive results on how much land cover types have changed to other land cover types

Conclusion and Recommendations

Conclusion: There is evidence in land cover change (for

example, from natural forests and grass to rural development

Recommendations Need to conduct a more rigorous study to

determine how much land has changed to other uses to avoid future pollutions in the river.

Need to re-evaluate the effectiveness of the Wild & Scenic Rivers Act (WSRA) of 1969

Thank you!

Questions!