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Research and Methodology for the Closed Landfill Inventory

The Houston-Galveston Area Council (H-GAC) selected the consultant team of Wilbur Smith Associates (WSA) and Corrigan Consulting, Inc. (CCI) to assist in developing the 2000-2002 phase of the closed municipal landfill inventory for H-GAC’s 13-county region.

Organize and Review Existing Data Establish Project Procedures Conduct Pilot Study

Evaluate Pilot Study Results and Finalize Inventory Procedures

Conduct File Research at TCEQ Central Records

Complete Site Visits

Utilize Aerial Photography

Build Inventory Database

Research Current Property Ownership

Create Site and Landfill Boundary Maps

Prepare Inventory Report

Invite Public Input

Image of Closed Landfill

Organize and Review Existing Data
The project began with consultant personnel reviewing and sorting through files containing historical reports and documents, various data and maps, and other information from previous inventory efforts plus the statewide data compilation work conducted by Southwest Texas State University (SWT) under contract to the Texas Commission on Environmental Quality (TCEQ, formerly the Texas Natural Resource Conservation Commission). These materials had been provided to H-GAC by the TCEQ or were already available to H-GAC. Database files provided by the TCEQ - one for th epermitted sites and one for the unauthorized sites - were used both as a guide for organizing the site materials as well as to begin to assess what was already known about each site.
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Establish Project Procedures
Based on the sorting and evaluation of the existing available materials, the current information situation was assessed, data gaps and needs identified, and potential information sources considered. This initial project step also included ongoing discussion of inventory logistics and priorities between H-GAC and its consultant team, particularly since the available project budget would only allow the expenditure of about $500 per site. The shared objective was a cost-effective project approach that would yield meaningful results and valuable site information consistent with TCEQ guidance.
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Conduct Pilot Study
H-GAC agreed with the consultant team’s suggestion that a brief initial pilot study be conducted at the beginning of the inventory process to develop an even more effective approach for the remainder of the project. It was determined that this approach would enable both H-GAC staff and consultant personnel to achieve a better understanding of the inventory logistics, including the availability of adequate historical information, the sophistication and reliability of local appraisal district databases and other data sources, and the likelihood of establishing landfill unit boundaries with any degree of confidence in the absence of site visits. Most importantly, the pilot study results would clarify the amount of project resources that could feasibly be devoted to each landfill site during the overall inventory process and whether some type of project phasing or priority-setting among sites might need to be considered in light of budget limitations.

The idea was to select approximately 10 percent of all the closed landfill sites identified in the H-GAC region – about 50 of 500 total sites – so the consultant team could work through the same series of steps anticipated for the overall inventory process. The 10-percent sample was drawn from an area that included mainland Galveston County, southeastern Harris County and northern Brazoria County. This was roughly the area south of State Highway 225, south and east of the Sam Houston Tollway, and east of State Highway 288. This area offered a mix of permitted and unpermitted sites, a range of settings from very urban to very rural, and three counties that were likely to have varied levels of data availability and information technology. Approximately three to four months of the initial 19-month project timeframe was devoted to the pilot phase. The pilot phase was also important for considering how boundary confidence levels would be assigned through the inventory process.
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Evaluate Pilot Study Results and Finalize Inventory Procedures
The consultant team reviewed the pilot study results with H-GAC staff, highlighting the information that had been compiled (or determined unavailable) for the initial sampling of sites and identifying “lessons learned” and implications for the remainder of the inventory process. The discussion focused on which inventory methods could be applied most feasibly and effectively the rest of the way to stay within established budget and time constraints. Perhaps the most important conclusion at this point was the value of trying to visit as many sites as possible to confirm site locations since the latitude/longitude coordinates and/or verbal site location descriptions in the TCEQ databases were not always reliable. If a site could not be located with confidence or at all, then there was no point in continuing with other inventory efforts for such sites, such as reviewing historical aerial photography, recording existing and adjacent land use, and obtaining information on current property ownership. This was a critical decision since H-GAC staff, at the start of the project, had indicated that budget limitations would probably make it impossible to conduct extensive field work.
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Conduct File Research at TCEQ Central Records
Following the pilot phase and as a result of further TCEQ guidance at the statewide TARC workshop, it was determined that it would be worthwhile for consultant staff to spend time in Austin working with TCEQ files for both the permitted and unauthorized sites. This was another significant project decision early in the 2000-2002 inventory period since this activity had not been contemplated by H-GAC in selecting a consultant or by the consultant team in preparing a detailed scope of services and project budget. However, TCEQ staff explained that archive files at the TCEQ Central Records office in Austin had not been researched in depth by the Southwest Texas State University team due to time and budget limitations, yet these files likely contained much valuable information that would be an important starting point and could not be found elsewhere.

Consultant personnel confirmed through an initial trip to Austin that the files indeed often contained landfill maps and surveys as well as various “paper trail” items, such as historical correspondence, site inspection reports and other materials that sometimes confirmed landfill location, size and extent, dates of operation, ownership, and other key information needed for the inventory. Due to travel and budget constraints, WSA hired two student interns from the University of Texas at Austin. The interns completed as much of the data collection form for each site as they could and also photocopied relevant maps, legal descriptions, affidavits, correspondence, inspection reports and other relevant items to include in the site files.
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Complete Site Visits
Following completion of the pilot study phase, site visits became the central focus around which much of the inventory effort was organized. Site visit preparation included reviewing the file for each site to determine how much information had been compiled and how promising a site appeared for further investigation based on the extent and quality of locational information and the overall availability of information and research leads. Site visit preparation also included reviewing aerial photography, as explained in the next section. Site visit activities were also carefully planned and coordinated to ensure that clusters of multiple sites would be visited in a time-efficient and cost-effective manner. It was recognized that site visits would be less productive in the case of large private properties and mostly rural surroundings where on-site conditions could not be observed from adjacent roads or the property perimeter. All of these factors were considered in determining whether to even attempt a site visit or to set aside a site as unlikely to yield much more useful information for the inventory. Where site visits were made, the purpose was to field verify the site location relative to the latitude/longitude coordinates and site location description in the TCEQ database. In some cases when the site location was highly uncertain, inventory research could not proceed much beyond this point unless other leads were available about the site. When a location match was confirmed, then field information was collected regarding current site conditions, land use in the vicinity, the likelihood that a site had actually operated as a landfill in the past, and any physical evidence of landfill extent and boundaries (e.g., obvious hills or mounds, areas of surface disturbance or grading, changes in elevation near fence or property lines, presence of sand pits or ponds, surface dumping or accumulation of waste, any signage indicating closed landfills or current site activities, etc.). Digital photographs were taken during many site visits, both of the current property situation (sometimes at a locked gate or the closest accessible point to the site) and any adjacent land use activities. All this information was recorded on the data collection form for the site, including other general notes and observations.
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Utilize Aerial Photography
Aerial photography was used both as an initial resource for viewing a potential site location and its vicinity and as a means to detect and confirm past site disturbance and potential or definite landfill activity. During site visit preparations, the “Terraserver” Web site (http://terraserver.microsoft.com/default.asp) was used to view, print and download black and white aerial images that were typically from 1995 and provided by the U.S. Geological Survey. These Terraserver images were available for most of the H-GAC region, although coverage was lacking for some rural areas. For some sites, historical aerial photography was ordered either through private vendors or from the interagency Texas Natural Resources Information System (TNRIS) in Austin. A series of historical images separated by years or even decades would often provide a sure sign of how a site had been used and eventually been impacted by urbanization. Budget limitations prevented the consultant team from using this tool for each individual site, so aerial photography orders were often a priority where a cluster of sites needed investigation. As part of site visit preparations, field personnel often consulted commercially-available Key Map atlases to locate a site relative to the local street and waterway network and other landmarks and development. Key Map page and grid references appear in places in the inventory database and report, but not universally since this reference tool was not used for all sites and is only available for the core counties in H-GAC’s region (Brazoria, Fort Bend, Galveston, Harris and Montgomery, to name a few).
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Build Inventory Database
Utilizing the database structure that was developed and refined through the pilot study phase, the consultant team gradually built a database with records for each site containing new information compiled through site research or falling back on the data that had been supplied by the TCEQ. Data was entered from the data collection forms for each site. Significantly, the database sometimes references one-of-a-kind maps and materials that are now kept in the hard-copy site file. These files are the ultimate source of information on each site while the database provides the basis for publishing the hard-copy inventory report that documents the status of research and available information for each site. An important component of the data collection form and database is an “overlapping sites” field where potential linkages between two or more sites were noted. This appears in the final inventory report as “related fields” to document where multiple site numbers may be related due to a common property involved (or sites in close proximity), common property ownership, overlap in landfill history or operations, or other potential connections between sites. A common example is for a site to have been assigned a “P” number when it entered the permit application process but also have a “U” number from a time when it operated without authorization. As the inventory database was built and reviewed, this was the means for identifying remaining data gaps for each site as recorded in the inventory report. Where a field remains blank in the database and report, this means that information either was not available or was not considered reliable enough to include. During preparation for data entry, this is the point when a determination was made to suspend research on certain sites where information was lacking, if such a decision had not already been made during site visit preparations. A “research suspended” field appears in both the database and inventory report with an explanation of the difficulties encountered, usually related to the inability to pinpoint a site location and proceed with information gathering for a site. As land use information was entered into the inventory database based on the site visit results, the following standard land use terminology was used for the H-GAC sites:

Vacant: No current visible use of the property, either in structures or on the land.
Agriculture: Use of the property for crop production or pastureland.
Residential: Use of the property for any range of residential uses, from single-family dwellings (including manufactured homes) to duplexes, triplexes and other multi-family residential developments.
Commercial: Use of the property for non-residential activities such as retail stores, offices and other commerce.
Industrial: Use of the property for intensive non-residential uses involving manufacturing, processing, assembly or warehousing/distribution of products.
Mining: Use of the property for oil and gas exploration and production activities.
Public / Semi-Public: Use of the property for governmental buildings or functions, including schools, or for non-profit or private activities involving public assemblies (e.g., membership organizations).
Water: Waterways (bay, lake, river, creek, bayou, drainage channel, etc.).
Recreation: Use of public or private property for parks, playgrounds and recreational pursuits.
Institutional: Use of the property for community functions that attract significant visitors, such as hospitals and churches.
Waste Disposal: Use of the property for apparent waste handling and/or disposal purposes, including sites with active dumping, truck activity, transfer station facilities, etc.
Closed Landfill: Sites with no other apparent use or development aside from the closed landfill identified at that location.

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Research Current Property Ownership
Visits were made to county appraisal district offices to obtain information on current property ownership in cases where the supposed location of a closed landfill unit was successfully matched to a specific property or set of parcels. The level of technology and information accessibility varied between counties. All of the appraisal districts visited had at least one public computer terminal and a set of parcel maps. Most of the districts also have Web sites, although not all the county sites are interactive with real property data accessible for on-line viewing, queries and printing. Of the 13 counties in H-GAC’s region, only six counties had sites that were useful for online property research during the 2000-2002 inventory phase:
Austin County: www.austincad.org
Brazoria County: www.brazoriacad.org
Chambers County: www.chamberscad.org
Galveston County: www.galvestoncad.org
Harris County: www.hcad.org
Montgomery County: www.mcad-tx.org

Fort Bend, Liberty, Waller and Wharton counties had simple Web sites with basic appraisal district contact information and no interactive elements. The appraisal districts in Colorado, Matagorda and Walker counties do not yet have a Web presence. As the most populous and urbanized county in the region, Harris County obviously has the most sophisticated Web site, including the capability to view, print and download property maps. This enabled the consultant team to complete much of its Harris County property research on-line through the Internet.
Depending on the information available for a site, property ownership matches could be made by an individual’s name or a street address. Sometimes the landfill site was located on a property map and then the current ownership recorded for that property. Data storage and retrieval systems were different in every county, though often similar. District staff were very helpful with property research efforts.
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Create Site and Landfill Boundary Maps
For each site where a landfill boundary representation was possible based on available information, a site map was prepared to illustrate the exact or approximate location and boundaries of the subject landfill relative to other geographic references. Where an exact boundary could not be depicted, a ¼-mile radius circle was placed around the supposed closed landfill location. A map could not be generated at all in cases where the basic site location was still unknown.

Line maps created in ArcView GIS were eventually selected for the inventory report given the greater cost and logistical difficulties of using other possible base map options, such as the high-resolution aerial imagery being acquired by H-GAC (not yet available for the entire 13-county region) or color infrared Digital Orthophotography Quarter Quads (DOQQs).
Given the sheer volume of sites in the H-GAC region and associated inventory effort, a script was created within ArcView to automatically generate the GIS views and layouts for each site map required for the inventory report. Specifically, the script cycled through each individual site and created one view and one layout per site that included: the subject site location; the location of any nearby sites; roads, streams and railroads in the area (obtained from the TIGER files accessible through ESRI’s Web site); and, GPS coordinate points if these were collected during the site visit. The site maps were generated at a scale sufficient to show the local street network in the site vicinity. A smaller map to the side shows the location of each site within its county and relative to all other sites in that county. The site maps also include appropriate disclaimer language clarifying the purpose of the state-mandated inventory and the limitations of this information.

When an actual boundary is depicted in the inventory report, it is based on the results of site research or was adapted from the GIS shapefiles previously created by the SWT inventory team. Otherwise, the standard ¼-mile radius circle is shown. After considering various boundary confidence approaches, such as a typical “high”, “medium” and “low” approach, it was decided to use a more descriptive method as follows:

Exact Boundaries Known: A reliable landfill unit boundary has been confirmed and can be readily mapped in GIS. (Highest Confidence, although orientation of the boundary may still need clarification in some cases)
Good Approximation: Some form of boundary illustration is available, either from a survey map, technical report or other records, and is consistent with acreage data or other site information. Affidavits and narrative legal descriptions provide a good starting point but are sometimes difficult to translate into map form, especially when not accompanied by a property illustration. (High to Medium Confidence)
Estimated: A boundary was estimated based on aerial photography, field investigation or some other means but may be difficult to confirm without corroborating information about the site. (Medium to Low Confidence).
Unknown: Little, if any, information is available about the site – or nothing directly related to the size, extent or likely boundaries of the former landfill. (Lowest to No Confidence)

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Prepare Inventory Report
The results of the inventory process were compiled into report form, first for draft review purposes, and ultimately to document the results of the 2000-2002 inventory phase. A loose-leaf binder format was selected to ensure ease of use and updating. The report is organized by county.
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Invite Public Input
Consultant personnel accompanied H-GAC staff to a series of public meetings in November 2001 to present and accept comments on the draft inventory report. The meetings were arranged based on the eight subregions delineated in H-GAC’s regional solid waste management plan and included:

November 7, 2001 Fort Bend County (Rosenberg)
November 7, 2001 Colorado, Matagorda and Wharton counties (Columbus)
November 7, 2001 Montgomery and Walker counties (Huntsville)
November 14, 2001 Austin and Waller counties (Bellville)
November 19, 2001 Harris County (Houston)
November 20, 2001 Brazoria County (Angleton)
November 20, 2001 Galveston County (Texas City)
November 27, 2001 Chambers and Liberty counties (Monroe City)

At each meeting, consultant personnel gave a brief presentation on the inventory purpose, background and status. Then meeting participants were able to review the draft inventory results for sites of interest, ask questions, and offer corrections or clarifications for the final report and ongoing inventory research. The consultant team also provided periodic briefings during the 2000-2002 inventory phase to H-GAC’s Regional Solid Waste Management Committee. At its meeting on January 23, 2002, the committee recommended adoption of the new inventory by H-GAC’s Board of Directors. A final public hearing on the 2000-2002 inventory results was held at H-GAC on January 31, 2002, after which the final revised inventory was forwarded for H-GAC Board action in February 2002 prior to delivery to the TCEQ.
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Disclaimer
This CLOSED OR ABANDONED MUNICIPAL SOLID WASTE LANDFILL INVENTORY was prepared from information furnished by the Texas Commission on Environmental Quality ("TCEQ"), permitting records on file with TCEQ and the Texas Department of Health, and from aerial photography and GIS data developed by H-GAC. The county map, individual site maps, and legal descriptions of the closed or abandoned municipal solid waste landfills represent TCEQ's and H-GAC's best judgment about the landfills' location, but neither TCEQ nor H-GAC warrants the accuracy, timeliness, or completeness of the maps or legal descriptions. Moreover, because TCEQ and H-GAC have inventoried only known municipal solid waste landfills, TCEQ and H-GAC make no representation about whether a specific tract of land may overlie an unknown municipal or other solid waste landfill.

Houston-Galveston Area Council - Solid Waste Management Program - December 2008