BIG CREEK LAKE. By; James Madden April 30, 2012

Transcription

1 BIG CREEK LAKE By; James Madden April 30, 2012

2 Introduction 3 Agenda 4 Objectives 5 Land Use Classification 6 Supervised Classification 7-9 Iso-Cluster Unsupervised Classification Interactive Supervised Classification 12 Manual Classification 13 Bathymetry of Big Creek Lake Turbidity of Big Creek Lake Big Creek Lake Watershed Project Buffer Strip Department of Natural Resources Park Planning 27 Management 28 Conclusion 29 Questions 30 Photo URL s 31 Works Cited 32 TABLE OF CONTENTS

3 Located 11 miles north of Des Moines Built by the US Army Corps of Engineers in the 1970 s Under the authority of the Iowa DNR 883 acres in area Over 2 million visitors/year Offers camping, swimming, boating, fishing, hiking Diverse fish habitat (Walleye, Bluegill, Channel Catfish, Crappie, Largemouth Bass, Smallmouth Bass, Muskie) INTRODUCTION

4 In recent years, the water quality at Big Creek Lake has shown signs of major degradation. Ben Dodd, Fisheries Biologist, Iowa DNR Objectives Procedures/Test Conclusion Questions AGENDA

5 Why is GIS important to Big Creek Lake? - Revenue for the state - Constant Changes - Offers means to not only map the lake but to apply various important analyses Objectives: 1. Land Use Classification 2. Bathymetry Analyses 3. Watershed Analyses/Buffer Strip 4. Parks Planning OBJECTIVES

6 Why is it important? - lake extent - recreation area - hunting area planning/building Methods: - supervised classification - unsupervised classification - interactive supervised classification - manual classification LAND USE CLASSIFICATION

7 What is a supervised classification? - a pixel based image analyses technique - uses class information input by the analyst before statistical analysis and classification of the image - the analyst must select training samples - training samples should be made based on homogenous sets of cells - three types: interactive supervised classification, maximum likelihood classification, class probability - we will do max likelihood classification SUPERVISED CLASSIFICATION

8 Steps: 1. Create Shapefile 2. Clip the extent we will use 3. Select training samples 4. Apply classification 5. Label fields SUPERVISED CLASSIFICATION (CONT.)

9 Hmm? Why the error? SUPERVISED CLASSIFICATION (CONT.) Unless you are trying to get fired or fail a graduate project you will have to produce a more representative map. How might we do this? 2 ways: - increase training sample size - use different classification This is better but we still see problems due to mixing pixel values

10 It is the only unsupervised image classification tool available in Arc It does not offer control over the number of iterations used to define the clusters I applies the classification prior to the user determining any associations between pixels User determines the number of classes that will be used to determine the output ISO CLUSTER UNSUPERVISED CLASSIFICATION

11 The reason we see a vast improvement in the unsupervised classification is due to the low resolution in the image. With the training samples in the other classifications we see the pixels from tree covered areas mixing with the pixels associated with the water Who cares, the original image is pretty handy itself, I mean obviously we can tell what is what in the original image.. ISO CLUSTER UNSUPERVISED (CONT.)

12 Much better results Conducted by the computer itself for more realistic results Requires no input from the user, classes are automatically generated based on pixel values No sample points No setting the number of classes Automatic INTERACTIVE SUPERVISED CLASSIFICATION

13 Requires you to know the land cover in the area Much better for larger areas when the spatial resolution is not that good How do you do it? - first survey your area - create a boundary polygon - begin forming lines and polygons - best to form a feature class - very time consuming for areas such as big creek VS. MANUAL CLASSIFICATION

14 Bathymetry relates to the depth of a water body Measurements made are sort of like the opposite of contour lines on a ground surface map 2 ways to do this: - old fashioned; a prod - new way; remote sensors BATHYMETRY OF BIG CREEK LAKE

15 Why might knowing the depth of a lake be useful? - fish habitats - swimming areas for children - ice fishing (limnology) - boating areas Do you want your child swimming in areas where there is deep water? Does the fisherman want your child splashing around in his spot? Would you take your houseboat into an area with a depth <3 feet? - Could you see yourself addressing these issues in say a renovation program for the DNR? BATHYMETRY OF BIG CREEK LAKE (CONT.) -Courtesy Prof. John Downey ISU

16 Bathymetry is information concerning water depth and ocean floor Can be measured using sonar and manually Remotely we measure bathymetry variations using wavelengths of solar energy The brightness of radiation decreases substantially with depth Dark colors indicate deep basins BATHYMETRY OF BIG CREEK LAKE (CONT.)

17 BATHYMETRY OF BIG CREEK LAKE (CONT.)

18 5/21/2012 7/9/2012 8/20/2012 TURBIDITY OF BIG CREEK LAKE What causes turbidity? A number of reasons: - erosion - intensive ag in the area - poor land management - tile, tile, tile - nitrogen, phosphorus major contributor

19 Parameter 5/21/2012 7/9/2012 8/20/ Lake Depth (m) Thermocline N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A Depth (m) Secchi Disk Depth (m) Temperature( o C) Dissolved Oxygen (mg/l) Dissolved Oxygen Saturation (%) Specific Conductivity (μs/cm) Turbidity (NTU) Chlorophyll a (μg/l) Total Phosphorus as P (μg/l) - Courtesy Prof. John Downey ISU Why is it important for us to study this? fish habitats it is recommended that we maintain <50 for lake aquatic life 1-5 ntu for human consumption Turbidity increases the risk for waterborne disease What stands out? TURBIDITY OF BIG CREEK LAKE (CONT.)

20 The Boone and Polk Soil & Water Conservation Districts are sponsoring the Big Creek Lake Watershed Project aimed at improving and protecting water quality in Big Creek Lake. The Iowa Department of Agriculture and Land Stewardship and the Iowa Department of Natural Resources are providing funding for the project. Those who live and farm within the Big Creek Lake Watershed may be eligible for up to 75% or even 90% in cost share on agricultural conservation practices such as terraces, sediment basins, waterways, pasture management, stream bank stabilization and many more. All these practices are aimed at improving the water quality of Big Creek Lake. - Big Creek Watershed Project Lake has shown major signs of: - Erosion - High bacteria levels - Algae blooms - Sedimentation - Major phosphorus dumping Total Phosph orus as P (μg/l) BIG CREEK LAKE WATERSHED PROJECT

21 A small proposal to improve a section of the lake: - For this portion of the project a line segment was taken in the section of the lake shown in this image. The proposal is to build a buffer strip which will trap nitrogen and phosphorus runoff from the local ag in the area. - other practices equally important: as we can see the watershed is rather large and a number of streams contribute to the high rates of sedimentation we see in the lake - this is very detrimental to fisheries and water quality - a roughly 30 meter long buffer strip along the west central portion of the lake BIG CREEK LAKE WATERSHED PROJECT (CONT.) A small proposal indeed but a very big watershed. Lot of potential money here for ISU and its graduates - Big Creek DEM - Contour map (10 meter intervals)

22 - From our base map we can see something is not right - Our coverage area far extends the boundary of the watershed - What do we do? - Does a clip by mask sound right? - Again, create Shapefile, digitize boundary, extract by mask (a spatial analyst tool) - Clip the DEM to the specified area - Redo the contour BIG CREEK LAKE WATERSHED (CONT.)

23 - Much better - We have our contour lines separating elevations of 5 meters - So how do we know this is right? BIG CREEK LAKE WATERSHED (CONT.)

24 - GOOGLE EARTH! - When in doubt go with the tried and true 281meters BIG CREEK LAKE WATERSHED (CONT.)

25 GPS Line data was taken for a hypothetical buffer strip along a west central portion of the lake The area measured was roughly 329 meters in length GPS/GIS allows us to visually layout the area after a short survey of the land - we can measure the length of the strip - we can classify the land cover in the area - we can determine our needs BUFFER STRIP

26 Is our proposed area acceptable to build on? - slope of the land was roughly 8% - about 80 feet or 24 meters Slope of Land (%) Minimum width of Buffer Strip (feet) BUFFER STRIP (CONT.)

27 So you are in charge of parks planning and management for Big Creek Lake You are highly motivated and want to provide the best park in central Iowa for camping, fishing, safe swimming and boating. You know campers need grass or concrete covered land for their rv s You now certain fish like particular habitats You know people need a shallow are for swimming You know boaters need deep areas for their boats And you know these activities don t lend themselves to one another all that well + DEPARTMENT OF NATURAL RESOURCES PARKS PLANNING = Success

28 So where do we put our different sites so that we best serve the public? - with this model we can make recommendations to local fishers in the area - we can make regulations as to where one can camp vs. swim or places where they can do both - we can make analyses for clearing land for extending trails/roads - we can make decisions for building various things for the public (snack bar, bathroom, showers) MANAGEMENT Swimming Camping Fishing Hiking

29 Three image classification techniques were tested for this project The bathymetry of Big Creek Lake was analyzed Watershed restoration for the lake was discussed Parks management concerns were addressed CONCLUSION

30 QUESTIONS??????

31 lhttp://joyerickson.wordpress.com/2011/04/21/question-of-the-day-907/ PHOTO URL S

32 Big Creek Lake, Iowa, USA. Lakes for Vacation and Recreation. Accessed; April 22, Big Creek Lake Watershed Project. Accessed; April 24, Big Creek State Park. Iowa52. Accessed; April 23, GISU. ISU GIS Facility. Accessed; April 22, &layer=naip_2010_nc&action=zoomout&pwidth=600&pheight= 450&x=265&y=151 Iowa Lakes Information System. IowaDNR. Accessed; April 24, x?ryear=2012&lake_id=009&bk=1#1 Oil and Gas Business. Energy Dictionary. Accessed; April 24, g=afqjcngjd8qwsddjdjf26togo5pag44-aq.html&ved=0cbkqfjae Water Sheds. Accessed; April 24, Water, Wastewater & Wetlands. MassDEP. Accessed; April 29, WORKS CITED