Geog 676 - Final Report - 31May95 - Joseph Campo

Suitablility Analysis for an Intermountain Solid Waste Facility

A Study for Cache County, Utah

Abstract

This project's objective is to complete a mini site analysis of Cache County looking for sites which are potentially suitable for a future sanitary landfill. The methodology and selection criteria were established. Using ARC and ARCPLOT, new data coverages were created based on existing coverages. An analysis was performed using ARCPLOT and ARCEDIT to determine potential sites which met all of the selection criteria. Several sites met all selection criteria. Finally, problems encountered were described and general conclusions were drawn.

Table of Contents

• I/ Introduction
• II/ Objectives
• III/Limiting Factors
• IV/ Methodology
  1.Establish Criteria
  2.Create Analysis Coverages
  3.Analyze Analysis Coverages
  4.Examine Results
  
• V/ Problems Encountered During Project
• VI/ Conclusions

II/ Objectives

III/ Limiting Factors

• Limited amount of data.
  The most critical limiting factor is the amount of data available for this study. My thesis research will analyze many more factors than was possible based on the limits of this project. This is why I refer to this project as a "mini-analysis".
• Another important limiting factor is my lack of experience with the capabilities of the GIS system. When I gain more hands-on experience using GIS, I am hopeful that I will be able to do a higher quality analysis than was possible for this project.

IV/ Methodology

1. Establish Criteria
2. Create Analysis Coverages
3. Analyze Analysis Coverages
4. Examine Results

Step 1 : Establish Criteria

1. sites should lie 300 meters beyond hydrologic features
2. sites should lie 800 meters beyond built up areas
3. sites should lie 300 meters beyond existing fault lines
4. sites area must be at least 200 acres in size

Based on these criteria, the following coverages were used:

1. CACHE_HYDRO - Hydrology
2. LANDU_CA - Land-use
3. FAULT_CA - Fault lines

Additional coverages consulted were the following:

1. UTAHOWN_CA - Land ownership
2. U104_CA - Geology

Step 2 : Create Analysis Coverages

In this step, I created new coverages based on the criteria in step 1 being applied to the coverages indicated above.

A/ Hydrology

1. BUFFER CACHE_HYDRO CA.HYDRO.BUFF300 # # 300

Hydrology Coverage: Waterbodies Buffered By 300 Meters: CA.HYDRO.BUFF300

B/ Land use - Built-Up Land

1. RESELECT LANDU_CA USE_CA.B1 This created a new coverage USE_CA.B1
2. RESEL COVER CN 'Built-Up' This reselected only Built-Up areas
3. BUFFER USE_CA.B1 BUILTBUF800 # # 800 This created the 800 meter buffer

Built-Up Coverage: Built-Up Land Buffered By 800 Meters: BUILTBUF800

C/ Fault Lines

1. BUFFER FAULT_CA FAULT_CA.BUFF300 # # 300

Fault Line Coverage: Existing Fault Lines Buffered By 300 Meters: FAULT_CA.BUFF300

D/ Add Buffer ID Item, Create Final Buffer Coverage, and Sum Total Buffers

Add Buffer ID Item:
In ARCINFO, an item titled BUFF1 (fault lines), BUFF2 (waterbodies), and BUFF3 (built-up areas) was added to each respective coverage's PAT. Each BUFF takes the inside buffer value of 100 based on this computer assigned amount.

Create Final Buffer Coverage:
I then created the final buffer coverage which is a union of all 3 previously created buffer coverages. As follows:

1. UNION BUILTBUF800 CA.HYDRO.BUFF300 BU_HYDRO_BUF
2. UNION BU_HYDRO_BUF FAULT_CA.BUFF300 FINAL_BUF_2

Final Buffer Coverage: Union of All Three Previous Buffer Coverages: FINAL_BUF_2

Sum Total Buffers:
Using ARCINFO, an item titled BTOTAL was added to the PAT of Final_buf_2. Using the calc command, BTOTAL was designed to total the amounts of BUFF1, BUFF2, and BUFF3. Therefore, any area with BTOTAL of 300 means that within that area, all 3 buffers intersect. Any area with BTOTAL = 0 is outside of all buffered areas and is therefore a potentially suitable site for a landfill.

Step 3 : Analyze Analysis Coverages

Goal 1: The first goal is to isolate those areas from the Final_Buf_2 coverage which have a BTOTAL = 0. This was accomplished with 2 successive reselect entries using ARCPLOT.

The first entry was as follows:

1. RESEL FINAL_BUF_2 POLYS BTOTAL = 0

This reselection shows only those polygons with BTOTAL = 0. This means that they are outside all buffered zones and potentially suitable for a landfill. This ARCPLOT reselection is shown as follows:

Goal 2: The second goal was to find those land parcels with an area of at least 200 acres. See IV/methodology/ Step 2 above. This figure was established as an approximate area needed for an average 25 year disposal capacity landfill. This figure will serve for the purpose of this project. I found the formula "multiply acres by 4047 to obtain square meters" in a soil science book (Foth 1990). This gave me a minimum area requirement of 809,400 square meters. To discover those parcels with this size I performed another reselect entry as follows:

1. RESEL FINAL_BUF_2 POLYS AREA > 809400

This produced the following ARCPLOT reselection, using polygonshades, shown as follows:

Step 4: Examine Results

The lighter cross-hatched areas meet all the required site criteria for this mini-analysis and may be considered as potential suitable sites for a future sanitary landfill. Many potential parcels exist on land owned by varied interests (private, state, and federal etc.). Much of the land shown on my final coverage is in the national forest boundary. This problem will be discussed in the "Problems Encountered" paragraph below.

V/ Problems Encountered During Project

1. The original methodology involved using the erase command in ARC as per the text Understanding GIS-The ARC/Info Method, page 8-16. However, no one seems to use this command and I was unable to resolve problems which came up as to incorrect reselections.
2. Problems came up in unioning the 3 buffer coverages regarding the value of inside buffer zones at 100. It took a while to resolve this problem.
3. Many problems came from trying to mask off the National Forest Boundary, which I have been unsuccessful in resolving. In ARC, when I reselected out landowners nc 'forest', ARCPLOT revealed that the entire landownership map had been selected, during every attempt. Perhaps I was doing it incorrectly.
4. I spent a great deal of time unsuccessfully trying to resolve a union problem with Final_buf_2 and Utahown_ca coverages. I originally intended to union these 2 coverages and then reselect areas showing private or state land ownership. However, after executing the union command, the polygon attribute that I wanted to reselect from, names, did not come through to the new coverage Pot1. Many different attempts failed to resolve this problem. This is why the final reselection shows land within the National Forest boundary.
5. Many problems using reselect in ARC which did not generate a correct output. Again this may be due to incorrect usage.

VI/ Conclusions